3/3 TOP-Selling US Fish Oils Exceed Maximal Peroxide and Total Oxidation Levels - Levels Roughly 4000% Higher Than in Medical Grade N3 Supplements, Harvard Study Shows

The US' favorite fish oil supplements: Dirt cheap and still not worth the money. Better buy fish - fresh fish.

"I told you so!" That's how someone else in my position would probably start today's blogpost. In view of the fact that "smartassing" is not exactly an effective means of education, I will yet refuse from reminding you that I've been reporting about unwanted side effects of the gold-ish pills that claim to have "fish oil" in them on various occasions.

And guess what!? The publication of a recent study by scientists from the Cardiovascular Division, Brigham and Women's Hospital at the venerable Harvard Medical School, gives me yet another reason to rant against the evermore popular fish oil supplements.

You can learn more about omega-3 & co at the SuppVersity

Fish Oil Makes You Rancid?

POPs in Fish Oils are Toxic!

N3/N6 Ratio Doesn't Matter

MUFA & Fish Oil Don't Match

Fish Oil Doesn't Help Lose Weight

Rancid Fish Bad 4 Health

In their study, the scientists analyzed 3 commonly available fish oil dietary supplements and found that (a) their level of omega-3 fatty acids varied significantly, that (b) they contained tons of other fats that you would ask to be paid for to consume if you knew about them and, that (c) the caps were so full of oxidized fats that they exceeded international standards and may (d) may harm, rather than help with your health.

No, we're not talking about cheap Chinese internet purchases, bro!

The Harvard scientists bought the "three top-selling fish oil DS [dietary supplements] in the United States and to examine the extent of oxidative damage in the DS as compared with chemically characterized standards with respect to purity and ability to prevent human sdLDL oxidation in vitro" (Mason. 2016). The commonly heard excuse that this is "just a problem with the cheap Chinese stuff" is thus as useless as it is ridiculous in view of the data from the study at hand.

Figure 1: The TOP3 US fish oil products are rancid... well, mostly (right hand side) and they have almost no ability to prevent human LDL particles from oxidation, as the results of the MDA test on the left indicates (Mason. 2016).

Compared to the medical grade control, the US top-sellers look as if they had been tainted with motor oil from a fishing cutter. Speaking of which: I would not guarantee that the 34%, 21% and 24% of "other oils" in this so-called dietary supplements do not include at least tiny amounts of mineral oils.

Your fish oil contains 4000% more oxidized fats than prescription fish oil! That's a huge problem, because many of the studies you're so fond of, because they seem to prove how healthy fish oil is, have been done with medicinal grade fish oils. Accordingly, the results of these studies have ZERO predictive power with respect to what your "machine oil" fish oil will do to your health. Speaking of "your" - it is not impossible that the oxidative damage occured during storage, which reminds me to remind you NEVER to use fish oil in a bottle that's constantly exposed to pro-oxidative oxygen, whence you've opened the bottle. Note: If stored in the fridge (4°C) the shelf life of the fish oil in fresh fish is, as Boran et al. show in their 2006 paper in Food Chemistry ~ 90 days.

In fact, the scientists measured not just primary oxidation products, as the highly elevated peroxide levels, an indicator of high levels of primary oxidation and hydroperoxides, confirm, but also secondary products of the decomposition of the primary oxidation products during continued exposure to oxidative conditions, as they ar detected in the p-anisidine test.

Figure 2: Indeed, there was also some "fish oil" in the caps - emphasis on "also" and "some" (Mason. 2016)!

The total oxidation levels in Figure 1 were then derived from the peroxide and anisidine values indicate without fail that "[a]ll three DS exceeded the recommended maxima for peroxide and total oxidation values (5 meq/kg and 26, respectively) when normalized to 1 g OM3FA (based on the number of capsules needed to achieve 1 g of OM3FA)" (Mason. 2016). The latter is particularly shocking in view of the fact that the prescription product of pure OM3FA did not contain significant levels of these oxidation products under identical test conditions. Any studies on the health effects of fish oil - mostly conducted with medical grade capsules - is thus meaningless for the average consumer who shies away from the exorbitant costs of LOVAZA and co. - a bad mistake, as it turns out, now, that the Harvard scientists' study shows that EPA and DHA containing oxidized trash fats from the dietary fish oil supplements have a >77% reduced ability to protect your LDL oxidation from (>90% protection for pure products, a meager 21 ± 4% for the "fish oil" you have probably been buying for years).

Speaking of "for years": Is it possible that you've done more harm than good in the past years of consuming copious amounts of fish oil to your health? Yes, it is, but in view of the fact that even the "motor oil" version of fish oil in the average US dietary fish oil supplement (the brand names are obviously undisclosed = not mentioned in the paper) was still anti- and not pro-oxidative, it's more likely that you have only wasted time and money.

Only three brands, but unfortunately in line with previous research: The scientists make no secret of the fact that a major limitation of their study "is that, although [they] evaluated the top-selling DS in the United States, [they] only assessed three products given the scope of this initial investigation" (Mason. 2016). Bad luck for fish oil fans: e results of this study are consistent with previously published analyses of DS with respect to content and oxidative damage" (ibid.) - studies that didn't just find oxidized fatty acids, but also heavymetals and cholesterol in the pills.

So what do we make of these results? Well, I guess it depends on how indoctrinated you've already been about fish oil being an essential supplement (the word "supplement" already implies that it cannot be essential). If you actually believe in the magic of fish oil (imho bogus for healthy individuals), you should go and buy pharma grade fish oil spending your whole monthly supplement budged on fish. If, on the other hand, you've any sanity left, you simply do what I've been recommending for years: eat your fatty fish once or twice per week (doesn't have to be wild-caught | Farmed Fish is Less Poluted and Has More Omega-3) | Comment!

References:

• Boran, Gökhan, Hikmet Karaçam, and Muhammet Boran. "Changes in the quality of fish oils due to storage temperature and time." Food chemistry 98.4 (2006): 693-698.
• Mason, PR and Sherrat SCR. "Omega-3 fatty acid fish oil dietary supplements contain saturated fats and oxidized lipids that may interfere with their intended biological benefits." Biochemical and Biophysical Research Communications - Available online 21 December 2016 | In Press, Corrected Proof

Protein Oxidation 101: 8 Simple Rules to Minimize PROTOX and Maximize the Proven Benefits of High(er) Protein Diets

You're not going to like it, but not all of the protein foods in this photo deserve the attribute "SuppVersity Suggested"

I usually try to keep my promises,... even if this means hours of research and ending up with the conclusion that "more research is necessary"... and no, you don't have to worry, there's more than that in the following ~4500 words + 45 references (not including those I didn't copy from the reviews I cite): plenty of information about the effects of cooking, storage, temperature changes, physical processing, and - you're lucky - a preliminary list of 8 tips / rules (and short explanations) that will help you minimize the amount of oxidized protein in your diet, without having to cut back on the intake of your beloved protein ;-)

For those of you who are now wondering PROTOX is / are and why they are (literally) a matter of life or death, I suggest you go back to my previous article about the (ill) health effects of oxidized dietary (!) proteins from Thursday, May 19, 2016 (read the article | as always, for free!).

This is not an anti-high-protein article. It is one arguing in favor of "treating your protein right"

Are You Protein Wheysting?

5x More Than the FDA Allows!

More Protein ≠ More Satiety

Protein Oxidation = Health Threat

Protein Timing DOES Matter!

More Protein = More Liver Fat?

In view of the fact that this article got longer than the average "101" article, I'd suggest that anyone who is in a hurry fast forward to the list of eight simple rules I announced in the title of this article. You can bookmark the rest for later, print it to read it in bed or simply rely on my interpretation of the implications of what we know about the various ways processing and storage can damage proteins :

• Cooking, frying, baking, i.e. heat treatment(s), in general - While you don't have to eat your meat, fish and dairy raw, those of you who "fry their proteins to death" and eat their steak well-done are at a higher risk of exposing themselves to exuberant amounts of oxidized proteins than the rare steak conconnoisseurs.
  
  While the number of studies testing for protein oxidation in meats during cooking is higher than those on any other protein source, their number is, compared to the one of studies investigating the oxidation of fats and cholesterol in meat products, still low and their significance is crippled by the use of either inappropriate markers of protein oxidation or different markers that make it virtually impossible to compare the results of one study to another.
  
  An example of the initially mentioned problem, i.e. the use of inappropriate markers of protein oxidation, would be the 1997 study on the effects of different cooking methods on some lipid and protein components of hamburgers by Rodriguez-Estrada, M. T., et al. (1997). Their use of free form amino acids as marker of protein oxidation suffers from the presence of the latter in raw meat and their drip loss during cooking.
  

  

  Figure 1: In contrast to the amount of free amino acids, the formation of Schiff bases provides reliable information about the oxidation of protein during e.g. cooking (data from Gatellier. 2010).

  A much better way to estimate the degree of protein oxidation in meat and other high protein foods is the formation / presence of Schiff bases. The latter are precursors to maillard products of which studies indicate that they have divergent effects on human health: with some of them being implicated in the development of diabetes mellitus, cardiovascular complications, and Alzheimer's disease and others ostensibly helping with gut health, inflammation, and chemoprevention (the benefits appear to be mediated by hormesis or the effect of these molecules on the make-up of your microbiome | Smith. 1994; Somoza. 2005; Tuohy. 2006; Tessier. 2012). Measuring these byproducts of reactions between proteins and aldehydic products, as it was done by Gatellier, et al. (2010 | see data in Figure 1), provides significantly more reliable information about the degree of protein oxidation in foods than the measurement of the amount of free amino acids which would suggest that raw meat was more oxidized than cooked meat (cf. Rodriguez-Estrada. 1997), because the drip loss of amino acids is falsely interpreted as a reduction in protein oxidation compared to the raw product. That this is not the case and heating meat and other high protein foods will increase, not decrease the amount of oxidized proteins can be seen in the data from Gatellier, et al. in Figure 1.
  
  Furthermore, Gatellier's and other studies indicate that the formation of protein oxides which starts at relatively low temperatures of only >65°C does not begin to really take off before temperatures of 123-207°C - temperatures as you would see them if you fry your foods and can be reduced (albeit not significantly | 1300% increase vs 3500% increase | cf. Figure 2) if the cattle has been fed anti-oxidant rich diets.
  

  

  Figure 2: Effect of diet and cooking parameters on protein oxidative modifications (Gatellier. 2010).

  This is not surprising, as it has long been established that increases in lipoxidation products go hand in hand with increased oxidative damage to proteins (Requena. 1996). Any diet that would modify the concentration of certain lipids and lipid protecting antioxidants (like vitamin E) will thus change both, the oxidation of fats and proteins in high protein foods. The reverse applies to pro-oxidant diets (e.g. with rancid oils), like the one Zhang et al. (2010) used in broiler chickens whose breast meat would then show increased levels of oxidized proteins.
  
  You must not forget, however, that the data in Figure 1 also shows that even the quality L+R meat is not fully protected from oxidation when it is heated at high(er) temperatures for more than 60 seconds - and that's something that is going to happen even for the most bloody (non-raw) steak. "t "and "T", i.e. time and temperature, are thus not the only, but the most significant determinants of  protein oxidative modifications (cf. Figure 3).

An increased drip loss suggest increased protein oxidation: It's not just annoying if your meat weights only half of what it weighed before cooking, it is also an albeit not 100% reliable indicator or, I should say, correlate of increased protein oxidation. That's at least what a 2012 study by Traore et al. indicates: in said study, the researchers analyzed the effects of heat treatments on meat from the M. longissimus thoracis from Galia and Redone pigs. What they found was a striking and statistically significant correlation between the presence and level of oxidized proteins and the drip loss during cooking / frying. This observation does not only suggesting a possibly reduced ability of oxidized proteins to retain water, but also the possibility of using the drip loss, which is a marker of meat quality, anyways, as an easily accessible indicator / estimate for protein oxidation.

• 

  Figure 3: Time matters, but heat, too - Markers of protein oxidation in meat exposed to 100°C (grey) and 270°C for the time in minutes indicated on the x-axes (Santé-Lhoutellier. 2008).

  In fact, previous research confirms and underli-nes the importance of time and tempera-ture and indicates that even at temperatures of only 100°C, the level of oxidation products in meat proteins will double within just 5 minutes.
  
  When the time of exposure is short, the corresponding +200% increase in carbonyls (a marker of PROTOX | see Figure 3) that occurs at low temperatures is allegedly relatively small. If you are into slow-cooking your meats at "low" temperatures for several minutes, any low temp. advantage would be lost, though.
• Traditional processing methods to increase the storage time like dry-curing or fermentation - In contrast to the effects of heat treatment(s), the ones of other common processing methods are comparably under-researched. What we do know, however, is that dry-curing meats (and probably dry-aging, too - although a study on that has still to be done, to answer your Facebook question honestly, Matthew) can lead to sign. hydrolytic degradation of proteins (Toldrá, 1998). Furthermore, recent studies indicate that meat proteins will also undergo different, often more intense (compared to proteolysis) oxidative reactions during dry curing (Estévez. 2011).
  

  

  Figure 4: Carbonyl content (nmoles/mg protein) in longissimus dorsi (unprocessed) and dry-cured loins from different pigs on diefferent diets; % indicates relative increase in protein oxidation (Ventanas. 2006).

  Studies carried out by Ventanas et al. (2006 & 2007) prove the presence of significant amounts of protein carbonyls in dry-cured loins and hams  - a process of which the researchers study shows that it was, once again, linked to the lipid oxidative reactions that occur during curing. 

Steaming uses temps >60°C where proteins start to oxidize and steaming takes its time. It is thus not per se safe.

Steaming is not the solution: Unfortunately, detailed comparisons of the effects of steaming, microwave cooking, smoking, grilling, frying, and other cooking methods are not available - temperature level and duration of heat treatment have been the major focus in the literature and the results indicate that even "low" temperatures, such as the 100°C of steam will induce significant damage to meat, poultry or fish proteins during the 5-10 minutes they have to be exposed to the thermic treatment; that's because even at temperatures only slightly >60 °C can cause the oxidative cleavage of the porphyrin ring, which in turn will result in an increased release of heme iron, which has been shown to drive both, lipid and protein oxidation (Miller. 1994).

• The hams, which are subjected to longer and more severe drying conditions, were found to have considerably larger amounts of protein carbonyls than the loins (≈ 9 nmol/mg protein vs. ≈ 1.3 nmol/mg protein). The manufacture of dry-cured meats involves a lengthy process (up to 36 months for Iberian dry-cured hams) and several operations such as salting, post-salting, drying and cellar (Ventanas. 2007). Little is known about the impact of each step on the onset and intensity of the oxidative reactions affecting to meat proteins. What studies have shown, however, is that ..

  "[s]alting, which is a common operation for the manufacture of numerous meat products, may have an impact on protein carbonylation. The addition of sodium chloride has an impact on the ionic strength of the environment which in turn, affects the degree of assembly of MP (Wick, 1999) their exposure to pro-oxidants and hence, their susceptibility to carbonylation (Montero, Giménez, Pérez-Mateos, & Gómez-Guillén, 2005). In addition, several authors have proposed that NaCl could enhance the activity of Fe3+ or that Cl− derived from NaCl would improve the solubility of such ion, hence, stimulating their pro-oxidant effects (Kanner et al., 1991 and Osinchak et al., 1992)" (Estévez. 2011).

  Accordingly, you can assume that the protein oxidation increases with the amount of salt that's used when meat or, as the study by Osinchak et al. shows, fish is cured - an interesting observation that should remind you of the link between high salt intakes and heart disease, of which said link suggests that it could at least partly be mediated by the effect of salt on protein oxidation in processed meats and other high protein foods.
• Storage, cooling, freezing, high pressure and irradiation to reduce bacterial contamination, and packaging - You already know that cooked protein products have increased carbonyl levels compared to raw samples (1–3 nmol/mg protein in raw vs. 5 nmol/mg protein in cooked products), but the heat exposure is not the only threat to the proteins' integrity: cutting, mincing, and all the other processing steps protein foods undergo will likewise make significant contributions to the formation of protein carbonyls and other processes of protein oxidation.
  

  

  Figure 5: Evolution of protein oxidation in liver pâtés from Iberian and white pigs (note the difference that exists even before storage) under refrigerated storage (Estévez & Cava. 2004).

  In contrast to the former processing steps, the effects of subsequent refrigerated storage, has also been extensively studied - with disconcerting results, namely significant increases in the concentration and oxygenation of non-heme iron and thus the extent of lipid and protein oxidation (Estévez & Cava, 2004) which can render certain meat product, like liver pâtés that are refrigerated for several months quasi non-suitable for human consumption (see Figure 5) and will still significantly increase the protein oxidation of other less processed foods w/ lower amounts of iron such as chicken legs and breasts (see Figure 6)
  

  

  Figure 6: Changes in carbonyl content in chicken (a) leg meat and (b) breast meat as affected by freezing temperature and 6 months of storage at different freezing temperatures (Soyer. 2010).

  Now, freezing, which is particularly damaging if it is done at rather low temperatures at home (cf. Figure 6), is not the only storage method that increases the protein carbonyl content of meat and other high protein foods. In fact, storage per se will trigger natural biochemical processes that will inevitably favor protein oxidation. In that, decreases in pH and increases in the concentration of H+ ions are only one of various drivers of oxidative stress that can increase the susceptibility to protein carbonylation / oxidation - processes that will be further accelerated when meat is irradiated (common practice in the US meat industry) to kill bacteria (compare the size of the orange with the blue bars in Figure 7).
  

  

  Figure 7: Effect of Storage Time (12 Days) on Nonirradiated and Irradiated Raw Chicken Breast Meats Stored at 5 °C on Carbonyl Content as Lipid (in µmol Acetophenone/10 g Meat | Rababah. 2004)

  It is thus not surprising that Martinaud, et al. (1997) observed a significant increase of the carbonyl content in meat from beef longissimus lumborum and diaphragma pedialis muscles: from 3.1 to 5.1 nmol/mg protein and from 4.8 to 6.9 nmol/mg protein, respectively, during only 10 days of chill storage. Subsequent studies confirmed the occurrence of protein carbonylation during aging/chill storage of beef, pork, poultry, turkey, lamb, rhea, ostrich meat and eggs, in which Liu et al. (2009) found a 60% increase in egg white and a 41% increase in egg yolk protein oxidation.

Make no mistake: Eggs are healthy!.

Speaking of eggs, ... the change of the textural and structural quality of egg yolk and white upon heating is not the only change egg proteins will undergo while being heated at temperatures above 70 °C at atmospheric pressure or being exposed to high pressure of >500−600 MPa which will trigger the oxidative formation of disulfide bonds among the egg proteins (Van der Plancken. 2005 & 2006). That doesn't change my conclusion that the presence of oxysterols (oxidized cholesterol) is probably of greater health relevance than the lack of heat stability of egg proteins.

• Due to the large variability of the data reported by different authors for the amount of protein carbonyls in similar meat samples analyzed, it is unfortunately not possible to infer general patterns (Estévez. 2011) - that's also because the "extent of protein carbonylation is highly dependent on the origin of the meat, type of muscle, species and the storage [and feeding] conditions" (Estévez. 2011).
  
  Another thing that appears to be proven is the fact that beef is significantly susceptible to protein carbonylation than pork - a fact scientists ascribe to the noticeably larger amounts of iron and myoglobin in cattle muscles (Lund. 2007a,b). Accordingly, it can hardly surprise you that a similarly lower propensity for protein oxidation has been found by Mercier et al. (1998) when they compared beef and turkey meat.
  

  

  Figure 8: Determinants of the susceptibility of meat(s) and poultry to protein oxidation.

  If the differences are in fact, as the scientists argue, due to the different amounts of iron and myoglobin in various muscle meats, it is not just logical that (a) beef is more susceptible to protein oxidation than pork, but also that (b) pork more prone to protein oxidation than poultry and that (c) gylcolytic, low fat, low myoglobin (strength) type muscle meat is less susceptible to carbonylation than oxidative, high fat, high myoglobin (endurance type) muscle meat (Filgueras et al., 2010) - how oxidized the protein in your meats is will thus depend on both, species and the cuts you choose (+ other previously discussed factors).
  

  

  Figure 9: Levels of AAS (a) and GGS (b) in dry-cured ham as analysed by LC–MS. Mean values correspond to area units from the peak integration of EIC for [M+H]+267 (AAS–ABA) and for [M+H]+253 (GGS–ABA) and corrected considering the total protein content of each batch. Different letters on the bars denote statistical differences (p < 0.05) amongst means. IF (intact format), CSF (conventional-sliced format) and ASF (alternative-sliced format - which also influence markers of protein oxid. | Fuentes. 2010).

  How significant the effects of other emerging processing technologies such as the application of hydrostatic pressure, which is used as an alternative to irradiation and pasteurization to kill bacteria, eventually is, has not yet been fully elucidates. While studies by Cava et al. (2009) and Fuentes et al. (2010) indicate that the application of high pressure can causes a significant increase on the amount of specific protein carbonyls, α-aminoadipic and γ-glutamic semialdehydes (AAS and GGS), "as a likely result of physico-chemical changes induced by hydrostatic pressure including tissue disruption and increase of free catalytic iron" (Estévez. 2011), the evidence is far from being conclusive and the pressure in your pressure cooker (~100 MPa or 15 psi) is 6 times lower than the 600 MPa used by Cava et al. (2009) and applied for a 100x shorter time periods than it took to produce significant protein oxidation in Cava et al. (2009) at 300 MPa. So the pressure in a pressure cooker is probably less of an issue than the time your meats and other protein sources will spend in it at high temperatures.
  
  The same goes for the commonly used modified atmosphere packaging (MAP), which has been shown to contribute to increased myosin cross-links, and increased protein carbonyls especially if the "modified atmosphere" is high in oxygen (70% to 80% | Lund 2007a,b) - a condition that has been shown to reduce the formation of thiol groups, i.e. fat oxidation, but has the obvious downside of increasing protein oxidation. Alternative packaging methods would be available, 100% nitrogen (results are mixed, e.g. Zanardi. 2002; Leygonie. 2011) or vacuum-packaging (effectively reduced protein oxidation during storage compared to MAP | Lagerstedt. 2011), for example, but just like the use of additives and ingredients with proven antioxidant capacity they are rarely used and more research is necessary to determine which of them offers the best protection to both proteins and fat.
• None-meat, -poultry or -fish proteins react similarly - While there's lots of research on protein oxidation in meats, studies on other food sources are scarce, but show similar trends with respect to processing-induced protein oxidation.
  
  In cheeses, for example, the lowest amounts of protein oxidation are found in "unripe" raw milk cheeses or cheese that was produced from milk that was semi-cooked or pasteurized at low (vs. high as in UHT milk) temperatures (Fedele. 2001).
  

  

  Figure 10: Protein-bound carbonyls (PC) in selected cheeses from differently processed milk, i.e. unheated, semi-cooked and cooked milk as a raw ingredient (Fedele. 2001).

  With the processing temperature, the amount of protein-bound carbonyls (PC), the previously discussed marker of protein oxidation, increases, significantly. In Figure 10 illustrates that pretty well, after all, the cheeses that were made from cooked milk all have sign. higher PC levels than those from raw or semi-cooked milk. Much in contrast to meats, the storage or, in the case of cheeses, ripening processes does not trigger a continuous increase in protein oxidation (data not shown): For Grana Padano, a cheese that's produced from cooked milk, for example, the rapid (+30%) increase in protein carbonyls in the first 1-3 months of ripening does not continue and the level of PCs remains relatively stable for the rest of the several months period spanned by the study by Fedele et al.
  
  

  

  Figure 11: Kinetics of protein carbonyl generation by UV or fluorescent photooxidation. Protein carbonyls were determined in milk exposed to UV or fluorescent (FL) light, as a function of time of exposure to radiation. ■ = whole milk (WM) exposed to FL light; ● = skim milk (SM) exposed to FL light; □ = WM exposed to UV light; and ◯ = SM exposed to UV light (Scheidegger. 2010)

  Next to high temperature exposure (and yes, there will be some protein oxidation during pasteurization, but the process is fast enough to make the effects negligible | Table 1), UV radiation is a se-cond threat to dairy proteins.
  
  As the data in Figure 11 goes to show you, it takes only a few hours under a 15W UV lamp and/or a similarly "weak" fluorescent lamp to trigger rapid increases in protein oxidation in "milk", or rather what Scheidegger, et al. call milk, i.e. a liquid that was produced from water with commercially processed spray-dried whole milk powder, of which you can already expect that it has sign. higher baseline PC levels than regular milk.
  
  To deliver milk in regular, opaque tetra packs instead of the hipster glass bottles is thus a very good idea! Much in contrast to the use of regular or hypoallergic milk powders in processed and baby foods, the consumption of sweet condensed milk or its unsweetened alternative, evaporated milk.
  

  

  Table 1: Lysine damage in commercial milk samples (Mauron. 1990).

  Just like roller dried milk powder which is used in chocolates, and spray-dried lactose-hydrolized milk powder of which I have to admit that I don't know in which processed junkfoods it is used, the former food ingredients harbor significant amounts of blocked lysine, a previously discussed marker of protein oxidation that occurs relatively early during the oxidation process.
  
  Corresponding data for vegetable proteins is unfortunately not available. Even though vegetable proteins usually don't come with high amounts of easily oxidizable lysine (casein has a 2.0 ratio of lysine to arginine, soy's ratio is 0.9 | Kritchevsky. 1979), iron and myoglobin, soy, pea, hemp, bean and other vegan / vegetarian protein sources are not immune to processing, i.e. heat-, light-, and pressure-induced protein oxidation or the ongoing deterioration of their protein structure during storage. Whether these effects are strong enough to turn an originally antioxidant or neutral food protein into a pro-oxidant dietary ingredient, will yet need further clarification in realistic scenarios. Initial evidence that this could be the case comes from a 2015 study by Chen et al. who administered heat-oxidized soy protein to broiler chickens and observed that it would impair the chickens growth performance - probably as a result of negative effects on the digestive function. 

Don't be a fool: There's no evidence that protein powders are "adulterated" with exorbitant amounts of protein oxidation products; and, even more importantly, the currently available evidence in favor of the beneficial health effects of whey and co. clearly refute the practical health significance of the most likely existing amounts of protein oxidation products in the average protein powder.

Where's the info about whey, casein and other protein powders? In view of the fact that I can only report data that exists, it is very difficult for me to answer one of the most frequently asked questions I got after the publication of my original article on protein oxidation, namely: "What about my whey protein?"

What I have found out, though, is that whey proteins, like any other protein food, undergo heat-induced protein damage. For whey protein concentrates, Rector et al. report a rapid degradation of protein complexes when the protein is stored above the critical 60-65°C margin (Rector et al. used 80°C). Storage at 25°C for 1 year, on the other hand, resulted in polymerization of "only" 18% of the monomeric beta-lactoglobolins, and did not involve the formation of intermolecular cross-links, a characteristic feature of protein oxidation (Morr. 1993).

Whether the amount of protein oxidation products that certainly exist in casein, whey, soy, pea, and other protein powders is health-relevant, is therefore highly questionable. Furthermore, the well- and widely-established antioxidant effects of whey, which include, among other things, a reduction of protein oxidation in vivo (e.g. Haraguchi. 2011), would suggest that that the average whey protein doesn't just compensate, but over-compensate any potentially pro-oxidative effects of existing protein oxides by the anti-oxidant effects of its various antioxidant proteins and peptides (Tong. 2000; Peña‐Ramos. 2004; Peng. 2009).

In this context it may also be worth mentioning that a study by Fenaille et al. (2006), which investigated the protein-carbonyl (PC) levels in infant protein powder formulas, and is thus the study that comes closest to an analysis of PC levels in commercially available protein powders, found the amount of oxidized proteins to be not much different from those in unprocessed, cold-stored meat products. If certain quality standards during the production are met, it is thus unlikely that any potential worries you may have that protein powders could be much unhealthier than meat or other protein sources are warranted.

Wow, that was a lot of information on what you want to do or not do to reduce the oxidation of proteins. Since skipping on all protein containing foods and/or resorting only to raw meats, fish and milk is probably not an option. I have tried to use the previous information to phrase a few suggestions on what to do and not to do in order to limit your PROTOX exposure:

• 

  Figure 11: Influence of freeze–thaw cycles on TBARS (fat) & carnonyl (protein oxid.) in pork (Xia. 2009)

  buy, cook and eat fresh - it doesn't take heat to damage proteins, storage - even at very low temperatures - will also induce significant increases in protein oxidation; accordingly it makes sense to buy meat, poultry and fish fresh and to avoid storing and refrigerating them (esp. in view of the fact that storage / refrigeration in regular refrigerators will be more damaging than refrigeration of meats in much more efficient industrial refrigerators | Figure 11)
• avoid irradiated and or high pressure treated, industrially processed meats and prefer vacuum packaged meats over meats in modified atmosphere packaging w/ extra high oxygen levels (nitrogen is no problem) - the less processed and messed up the meat you buy, the less significant any further increases in protein oxidation you may induce at home will be; you should also ask your butcher if he already froze and thawed the allegedly "fresh" meat he offers - you may not believe it, but much of the "fresh" meat has actually been refrigerated and thawed at least once - especially, the more exotic cuts; also, vacuum packaging your meats at home makes as much sense as any other way of repackaging it to keep them fresh - none of them is going to be worse than simply putting the meat into the fridge in nothing but a simple plastic bag; pressure cooking is, as discussed previously probably not an issue (due to the comparatively low pressure), but the time your meats and other protein sources spend in the pressure cooker at relatively high temperatures could be
• use culinary herbs and spices - even though there is no data for each and every culinary herb and spice, the data that exists shows sign. reductions in protein, fatty acid oxidation and the formation of advanced glycation end-products (AGEs) for cloves, ground cinnamon, ground Jamaican allspice, apple pie spice, oregano, ground pumpkin pie spice, marjoram, sage, thyme, gourmet Italian tarragon, mint, rosemary, Italian poultry seasoning, turmeric, curry powder, chili powder, basil, nutmet, ginger, parsley, black pepper, and rosemary (Dearlove. 2008; Haak. 2008);
  

  

  Figure 12: Protein hydrazones (expressed as nmol hydrazones/mg protein) gain during refrigeration of cooked burger patties with added fruit extracts and quercetin (Ganhão. 2010).

  and using high polyphenol oils like virgin olive oil for cooking and in marinades may further reduce the protein oxidation; speaking of which, marinades and or fillings and the addition made from antioxidant-rich fruits or plant products (e.g. onions, garlic and other high quercitin foods that mimic the addition of pure quercitin in Ganhao (2010) | Fig. 12) have also been shown to help minimize protein oxidation not just during cooking, but also during storage
• appreciate quality, non-cured meat - a high drip loss (meaning the weight of your meat is significantly reduce when you cook it) is a common marker of low meat quality and a correlate of high protein oxidation (Traore. 2012); the same goes for the loss of water that occurred way before you bought the meat during curing; and, yes, this means if there's a significant source of oxidized proteins in your diet, your beef jerky, bacon and other cured meats are the prime suspects - not only, but especially if they're also high in salt
• choose low(er) fat meats, poultry, fish, dairy and vegetable protein over iron- and myoglobin-laden red meats - it's not just the lower iron and myoglobin content of poultry and fish that makes them more resilient to protein oxidation, it is also their low(er) fat content, which reduces potential cross-reactions of oxidized fats with proteins; this does not mean that you cannot eat fatty cuts of red meat, at all, but there's more than just epidemiological evidence that the consumption of high amounts of processed and/or improperly stored or packaged red meat is problematic; not just, but also because of high levels of oxidized proteins

• 

  Don't do everything the print on these packs tells you: While you certainly don't want to eat these silica packets, you also don't want to throw them away before you emptied your protein tub - they will help to keep your protein (and other supplements) dry!

  store your protein powders cool, dry, and by any means not in the sun - there's no evidence that protein powders could be a major source of oxidized proteins in your diet - unless you do your best to make them go rancid by (a) rehydrating and storing them as an RTD, which will significantly increase the amount of volatile compounds even if the product is cooled (Park. 2016 / storing the protein with or at least not removing the silica gel packets (see photo on the right) may also help), (b) storing your protein powders in transparent containers in the sun, or (c) putting your protein tubs right next to a radiator or any other heat source
• prefer raw or pasteurized over ultra-high temperature processed (UHT) milk / dairy products - in contrast to what the scaremongering on the internet would suggest the short application of relatively low temperatures (72°C) during the pasteurization process does not induce significant damage to the protein-structure of dairy products; that's in contrast to UHT, which is done with at least 53°C higher temperatures and is notorious for its effects on the protein structure - an effect you will even taste and smell (Clare. 2005)
• go easy on the heat and keep the duration of any heat exposure short - "well-done" or "tar-black" are words you shouldn't be forced to use to describe your dietary protein sources; you also don't want to simmer your meats and other high protein foods at 100°C (or even >65°C) for hours or fool yourself to believe that steaming your fish at 100°C for 10 minutes was so much better (in terms of protein oxidation) than frying it for 2 minutes

Figure 13: A comparison of the initial and progressing oxidation of myoglobin (data expressed as % of total myoglobin) in intact and minced slices of beef gluteus medius samples (3 mm thick) that were observed by Ledward & MacFarlane observed in their 1971 study clearly suggests that (a) the process of mincing induced protein oxidation and (b) makes the meat more susceptible to progressing protein oxidation during storage.

Any Facebook-questions left? Yes, the thing about gelatin. Well, I have to admit that I neither know why one would even remotely consider consuming gelatin in amounts that would make it worth worrying about its oxidized protein content, nor whether gelatine even contains oxidized protein. In view of the fact that EAAs like lysin appear to promote protein oxidation just like iron and myoglobin, and considering the fact that gelatin contains neither of them in sign. amounts, I do yet have my doubts that gelatin is a sign. source of PROTOX in your diet, Gillian.

And Kirill, reliable data on the protein-carbonyl content of ground vs. non-ground beef is not available. The increased surface (=more oxygen exposure = iron / hemoglobin oxidation) and the heat that is produced when you mince it, would suggest ground beef will have higher higher amounts of oxidized proteins. Evidence that this hypothesis is accurate comes from a 1971 study by Ledward & MacFarlane who observed higher levels of oxidized myoglobin in minced vs. intact beef (see Figure 13).

Now, before I leave you totally confused about your diet, let me add this: Neither this, nor the previous article I wrote about the health effects of protein oxidation should be misunderstood as anti-protein propaganda. Protein oxidation is, after all, only one out of a myriad factors that will determine the health effects of your diet. If you know about it and take the previously outlined measures to keep your intake of oxidized proteins in check, there's no good reason to assume that the occurrence of oxidized proteins in animal, vegetable or other protein sources would be reason enough to sign. limit their intake, let alone avoid them altogether | Comment!

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• Kritchevsky, David. "Vegetable protein and atherosclerosis." Journal of the American Oil Chemists’ Society 56.3 (1979): 135-140.
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• Ledward, D. A., and J. J. Macfarlane. "Some observations on myoglobin and lipid oxidation in frozen beef." Journal of Food Science 36.7 (1971): 987-989.
• Leygonie, C., T. J. Britz, and L. C. Hoffman. "Protein and lipid oxidative stability of fresh ostrich M. Iliofibularis packaged under different modified atmospheric packaging conditions." Food Chemistry 127.4 (2011): 1659-1667.
• Liu, X. D., et al. "Effect of irradiation on foaming properties of egg white proteins." Poultry science 88.11 (2009): 2435-2441.
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• Osinchak, Joanne E., et al. "Effect of NaCl on catalysis of lipid oxidation by the soluble fraction of fish muscle." Free Radical Biology and Medicine 12.1 (1992): 35-41.
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Exercise Intensity, Oxidative Damage, Glycogen Depletion and Supercompensation. Plus: Optimal 0-12h Post Workout Glycogen Repletion Protocol For Performance Athletes

Do they train at the right intensity and what is the right intensity? What's right, anyway? Lot's of questions, tons of words, a couple of answers and some interesting revelations in today's 2nd article of the SuppVersity Exercise Science Week.

This is day 2 of the SuppVersity Exercise Science Week -- another day, another news. After you've learned about the various mechanisms by which exercise will induce structural changes to your beer belly, lover handles and other problem and non-problem areas, in yesterday's first article of the SuppVersity Exercise Science Week, today's post does actually pick up on the notion of the superiority of high intensity exercise and takes a look at how low vs. high(er) intensity endurance exercise effects the antioxidant defense system of the body. This will lead us to an issue that was once considered to be a downside of high intensity workouts: their notoriousness to deplete muscle glycogen, of which we now know that it is actually one of their fundamental strengths. When we are done with that, it's about time for the sweet dessert. The latter is going to have three courses and will help you achieve maximal muscle glycogen supercompensation after a workout.

Where does the idea that you better work out at low intensities come from?

I have made it a (enervating?) habit to include a small reminder of the "dark side" the same beneficial exercise stress that elicits muscle gains, fat loss, and improvements in conditioning and overall health can have, whenever you don't allow for adequate recovery and nutrient supply, in almost every of the articles pointing to the superiority of high intensity training vs. training in the comfort zone (click here to read up on a couple of these articles).

Figure 1: A comprehensive study by Carey revealed that the increase in ratio of fat-calories to total energy ependiture, when you train in the "fat burning zone" is 3% for men, 5% for women. The total amount of fat is yet higher above the "zone" and, most importantly, the current research suggests that the glycolytic effect, which is inversely related to the relative fat oxidation, is what triggers most of the beneficial metabolic effects.

The question, how pronounced the differences actually are, on the other hand, is not just rarely addressed here at the SuppVersity, it's also something scientists are still trying to elucidate. Usually you will see creatine kinase, an accepted marker of skeletal muscle damage being accessed before and after a workout, but as I have pointed out in previous articles, my personal experience tells me that an intense strength workout is - despite its ability to increase CK levels in training noops by up to 10,000% (x100, no typo - eg. Sewright. 2008) less prone to send you down into the abyss of the Athlete's Triad, than working out for hours (worst on a daily basis) in the purported fat burning zone, i.e. the target heart rate where you'll satisfy the greatest part of your metabolic demands from body fat and of which Carey has been able to show in "relatively fit" male and female runners that it is at least 30% below the anaerobic threshold (AT: 155Hb/min; Fat Burning Zone: 105Hb/min; cf. Carey. 2009).

Aside from that, Carey's results also support the observation Wilson et al. formulate in their recent review of concurrent training, namely that "most dramatic loss in fat mass occurr[s] from moderately high to very high intensities" (Wilson. 2012). In this context, the scientists' definition of "moderately high" is already way beyond the alleged zone of maximal fat loss. "Dramatic" is by the way also an excellent attribute for the 4.5x higher fat loss effect Wilson et al. computed for the highest vs. medium exercise intensities  (91-100% vs. 61-80% HRMax) based on the data they collected for their review.

"Better fat loss, w/ high intensity, aha... but isn't that at the cost of increased oxidation?"

In view of the fact that will be coming back to the issue of "optimal fat loss" later this week, anyway, I guess it's best we get back to the topic at hand and take a look at the toll endurance workouts at different exercise intensities actually take on your antioxidant defense system. As mentioned before, it is still far from being certain which markers you would actually have to measure to get a clear picture of how much stress and damage a given exercise regimen is inflicting. Compared to the creatine kinase levels, the measurement of markers of the activity and status of the anti-oxidant defense system, which was the main outcome variable in a study by Takahasi et al. does yet appear to be more relevant - if not with respect to exercise performance than certainly with respect to overall and metabolic health.

Figure 2: Changes in myeloperoxidase, heart rate, rate of perceived exertion and trolox equivalent antioxidant capacity (TAEC) in eight healthy and untrained males aged 22.6 ± 1.4 years (mean ± SD), with 67.7 ± 4.1 kg body mass, 175.2 ± 3.7 cm height, and 15.1 ± 2.2% body fat after 20min of exercise at 70%, 100% or 130% of the anaerobic threshold.

On three separate occasions, the Japanese researchers studied the effect of different exercise intensities. The latter ranged from 70% over 100% to 130% of the anaerobic threshold and would thus represent exercising in the "fat burning zone" at moderately high intensities and high intensities.

The first thing the scientists registered was that the pre to post increase in oxidative stress at the low and medium intensities did not even reach statistical significance. The "pro-oxidative" effects of the high intensity trial, on the other hand, were statistically significant. Yet, if you look at the actual data in figure 2, I'd guess that you will - just like me - ask yourselves what all the hoopla was about: The absolute differences are mediocre, at best and their physical not statistical significance is highly questionable; and that's not just because the trolox equivalent antioxidant capacity (TEAC) actually increased from pre to post exercise (from allegedly lower pre levels in the 130% trial than before the other exercise tests.

Training at higher intensities is demanding, yeah... but not overtly demanding!

Now, all these statistical significances were calculated on a pre vs. post basis. Intensity-specific differences on the other hand were not observed. We do therefore have to be cautious not to misinterpret the scientists very own and actually non-judgmental conclusion ...

"We found that plasma concentrations of d-ROMs increased as a result of 20 min of exercise above AT. Exercise above AT also increased enzymatic and nonenzymatic antioxidant capacity. On the other hand, there was no effect after 20 min of exercise at 70–100% AT, suggesting that exercise under the AT level does not produce oxidative stress damage." (Takahashi. 2013)

... as an advice to stick to "exercise under the AT [anaerobic threshold]". There are already way too many people wasting their time on the cross-trainers of this word - don't join them, but don't overexert yourself either.

The "Iranian HIIT Solution" has already proven that a minimalist HIIT regimen in the form of 3x200m sprint sessions per week can make all the difference esp. for someone who has never participated in regular activity before (read more).

A single bout of intense exercise leads to significant improvements in glucose and lipid metabolism in obese individuals, that's the latest result of another very recent study that was conducted at the University of Glasgow (Whyte. 2013). The protocol consisted of nothing more than " four maximal 30-s sprints, with 4.5min recovery between each (HIIT), or a single maximal extended sprint (HIT) matched with HIIT for work done". With 20% higher mean power during the sprints the temporary intensity was higher, in view of the fact that the overall exercise duration was longer and there was no time for in-between sprint glycogen replenishment. Thu it's actually not surprising that the acute increase in insulin sensitivity did reach statistical significance only after the extended sprint session. The overall metabolic benefits (non-significant improvements in glucose and lipid metabolism) on the day after, of which we can assume that they were not brought about by the immediate reduction of muscle glycogen, were identical for both conditions, while the the total and relative increase in fasting fatty oxidation was more pronounced after the HIIT protocol (total: 63% and 38%; relative, based on RER: 11% and 8% ).

Figure 3: Oxidative stress and glycogen depletion are important triggers of the beneficial effects of exercise on glucose metabolism ( (based on Kawanaka. 2012).

If we go a step further and think about whether or not oxidative stress is actually something you would want to avoid at all costs, the figure from Kentaro Kawanaka's recently published alongside review of the regulation of glucose transport in skeletal muscle during and after exercise (see figure 3) can help us make up our minds. If you take a look at my mark-ups it's plain to see that ROS production and the increase in AMP (quasi "used ATP") and decreases in ATP and phosphocreatine (PCr) are major signals for the activation of a hitherto incompletely understood signaling cascade that results in increased glucose uptake by the muscle. That's the same glucose uptake, by the way that makes the most significant difference between the "normal" and, insulin-intolerant individual and makes an ideal stepping stone to full-blown diabesity (=obesity + diabetes type II).

"So, what exactly is the effect size of these improvements? Are the worth the sweating?"

To illustrate the quantity of these effects, Kawanaka uses data from a 2009 study by Koshinaka et al. who subjected rats to an acute bout of 3x20s "high-intensity sprint interal swimming" and measured muscle glycogen levels and glucose transport at different timepoints in the 16h window after the workout.

Figure 4: Insulin and non-insulin stimulated glucose transport in rat epitrochlearis muscle at rest and 4 hours after cessation of HIIT exercise (left); muscle glycogen repletion and supercompensation after a workout (from Kawanaka. 2012 based on Koshinaka. 2009)

If we take into account that 3h(!) of continuous swimming elicited the exact same improvement in glycogen uptake as those 3x20s all out "sprints", I probably don't have to say it "appears" as if the synergistic combination of brief HI(I)T training and an appropriate diet will be more productive than the endless hours on an elliptical way too many (often unfortunately female) trainees are still performing in the desperate hope to finally shed the fat from whatever problem areas they have or believe they'd have.

Glycogen supercompensation: This is how it's done

There is yet more to the Koshinika study than another confirmation of the usefulness of HI(I)T exercise for fat loss, fitness and fabulous health. The data Koshinaka et al. collected does also tell us something about post workout glycogen repletion. Most importantly (at least in my humble opinion) that the first, immediate post-exercise phase is characterized by a rapid non-insulin dependent increase in glucose uptake. The latter is actually just as high (>5µmol/g/20min; respective data is not shown in figure 4) as the maximally measured glucose uptake in phase II, in the course of which the presence of insulin has a dose-dependent beneficial effect on the total amount of glucose that's going to be shuttled into the muscle (see figure 4, left). With phase III being characterized by saturated (in fact more than saturated) glycogen stores, these observations would suggest that an "optimal" glycogen replenishment protocol would look somewhat like this:

When you increase your calorie intake on a bulk, you better go really high carb + low fat, if lean gains are what you're looking for. This is at least what a 2011 study by Mendes-Netto suggests (read more)

1. phase I: immediately post > fast absorbing carbohydrate source -- what's important during the immediate post-workout phase is exclusively the availability of glucose, insulin the presence of extra high insulin levels is more or less unnecessary
2. phase II: post workout phase (<8h) > high GI carbohydrate source -- once the glycogen levels have reached a certain level the supercompensation process requires the presence of additional insulin, therefore your post-workout meal should not be carb-free or extremely low GI
3. phase III: recovery phase (>8h) > low GI carbohydrate source -- the glycogen stores have already reached higher than baseline levels, the presence of high levels of insulin in this phase would be counterproductive as it would actually drive glucose uptake by the adipose, not the muscle tissue

Whether this maximum glycogen repletion protocol does in fact make sense for everyone is yet another question, though. For someone who trains twice a day, like Arnold, it certainly does. The same goes for endurance athletes looking for maximal performance. If Lance Armstrong, for example, would ever be allowed to compete again, he would best go for a fast absorbing carbohydrate source like Vitargo right after the race, a huge bowl of pasta and some sugary grape juice as his first meal after the race and some slow digesting carbs like a couple of bowls of oats later that day to ensure optimal glycogen levels on the next day of the Tour -- what neither Lance nor you should not forget, though, is to add some protein to the equation, even if building muscle is not your goal, the protein will speed up the replenishment of muscle glycogen (Zawadski. 1992)

"But how important is muscle glycogen, anyway?"

For the average trainee it does yet remain questionable whether or not this protocol will actually yield noticeable benefits. While it is important to replete the glycogen stores, the advantages of doing this as fast as possible are actually not really relevant for someone who trains 3-4 times per week in order to promote health, well-being and a leaner, more muscular (but not freakish) physique. Especially with respect to the latter, the majority of the more recent studies clearly suggests that muscle protein synthesis is, in the short run, not impaired by low levels of muscle glycogen (click here to learn more).

What you should never forget, though, is that your body will interpret chronically low muscle and liver glycogen levels as a clear-cut indicator that you're starving. The results are a reduced metabolic rate and the shut down of "auxilliary" and costly bodily functions such as the reproductive machinery, etc. - and we don't want that to happen, right?


References:

• Kawanaka K. Regulation of glucose transport in skeletal muscle during and after exercise. 2012. J Phys Fitness Sports Med, 1(4): 563-572.
• Koshinaka K, Kawasaki E, Hokari F, Kawanaka K. Effect of acute high intensity intermittent swimming on postexercise insulin responsiveness in epitrochlearis of fed rats. Metabolism. 2009; 58: 246-253.
• Takahashi M, Suzuki K, Matoba H, Sakamoto S, Obara S. Effects of different intensities of endurance exercise on oxidative stress and antioxidant capacity. J Phys Fitness Sports Med. 2013 1(1): 183-189.
• Sewright KA, Hubal MJ, Kearns A, Holbrook MT, Clarkson PM. Sex differences in response to maximal eccentric exercise. Med Sci Sports Exerc. 2008 Feb;40(2):242-51.
• Whyte LJ, Ferguson C, Wilson J, Scott RA, Gill JM. Effects of single bout of very high-intensity exercise on metabolic health biomarkers in overweight/obese sedentary men. Metabolism. 2013 Feb;62(2):212-9.
• Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, Anderson JC. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. J Strength Cond Res. 2012 Aug;26(8):2293-307. 
• Zawadzki KM, Yaspelkis BB 3rd, Ivy JL. Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol. 1992 May;72(5):1854-9.

Selenium, the Fertility Mineral!? Organic and Inorganic Selenium Ameliorate Reductions in Testosterone, Testicular Damage and Abnormalities in Sperm Quality in Obese Mice

Image 1: With enough selenium in vivo, "in vitro" (-fertilization) may not be necessary.

If you have not heard about it in one of my previous blogposts, you may probably heard about the antioxidant, pro-fertility effects of selenium in the context of Tim Ferris' "selenium experiment" in the 4-Hour-Body. Ferris claimed that by just eating a handful of Brazil nuts (544µg selenium per ounce) every day shot his testosterone levels and libido through the roof. Now, what most people probably overheard, though, was that Ferris was selenium deficient to begin with. Just as every bodybuilder's holy grail, zinc, selenium won't help up your testosterone or fertility if you have already plenty of the potentially toxic trace mineral in your diet. In view of its central role in the antioxidant defense system of our bodies, it is however likely that selenium requirements increase, whenever our bodies are exposed to increasing amounts of oxidative stress.

When your body fat sets your testicles on fire, selenium may come to a rescue...

One of the most common causes of increased oxidative stress, these days, are the increased levels in highly oxidizable very-low density cholesterol and triglyceride levels which appear to be an almost inevitable consequence of the "modern" lifestyle (=sitting on the couch and washing down your fast-food, as well as your low-fat "healthy" cereals, pasta and rice with soda). A recent study from scientists from the Institute of Nutritional and Metabolic Disorders of Domestic in China does now show that an adequate amount of dietary or supplemental selenium, which is, as you may gather from the data in table 1, pretty scarce in everything that was not grown or raised on selenium-rich soil, may not be able to reverse all negative side-effects, but could ameliorate them so that reproduction would still be possible (Ibrahim. 2011).

Table 1: Selenium content of common foods (based on data from the NIS. 2011)

While the basal diet, which had been enriched with cholesterol, lard and cholic acid, so that it would mimic the obesogenic high carb + high fat diet, researchers love to mislabel HFD (high fat diet), contained only 0.04 µg/g of selenium (without the addition the lard, i.e. for the control group, the se-content was 0.05µg/g), both the inorganic selenium HF-diet and the diet of the animals that received a combination of (organic) selenium (75% selenium-methionine) and probiotics (C. utilis and S. thermophilus strains) contained ~6x the amount of selenium (0.3µg/g chow). For humans this would translate to ~1.2µg/kg and 7µg/kg, respectively (since the scientists did not report food intake and body weight of the animals, I based this calculation on the respective data from other HFD feeding studies with mice).

Amelioration? Yes! Reversal / complete prevention? No!

After 75 days on control, high fat, high fat + probiotic only, high fat + inorganic selenium only, and high fat + 90% organic selenium + probiotic diets, the testis of the mice showed histopathological changes even a non-expert as I am one would identify as "probably not healthy" (cf. illustration 1):

Illustration 1: Compilation of the histopathological examination of murine testes (H & E, ×400; based on Ibrahim. 2011)

The evident degenerations, decreases in cell population, and irregularities went hand in hand with a pretty profound changes in the quality of sperm (cf. figure 1), which were ameliorated, yet not prevented in the selenium and selenium + probiotic groups.

Figure 1: Measures of sperm quality - sperm count and motility (left); relative incidence of sperm with abnormal heads and tails (right; data based on Ibrahim. 2011)

In that, it is noteworthy that the selenium + probiotic (SePro) group had an only 1.5x increased amount of sperm with abnormal tails. The latter can thusly hardly be the reason for the -20% reduction in overall sperm motility.

Figure 2: Lipid (left axes) and testosterone (right axes) levels in the different groups (left); HDL to total cholesterol ratio and change in testosterone levels compared to control (right; data calculated based on Ibrahim. 2011)

In view of the fact that the male gonads do not only produce sperm, but also testosterone, it is not surprising that selenium and selenium + probiotic supplementation had a similar ameliorative effect on the diet induced reduction -47% reduction in testosterone (cf. figure 2). The +3% increase in serum testosterone (over the obesogenic diet group) in the probiotic only group, on the other hand, lacked statistical significance.

Image 2: The importance of selenium for thyroid function, specifically the local conversion of the "inactive" T4 to the "active" T3 is not the only reason why women should try to achieve adequate selenium intakes, as well.

Selenium for women? While it appears that research has hitherto focused on the role selenium plays in male health, there is a handful of studies which suggest that adequate levels are just as important for women, as they are for men. The results of a Polish study from 2006, for example, stand in line with the, as of late, controversial anti-carcinogenic effect selenium is supposed to have on prostate cancer. According to the authors, the provision of selenium supplements to women with a genetic disposition for breast and ovarian cancer led to a small, but statistical significant reduction in cancer rates (Huzarski. 2006). In 2009, Hermsdorff et al. observed a statistical significant inverse correlation between selenium intake and serum levels of retinol-binding-protein 4, a marker of whole body inflammation and purported contributer to insulin resistance and diabetes (Yang. 2005), in 74 young (~20y) healthy women (Hermsdorff. 2009). In post-menopausal women, Llaneza et al. found a non-negligible association of low-serum selenium levels and higher LDLc and triglyceride levels (Llaneza. 2009). A 2007 study by Negro et al. underlines the particular importance of adequate selenium levels for thyroid health during and immediately after pregnancy (Negro. 2007). And according to a recent review of the role of selenium in reproductive health, low selenium levels in the follicular fluid are a characteristic feature of "unexplained infertility" in women.

As far as the "potency" of the probiotics is concerned, the study was thusly quite disappointing. That the scientists who were proud to have developed a "Se-enriched probiotic as a new feed additive product for promoting animal industries" do not explicitly state that, is understandable, but won't stop me to repeat my previous recommendation to just add a handful of brazil nuts to your diet on a regular basis to make sure you satisfy your selenium requirements.

Selenium intoxication from Brazil nuts? I don't think so...

Image 3: Eating lots of brazil nuts and other selenium rich foods until they achieve what the US consider "toxic" serum and plasma levels does not seem to impair the health of the inhabitants of the regions around the Tapajós River in Brazil - on the contrary, their cardiovascular health is outstanding (Lemire. 2011)

That this practice is not going to result in selenium toxicity has, by the way, been shown only very recently in one of those studies that analyze traditional diets, which have become so in-vogue, as of late. Lemire et al., who analyzed blood (B-Se) and plasma (P-Se) samples from members of the communities which live along the Tapajós River in Brazil, did not only find that these people had selenium levels well beyond what is "considered toxic" in the US, they also state that their results "support the need to re-assess Se toxicity considering factors such as the chemical form of Se exposure, route of exposure (inhaled versus ingested), co-exposures to toxic elements such as mercury" and hint at "a possible association between high Se status and cardiometabolic health in this study population." (Lemire. 2011) So, men or woman, fertile or infertile, fat or lean... you better make sure you get your share of brazil nuts, today ;-)