Eating a fish-rich diet may help counteract some bad effects of having a genetic variant linked to diabetes, a new study suggests.
A common variation of the gene called TCF7L2 has been linked to higher risk of type 2 diabetes. The variant, known as the T form, may also raise the risk of heart disease and stroke, but studies have had mixed results. Part of the uncertainty may stem from people’s diets, a study published August 13 in Diabetes Care suggests.
Researchers analyzed data from more than 7,000 people who were assigned to eat one of three diets for seven years: a low-fat diet or one of two Mediterranean diets — one heavy in fish, olive oil and complex carbohydrates such as whole grains, or one that emphasized nuts instead of oil.
People with two copies of the gene’s T form who stuck to either Mediterranean diet had lower blood sugar levels than did people with the same genetic risk who ate the low-fat diet. And the Mediterranean diet erased any genetic discrepancy in stroke risk. People with two copies of the T form had three times the stroke risk on the low-fat diet.
Sticking to the diet was important: People who consistently cheated on the Mediterranean diet did not get the health benefits.