Mayo Without Eggs? Must be the Mayo Clinic!

Eggs. People either fear them or think they are egg’cellent. Okay okay I won’t egg you on with anymore puns (oops!). In any case, TheFatNurse has parents who seem to think egg yolks are heart attacks waiting to happen due to the cholesterol content. Even the respected Mayo Clinic agrees, eggs should be limited via the 300 mg per day rule.

“One large egg has about 186 mg of cholesterol — all of which is found in the yolk. Therefore, if you eat an egg on a given day, it’s important to limit other sources of cholesterol for the rest of that day. Consider substituting servings of vegetables for servings of meat, or avoid high-fat dairy products for that day.”

“Although eating too many eggs can increase your cholesterol, eating four egg yolks or fewer on a weekly basis hasn’t been found to increase your risk of heart disease.”

Wait is their suggestion to max out on 4 eggs a week? TheFatNurse sometimes eats 4 eggs just for breakfast! More importantly, TheFatNurse thought it caught the Mayo Clinic in the shackles of irony since “The Mayo Clinic Diet” has eggs as the main part of its diet!

“The origins of the Mayo Clinic diet are unknown and, as the prestigious Mayo Clinic has declared time after time, this diet has nothing to do with them. The diet’s main component is egg, since it advises the consumption of between 4 and 6 a day “

Alas…that would have been too easy…but there still is irony yet! After all, what is one of the main components of Mayo…EGGS!

So where did this idea of egg consumption being harmful come from? It all goes back to the controversial but often accepted medical “fact” of the lipid hypothesis where eating saturated fat raises cholesterol and cholesterol causes heart disease. For a brief history see below:

So what does some of the current medical literature say on egg consumption?

“Several studies have examined egg intake and its relationship with coronary outcomes. All but one failed to consider the role of other potentially confounding dietary factors. When dietary confounders were considered, no association was seen between egg consumption at levels up to 1+ egg per day and the risk of coronary heart disease in non-diabetic men and women”

From the Journal of the American College of Nutrition *TheFatNurse only read the abstract

“Multivariate models adjusting for health, lifestyle and dietary factors indicated that ‘high’ egg consumption (7 times/week v. ,1 time/week) was not associated with significantly increased CHD mortality (HR51?13, 95% CI 0?61, 2?11 (men); HR 5 0?92, 95 % CI 0?27, 3?11 (women)…We did not find a significant positive association between egg consumption and increased risk of mortality from CHD or stroke in the US population. These results corroborate the findings of previous studies.

From Public Health Nutrition *TheFatNurse only read the abstract

“During a median follow-up of 6.1 years, 91 new confirmed cases of CVD were observed. No association was found between egg consumption and the incidence of CVD (HR: 1.10, 95%confidence interval: 0.46–2.63) for the highest versus the lowest category of egg consumption

From the European Journal of Clinical Nutrition *TheFatNurse only read the abstract

there is little evidence from epidemiological studies for associations between dietary cholesterol or the consumption of cholesterol rich foods and cardiovascular disease risk, or from intervention trials for major effects of dietary cholesterol on blood cholesterol levels. By contrast, evidence is emerging from epidemiological studies that consumption of eggs is associated with cardiovascular disease in diabetics, and from intervention trials that dietary cholesterol has greater effects on blood cholesterol levels in insulin resistant people. Since insulin plays a role in cholesterol homeostasis, these are not surprising findings.”

From Lipid Technology *TheFatNurse only read the abstract

“Our analysis shows that the combination of modifiable lifestyle risk factors accounts for less than 40% of the population CHD mortality. For the majority of U.S. adults age 25+, consuming one egg a day accounts for <1% of CHD risk. Hence, focusing on decreasing egg intake as an approach to modify CHD risk would be expected to yield minimal results relative to changing other behaviors such as smoking and other dietary habits.”

From Risk Analysis *TheFatNurse only read the abstract

The European countries, Australia, Canada, New Zealand, Korea and India among others do not have an upper limit for cholesterol intake in their dietary guidelines. Further, existing epidemiological data have clearly demonstrated that dietary cholesterol is not correlated with increased risk for CHD. Although numerous clinical studies have shown that dietary cholesterol challenges may increase plasma LDL cholesterol in certain individuals, who are more sensitive to dietary cholesterol (about one-quarter of the population), HDL cholesterol also rises resulting in the maintenance of the LDL/HDL cholesterol ratio, a key marker of CHD risk… The lines of evidence coming from current epidemiological studies and from clinical interventions utilizing different types of cholesterol challenges support the notion that the recommendations limiting dietary cholesterol should be reconsidered.

– From Current Opinion in Clinical Nutrition & Metabolic Care *TheFatNurse only read the abstract

“While dietary cholesterol, of which egg yolks are a major source, was once thought to play a primary role in determining plasma cholesterol levels, and therefore CHD risk, scientific opinion appears to be shifting to the belief that it may have a negligible effect in most healthy people.

– From Today’s Dietician

Bottom Line: TheFatNurse thinks you get the point. There are plenty of  studies you can find showing the association between eating one egg or more daily and heart disease being murky.  So does this mean you should go out and eat eggs for breakfast, lunch and dinner while downing egg nog and ramos fizzes in between? No of course not! That’s GROSS! However, egg consumption could be an interesting topic to bring up with your primary care provider who would know you, your physiology and any underlying pathologies you may have if egg consumption worries you. Some pathologies such as insulin resistance may make high egg and dietary cholesterol harmful as suggested by some studies.

To be fair, lots of the studies considered 1-2 eggs a day as a high daily egg consumption. If one were to just eat only 1 egg and adjust for the 300 mg daily allowance as the Mayo clinic suggests then you will still be within their guidelines even with them quoting 4 eggs a week or less from studies. TheFatNurse only selected the Mayo Clinic as a source of standard egg guidelines because TheFatNurse likes the taste of mayo. The egg topic is more of a primer to ask an even grander question: Is it really clear that cholesterol causes heart disease?

WHAT…I know…this was probably your response:

Just keep an open mind! Read some of TheFatNurse’s cholesterol related postings, browse some of the links in the Dispatch section. Need something visual first to open your mind? Take a look at this graph from the famous Framingham Study:

Unless they had hypercholesteremia, coronary heart disease effected people almost at the same rate despite their cholesterol levels

Intrigued? Browse some past and future cholesterol related postings, check out the Dispatch link or view this University of South Florida video which does a pretty good general overview of the controversy of cholesterol (you do not have to agree with his diet choice per se, just listen to the references he brings up on cholesterol):

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