3-4 Egg Yolks per Day May Normalize Your Lipids, Reduce Liver & Abdominal Fat as Well as Your CVD & NAFLD Risk

Three whole eggs deliver the most effec-tive "dose" of  egg yolk to improve your blood lipid levels - mores specifically: triglycerides ↓ and LDL ↓ but HDL ↑

Because of their cholesterol content, eggs have long been touted as a driver of heart disease. As a SuppVersity reader, you know that there are multiple reasons why the notion that the consumption of eggs, or rather egg yolks, would increase your cardiovascular disease risk: (a) there's no mechanistic "if your cholesterol is high, your CVD risk is also high"-link; (b) a causative link between the consumption of dietary cholesterol and serum cholesterol does not exist - at least not in the majority of people; (c) substances in egg yolks, in particular, have been shown to modulate the physical characteristics of your lipoproteins (learn more) and will thus lower, not increase your CVD risk.

Since you know all that, it may seem less important for you than your doctor and other people who may still believe that cholesterol was a dietary villain you'd better avoid altogether to read about egg yolks recently discovered ability to significantly decrease your blood lipid levels.
Ok, eventually, this preliminary study confirms the ability of egg yolks to reduce the blood lipid levels in rats, not men. Its results are yet in line with human studies (Fernandez. 2006) and case reports such as Fred Kern Jr's paper with the telling title "Normal plasma cholesterol in an 88-year-old man who eats 25 eggs a day", a paper that was published in the New England Journal of Medicine in 1991, a decade during which the number of people, let alone well-known scientists who questioned the detrimental health effects of cholesterol was low, if not zero.

Table 1: Fatty acid profile and cholesterol content of pork belly oil and egg yolk (% of total fatty acid | Park. 2016)

Today, people (including a handful of doctors and scientists ;-) acknowledge that the ingestion of eggs has been reported to lower, not increase blood cholesterol levels. In the absence of a mechanistic explanation for this phenomenon, however, large parts of the medical establishment still doubt that the anti-CVD and anti-cancer effects of eggs are driven by anything but their relatively high content of anti-oxidants. To identify the actual biochemical metabolic mechanisms by which the oral administration of egg yolk affects blood lipid reduction scientists from the Kangwon National University conducted a preliminary rodent study in which they observed similar reductions in 'bad' blood triglycerides and total cholesterol, as well as increases in 'good' high-density lipoprotein cholesterol as they were observed in the egg eating minority of human subjects in epidemiological studies.
This alone may not sound exciting enough for yet another rodent study to make it into the SuppVersity news. What is exciting enough, though, is the fact that the study is the first study to include another high cholesterol product in a control diet: pork belly oil - an "egg yolk analogue" that has a similar, but not identical fatty acid content as egg yolk (see Table 1); and here's how the study that obviously had a saline control group, as well, worked:

• rats were fed, ad libitum, a purified pellet diet and drinking water for 6 weeks, and egg yolk or other treatments were orally administered every day at a fixed time;
• the amount of egg yolk / pork belly oil, namely 5mg/kg, i.e. the human equivalent of approximately 3-4 egg yolks, had been determined based on data from preliminary experiments in which the authors found that this was the amount of egg yolk where the blood lipid lowering effects plateaued (i.e. didn't increase further, when more egg yolk was fed);
• feces, blood, weight and food intake were measured and/or analyzed daily / weekly;
• liver and abdominal fat were determined at the end of the 6-week study

The rats' food intake was examined every 3 days. Their body weight was measured once per week. Based on this data the so-called "diet efficiency" was calculated as the ratio of the diet intake to the daily average body weight gain (diet intake/body weight gain).

Figure 1: Body weight gain and diet intake of rats after oral dosing of egg yolk (Park. 2016).

As you can see in Figure 1, the latter, i.e. the "diet efficacy", was significantly higher for the pork-belly oil group (T2) in which the rodents gained significantly more body weight, even though they had a (likewise significantly) reduced food intake.

Beyond cholesterol: weight and body composition improve as well

Against that background, it is not really surprising that the animals "pork belly group" had also accumulated more abdominal and liver fat than those who were fed with egg yolk and ended up being a non-significant 10% leaner (as in having 10% lower abdominal fat masses) than their peers who received nothing but slightly salted water (saline placebo) on top of their std. rodent diet.