The association between egg consumption and diabetes is inconclusive. In the USA, egg consumption has been shown to increase the risk of diabetes. However, studies on egg consumption and diabetes are limited in Asia with conflicting results.

Continuous effects have been made to study the impact of egg consumption on the risk of diabetes considering that egg has become a common food in the last three decades in China.

In our study, we were interested to see the trajectory of egg consumption between 1991 and 2009 and to examine its association with the risk of diabetes among adults attending the China Health and Nutrition Survey. The study included 8,545 adults aged ≥ 18 years old. The participants were followed up every 2-4 years to measure their dietary habits and health conditions. In 2009, 11.1% of the participants had diabetes based on the measured blood glucose and a history of diabetes. 

We found that egg consumption nearly doubled in 2009 from 16 g/day in 1991. In this prospective study higher long-term egg consumption increased the risk of diabetes among Chinese adults by approximately 25% (comparing the 4th to 1st quartiles of the intake).

Based on the egg consumption patterns over the 18 years, participants were categorized into three distinct groups: low, medium and high. Compared with the low intake group (below 20 gram per day), both medium (20-40 gram per day) and high intake group (above 50 gram per day) were more likely to have diabetes. Habitual intake of one egg a day increased risk of diabetes by 60% as compared with those with a quarter egg per day. The result was generally consistent with a meta-analysis of 12 cohort studies reporting a 39% increased risk.

This is the first study conducted in a large sample in Chinese adults to investigate the longitudinal association between long-term egg consumption and diabetes. Our results suggested that higher egg consumption was positively associated with the risk of diabetes in Chinese adults.

The exact mechanisms linking egg consumption and diabetes are unknown. There has been speculation that trimethylamine-N-oxide (TMAO) could be a mediator. Choline from egg yolk can be transformed by gut microbiome to TAMO, which increases LDL oxidation and promotes inflammation and alterations of glucose homeostasis.

During the past three decades, China has been undergoing dramatic lifestyle change with a significant decrease in physical activity levels and a substantial increase of the consumption of meat, egg, cooking oil, and ultra-processed foods.  Egg is an important component of the modern Chinese diet. The association between egg consumption and diabetes could be an indicator of the overall effect of a sedentary lifestyle and modern dietary pattern on diabetes.

Based on the findings, we believe that Dietary Guidelines for the Chinese population should be evidence-based and a healthy diet incorporating egg consumption level should be promoted.

You can access ‘Higher egg consumption associated with increased risk of diabetes in Chinese adults – China Health and Nutrition Survey’ here.