US Dietary Guidelines Effectively Limit Insulin Resistance in Women

[Admin]

April 5, 2007 — A study found that a diet following the 2005 Dietary Guidelines for Americans (DGA) may be effective to limit insulin resistance in women, but the benefits did not occur in men, according to the results of a study from the Framingham Offspring Cohort reported in the April issue of Diabetes Care.

"No study to date has examined the relation between adherence to the 2005 DGA and CVD [cardiovascular disease] risk or intermediate markers of risk," write Jeanene J. Fogli-Cawley, MS, RD, from the Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston, Massachusetts, and colleagues. "We developed the 2005 Dietary Guidelines for Americans Adherence Index (DGAI) to determine whether a diet consistent with the 2005 DGA was associated with a lower risk of chronic disease. This study assessed the relationship between adherence to the 2005 DGA and insulin resistance, as measured by HOMA-IR [homeostasis model assessment of insulin resistance], and fasting insulin in the Framingham Offspring Cohort."

At the fifth examination of 3082 participants in the Framingham Offspring Cohort, from January 1991 to June 1995, the investigators evaluated cross-sectional associations between DGAI score and degree of insulin resistance as measured by HOMA-IR and fasting insulin.

After adjustment for age, sex, and waist circumference, participants in the highest quintile category of the DGAI score had significantly lower HOMA-IR than did those in the lowest quintile category (6.4 vs 6.7; P = .04).

There was a significant interaction between DGAI score and sex. On stratification, the association appeared to be largely confined to women (5.9 vs 6.6; P < .001), and no association was apparent in men (7.2 vs 7.1; P = .30). Associations between the DGAI score and fasting insulin were similar.

"Consumption of a diet consistent with the 2005 DGA may be an effective means to limit insulin resistance in women," the authors write.

Study limitations include DGAI designed specifically for use with the Harvard semiquantitative food frequency questionnaire, limiting the ability to measure energy intake accurately; cross-sectional and historical analyses; and possible confounding by determinants of insulin resistance or other healthy behaviors.

"In the Framingham Offspring Cohort, we observed that a higher DGAI quintile score was associated with a lower HOMA-IR in women, suggesting that adherence to the 2005 DGA recommendations may favorably affect insulin resistance, an important intermediate marker of CVD and type 2 diabetes risk," the authors conclude. "More definitive studies are required to document the benefit of following a diet consistent with the 2005 DGA. Further work should concentrate on prospective assessment of adherence to the 2005 DGA and intermediate markers of risk for CVD and diabetes, such as insulin resistance, inflammatory markers, and metabolic syndrome."

The Helen Smith Brownstein Memorial Scholarship, the US Department of Agriculture, and the National Institutes of Health, National Heart, Lung, and Blood Institute's Framingham Heart Study supported this study.

Diabetes Care. 2007;30:817-822.

Source: http://www.medscape.com/viewarticle/554709?src=mp