A fatty acid found in dairy products could help to prevent diabetes, according to new research.
The human body is unable to produce the trans-palmitoleic acid compound but it occurs naturally in the dairy fat of milk, cheese, yoghurt and butter.
Now scientists in the US believe the compound could help tackle type 2 diabetes.
Some 2.3 million Britons suffer from type 2 diabetes, with another 500,000 cases thought to be undiagnosed.
The latest research by Harvard School of Public Health, published in the Annals of Internal Medicine, involved more than 3,700 people.
They were followed for 20 years by researchers looking at the risks of developing cardiovascular disease as people get older.
Measurements included blood glucose and insulin levels, and levels of fatty acids (including trans-palmitoleic acid) in the blood.
The results showed that higher levels of trans-palmitoleic acid were associated with healthier levels of blood cholesterol, insulin levels and insulin sensitivity, even when other factors were taken into account.
Overall, people with the highest levels of trans-palmitoleic acid had about a 60% reduced risk of developing type 2 diabetes, compared to those with the lowest levels.
The authors called for further studies but lead author, associate professor Dariush Mozaffarian, said "the magnitude of this association is striking".
The study also appears to confirm previous research showing that a diet rich in dairy foods is linked to lower risk of type 2 diabetes and related metabolic abnormalities.