Eggs and type 2 diabetes: the science is not over
How many eggs are healthy? There is always a lot of discussion about that. And recently, this discussion has been rekindled by the results of a large survey among Chinese. Eating at least 1 egg a day was found in this study to be associated with a greater chance of developing type 2 diabetes. Do eggs really increase the risk of diabetes?
To go straight into that last question: science does not yet have an unequivocal answer. According to the researchers, higher egg consumption is associated with a higher risk of type 2 diabetes. But it is still too early to conclude that eggs actually cause diabetes. This requires further research.
Chicken or egg?
There are different types of research in nutritional science. Each species has a different ‘evidence’. In this study It was a so-called observational study. This means that researchers follow a large group of people for a long time without changing their situation. In this case, a group of 8,545 Chinese with an average age of 50 years was followed. These people were asked how many eggs they were used to eating. After 18 years, the researchers looked at whether there is a relationship between egg consumption and the risk of developing type 2 diabetes. That was the case: Over the course of the study, Chinese who regularly ate one or more eggs a day were 60 percent more likely to develop type 2 diabetes than Chinese who ate just 1 egg a week. However, this does not automatically mean that eggs cause diabetes. In this type of research, it is not clear which is the chicken or the egg. Did these participants develop type 2 diabetes from eating eggs? Or is there another cause that caused them to develop diabetes and does that cause happen to be associated with higher egg consumption?
Western eating habits
What do the researchers themselves say about it? They report that more research is needed to find out whether a high consumption of eggs actually increases the risk of diabetes. They also report that the traditional Chinese diet is westernizing and that this can have consequences for health. It is already known that the risk of diabetes is associated with Western eating habits, such as higher consumption of animal and processed foods. Finally, the researchers report that egg consumption almost doubled during the study period. At the start, the participants ate an average of more than 2 eggs per week and at the end more than 4 eggs per week. Higher egg consumption could indicate more Western eating habits. So perhaps it is not the eggs themselves that increase the risk of diabetes, but mainly the more Western eating habits. For example, eggs are also used in snacks and pastries. Note that these are just speculations. The study does not provide any evidence for this either.
What research can provide evidence?
Intervention studies have more evidence. Researchers then consciously change one factor and keep other possible influencing factors the same. To show that eggs cause diabetes, a large group of people would have to eat more eggs for years. Do they then develop diabetes more often than another group of people who have stopped eating more eggs? Such a study was conducted a few years ago with a small group. It is the so-called Diabetes and EGG Study (DIABEGG), which was published in 2018. It involved 128 people with type 2 diabetes or prediabetes. Half were prescribed an egg-rich diet with 12 eggs per week. The other half ate a maximum of 2 eggs per week. The result after 1 year: the cholesterol values, blood glucose values and blood pressure did not differ between the two groups. A side note: The study was co-funded by the Australian egg industry, but the researchers emphasize that this did not affect the results of the study.
How many eggs do education authorities recommend?
Eggs are in the Wheel of Five. They contain many good nutrients such as vitamins, minerals and proteins. But eggs also contain a relatively high amount of cholesterol and saturated fat. That is why the Nutrition Center uses a maximum of 2-3 eggs per week (for vegetarians 3-4 eggs per week). The Dutch Diabetes Federation is somewhat less strict: the recently published Dietary Guidelines for Diabetes states that the link between eggs and diabetes is unclear. According to the federation, eggs are part of a healthy diet for people with diabetes. However, people with diabetes are advised not to eat more than 7 eggs per week because there are indications that more than 7 eggs per week increase LDL cholesterol.
