T Nation

Egg Yolks question

This is aimed at John Berardi, but I’d appreciate any feedback. The average cholesterol content of one egg yolk according to many sources I’ve read is around 350mg…which also according to some sources is the upper limit of cholesterol one should consume per day. However, I also understand from reading many t-mag articles that some cholesterol intake is very important for maintaining one’s natural testosterone levels. So, my question is this – what have studies indicated regarding the direct correlation between eating whole eggs and a rise in blood cholesterol, especially LDL.

Thanks in advance to whomever can clue me in here…

E: Great question…and one that the margarine and trans-fat industry has totally confused the public on for literally decades.

1)DIETARY intake of cholesterol has little effect on our blood cholesterol level; lipid metabolism (especially the hyper-lipidemias) are overwhelmingly dependent on genetics. The majority of the cholesterol in out blood is manufactured by the body, NOT ingested. Even those with true hyperlipidemias find that cholesterol levels are affected little by diet. Medications are often required for treatment.

2)Recent revelations have shown that the real culprit in heart disease is not the cholesterol we injest, but the high level of trans-fatty acids found in processed foods, margarines, vegetable oils and the like. It is MUCH healthier to eat whole eggs (with all kinds of nutrients, including lecithin) than to eat some bagel or ear of corn smothered with margarine.(can you believe that for years these types of things have been pushed as being “heart healthy?”)

So…eat your eggs (especailly the Omega-3 enhanced)…exercise (to increase your level of HDL or “good” cholesterol)…and above all…dramatically decrease your ingestion of trans-fatty acids!

Hope this helps!

I just wanted to give a little more info on what I think is a VERY important topic for the health conscious

1)TRANS fatty acids (created by the hydrogenation of vegetable oils to make them “hard” and thus more shelf stable) are not metabolized efficiently by the body. They create havoc for the bodies enzyme systems. Because of their “foreign” configuration, they become “rancid” within arteries, and in an attempt to metabolize them, the body produces enormous amounts of free radicals, thereby damaging very delicate arterial walls. The problem? The margarine, processed food, vegetable oil (corn and soy especially) and Hydrogenated Oil (as additive) industry is multi-billion dollar in scope. And what they push is killing us as readily as cigarettes.

2) What should we do? a) Avoid margarine, processed foods, “hard” vegetable oils and any processed oils. b)Increase your consumption of NATURAL Omega 3 oils, flax, Olive, etc. c) Don’t be afraid to consume eggs (WITH occasional yolks; remember they WON’T significantly increase your cholesterol AND the yolk contains artery-friendly lecithin). d) DON’T be afraid of consuming saturated fat (as is in animal meats) but in moderation. e) Make fresh water “fatty fish” a welcome staple to your diet (e.g. Salmon) and f) EXERCISE!

The food industry may hate you…buy your heart and arteries will thank you!

Peace. Mufasa

Like so many questions asked on this forum, the answer to your inquiry has already been provided. Go to http://t-mag.com/articles/195bio.html (remove any spaces) and read the first “noteworthy presentation.”


I’m not sure who bumped or this or why but I’m quite sure John won’t be adding anything.

Mafusa is right. Is there additional information you are looking for?

A few points to consider.

  1. I agree that choesterol intake isn’t the most important factor, and other factors are - TFA, fiber, saturated fat, etc, but it is important, as specifically to the person’s question, as egg cosumption drops, LDL decreases (AJCN last yr or 2000). Probably as with anything, there is a polymorphism for the trait. Saturated fat in the yolk may contribute to this response since saturated fat decreases LDL receptor abundance and stimulates HMG-COA red.
  2. You have underestimated the power of diet on cholesterol levels. Look up Esselstyn, Ornish, Barnard and Castelli on Pubmed. Specifically Barnard published a paper in A J Card in '97 which showed a 20% reduction in total cholesterol with drug therapy. 3 weeks of subsequent diet and exercise therapy reduced total choelsterol an additional 20%. Thus, the subjects cholesterol dropped from 276 to 178 with drugs + 3 weeks of diet.

One egg has about 200 mg of cholesterol and the average person absorbs around 50% of dietary cholesterol (J. Lipid Research last yr).

Good luck

I also remember that even the studies that found a supposed correlation between egg yolks and cholesterol (and thus, purportedly, heart disease) also found that high-intensity exercise negated the effect. So even if you believe the old studies, if you exercise you’re okay.

On a personal note, I eat eggs almost every day, sometimes up to 10-12 per day, have for decades, and while not all of them include the yolks (I’m with Dorian Yates on liking the amino acid profile of “some” yolks combined with a bunch of whites), it’s still enough to give an 80’s nutritionist a good internal hemmorage at the very idea. And I’m fine. Cholesterol is genetically determined to an overwhelming degree. Don’t let anyone tell you differently.

Thanks, Prof!

Were the people in the studies individuals with various forms of hyperlipidemias?

The other point that is hotly debated by many is this: Do you reduce the incidence of Cardiovascular disease merely by reducing cholesterol levels, or is it by significantly decreasing the Tran-Fatty Acids in the diet and exercising? Recent research suggest the latter…

Facts like this one from Berardi’s article tend to make me think it’s not all about cholesterol levels:

“• While the current North American cardiovascular disease paradigm is centered on blood cholesterol management, cholesterol can’t account for the declining CV health of the people. In fact, there is no difference in blood cholesterol levels between North Americans and the Japanese, but North Americans have a 626% higher CV disease mortality rate!”

Just one more thing to think about.

Thanks for the replies. I had fully researched all the material presented in t-mag regarding cholesterol, as well as cholesterol/egg information from other sources, I was just looking for more information or a nod towards any angle I had not yet researched. It seems that from everything I’ve read, the ‘dangers’ of egg consumption are highly overrated, but it also does not seem that all questions are answered. Of course, when are they ever answered fully in nutritional science?

Prof R – thanks. Unfortunately, the addition of drugs to the study diminishes the relevance, plus, as SteelyEyes pointed out in the quote from the Berardi article, it seems that a definite correlation between cholesterol levels and cardivascular disease has not been adequately proven…not to mention the whole ‘correlation is not causation’ paradigm. I eat several of the Omega-3 enhanced eggs a day, and I’m not going to worry about that consumption for the time being especially given my activity level, and that’s based largely on Berardi’s information…however I will keep my eyes open for all relevant research.

I wonder if there are studies involving egg yolks as the only significant fat source for an extended period of time.

Still searching, but thanks for the responses…

E: Boy…wouldn’t it have been GREAT if the Framingham Studies could have had two “arms”, with one showing the long term effects of reducing and/or eliminating Trans-Fatty acids from the diet? (Considering that it is SUCH a big buisness, either the studies would have been “snuffed out” or funding would have been difficult…just more a thought more than anything…).

Maybe this type of long-term study will be done some day.

Very true…fortunately I really watch trans-fatty acids closer than probably any other one thing in my diet. Plus, I have an extreme superstitious fear of any ‘food’ product that requires the invention of a new word or string of words to describe it, especially if that name has more sylables than your average Barenaked Ladies song…

Recent evidence points out that cholesterol may act as an anti-oxidant and that is why it tends to rise with age. My grandma is 92 years old and has had a level of 400 for the last 40 years with no health problems except for a broken hip and arthritis that caused her to retire at 81 from a day labor job. Polyunsaturate intake at high levels initially can lower serum cholesterol levels as their nature is to make cells less stable than saturates: Cholesterol is transported from the blood to other parts of the body as a protective agent. George Mann, one of the original directors of the Framingham study made a statement to the effect that the higher the dietary intake of cholesterol and saturated fat the less of a correlation to heart disease. After he left he went over to Kenya to study the effects of diet on the Masai. He found that with daily intakes of as much as 400 grams of saturated fat the Masaai on their traditional diet of raw Milk (soured), blood, butter and some meat, expierence very little heart disease, and their blood cholesterol levels are usually in the middle 100’s. Also, low amounts of Cholesterol have been correlated with depression, suicide, strokes, and violence. Speculation is that cholesterol affects serotonin receptors in the brain.

I just had my cholesterol level checked by my doctor. My total cholesterol is 72, and I eat nine egg yolks a day (12 eggs total). I haven’t seen any study that shows that dietary cholesterol increases blood cholesterol.

DAMN! 72? I think my sweat has more cholesterol! Does that type of thing run in your family? If not, do you think there are other factors in your diet and exercise which might contribute to such low levels?

The subjects did not have any genetic hyperlidemias. The majority have elevated cholesterol because of the gene-diet interaction, probably resulting form polymorphisms in genes regulating choelsterol metabolism. As you know, some people can eat a lot of choelsterol and their blood levels don’t change much.

(Do you reduce the incidence of Cardiovascular disease merely by reducing cholesterol levels, or is it by significantly decreasing the Tran-Fatty Acids in the diet and exercising?)
This is not easy to answer, simply because studies in humans that decrease choelsterol intake, usually also decrease saturated fat and thus you don’t know the relative importance of each. My guess is that decreasing TFA alone will improve the lipid profile, and recent studies suggest that ingesting them increases CAD risk (Arterioscler Thromb Vasc Biol 2001 Jul;21(7):1233-7). So TFA are probably more important than choelsterol consumption, but lowering both is better. Something else you may find interesting is that insulin can regulate plasma lipids and so lowering refined-carbohydrate intake can improve the lipid profile. Whether this is independent of the effects of fiber is not known. This is why studies using a step I AHA diet see an increase in TG - they use refined carbohydrate. However using unrefined carbohydrate eliminates this response.

The authors I mentioned have shown the same response in the absence of drug therapy (Barnard, R. J. Effects of life-style modification on serum lipids. Arch Intern Med 151: 1389, 1991)
For the quote mentioned, yes its a multifactorial disease, but cholesterol is important and actually CV health is improving, not declining. Why? we don’t know yet, probably better therapies, etc.

Forgot to leave a reference. In Assmann et al Arterioscler Thromb Vasc Biol. 1999;19:1819, 1999 they discuss the clinical trials that have shown that cholesterol lowering decreases CAD.

For the one with a cholesterol of 72, you are the exception, thank your parents and that is impressive!