New research presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Madrid, Spain, showed that consuming fruit, oats, and rye in childhood is associated with a higher risk of developing type 1 diabetes (T1D). On the other hand, eating berries is linked to a lower likelihood of developing the condition. T1D is an autoimmune disease in which the immune system attacks and destroys the insulin-producing islet cells in the pancreas, leading to insufficient insulin production to regulate blood sugar levels properly.

The exact trigger for the immune system’s attack is not known but is believed to involve a mix of genetic predisposition and environmental factors like viruses or certain foods. T1D is the most common form of diabetes in children and is on the rise worldwide. The global number of T1D cases is expected to double in just 20 years, from 8.4 million in 2021 to 17.4 million by 2040. Finland has the highest incidence of T1D globally, with 52.2 cases per 100,000 children under the age of 15, which is over five times higher than in the 1950s. Professor Suvi Virtanen, of the Finnish Institute for Health and Welfare in Helsinki, Finland, who led the research, stated, “Type 1 diabetes imposes a significant burden on the patient and their family, requiring lifelong treatment. It can lead to complications such as eye, heart, nerve, and kidney problems, shortened life expectancy, and substantial healthcare costs (around 1 million euros per patient in Finland). The rapid increase in type 1 diabetes in children suggests that environmental factors play a crucial role in the development of the disease. Identifying these factors will provide opportunities to develop strategies to prevent it and its complications.” 

While numerous food items have been linked to the attack on insulin-producing cells and T1D, there is a lack of high-quality evidence from prospective studies, and the existence of a link remains controversial. To address this, Professor Virtanen and colleagues explored whether diet in infancy and early childhood was associated with the development of T1D in thousands of children in Finland. They followed 5,674 children with genetic susceptibility to T1D from birth to the age of six. Food records completed by their parents repeatedly from the age of three months to 6 years provided information on the entire diet. By the age of six, 94 of the children had developed type 1 diabetes, and another 206 developed islet autoimmunity, putting them at a substantially increased risk of developing T1D in the next few years. When considering the entire diet, several foods were found to be associated with a higher risk of developing T1D.

“To the best of our knowledge, this is the first time a child’s entire diet has been considered at the same time,” says Professor Virtanen. The results show that the more fruit, oats or rye children ate, the more their risk of T1D increased. In contrast, eating strawberries, blueberries, lingonberries, raspberries, blackcurrants, and other berries appeared to protect against T1D. The more berries a child ate, the less likely they were to develop T1D. “Berries are particularly rich in polyphenols, plant compounds which may dampen the inflammation that is associated with the development of type 1 diabetes,” says Professor Virtanen.  “On the other hand, fruits may contain harmful substances that don’t occur in berries. For example, berries can be free of pesticides that are found on other fruits.”

Oats, bananas, fermented dairy products (such as yogurts) and wheat were associated with an increased risk of islet autoimmunity, whereas cruciferous vegetables, such as broccoli, cauliflower and cabbage, were associated with decreased risk. All of the associations were independent – they occurred regardless of the other foods eaten. “It is important to find out which factors in these foods are responsible for these associations,” says Professor Virtanen.  “Are the same causative factors or protective factors found in several foods? “If berries are found to contain a particular protective factor, for instance, either that substance or berries themselves could used to prevent T1D.” It is, however, too early to make any dietary recommendations.

Professor Virtanen says: “Many foods of the foods that we found to be associated with increased risk of type 1 diabetes and the disease process are considered part of a healthy diet and it is important that our results are replicated in other studies before anyone considers making changes to their child’s diet.”