Background: Previously published research that examined the effects of high egg consumption in people with type 2 diabetes (T2D) produced conflicting results leading to recommendations to limit egg intake. However, people with T2D may benefit from egg consumption because eggs are a nutritious and convenient way of improving protein and micronutrient contents of the diet, which have importance for satiety and weight management.
Objective: In this randomized controlled study, we aimed to determine whether a high-egg diet (2 eggs/d for 6 d/wk) compared with a low-egg diet (<2 eggs/wk) affected circulating lipid profiles, in particular high-density lipoprotein (HDL) cholesterol, in overweight or obese people with prediabetes or T2D.
Design: A total of 140 participants were randomly assigned to one of the 2 diets as part of a 3-mo weight maintenance study. Participants attended the clinic monthly and were instructed on the specific types of foods and quantities to be consumed.
Results: There was no significant difference in the change in HDL cholesterol from screening to 3 mo between groups; the mean difference (95% CI) between high- and low-egg groups was +0.02 mmol/L (−0.03, 0.08 mmol/L; P = 0.38). No between-group differences were shown for total cholesterol, low-density lipoprotein cholesterol, triglycerides, or glycemic control. Both groups were matched for protein intake, but the high-egg group reported less hunger and greater satiety postbreakfast. Polyunsaturated fatty acid (PUFA) and monounsaturated fatty acid (MUFA) intakes significantly increased from baseline in both groups.
Conclusions: High egg consumption did not have an adverse effect on the lipid profile of people with T2D in the context of increased MUFA and PUFA consumption. This study suggests that a high-egg diet can be included safely as part of the dietary management of T2D, and it may provide greater satiety.
Alex’s Notes: Current US dietary guidelines for people with type-2 diabetes (T2D) recommend that dietary cholesterol be limited to less than 300 mg/day, which is the equivalent of about 1 large egg, and further recommend eggs be limited to less than four per week, while the Australian National Heart Foundation recommends a maximum of six eggs per week for everyone. Conversely, the UK has no such recommendations.
Several observational studies have provided support to these recommendations, finding eggs to be associated with worse cardiovascular outcomes in T2D despite not having an association in the general population. But observational studies are fraught with confounding variables. In fact, to date only one randomized controlled trial of egg consumption in T2D has been conducted in which people with T2D consumed a hypocaloric diet containing two or zero eggs per day. Both groups lost the same amount of weight and had similar improvements in blood lipids, blood pressure, and glycemic control. However, weight loss itself has beneficial effects on blood lipids that may outweigh and differences egg consumption would lead to.
Thus, the current study had a 3-month intervention period of weight maintenance to determine the potential health effects of a high-egg diet in people with prediabetes and T2D.
Ultimately, 140 participants (average age of 60 years) with either T2D or prediabetes and a BMI greater than 25 (average 35) were recruited. They were randomized to a high-egg diet (2 eggs/day, 6 days/week minimum) or a low-egg diet (<2 eggs/week w/matched protein from lean meats) and instructed not to change activity levels. Blood-borne and anthropometric measurements, nutritional analysis, and a few questionnaires were completed at baseline and after the 3-month intervention.
Comparing the two groups after three months, there were no significant differences for changes in total, LDL, and HDL cholesterol, triglycerides, fasting glucose, HbA1c, waist circumference, total body fat, lean-body mass, blood pressure, or heart rate.
As expected per study design, both groups successfully maintained their weight and had equivalent protein intake (~20% kcal). Moreover, both groups reported an overall satisfaction with their diets, but the magnitude of satisfaction favored the high-egg group. The high-egg group also found the diet to be less boring and contain more enjoyable food compared to the low-egg diet. Interestingly, despite equivalent protein intake, the high-egg group also reported less hunger and greater satiety after breakfast (when eggs were consumed) in comparison to the low-egg group.
Despite any observational studies suggesting otherwise, this randomized clinical trial successfully supports the notion that moderate consumption of eggs is not detrimental to people with T2D. In fact, egg consumption showed significantly greater food-acceptability and appetite reduction compared with a low-egg diet, suggesting that incorporation into diets may be advantageous in those who have problems stemming from excess weight.