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Eggs May Not Spell Higher CVD Risk Among T2D Patients

— Dozen a week OK in industry-funded study, but lots of criticism from nutrition experts

MedpageToday

Eating 12 eggs in 1 week was apparently not tied to an increase in cardiometabolic risk factors among people with type 2 diabetes (T2D), according to a randomized study sponsored by the Australian egg industry.

In the Diabetes and Egg (DIABEGG) study, participants who went on a high-egg diet (defined as eating more than 12 eggs a week) or a low-egg diet (no more than one egg a week) during a 3-month weight-loss period lost the same 3.1 kg (6.8 lbs) of weight over a subsequent 6-month follow-up period. Moreover, the results showed no difference in glycemia, traditional serum lipids, markers of inflammation, oxidative stress, or adiponectin between the groups during this time.

Action Points

  • A high-egg diet for 12 months, which included a 3-month weight-loss phase, had no adverse effects on cardiovascular risk factors, inflammatory or oxidative stress markers, or measures of glycemia, in individuals with prediabetes or type 2 diabetes.
  • Note that criticisms of the study include its sponsorship by the Australian egg industry, the timing of blood samples, and findings that are contrary to other data and to some national health recommendations.

"This extends our previous finding that a high-egg compared with a low-egg diet has no detrimental effect on cardiovascular disease risk factors in persons with prediabetes or T2D during 3 months of weight maintenance by showing that the same is true during weight loss and for a 12-month period," wrote Nicholas Fuller, PhD, of the University of Sydney, and colleagues in the study published online in .

"These findings do not align with the health recommendations of some countries that specifically recommend a low-egg diet for people with T2D. Our findings suggest that a high-egg diet is safe for those with T2D -- just as for the general population -- without adverse consequences for cardiovascular risk factors."

Asked for her opinion, Marion Nestle, PhD, MPH, of New York University, who was not involved with the study, told 鶹ý that the most important dietary risk for T2D is being overweight and that there is no reason to think that eggs promote weight gain more than any other food. Although the study results are therefore "predictable and not surprising," she noted that eggs are still high in cholesterol and that dietary guidelines recommend eating as little of it as possible.

"This study is funded by the Australian egg industry. Such studies almost invariably produce results favorable to the sponsor's interest," she also cautioned.

For the DIABEGG study, participants with prediabetes or T2D (n=128) started with a 3-month weight-maintenance stage before being prescribed a daily energy restriction of 2.1 MJ (502 calories) for 3 months of weight loss. As for the dietary choices, emphasis was placed on replacing saturated fats with monosaturated and polyunsaturated fats in both groups.

Patients tended to self-report "satisfactory" adherence to the allocated diet, though there was no significant difference in egg consumption from 6 to 12 months (P=0.56), the researchers noted.

Follow-up blood samples were taken in the morning after an overnight fast, and this way of measuring cholesterol was highlighted by J. David Spence, MD, of Roberts Research Institute at Western University in London, Ontario, who was also not involved with the study: "It does not matter whether egg intake increases fasting blood levels of cholesterol; the cholesterol is made by your liver overnight; the fasting cholesterol has almost nothing to do with what you ate yesterday," he told 鶹ý.

"But for 4 hours after a high-cholesterol meal the arteries are twitchy, sticky, and inflamed. Diet isn't about the fasting state; it's about the 'fed' state. The focus on fasting cholesterol levels is a classic red herring employed by the egg industry over and over again."

Spence also took issue with the authors' assertion that eggs can be part of a healthy diet for healthy people, calling eggs "not safe for anyone at risk of heart attacks or strokes" and "particularly not for diabetics." It is especially hard to show the harm from eggs in the U.S., where the diet is "so bad that it's hard to show that anything makes it worse," he added.

"In Greece, however, where the Mediterranean diet is the norm, an egg a day increased coronary risk five-fold, and even 10 grams a day of egg -- a sixth of a large egg -- increased coronary risk by 50%. It would be much better to follow a Mediterranean diet and use egg substitutes ... instead of whole eggs."

  • author['full_name']

    Nicole Lou is a reporter for 鶹ý, where she covers cardiology news and other developments in medicine.

Disclosures

The study was supported by a research grant from the Australian Egg Corporation.

Fuller disclosed receiving research grants for other industry-sponsored trials and is the author of a weight-loss book.

Nestle is the author of several books on food politics.

Spence reported no relevant ties to industry.

Primary Source

American Journal of Clinical Nutrition

Fuller NR, et al "Effect of a high-egg diet on cardiometabolic risk factors in people with type 2 diabetes: The Diabetes and Egg (DIABEGG) Study -- randomized weight-loss and follow-up phase" Am J Clin Nutr 2018; DOI: 10.1093/ajcn/nqy048.