High-fat diet may impair cognition in diabetics

Diets rich in saturated and trans fats and low in polyunsaturated fats are associated with thinking or "cognitive" problems in women with diabetes, according to new report.

Prior research has indicated that diabetics are at increased risk for cognitive impairment in late life. Whether there are any lifestyle factors that can be changed to reduce this risk, however, was unclear.

Dr. Elizabeth E. Devore, from Harvard Medical School, Boston, and colleagues theorized that by affecting sugar metabolism, dietary fat could influence cognitive changes in older adults with diabetes.

To investigate, the researchers used standard tests to assess thinking ability in 1486 women with type 2 diabetes who were at least 70 years of age and were enrolled in the Nurses' Health Study (NHS).

Thinking ability was tested once between 1995 and 1999 and then again two years later. Dietary fat levels were recorded starting in 1980.

The findings are reported in the journal Diabetes Care.

Women who consumed the highest amounts of saturated and trans fats experienced greater declines in thinking ability than women whose diets contained little of these fats. Comparing the thinking ability of women of the same age who consumed high and low amounts of these fats was really like comparing the ability of women who were 7 years apart in age.

Substituting polyunsaturated fats for saturated and trans fats, by contrast, reduced cognitive decline, the findings indicate.

"Further research is needed to confirm these findings and explore additional strategies for maintaining cognitive health in diabetics - especially in women, who have a higher lifetime prevalence of both type 2 diabetes and cognitive impairments than men," Devore and colleagues conclude.

SOURCE: Diabetes Care, April 2009.