Scientists at the University of Cambridge found that people who ate on average four and a half 125g pots of yoghurt each week reduced their risk of developing type 2 diabetes by 28% compared with those who did not eat them.
Those who ate all forms of low-fat fermented dairy products, including low-fat cottage cheese and fromage frais as well as yoghurt, reduced their risk of the disease by 24% compared with people who did not include them in their diet.
The health charity Diabetes UK says that, however encouraging the results, people should resist the temptation to regard yoghurt as a miracle cure for diabetes.
The researchers say that largely because of its saturated fat content, dairy products are traditionally seen as unhealthy. However, they do contain many important nutrients including calcium, vitamin D and magnesium.
Previous studies have examined the relationship between eating dairy products and diabetes, but results have been inconclusive. This prompted the authors to carry out this new investigation, using a more detailed assessment of dairy product consumption than was done in past research.
Data was drawn from the large EPIC-Norfolk study which includes more than 25,000 men and women living in Norfolk.
This information included a daily record of all the food and drink consumed in the course of a week by some of the participants when they entered the study in the 1990s. Among these were 753 people who went on to develop type 2 diabetes over the next 11 years.
These diet diaries were compared with 3,502 other study participants selected at random. This allowed the researchers to examine the risk of diabetes in relation to how much dairy produce people ate and also allowed them to break that information down into categories.
The study, which is published in Diabetologia, does not claim to have found proof that yoghurt can prevent diabetes. The authors acknowledge that those who ate yoghurt regularly may have had healthier lifestyles. For instance, they found that replacing a portion of crisps with a portion of yoghurt reduced the hazard of type 2 diabetes by 47%, suggesting that some of the protective effect may be attributed to avoiding unhealthy alternative food.
They also suggest some possible explanations for why fermented dairy products can cut the risk of diabetes, including the presence of probiotic bacteria and a form of vitamin K, which is part of the menaquinone family and associated with fermentation.
In a statement, lead author Dr Nita Forouhi from the University of Cambridge School of Clinical Medicine says "at a time when we have a lot of other evidence that consuming high amounts of certain foods, such as added sugars and sugary drinks, is bad for our health, it is very reassuring to have messages about other foods like yoghurt and low-fat fermented dairy products, that could be good for our health".
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