Eggs and health – what does the research show?

The egg industry is winning the PR war with “new science” designed to rewrite egg nutrition with a positive spin. We’ll expose some of the strategies the “new science” uses to design research that finds no adverse effects from egg consumption and take a closer look at what’s in an egg and how this may affect your health.

Egg nutrition facts:

  • No dietary fibre or resistant starch
  • 2/3 of the calories are present as fat
  • 30% of the fat is saturated
  • Relatively low in omega 3 fats (except for omega 3 enriched eggs)
  • Very high cholesterol content
  • High choline content leads to elevated blood TMAO levels
  • Amino acid composition optimised for growth, not health
  • Low in the antioxidants, lutein and zeaxanthin, that are spruiked as a health benefit.

Dietary fibre, including resistant starch, is a prerequisite for a healthy gut microbiome. Eggs have none. (See The Hungry Microbiome video from CSIRO to understand the role of resistant starch in supporting gut health).  In contrast to undigested starch, egg protein breaks down in the colon to produce toxic products such as hydrogen sulphide (known as ‘rotten egg gas’). High fat foods, like eggs, also lead to increased production of secondary bile acid which are carcinogenic.

TMAO (trimethylamine-n-oxide) is a newly recognised artery toxin that works with cholesterol to promote heart disease (see Tang et al 2013). Eggs are a rich source of the nutrient choline, which the gut microbiome of non-vegans metabolises into TMA (then converted to TMAO as it passes through the liver). The egg industry know about this issue and have attempted to shift the blame by funding research to show that eating fish leads to a rapid increase in blood TMAO levels (see Cho et al 2017).

Eggs are very high in cholesterol and this does raise blood cholesterol levels, up to a point where the body approaches a limit on how much dietary cholesterol can be assimilated into the blood, after which further increases in dietary cholesterol have less effect. Saturated fats are worse for raising blood cholesterol and most health authorities recommend that dietary saturated fat be limited to less than 10% of calories. Eggs far exceed this limit.

The claim that eggs are good for eye health because they contain the antioxidants, lutein and zeaxanthin, is ridiculous. Eggs, like other animal products, contain minimal protective plant nutrients and you would need to eat nine eggs to get as much lutein and zeaxanthin as one spoonful of spinach.

Eggs have been promoted as a perfect protein, despite being 2/3 fat by calories, because egg protein matches our own body’s essential amino acid requirements. That may be a good thing if you are trying to maximise growth with the least amount of protein possible but that’s not our situation. The research of T. Colin Campbell and others has shown that these ‘high quality’ animal proteins promote cancer growth. The high sulphur containing amino acid content of eggs (think rotten egg gas) and other animal proteins is also a problem for bone health and kidney function.

We hope that you are beginning to understand why oats are a better breakfast choice than eggs.

Eggs and disease risk:

  • Increased mortality compared to plant proteins
  • Increased cancer compared to plant proteins
  • increased risk of diabetes, and increased CVD risk for those with diabetes
  • increased risk of dying of prostate cancer

Egg industry funded research:

The egg industry has continued to pour money into revising the relationship between dietary cholesterol intake and blood cholesterol levels – this is demonstrated by the proportion of research funded by the USA egg industry: in 1992 industry funded 29%, in 2001 it was 41% and by 2013 it was 92%.

The egg industry funds research and promotes favourable findings to health professionals and the public. Often, the only favourable finding is that eggs were not demonstrated to have any adverse effects. Common strategies for designing such research is: compare eggs to other animal products, restrict calories during the research, select what is measured (not TMAO for example) and use subjects who are already ‘maxed out’ on high fat animal products.

Now imagine you are a researcher and your task is to design a study that shows eggs don’t raise blood cholesterol (much). You select your study subjects carefully – you don’t select healthy normal weight people with low blood cholesterol levels, rather you select overweight people with high cholesterol. Next you choose the baseline study diet to make sure that it is already maxed out in foods that raise blood cholesterol. After your research results are accepted for publication you can relax while your findings are widely publicised to doctors, dietitians and the public. Your research has become part of the “new science” that is debunking decades of consistent research demonstrating the link between heart disease and diets high in saturated fat and cholesterol (i.e. animal products).

An Australian study (Fuller et al 2015) funded by the egg industry compared the effects of eating 12 eggs per week with less than 2 eggs per week and found that there was no significant difference in blood cholesterol levels and other biomarkers. The subjects in the ‘low-egg’ group were instructed to match the protein intake of the high-egg group, i.e. they ate meat instead of eggs for breakfast. The subjects were diabetic or pre-diabetic and had an average BMI of 35. Both groups ate a diet low in fibre and high in saturated fat. A recent follow up study (Fuller et al 2018) found the “high-egg weight-loss diet exhibited no adverse changes in cardiometabolic markers compared with those who consumed a low-egg weight-loss diet”.  When this study was published, the media headlines exclaimed “eggs do not raise risk of heart disease” and “eggs might be good for you after all”. Half of the subjects were on cholesterol lowering drugs and continued to take them during the study, and they still had type 2 diabetes at the end of the study. A low fat whole food plant-based diet can reverse heart disease and type 2 diabetes.

Resources

Peer-reviewed studies

Studies showing eggs are associated with increased risk of chronic disease…

Egg industry funded peer-reviewed studies

Studies that show eggs in a favourable light…

Page created 9th May 2018
Last updated 9th May 2018