Scientists at the Harvard School of Public Health have identified a natural substance in dairy fat which it is claimed may reduce the risk of developing Type 2 diabetes. The compound, trans-palmitoleic acid, is a fatty acid found in milk, cheese, yogurt and butter. It is not produced by the body and so only comes from the diet.
Research reported in the 'Annals of Internal Medicine' involved 3,736 people over 20 years. They were asked once about their diet and other factors which might affect their health. Three years later they had their blood tested to measure fatty acid levels, including the amount of trans-palmitoleic acid, and after that information about their health was collected annually.
Researchers found that participants who said they ate more whole-fat dairy products had higher levels of trans-palmitoleic acid in their blood after three years. The research found people with higher levels were less likely to develop Type 2 diabetes than those who had low levels, and they also had healthier cholesterol and insulin levels.
Limitations to the study
The journal draws attention to several limitations of the study. Participants were asked only once about the foods they usually eat, and dietary habits may change over time. The blood levels of trans-palmitoleic acid measured several years later may have no longer related to the types of foods the participants originally reported eating. Therefore it is not possible to conclude from this study which foods, if any, result in greater levels of trans-palmitoleic acid in the blood. In addition, this kind of study cannot say whether trans-palmitoleic acid or some other unidentified factor was the cause of the positive health effects seen.
Warning not to exceed recommended amounts of dairy foods
Deepa Khatri, Clinical Advisor at Diabetes UK, said: “People should not take the findings of this research as a reason to exceed the recommended amounts of dairy food in order to reduce their risk of developing Type 2 diabetes. Milk and dairy foods can be high in fat, which if eaten in excess can contribute to weight gain. So it’s advisable to choose lower-fat dairy foods instead.
“More research is needed to see whether these trans-palmitoleic acids can play a useful role in preventing Type 2 diabetes. In the meantime however Diabetes UK advises that all people, with or without diabetes, should have a healthy balanced diet, low in fat, salt and sugar with plenty of fruit and vegetables. This is based on robust, nutritional research and it is not recommended for people to increase their intake of any one food type in order to reduce their risk of developing Type 2 diabetes.”