Egg-Ology Today: The Underappreciated Health Benefits of Egg Phospholipids, Proteins & Antioxidants in the Yolk

The yolk is where almost all the "good" stuff in the eggs resides. Throwing the yolk of the 1-2 eggs you eat per day away, as people have been doing it for decades is thus madness.

For decades eggs have been falsely accused of being the drivers of the heart disease epidemic (cardiovascular disease claims upwards of 17 million lives worldwide each year | WHO. 2011). More recently, however, the small "cholesterol bombs" have been acquitted of all charges and scientists begin to (re-)evaluate their already know, but largely ignored health benefits. Health benefits that are not solely related to their high protein content, by the way.

As a SuppVersity reader you will know that eggs are valuable protein sources, but don't worry: This is not what today's SuppVersity article is about. Rather than that I would like to highlight a much less-known egg constituent, the egg phospholipids.

Learn more about the effects of your diet on your health at the SuppVersity

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Dairy Protein Shoot-Out: Casein vs. Whey

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5 Tips to Improve & Maintain Insulin Sensitivity

The Paleo Diet Was Never Ketogenic!

Studies indicate that eggs are the major source of phospholipids (PL) in the Western diet; the same phospholipids that "have emerged as a potential source of bioactive lipids that may have widespread effects on pathways related to inflammation, cholesterol metabolism, and HDL function" (Blesso. 2015).

Table 1: Typical Composition of Egg Phospholipids | FA, fatty acid; LysoPC, lysophosphatidylcholine; LysoPE, lysophospha-tidylethanolamine; PC, phosphatidylcholine; PE, phospha-tidylethanolamine; PI, phosphatidylinositol; PL, phospholipid; SM, sphingomyelin. (Blesso. 2015)

"PL are key components of all biological membranes and are abundantly found in the diet, primarily as glycerophospholipid and sphingolipid classes. Dietary glycerophospholipids are made up of two fatty acids (FA), a glycerol backbone, a phosphate group, and a polar organic molecule (choline, serine, inositol, or ethanolamine).[...] The average large egg contains approximately 1.3 g of PL, which are almost exclusively found in the yolk. 

An egg breakfast improves the levels of triglycerides in active indiv. compared to an isocaloric bagel breakfast (Clayton. 2015).

Egg vs. oatmeal (more) and egg vs. bagel: You will probably still remember my recent article about a study by Ballesteros, et al. (2015) showing that an egg per day improves inflammation when compared to an oatmeal-based breakfast without increasing other cardiometabolic risk factors not just in healthy, but even in diabetic patients (read more | Ballesteros. 2015). In a similar, but more complex study, Clayton et al. (2015) found that compared to an isoenergetic breakfast with bagels, a daily breakfasts that includes two eggs will improve plasma triglycerides in active (resistance training) men and women.

A typical Western diet contains about 2–8 g of dietary PL per day. Estimates of average egg intake in the U.S. indicate that egg-derived PL contributes 10%–40% (or 0.8 g) of daily consumed PL. The major PL species found in egg include PC, phosphatidylethanolamine (PE), SM, and phosphatidylinositol (PI). The typical PL composition of egg is shown in Table 1, which reveals PC as the predominant species making up almost three quarters of the total PL. The typical FA compositions of egg PL species vary and are shown in Table 1" (Blesso. 2015).

Alongside carotenoids lutein and zeaxanthin, two potent anti-oxidant agents in eggs, and the previously mentioned phospholipids which have also been shown to

• 

  Eggs have beneficial effects on cholesterol in your cells | learn more

  decrease serum cholesterol levels in rats (Murata. 1982) and a reduction of the intestinal absorption of cholesterol (Jiang. 2001), 
• improve memory retention and increase acetylcholine concentrations, a neurotransmitter that decreases in concentration in cases of Alzheimer’s disease (Masuda. 1998;  Favreliere. 2003), as well as 
• improve liver function, and cancer prevention (Gutierrez. 1997),

there are also a hand full of peptide / proteins and related agents - mostly in the yolk of eggs - that make eggs a totally underestimated health food:

• 

  Table 2: Biological acitivities of egg proteins (Kovacs-Nolan. 2005)

  yolk proteins - ovalbumin, ovotranserin, ovucoid, ovomucin, lysozyme, as well as ovoinhibitor, vomacroglobulin, ovomacroglobulin and avidin have antibacterial activity and antihypertensive, immunomodulating, antiadhesive (=interferes with a key step of inflammation), antitumor, and antiviral activities (to find out what does what, check out Table 2 from Kovacs-Nolan. 2005);
• immunoglobulins - specifically immunoglobolin Y from egg yolk which has been shown to have antibacterial activity, antiviral activity, can reduce the incidence of dental caries, is used in anti-venoms, acts as an anti-inflammatory agent, and serves as a carrier for anti-cancer drugs (Mine. 2004);
• other components of the yolk - including phosvitin, sialyloligosaccharides and sialylglycopeptides, as well as the yolk lipids, lipoproteins, fatty acids, and cholesterol have scientifically proven antioxidant and antibacterial activities, as well (Kovacs-Nolan. 2005)

Men and women with familial hypercholesterolemia have a lack of / defective LDL receptors and a defective regulation of  the endogenous cholesterol production. For them reducing the intake of cholesterol and taking statins is in fact a good idea (Goldstein. 2015). The same may go for people with various other specific genetic polymorphisms a dozen of which have recently been summarized by Abdullah et al. (2015).

For 99% of us, there's no reason to be afraid of the cholesterol in eggs: Unfortunately, there's a small portion of the population whose genes predispose them to "abnormal" increases in serum cholesterol in response to increased cholesterol intake. Next to familial hypercholesterolemia (Goldstein. 2015), there are a number of other - albeit less threatening - polymorphisms (e.g. the ABCG5 polymorphism | Herron. 2006; see Abdullah. 2015 for a summary) which may explain why most (e.g. Nakamura. 2006), but not all studies refute the claim that an increased egg consumption triggers increases in cholesterol and subsequent increases in CVD risk in healthy indiv.

If you take a look at more general studies, and the negligible 0.38% increase of the LDL:HDL ratio McNamara et al. (2000) calculated per 100mg increase in cholesterol intake in their meta-analysis it is no wonder that all, not just "egg centered" epidemiological studies show that "dietary cholesterol is not related to coronary heart disease incidence or mortality across or within populations" (McNamara. 2000).

This does not mean that I recommend consuming 20 whole eggs per day. Especially for those of you who consume high amounts of carbohydrates, this may turn your diet into a highly unfavorable high fat + high carbohydrate diet, but 1-2 whole eggs a day ain't no problem; irrespective of what the rest of your diet looks like (assuming you don't belong to the previously mentioned group of people who are genetically disposed to have problems with their lipid metabolism) | Comment! 

References:

• Abdullah, Mohammad MH, Peter JH Jones, and Peter K. Eck. "Nutrigenetics of cholesterol metabolism: observational and dietary intervention studies in the postgenomic era." Nutrition reviews (2015): nuv016.
• Ballesteros, Martha Nydia, et al. "One Egg per Day Improves Inflammation when Compared to an Oatmeal-Based Breakfast without Increasing Other Cardiometabolic Risk Factors in Diabetic Patients." Nutrients 7.5 (2015): 3449-3463.
• Blesso, Christopher N. "Egg Phospholipids and Cardiovascular Health." Nutrients 7.4 (2015): 2731-2747.
• Clayton, Zachary S., et al. "Influence of Resistance Training Combined with Daily Consumption of an Egg-based or Bagel-based Breakfast on Risk Factors for Chronic Diseases in Healthy Untrained Individuals." Journal of the American College of Nutrition 34.2 (2015): 113-119.
• Favreliere, S., et al. "DHA-enriched phospholipid diets modulate age-related alterations in rat hippocampus." Neurobiology of aging 24.2 (2003): 233-243.
• Goldstein, Joseph L., and Michael S. Brown. "A Century of Cholesterol and Coronaries: From Plaques to Genes to Statins." Cell 161.1 (2015): 161-172.
• Gutierrez, M. A., H. Takahashi, and L. R. Juneja. "Nutritive evaluation of hen eggs." Hen eggs, their basic and applied science. 2nd ed. CRC Press, New York (1997): 25-35.
• Herron, Kristin L., et al. "The ABCG5 polymorphism contributes to individual responses to dietary cholesterol and carotenoids in eggs." The Journal of nutrition 136.5 (2006): 1161-1165.
• Jiang, Yongzhi, Sang K. Noh, and Sung I. Koo. "Egg phosphatidylcholine decreases the lymphatic absorption of cholesterol in rats." The Journal of nutrition 131.9 (2001): 2358-2363.
• Kovacs-Nolan, Jennifer, Marshall Phillips, and Yoshinori Mine. "Advances in the value of eggs and egg components for human health." Journal of agricultural and food chemistry 53.22 (2005): 8421-8431.
• Masuda, Y., et al. "Egg phosphatidylcholine combined with vitamin B 12 improved memory impairment following lesioning of nucleus basalis in rats." Life sciences 62.9 (1998): 813-822.
• McNamara, Donald J. "The impact of egg limitations on coronary heart disease risk: do the numbers add up?." Journal of the American College of Nutrition 19.sup5 (2000): 540S-548S.
• Mine, Yoshinori, and Jennifer Kovacs-Nolan. "Biologically active hen egg components in human health and disease." The Journal of Poultry Science 41.1 (2004): 1-29.
• Murata, Masakazu, Katsumi Imaizumi, and Michihiro Sugano. "Effect of dietary phospholipids and their constituent bases on serum lipids and apolipoproteins in rats." The Journal of nutrition 112.9 (1982): 1805-1808.
• Nakamura, Yasuyuki, et al. "Egg consumption, serum total cholesterol concentrations and coronary heart disease incidence: Japan Public Health Center-based prospective study." British Journal of Nutrition 96.05 (2006): 921-928.
• World Health Organization. Global Status Report on Noncommunicable Diseases 2010; World Health Organization: Geneva, Switzerland, 2011.

"Eggs" - 4-Letter Food Improves Both Cholesterol Particle & Phospholipid Profile + HDL-Driven Lipid Reverse-Transport

In addition to the previously reported improvements in cholesterol particle profile, the regular consumption of whole eggs increases HDL's ability to carry lipids out of the macrophages. If these accumulate, they will turn the macrophage into pro-atherogenic foam cells (cf. Eckardstein. 2001).

You will probably remember the long-boycotted(*) 2012 study by Blesso et al. which showed quite conclusively that daily whole egg consumption has a  beneficial impact on the HDL-C levels and the particle size profile of overweight and obese patients following a diet with a moderate amount of carbohydrates (read all about the study in the SuppVersity article from October 2012)

(*) I obviously have no evidence that the publication of the Blesso study was mischievously delayed, but it is unquestionably conspicuous that a paper with 100% convincing data that the witch hunt on eggs of the medical establishment is totally unwarranted was postponed from September 2012 (date of the online publication) to March 2013, isn't it?

Be that as it may, let's now after devoting our precious time to the always popular conspiracy theories, take a look at the actual news - news, which come right from the labs of the same laboratory, but this time with a slight twist:

"We recently demonstrated that daily whole egg consumption during moderate carbohydrate restriction leads to greater increases in plasma HDL-cholesterol (HDL-C) and improvements in HDL profiles in metabolic syndrome (MetS) when compared to intake of a yolk-free egg substitute. We further investigated the effects of this intervention on HDL composition and function, hypothesizing that the phospholipid species present in egg yolk modulate HDL lipid composition to increase the cholesterol-accepting capacity of subject serum." (Anderson. 2013)

As you gather from the above citation the dataset, or I should say the blood samples the scientists from the University of Connecticut analyzed to gather their data, were the same as in the previous study accordingly, there is little I could tell you about the 37 subjects (25 women; 12 men) classified with MetS who were recruited to participate in the previously described 12-week parallel, randomized, single-blind diet intervention.

Figure 1: Phospholipid composition of whole egg and egg substitute products; data displayed in mg/serving x 10,  y-axis logarithmically scaled (Anderson. 2013)

"During the 12-week study, subjects were instructed to follow an ad libitum moderate carbohydrate-restricted diet (25–30%) of energy from carbohydrates) in addition to consuming either three whole eggs (EGG group) or the equivalent amount of egg yolk-free egg substitute (SUB group) each day. The egg substitute product consisted of egg whites (99 %), 1 % xanthan and guar gums, beta-carotene for color, and provided 0 mg of cholesterol, whereas the daily serving of whole egg contained 534 mg of cholesterol." (Andersen. 2013)

In the course of the intervention the HDL-cholesteryl ester content in the blood of all subjects increased (relative to other forms of HDL). This increase was, as the data in figure 2 goes to show you, more pronounced in the SUB [=no egg yolks] group. The HDL triacylglycerol content, on the other hand, was reduced in the subjects receiving the whole eggs, only (EGG group). Consequently, the egg intervention resulted in an increases in HDL-CE/TAG ratios in both groups. More importantly, though, ...

Figure 2: Effects of egg feeding on HDL-phospholipid class distribution during moderate carbohydrate restriction  (Andersen. 2013)

"[...p]hospholipid analysis [ (PtdCho phosphatidyl-choline, PtdEtn phosphatidyl-ethanolamine, CerPCho sphingomyelin, LysoPtdCho lysophosphatidyl-choline, PtdIns phosphatidyl-inositol; cf. figure 2] by mass spectrometry revealed that HDL became enriched in phosphatidylethanolamine in the EGG group, and that EGG group HDL better reflected sphingomyelin species present in the whole egg product at week 12 compared to baseline." (Andersen. 2013)

In addition, and in line with previous results suggesting that greater enrichment of HDL in phospholipids—such as PtdCho and CerPCho—are associated with a greater lipid-accepting capacity
of HDL and/or human serum (Fournier. 1996 & 1997), the macrophage cholesterol efflux of the subject in the EGG group increased from baseline to week 12 (+2.4% from baseline). This physiologically highly relevant effect which correspond to the previously reported improvements in HDL particle profiles (see post from October, 2012) is the actual news this re-analysis of the blood samples has to offer, as it goes to show us that the beneficial effects of daily consumption of the "4-letter" food "eggs" does not only promotes favorable shifts in the particle size distribution of the lipoproteins in a patient group with a high baseline risk for cardiovascular diseases. No, the "bad" eggs also improve the HDL lipid composition (lowering the triglyceride content) and the function of the HDL molecules.

---

Bottom line: If you have been following the SuppVersity Facebook News over the past couple of weeks, you will now probably be thinking: "Wait a minute.. wasn't there..."? And yes, there was. Scientists from the IMIM-Research Institut Hospital del Mar in Barcelona, Spain (Farràs. 2013), have observed very similar effect in a rodent study in response to the consumption of the phenols from a highly praised "8-letter food": Olive Oil!
 

  "If we have not somehow pimped it, it can never be good enough!" appears to be one of the credos with which mankind approaches almost every natural health-remedy. In the past this approach was not particularly healthy, though... is phenol-enriched olive oil going to be the exception to the rule? (learn more)

I know that parts of the medical establishment are not going to like it, but a  short and concise bottom line of the study at hand could thus well be:  

Eggs and olive oil belong to the same category of health foods whose beneficial effects on lipid metabolism go well beyond promoting a more favorable lipoprotein profile. They will also boost the ability of the "good" cholesterol to do it's job and clear the otherwise plaque forming cholesterol from the cells... 

whether this message will ever make it into the headlines of the "science" colums of mainstream media is unfortunately highly questionable.

References:

• Andersen CJ, Blesso CN, Lee J, Barona J, Shah D, Thomas MJ, Fernandez ML. Egg Consumption Modulates HDL Lipid Composition and Increases the Cholesterol-Accepting Capacity of Serum in Metabolic Syndrome. Lipids. 2013 Jun;48(6):557-67.
• Blesso CN, Andersen CJ, Barona J, Volek JS, Fernandez ML. Whole egg consumption improves lipoprotein profiles and insulin sensitivity to a greater extent than yolk-free egg substitute in individuals with metabolic syndrome. Metabolism. 2012 Sep 26.
• von Eckardstein A, Nofer JR, Assmann G. High density lipoproteins and arteriosclerosis. Role of cholesterol efflux and reverse cholesterol transport. Arterioscler Thromb Vasc Biol. 2001 Jan;21(1):13-27. 
• Farràs M, Valls RM, Fernández-Castillejo S, Giralt M, Solà R, Subirana I, Motilva MJ, Konstantinidou V, Covas MI, Fitó M. Olive oil polyphenols enhance the expression of cholesterol efflux related genes in vivo in humans. A randomized controlled trial. J Nutr Biochem. 2013 Jan 17.
• Fournier N, de la Llera Moya M, Burkey BF, Swaney JB, Paterniti J Jr, Moatti N, Atger V, Rothblat GH. Role of HDL phospholipid in efflux of cell cholesterol to whole serum: studies with human apoA-I transgenic rats. J Lipid Res. 1996 Aug;37(8):1704-11. 
• Fournier N, Paul JL, Atger V, Cogny A, Soni T, de la Llera-Moya M, Rothblat G, Moatti N. HDL phospholipid content and composition as a major factor determining cholesterol efflux capacity from Fu5AH cells to human serum. Arterioscler Thromb Vasc Biol. 1997 Nov;17(11):2685-91.

Leaning Out on a Bulk? Approx. 6g of Phospholipid Bound DHA + EPA Per Day Could Make That Possible. Rodent Study Reveals Profound Difference to "Regular Fish Oil"

Can phospholipid-bound N-3s as in krill ward off the fat gain on a bulk?

Your daily visits, comments, feedback, criticism and obviously commendations are not only what makes the hours of work I invest into this blog worthwhile, they are also a constant source of "inspiration" and, as the latest post by Roy Nelson on the SuppVersity Facebook Wall goes to show you, oftentimes point me towards the most interesting stuff. In that, it does not really matter that Roy's question was more or less unrelated to what I personally found absolutely newsworthy in the study he referenced, a study which deals with fish oil supplementation and its *yawn* anti-inflammatory effects.

You learn from me, I learn from you

Now, I guess some of you are similarly fed up with those rodent studies like I am, but bear with me folks, Roy did in fact shoot the bulls-eye with this one (not sure if you realized that Roy, but you did ;-) After all, there was a certain twist to this study. A twist you have actually read about on the suppversity roughly 7 month ago, in a post with the suggestive title "Phospholipid or Triglyceride? What's in Your Fish Oil Caps? Only Phospholipid Based DHA+EPA Reduces Fat Cell Growth & Elevated Insulin Levels Despite Obesogenic Diet" (read more). Both studies, the one at hand, which was published only a couple of days ago in Nutrition & Metabolism, as well as the "old" study by Rossmeisel et al. (read up on the results), dealt with the difference between the "real-rodent-world" differences between triglyceride and phospholipid based n3-PUFAs.

Why are you talking about "n-3 PUFAs" and not simply about fish oil? There are actually two reasons, I am trying to avoid the term "fish oil" in this context. Firstly, real fish has both, triglycerides which make up >90% of the fat in fatty fish like salmon & co. And secondly, the way fish oil supplements are produced usually removes the last phospholipid fractions leaving you with nothing but the triglycerides (another reason to stick to fish as an animal, instead of fish as a gelatine cap ;-)

Rossmeisel et al. have already been able to show that the phospholipid-bound n-3 PUFAs (DHA and EPA) posses physiological effects the cheap triglycerides don't have to offer: They decrease the size of the fat cells and thus provide a structural advantage, the common triglyceride-bound forms of DHA and EPA do not have to offer.

Why is a smaller adipocyte size significant?

Remember the post on choline as part of a weight loss stack (read more)? Guess what: Choline is also part of most phospholipids.

I have been dabbling with adipocyte sizes in previous posts and freely admit that this is a too complex matter to actually support the statement that "small adipocytes are best" (learn more in previous posts).

In a hypercaloric diet scenario, as the one in the study at hand, a  decreased adipocyte size may yet well be considered the structural foundation of reduced baseline inflammation. after all, the size or you could as well say the filling level o the fat cells is directly associated with the amounts of pro-inflammatory cytokines they release (Skurk. 2007).

For those of you who are in fact dabbling with high levels of fat-induced inflammation (these are often the skinny fat guys and girls), this alone would therefore warrant the investment in Krill instead of fish oil, if you can't or don't want to get your dietary phospholipids from fresh fish. The new findings the study by Manar Awada and his (or her?) colleagues from the CarMeN Laboratory in Lyon, France, brings to the table are yet probably a more convincing argument for the majority of physical culturists:

Phospholipid-base N3-PUFAs reduce will cut body fat even on a HFD diet

Yep, that's right. If the results of the Awada study translate 1:1 from you rodents to physical culturists, you could in fact up your caloric intake by 50% and still lose 14% body fat compared to following a "species-appropiate diet" (in the case of a rodent that's obviously a high carb diet, with a macronutrient ratio of 19.1% protein, 57.6 carbohydrates and12.8% fat in it).

Figure 1: Energy intake and body composition (left) and lipid, glucose, insulin and leptin levels (right); data expressed relative to values from the regular low-fat chow group (Awada. 2013)

Now the data in figure 1 and the notion that you could cut body fat on a bulk certainly sounds too good to be true and to be honest, I have my doubts that someone whose following all the nutritional advice you get on the SuppVersity on an almost daily basis will see identical "real-human-world" results (specifically if your diet already contents phospholipid bound N3-PUFAs, which it will if you follow my advice to have fish once or twice a week). But let's be honest, if the consumption of phospholipid bound DHA and EPA at a dosage of 0.08g/kg body weight did nothing but blunt the almost inevitable fat gain on an intense (+50% increase in energy intake) "bulk", that would be awesome - wouldn't it?

What are the underlying mechanisms, here?

Krill protein offers non-negligible health benefits, as well (learn more).

I know many of you mainly interested in the practical implications, but especially, when we are dealing with data from rodent studies, we have to understand how a supplement works, in order to tell something about the probability that it will work in humans as well.

Against that background, it's well-worth to take a final look at those cellular parameters that may provide some clues on what it is that makes the phospholipid forms of DHA and EPA so superior compared to their conventional triglyceride counterparts.

Aside from a highly more pronounced increase in intra-cellular vitamin E (2.8x higher than HFD alone and 1.5x higher than HFD + triglyceride-bound omega-3s), there were yet unfortunately no statistically significant inter-group differences. Even in conjunction with the (probably related) yet statistically non-significant difference in markers of lipid peroxidation (4HHE 104, 89, 128nM and 4HNE 13, 6, 9nM in high fat, high fat + PL and high fat + TG, respectively), this is simply not enough to gain insight into the underlying mechanisms which lead to these highly desirable anti-obesity effects. So that we will, for better or worse, have to contend ourselves with the scientists' own conclusion that "further research is required to better understand the mechanism of action of PL carrier".

Figure 2: The PL N-3 content (g/100g dry mass) of fish is very heat stable compared to the triglyceride fraction of which are partly (baking) or totally (frying) lost when you process the raw fillets (Mai. 1978). So even if your fish has a relatively low PL content, that will at least remain where it is supposed to be ;-)

Bottom line: Without knowing the underyling mechanism and in the absence of respective human data, I am honestly hesitant to suggest you go and buy tons of krill oil supplements. After all, the human equivalent dosage of the amount of phospholipid bound DHA+EPA that was used in the study at hand amounts to ~6g per day. So even if found a product that's 100% phospholipid, 0% triglyceride you would have to take ~30 1g caps of regular krill oil which usually have ~200mg of DHA and EPA in them.

So unless you happen to have a cheap source of the purified omega-3 phospholipids the scientists used in their study, it will probably be more prudent to wait for the third SuppVersity post on this matter and invest the buckloads of money this will save you into fresh fish fillets. 

References:

• Awada M, Meynier A, Soulage CO, Hadji L, Géloën A, Viau M, Ribourg L, Benoit B, Debard C, Guichardant M, Lagarde M, Genot C, Michalski MC. n-3 PUFA added to high-fat diets affect differently adiposity and inflammation when carried by phospholipids or triacylglycerols in mice. Nutr Metab (Lond). 2013 Feb 15;10(1):23.
• Mai J, Shimp J, Weihrauch J, Kinsella JE. Lipids Of Fish Fillets: Changes Following Cooking By Different Methods. Journal Of Food Science. 1978; 43: 1669–1674.
• Skurk T, Alberti-Huber C, Herder C, Hauner H. Relationship between adipocyte size and adipokine expression and secretion. J Clin Endocrinol Metab. 2007 Mar;92(3):1023-33.

Mutant Milk!? New Research Fuels the Flames on Hushed Up Concerns About Ill Health Effects of Homogenized Milk

Image 1: Wolverine could be the only face of the "Got Milk" campaign who does not have to care about potential negative health effects of homogenized milk.

In view of the fact that even the Wikipedia article on milk mentions the long-touted hypothesis that the release of the  membrane bound (bovine) xanthine oxidase during the homogenization process and it's potential to generate reactive oxygen specimen could pose a serious health risk, it's quite funny that none of the multitude of papers on the pro- or anti-atheriogenic effects of milk ever mentions mentions the issue of homogenization.

Now even if we discard the potential negative effects of BXO, the results of a recently published paper from the Center of Specialized Nutrition in the Netherlands would still suggest that milk does at least lose some of it's beneficial health effects in the course of the homogenization process (Oosting. 2012).

Large and fluffy or small? That does ring a bell, doesn't it? 

In their experiments the Dutch scientists fed mice infant formulas with either small or large phospholipid coated lipid droplets. Probably to the utmost satisfaction of Danone, the producer of the large lipid droplet formula (Nuturis) and sponsor of the study, the mice who received the regular formula with small lipid droplets were fatter and had compromised lipid and blood glucose levels (see figure 1), as well as pathologically increased leptin levels (not shown in figure 1).

Figure 1: It may remind you of comparing apples and oranges, but let's be honest, if it were not for the disruption of the large fat globules during the homogenization process, similarly large phospholipids as those Danone plans to unleash onto our children would be present in milk, anyway.

Irrespective of the funding and product pimping, the results of this study could have major implications that reach way beyond infant formulas and parenteral nutrition. After all, homogenized milk is common used in all sorts of milk based or milk-containing products. It's shelf stable and above all highly standardized and easily processable by the dairy and food industry, who are still spending truckloads of money to find means to further reduce the unwanted clumping that's so characteristic for the naturally occurring large fat molecules most of the end-consumer don't want to float on top of their heated milk either.

So, if the bovine xanthine oxidase that's released during the homogenization process does not, as Ho & Clifford and other researchers argued in the late 1970s (Ho. 1977), pose a risk for heart disease, what about the structural changes in the lipid fraction of milk? Do we know anything about these at all and could they be the underlying cause of the increase in allergies, diabetes risk that have never been convincingly attributed to milk consumption in general or whole milk consumption in particular? Did we focus to much on the quantity and type of fat in the milk and overlooked its structural organization?

Though shalt not fix something that ain't broken!

In a 2007 review of the literature on the potential impact homogenized milk could have on our health, Mikalski discusses exactly this question: What's the physiological consequence of the physical "rupture of fat globules" which occurs during the heating and homogenization process and "creates a new interface" on the membrane of the fat globules so that "other surface active components" (Mikalski. 2007) will more or less randomly adsorb to the remnants and form a new structurally different membrane.

Figure 2: After the homogenization process took place none of the original functional large fat globules is left, smaller ruptured globules have taken their place and are used by other molecules as a "Trojan horse" (left), distribution of milk fat globule sizes in different types of whole milk - open circles - raw whole milk, full circles - whole milk homogenized at 5MPa, open squares - whole milk homogenized at 10 MPa, full squares - whole milk homogenized at 50MPa (partly adapted from Mikalski. 2007)

Unfortunately, the #1 compound that will bind to the now the disrupted surface structures of the molecules in the homogenized monster milk are casein micelles (Zahar. 1996). Yep, exactly those molecules, of which some scientists, though most of them discard the hypothesis that homogenized milk is not at least as good for you as regular milk, still speculate that they could be responsible for many if not all of the aforementioned negative health effects of milk (Kohno. 1994; Laugesen. 2003; Tailford. 2003).

Homogenized, fat reduced zombie milk?

Figure 3: Distribution of milk lipids in globule core, membrane and skim phase (top, based on Michalski. 2007) and electron micrographs at 15× and 100× augmentations of (A) raw, (B) pasteurised, (C) homogenised–pasteurised, and ultra-high-pressure homogenised milk samples at (D) 100 MPa (Zamora. 2012)

That the process of homogenization will also affect the normal distribution of tri- and diacylglycerols, which are necessarily released from the core of the ruptured fat molecules (figure 3, top - blue) and modify the intricate phospholipid structure of the membrane (figure 3, top - red) should be as obvious as the fact that those tri- and diacylglycerols, phospholipids, cerebrosides and gangliosides are suddenly part of the skim fraction are easily lost during further processing (such as the removal of fat) and will have different physical attributes, physiological effects, digestive properties and absorption kinetics (cf. Berton. 2012).

The degree of homogenization increases according to the pressure that's used to force the the hot milk between valve needle and seat of the homogenization machine, so that  the aforementioned effects are particularly pronounced in the high-pressure homogenized milk (also "ultra-homogenized" milk). Accordingly even the last few "unwanted" (by the food industry) larger, intact fat globules that are left in the regular homogenized milk (figure 3, C) break apart.

What used to be a huge container-like fat molecule in the raw milk (figure 3, A), survived the pasteurization process relatively unharmed (figure 3, B) is now, after it has been pressed with 100MPa through the valve of the homogenization machine, nothing but a heap of very shelf-stable and non-clumping, highly convenient debris (figure 3, D) - awesome, right?

Bottom line: Aside from the disgusting taste of what we here in Germany call "H-Milch" ("h" as in "haltbar", which denotes the longer shelf-life) the structural changes and the potentially problematic downstream effects of the homogenization process, such as

Image 2: Assuming that the plastic canister the girl on the right holds in her hands contains homogenized milk, it may in fact be better for the girl on the left, if it was fat free :-o After all, when the homogenized whole milk is further processed into 0.2% = no fat milk ~95% of the previously created mutant fat molecules will be removed ;-)

• a rise in potentially artherosclerotic free bovine xanthine oxidase, which would otherwise be "locked" in the the intact milk fat globule membrane (MFGM),
• the formation of new lipid layers from casein and other milk components and milk fat globule membrane fragments with potentially allergenic, and inflammatory properties,
• a decrease in curd formation / stability, an increase proteolysis and lipolysis (=digestion of the proteins and fats) and the subsequent increase in nutrient absorption and speed in the gastrointestinal tract with its potentially detrimental downstream effects on blood lipids, and
• the increased absorption of casein molecules and the loss of the beneficial health affects such as the anti-viral, antimicrobial, anabolic and gut protective effects that have been ascribed to the natural MFGM structure of milk

should be reason enough not to make the most convenient, but the most natural choice - and that irrespective of whether the milk is for a toddler, a child, a teen or an adult... and by the way, the changes the fat molecules in the milk are undergoing and the subsequent "mutant" protein + fat fragment structures they are forming make the otherwise nonsensical advice to use "low" or better "no-fat dairy" actually appear quite sensible.

Apropos "high fat dairy", did I mention that the "bad high fat cheese" is not just almost always made from regular, non-homogenized milk (which is hard to get, these days, as even the cooled milk is routinely homogenized, so make sure to check the label), but that its consumption is also associated with a decreased risk of developing metabolic syndrome (Høstmark. 2011)? No... well, than that's even more food for thought ;-)

References

• Berton A,Rouvellaca S, Robertd B, Rousseaud F, Lopez C. Effect of the size and interface composition of milkfatglobules on their in vitro digestion by the human pancreatic lipase: Native versus homogenized milk fat globules. Food Hydrocolloids. 2012; 29:1, 123–134. 
• Ho C, Clifford A Bovine milk xanthine oxidase, blood lipids and coronary plaques in rabbits.J Nutr. 1977; 107, 758–766
• Høstmark AT, Tomten SE. The Oslo health study: cheese intake was negatively associated with the metabolic syndrome. J Am Coll Nutr. 2011 Jun;30(3):182-90.
• Kohno Y, Honma K, Saito K, Shimojo N, Tsunoo H, Kaminogawa S, Niimi H. Preferential recognition of primary protein structures of alpha-casein by IgG and IgE antibodies of patients with milk allergy. Ann Allergy. 1994 Nov;73(5):419-22.
• Laugesen M, Elliott R. Ischaemic heart disease, Type 1 diabetes, and cow milk A1 beta-casein. N Z Med J. 2003 Jan 24;116(1168):U295.
• Michalski MC. On the supposed influence of milk homogenization on the risk of CVD, diabetes and allergy. Br J Nutr. 2007 Apr;97(4):598-610.
• Oosting A, Kegler D, Wopereis HJ, Teller IC, van de Heijning BJ, Verkade HJ, van der Beek EM. Size and Phospholipid Coating of Lipid Droplets in the Diet of Young Mice Modify Body Fat Accumulation in Adulthood. Pediatr Res. 2012 Jul 31.
• Tailford KA, Berry CL, Thomas AC, Campbell JH. A casein variant in cow's milk is atherogenic. Atherosclerosis. 2003 Sep;170(1):13-9.
• Zahar M, Smith D- Adsorption of proteins at the lipid-serum interface in milk systems with various lipids. Int Dairy J. 1996: 6, 697–708.
• Zamora A, Ferragut V, Guamis B, Trujillo AJ. Corresponding author contact informationChanges in the surface protein of the fat globules during ultra-high pressure homogenisation and conventional treatments of milk. Food Hydrocolloids. 2012; 21:1, 135–143.

Phospholipid or Triglyceride? What's in Your Fish Oil Caps? Only Phospholipid Based DHA+EPA Reduces Fat Cell Growth & Elevated Insulin Levels Despite Obesogenic Diet

Image 1 (Liliyu. 2007): Look no further, DHA+EPA in phospholipid form can be found right around the corner in the salmon-sashimi at your favorite sushi restaurant, for example.

I guess you will already have heard about the "huge quality differences" of different fish oil products, the manufacturers of the more expensive products usually use to justify the price difference to the average no-name fish oil cap from your favorite bulk supplier. You may also remember a previous SuppVersity post on the obviously over-blown problem with oxidized (=rancid) fish oil (see "Some Things Fishy: Oxidized Fish Oil Totally Benign!?"), which - much to the researchers' own surprise, worked just as well as regular, fresh fish oil (Ottestad. 2011). What you will probably not have thought about before, however, is the triglyceride to phospholipid ratio of your fish oil caps (Note: While there are intact phospholipids in raw or barely cooked fish, it is almost certain that most of them are destroyed / damaged in the industrial production of fish oil from the waste products of the fishery industry).

Di- vs. triglyceride - One letter can make all the difference

In a recently published study, Rossmeisl et al. report that the administration of the exact same amount of n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), either as tri- or diglyceride+pohosphate (as they are characeteristic for all phospholipids) had profoundly different effects on the amelioration of weight gain in a 9 week HFD overfeeding study and the reversal of obesity a second trial in which mice that had been subjected to an obesogenic high fat (+hypercaloric) diet for 4 months received chow that contained a dosage of 30g combined EPA + DHA per kg. With a food intake of ~65g per day and a mean body weight of ~30g (mid-trial) this yields the following rodent + human equivalent doses (HED, calculated for 80kg body weight) for the three treatment groups and two control groups in the overfeeding experiment:

• control - regular diet
• HFD - high fat diet (HFD) w/out supplement
• HFD+30TR - HFD + 0.16g/kg EPA+DHA from triglycerides; HED ~1g / day
• HFD+10PL - HFD + 0.05g/kg EPA+DHA from phospholipids; HED ~ 0.33g / day
• HFD+30PL - HFD + 0.16g/kg EPA+DHA from phospholipids; HED ~1g / day

Contrary to their identical ameliorative effects on diet induced weight gain, elevated plasma lipids and blood sugar levels, the triglyceride and phospholipid forms of DHA and EPA exerted very different effects on plasma insulin, adipocyte hypertrophy, hepatic steatosis (beginning NAFLD) and low-grade adipose tissue inflammation.

Figure 1: Body composition and glucose metabolism after 4 month HFD diet and subsequent 9 weeks of over-feeding on diets containing either no (control=100%) or 30g/kg diet DHA+EPA; data expressed relative to control (Rossmeisl. 2012)

As you can see in figure 1 only the phospholipid form of the n-3 polyunsaturated fatty acids reduced adipose tissue growth and hyperinsulinemia. And compared to the regular triglycerides, it also had much more pronounced effects on the accumulation of fat in the liver and the exuberant inflammation in the fat stores (WAT) of the animals.

A higher bioavailability of phosphate-bound EPA+DHA is probably only part of the story

Figure 2: Plasma, liver and white adipose tissue (WAT) levels of triglyceride (TL) and phospholipid varieties of DHA+EPA after 9 weeks on HFD diet with (w3TL or w3PL) or  w/out 30mg/kg chow DHA + EPA (Rossmeisl. 2012)

This is an interesting observation and the most straight forward explanation would actually be that due to their ability to be directly incorporated into the cell membrane the phosphate-bound lipids from the -PLI groups received would have a higher affinity to be incorporated into the liver and/or adipose tissue. And while the latter was not the case (cf. figure 2) the significantly more pronounced accumulation of omega-3 phospholipids in the liver of small critters, appears to confirm this hypothesis - or, as the Rossmeisl et al. put it:

Thus, the superior efficacy of dietary LCn-3 PUFA adminis-tered as phospholipids in terms of counteracting adverse effects of developing obesity was linked to the improved bioavailability of DHA and EPA, and to the accumulation of these fatty acids in phospholipids in metabolically relevant tissues.

If you take a closer look at the data, you will yet realize that the omega-3 content of the adipose tissue (WAT) is still pretty low. Other than in the liver, where the TG/PL ratio was significantly lower, when the animals received a phospholid enriched diet, the n3 concentrations were identical for both groups. A higher bioavailability alone could thus hardly explain the pronounced reduction in WAT inflammation and more importantly the ameliorative effect on adipocyte hypertrophy the researchers observed in the in reversal study.

Additional phospholipid advantage: Greater inhibitory effect on inflammatory ligand production

A closer analysis did yet reveal different / more pronounced downstream effects of the phospholipid treatment on the occurrence of the pro-inflammatory endocannabinoids 2-arachidonoylglycerol (2-AG) and anandamide (AEA) and the production of their EPA and DHA derived anti-inflammatory counterparts N-eicosapentaenoylethanolamine (EPEA) and N-docosahexaenoylethanolamine (DHEA). The former, i.e. the reduction of 2AG had already been implicated as one of the fundamental mechanism behind the anti-inflammatory effects of krill oil by Batteta et al. in 2009 (Batteta. 2009) and does - despite its obvious efficacy raise some safety concerns, as the synthetic cannabinoid receptor 1 antagonist rimonabant, which has been used very effectively to treat obesity had to be withdrawn from clinical practice due to intolerable adverse psychiatric side effects (mostly anxiety and/or depression, cf. Moereira. 2009).

Fish is still your goto source for DHA & EPA, as trigs and phospholipids in their natural ratio!

Image 2 (animalcrossingdaily): The fishcow! Well, personally I prefer to eat fish and beef, but if you happen to hit upon one of those, I bet their DHA + EPA content is about as "monstrous" as their overall look ;-)

Whether high doses of phospholipid enriched fish oil, as they are suggested by Rossmeisel et al. as an adjunct "treatment strategy for obesity-associated disorders" that should be preferred over regular triglyceride or ethyl-ester (Lovazza) based n-3 PUFA supplements, due to their to higher bioavailability an efficiacy (Rossmeisl. 2012), would actually produce similar adverse effects is questionable. At dosages corresponding to those used in the study at hand, i.e. 1g per day(!), I would say that this is very unlikely. In view of the still prevalent advice of (pseudo-)experts to start out with at least 5g per day of EPA + DHA, I wouldn't be so sure, though, that we are not already seeing the first "victims" of scientifically unwarranted fish oil overconsumption and subsequent endocannabinoid imbalances complaining of anxiety and chronic fatigue on bulletin boards, where one of the "standard treatments" people will suggest is to "up your fish oil intake"...

For you, as a diligent student of the SuppVersity, active and healthy physical culturist, the results of this study do not really make a difference, anyway. After all, you have always been getting your weekly dose of omega-3 fatty acids from fish, the natural source of both the triglyceride and phospholipid form of DHA and EPA, and grass-fed beef or lamb (even grain-fed beef is a relatively good source of omega-3, by the way, only the ratio of omega-6 to omega-3 is usually higher; cf. Wood. 2004) - didn't you?

References:

1. Batetta B, Griinari M, Carta G, Murru E, Ligresti A, Cordeddu L, Giordano E, Sanna F, Bisogno T, Uda S, Collu M, Bruheim I, Di Marzo V, Banni S. Endocannabinoids may mediate the ability of (n-3) fatty acids to reduce ectopic fat and inflammatory mediators in obese Zucker rats. J Nutr. 2009
   Aug;139(8):1495-501.
2. Moreira FA, Crippa JA. The psychiatric side-effects of rimonabant. Rev Bras Psiquiatr. 2009 Jun;31(2):145-53. Review.
3. Ottestad I, Vogt G, Retterstøl K, Myhrstad MC, Haugen JE, Nilsson A, Ravn-Haren G, Nordvi B, Brønner KW, Andersen LF, Holven KB, Ulven SM. Oxidised fish oil does not influence established markers of oxidative stress in healthy human subjects: a randomised controlled trial. Br J Nutr. 2011 Dec 5:1-12.
4. Rossmeisl M, Macek Jilkova Z, Kuda O, Jelenik T, Medrikova D, Stankova B, Kristinsson B, Haraldsson GG, Svensen H, Stoknes I, Sjövall P, Magnusson Y, Balvers MG, Verhoeckx KC, Tvrzicka E, Bryhn M, Kopecky J. Metabolic Effects of n-3 PUFA as Phospholipids Are Superior to Triglycerides in Mice Fed a High-Fat Diet: Possible Role of Endocannabinoids. PLoS One. 2012;7(6):e38834. Epub 2012 Jun 11.  
5. Wood JD, Richardson RI, Nute GR, Fisher AV, Campo MM, Kasapidou E, Sheard PR, Enser M. Effects of fatty acids on meat quality: a review. Meat Sci. 2004 Jan;66(1):21-32.