Wednesday, October 3, 2012

Particle Size & LCAT Analysis Shows: Three Whole Eggs per Day Improve Lipid Profile in Men & Women W/ MetSyn. Plus: Up to 700% Increased Lipid Oxidation in Hardboiled vs. Fresh Omega-3 Eggs From Hens on Fish Oil Enriched Diet

"Not the yellow part of the egg!", is the literal translation of "Nicht das Gelbe vom Ei!", which is German and means "not exactly brilliant" - telling isn't it?
As a regular here at the SuppVersity you will probably have come across a line like "make sure to get at least 20g of quality protein (meats, poultry, eggs, fish, dairy) with every meal!" at least once. If we discard the fish, which is, outside of the occasional discussions about mercury and other heavy metals in our food chain, about the only of these highly nourishing foods, the various experts appear to agree is healthy for you, all of them are to be consumed only "on occasion", "in moderation" and preferably in their "lean" or "low-fat" varieties. And while you (should ;-) have read about the beneficial effects of full-fat dairy, yesterday, and about the actually not so bad "bad meats" in the "Meat-O-Logy" post from August 17, 2012, I thought I'd take the forthcoming publication of a paper by Christopher N. Blesso, Jeff Volek et al. as incentive to remind you not to make the mistake and flush the yolk, the best part of the egg, down the toilette.

Recipe for disaster? Take 20 men and women with metabolic syndrome, 5040 whole eggs...

With 40 men and women aged 30–70 years who had been classified with metabolic syndrome the researchers from the University of Connecticut and University of Antioquia in Medellin, Columbia, intentionally picked a representative sample from the ever-increasing number of people with metabolic syndrome for their 12-week dietary intervention trial. I mean, who if not the men and women in this high risk group should suffer from the negative side effects of the cholesterol-laden yellowy, orange-yellow heart killers in disguise?

AHA Definition of Metabolic syndrome
according to Grundy. 2004
Abdominal obesity (waist)
  Men >102 cm
  Women >88 cm
Triglycerides≥150 mg/dL
HDL cholesterol
  Men 40 mg/dL
  Women 50 mg/dL
Blood pressure≥130/≥85
Fasting glucose≥110 mg/dL
The assumption that subjects with established metabolic syndrome (for the "official" criteria check out the table on the right) is however one of the very few things the study at hand and studies like the one that triggered such an upheaval in August (see Sciencedaily. 2012) have in common. Instead of relying on total, low density and high density lipoprotein levels in the sera of their study participants, Blesso et al. conducted a differential analysis that included paricle number, size (measured by nuclear magnetic resonance spectroscopy), apolipoproteins (apos), oxidized LDL (oxLDL), cholesteryl ester transfer protein (CETP) and lecithin-cholesterol acyltransferase (LCAT) activities at baseline and after 12-weeks on a carbohydrate-restricted diet (25%–30% energy) that contained either  3 regular whole eggs/day (EGG, n = 20) or the volume equivalent in form of a yolk-free egg substitute (manufactured by Sysco Corporation, Houston, TX).

Accordingly, the subjects in the "real egg group" (EGG) consumed approximately 534 mg cholesterol, 0 g carbohydrate, 16 g protein, 12 g fat per day (186 kcal) from hole eggs, while a single serving of the cholesterol and fat-free substitute (SUB) contained approximately 2 g carbohydrate, 14 g protein, no fat, no cholesterol and only 60 kcal.

To minimize possible confounding factors and allow for "blinding" (you can't tell me you don't taste the difference between egg whites and whole eggs, but alas...), the eggs / egg supplements were prepared in advance.
"Compliance was monitored by use of weekly questionnaires and collection of empty product containers. Participants were asked to maintain their normal physical activity, medications, and dietary supplement usage upon starting the 12-week study." (Blesso. 2012)
To be able to track the dietary intake of the subjects, all participants had to fill out 5-day dietary intake records (3 weekdays + 2 weekend days) at baseline, week 6 and week 12 of the study period. Based on the analysis of the respective data, the scientists determined that
  • increased relative protein intake from 17.3%± 3.0% to 23.9%± 4.1%
  • increased relative fat intake from 38.6%± 6.4% to 45.7%± 7.4%
  • reduced total energy intake of -24% for all participants
  • reduced relative CHO intake from 40.9 ± 7.4 to 28.3 ± 9.5% of total energy 
  • reduced absolute CHO intake from 211.9 ± 51.8 to 114.5 ± 55.0 g/d 
Moreover, there were "significant differences between groups for dietary cholesterol intake (EGG vs. SUB, P < 0.0001) and dietary choline intake (EGG vs. SUB, P < 0.0001)"
  • Δ cholesterol intake +106% in EGG vs. -38% in SUB
  • Δ choline intake +52% in EGG vs. -12% in SUB
In that, it is important to point out that these changes and their metabolic effect should not be seen in isolation, because choline plays a major role in the metabolism, transport and incorporation of cholesterol into the cell membrane (read more about choline in "Old School Supplements - Choline: Stronger, Faster, Leaner & More Muscular, or Just Another Dumb-and-Barbell Story?").

"So, the men and women in the egg-group did not die?"

Not exactly, no. Rather than being as bad as cigarettes (as the aforementioned "study" that was published roughly 2 months ago would make us believe; Spence. 2012), the consumption of three eggs per day lead to rather favorable changes in the lipoprofile of the EGG consumers:
Figure 1: Lipoprotein serum levels (left), particle size and ratio of LDL to HDL count (right) of the 37 participants who completed the 12-week trial (data expressed relative to baseline; calculated based on Blesso. 2012)
Contrary to the lipoprotein metabolism, which showed differential (and general positive) effects in response to whole egg consumption, the reductions in circulating insulin, HOMA-IR and triglycerides did not show statistical significant inter-group differences:
  • triglycerides: -29% vs. -18%
  • insulin: -21% vs. -14%
  • HOMA-IR: -22% vs. -18%
The existing changes were yet on average still somewhat more pronounced in the EGG group, which is an observation you could interpret as joint effect of low carb dieting + egg eating.

The same goes for the increase in LCAT activity the researchers observed only in the EGG group. Since LCAT is critically important in facilitating HDL particle stability and HDL maturation, its elevation in the EGG group
"[...] could be indicative of an enhanced capacity for HDL maturation and may help explain the shift towards larger HDL particles seen with egg feeding" (Blesso. 2012; my emphasis)
and would thus favor enhanced HDL-mediated reverse cholesterol transport from (e.g. the endothelium of your coronary heart arteries) back to the liver.

What about the lipid oxidation?
If we assume that part of the negative effects that have been ascribed to the consumption of egg(-yolks) are brought about by oxidized fatty acids and respective byproducts, it appears wise not to hard-boil your eggs, because the prolonged heat exposure during hard-boiling increases the oxidation of fatty acids. Aside from temperature and duration of the heat exposure, Cortinas et al. also identified the fatty acid composition of the eggs and their vitamin E content as crucial factors that will influence the formation of oxidized lipids. Since the fatty acid composition of the eggs depends on the diet the hens are fed, you would be particularly ill-advised to hard-boil eggs from hens who were fed a diet enriched in fish oil.
As you can see in the figure above the "fish oil eggs" with their readily oxidized long-chain PUFAs had by far the highest  TBA values (expressed as ng MDA/g dry matter) - specifically, if the hens did not receive additional vitamin E that would be transfered to the eggs and reduce the heat-induced oxidation of the long-chain PUFAs in the "omega-3 eggs" during cooking.
So what's the verdict? In conjunction with the aforementioned additive effects on glucose management and the slightly more pronounced decrease in oxidized LDL (both are probably rather a result of the -12% reduction in carbohydrate content of the participants' diets than the effect of the eggs), the statistically significant improvements in LCAT activity in the EGG eater group speak in favor of the notion that three whole eggs a day will still help you keep the doctor away. Whether they will suffice to throw his statins away, as well (see "Eat Whole Eggs All Day and Throw Your Statins Away?"), will yet have to be elucidated and appears overall questionable - and this goes regardless of whether you belong or don't belong to the relatively small subgroup of people who actually benefit from taking a statin, or not.

What stands out of question, however, is that the "side effects" of three egg yolks per day are quite distinct from those of cigarettes, the consumption of which the headline of the aforementioned ScienceDaily.com article implicitly equates with "egg yolk consumption". And just like smoking and eating eggs are two very different pairs of shoes, there is a huge difference between this well-controlled trial, on the one hand, and the undifferentiated observational hokum that got Spence et al. so much media attention back in August, when they concluded "Our findings suggest that regular consumption of egg yolk should be avoided by persons at risk of cardiovascular disease." (Spence. 2012), on the other hand.

References:
  • 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.
  • Cortinas L, Galobart J, Barroeta AC, Baucells MD, Grashorn MA. Change in α-tocopherol contents, lipid oxidation and fatty acid profile in eggs enriched with linolenic acid or very long-chain ω3 polyunsaturated fatty acids after different processing methods. J. Sci. Food Agric. 2003; 83: 820–829.
  • Grundy SM, Brewer HB Jr, Cleeman JI, Smith SC Jr, Lenfant C; American Heart Association; National Heart, Lung, and Blood Institute. Definition of metabolic syndrome: Report of the National Heart, Lung, and Blood Institute/American Heart Association conference on scientific issues related to definition. Circulation. 2004 Jan 27;109(3):433-8.
  • ScienceDaily. Egg yolk consumption almost as bad as smoking when it comes to atherosclerosis, study suggests. August 13, 2012 < http://www.sciencedaily.com­ /releases/2012/08/120813155640.htm > accessed on October 03, 2012.
  • Spence JD, Jenkins DJ, Davignon J. Egg yolk consumption and carotid plaque. Atherosclerosis. 2012 Oct;224(2):469-73.

25 comments:

  1. There's so much great info on this site, but I have yet to make it reading through an entire post. Too many muddled, run-on compound sentences, poor grammer, and undisciplined use of all sorts of bolding, italics, underlines, all CAPS, acronyms, etc.

    And I say this (as) Male with BMI± 55.0 % and (EGG, n = 20) DIETARY habits!!!

    ReplyDelete
    Replies
    1. I am not sure where the citation comes from, but I see the point. I did skip the italics and bolding for some time and got the exact opposite feedback that people did not like to read everything and would prefer some orientation to "hop around"

      I will stick to less mark-ups and try to make shorter sentences without the typical German "run-on compound sentences", but since I am actually always in a hurry putting these things together I can't promise there won't be no glitches in the future

      Delete
    2. Thanks for response.

      My citation was meant to be satirical (though I'd have to say it's the compound sentences, with missing punctuation and loose grammar, that's the main issue.)

      Lastly, one more constructive comment and and question. You mention in the headline that hard-boiling actually increases oxidation with Omega-3 eggs. Comment is that there's no discussion in the body of the post (would seem warranted if it appears in headline, and also because it's an inherently provocative idea.) How could hard-boiling cause more oxidation than scrambling--seems very counter-intuitive? Is there some unique property of Omega-3's that causes this?

      Delete
    3. yeah, it actually is... I will add a couple of sentences. To explain that - hold on (today I happen to have another 30min ;-)

      Delete
    4. quote: [the exact opposite feedback that people did not like to read everything and would prefer some orientation to "hop around"]

      I'd agree with that about the bolding being good. I suggest a poll of the readers sometime to see which side has more people.

      As far as the rest, I'd suppose that spending time and effort to straighten out the spelling and grammar would only backfire - because that mental effort would only interfere with the natural flow of getting the ideas out.

      Also, IMO organizing the references into a list might unnecessarily be taking up a lot of your time. Even though it looks more sciencey, the old clickable inline way was superior.

      Delete
  2. You know, I don't normally like to talk about format issues, but as Charlie said, I find the same thing to be true for me. I often find myself losing track and just skipping around too much.

    In the days of the internet where people like to bash others, I hope that doesn't come off wrong.

    ReplyDelete
    Replies
    1. I can live with constructive criticism, don't worry - for more, please read the comment above

      Delete
    2. I've been wanting to comment on some of these issues myself but haven't for fear of seeming too negative.

      I love the content on this site, but reading these articles is difficult. As someone else pointed out, run-on sentences that meander about are quite challenging to follow and often leave me just skimming for conclusions.

      Regarding formatting, there are a couple simple fixes you could make that would make the articles easier to read (and would probably make the long sentences easier to deal with):

      1. Pure black text on a pure white background is hard to read. Consider either making the text less dark or the background less bright.

      2. Get rid of the justified text, it is notorious for being difficult to read on electronic devices.

      Some references:
      http://www.rnib.org.uk/professionals/webaccessibility/articles/Pages/justified_text.aspx
      http://uxmovement.com/content/6-surprising-bad-practices-that-hurt-dyslexic-users/

      Delete
  3. I stopped buying omega-3 eggs because it honestly seemed kind of weird. I eat some form of fish for at least one of my meals everyday (usually sardines), and I take 1-2 tsp of cod liver oil. Whenever I eat eggs they are hard-boiled though because I have a machine that steams them while you wait (much more convenient then actually boiling).

    On a side note, maybe add a quick red info box (if you have spare time) about cooked vs. raw eggs (i.e. albumin, egg whites, and biotin, protein bio-availability, etc.). I think it might be an insightful little piece for the Bros who still chugs raw eggs.

    ReplyDelete
    Replies
    1. The old phrase was "why do I have to run my O3 through a chicken?"

      For anyone who is interested, here are two absorption studies to throw into the pot:
      http://jn.nutrition.org/content/128/10/1716.long
      Digestibility of Cooked and Raw Egg Protein in Humans as Assessed by Stable Isotope Techniques

      http://ajpgi.physiology.org/content/277/5/G935.full
      Amount and fate of egg protein escaping assimilation in the small intestine of humans

      (I probably got those from somebody here.)

      Delete
  4. [b]BE BOLD![/b] but whatever you do, never stop! :)

    ReplyDelete
  5. Thanks for your grateful informations, this blogs will be really help for Science news.

    ReplyDelete
  6. Dr Andro's command of English is truly impressive. Occasional sentences can be rather "Teutonic" in structure but the information content is very high. I can't watch science programs on TV any more because they are such thin gruel. I'm too used to gulping in hecatombs of data from blogs like this one.

    Most off all his graphs are really impressive. He has the consistently best graphs of all the nutritional science blogs I read.

    ReplyDelete
    Replies
    1. Agreed! Personally, I rather like the writing style! My wife is not a native English speaker, and I can't learn a second language to save my soul, so I am doubly impressed!

      Delete
    2. I agree too. I like his writing and despite a few run-on sentences here and there, the clarity is great once you get used to his writing style.

      I really like the take home message summaries at the end of the post as well as his references. Too many blogs leave the latter out and only tell half the story.

      Keep up the work Dr. Andro! Been reading since 2010!

      Delete
  7. Guys... instead of being worried about oxidation & co... cook just the egg-white (for improved digestion and less avidin) and eat the yolk RAW, as it is supposed to be. :)

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  8. 25 minutes steam cooked in the rice cooker... 36 eggs done. Easy peasy.

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  9. I seriously don't think eggs is good for anyone. Read why i said so here: http://www.facefinal.com/2012/07/how-do-we-get-cholesterol.html

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  10. Eggs should really not be eaten. You can find out for yourselves here: How do we get cholesterol

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    Replies
    1. That website has to be the most inaccurate load of s**t I have ever read. With all due respect, eggs are one of the best things you can eat in terms of protein quality, vitamin & minerals (choline anyone?), and healthy fats. Also, your body is amazing at self-regulation: as your cholesterol intake increases, your liver makes less and vice-versa.

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    2. I dont think you understand what is written on that website. The post on that website is for people who want to be healthy!

      Delete
  11. In the interests of fairness, it should be mentioned that Volek is an avid LC advocate. AFAIK, he has at least one LC book out, he is on some Atkins Science Board, and he even does a commercial for some sports drink (called something like UCAn). Does that mean he is incorrect? No, but it certainly does mean he's not neutral.

    Does he get any money from the Egg Board?

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  12. Thanks for this posting!
    Nice & very informative blog.
    Particle Size Analysis System is used to obtaining real size and shape measurements with results that are accurate, reliable and reproducible.

    ReplyDelete