Dietary eggs, egg nutrients, polygenic score for body mass index, “Western pattern” diet, and weight change, a prospective analysis in the Women's health initiative

Background & aims

Eggs contain nutrients which could help enrich the diets of postmenopausal women. Egg consumption and elevated body weight have been associated with elevated risk of serious chronic disease. It is possible that elevated body weight mediates between egg consumption and serious chronic disease. However, few studies exist on the link between egg consumption and body weight in post-menopausal women, and none of them accounted for genetic weight gain predispositions. Our objective was to examine associations between egg consumption, body weight, and genetic predisposition for an elevated Body Mass Index (BMI), in postmenopausal women.

Methods

We analyzed data from 4439 healthy Women's Health Initiative participants of European descent during a 6-year follow up using multivariable generalized linear mixed models to prospectively evaluate egg and egg-nutrient intake (measured by a food frequency questionnaire) against body weight and a BMI polygenic score (PGS-BMI) derived from GWAS meta-analysis effect-allele frequencies.

Results

We found a positive prospective association between change in egg intake and body weight during the 6-year follow up. For instance, at year 3, women whose intake had increased by 2.0 eggs/week had gained 0.70 kg (95%CI: 0.34, 1.07, p = 0.0002) more than women whose intake had decreased by 2.4 eggs/week, p-linear <0.0001. Cholesterol-intake and choline-intake, but not betaine-intake, showed similar significant associations. Exploratory analysis revealed that: 1) women only demonstrated these significant associations if they exhibited higher intakes of “Western-pattern” foods including processed and red meats, French fries, sweets and deserts, sugar-sweetened beverages, fried foods, and dietary fat, and dietary energy; and 2) there was a significant positive prospective association between PGS-BMI and body-weight change, but only in the top quintile of egg-intake change.

Conclusions

We found significant positive prospective associations between weight change and changes in egg intake, cholesterol intake, and choline intake among healthy postmenopausal women of European ancestry in the Women's Health Initiative. Exploratory analyses revealed that: 1) these significant associations only obtained among women who ate large amounts of “Western-pattern” foods; and 2) women with a higher genetic susceptibility for an elevated BMI gained more weight only if they increased their egg intake considerably. Our results require confirmation.