"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.

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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.