Changes in Diet Can Impact Future Need for Insulin in Postmenopausal Women

Overhead view of bowl of grain cereal on wooden table with a mug of tea and magazine

An analysis of the effect of diet on postmenopausal women as part of the Women’s Health Initiative shows that reducing fats and increasing vegetable, fruit, and grain intake can reduce the risk of needing insulin in the future.

Published in Diabetes Care, “A Low-Fat Dietary Pattern and Diabetes: A Secondary Analysis From the Women’s Health Initiative Dietary Modification Trial” utilizes the data from the Women’s Health Initiative to investigate the effects of dietary intervention on diabetes and diabetes treatment in postmenopausal women.

The Women's Health Initiative (WHI) is a long-term national health study which focuses on strategies for prevention of heart disease, breast and colorectal cancer, and osteoporotic fractures in postmenopausal women. The MedStar Research Institute joined the study as a collaborating center in 1994, under the direction of Barbara Howard, PhD.

Launched in 1993, the WHI enrolled 161,808 women aged 50-79 into one or more randomized Clinical Trials (CT), testing the health effects of hormone therapy, dietary modification, and/or calcium and Vitamin D supplementation or to an Observational Study. A total of 48,835 women were randomized to a comparison group or an intervention group that underwent a behavioral/nutritional modification program with the goal to decrease fat intake and increase vegetable, fruit, and grain intake.

Ninety-three percent of participants completed the intervention over an average of 8.1 years. More than 70% participated in the follow-up through September 2015.

This secondary analysis found that the dietary intervention in postmenopausal women did not increase the risk of diabetes and may have actually slowed progression. This was measured by the number of women who began insulin while part of the study. Women who were part of the intervention group had lower rates of initiation of insulin therapy, and women with baseline waist circumference ≥88 cm and worse metabolic syndrome scores had the greatest reduction in risk of initiating insulin therapy.

These results are important because weight control is a key objective for persons with type 2 diabetes and this shows in a long-term study that reducing fat intake is not harmful and can be beneficial.

This data was substantiated by data collected during the cumulative follow-up years. During the follow-up period, baseline glucose was measured in years 1, 3, and 6. In those participants with measured biomarkers, the intervention reduced the risk of developing glucose ≥100 mg/dL by 25%.

Dr. Howard is the lead investigator on this study and remains an active Senior Scientist and former President of MedStar Health Research Institute.

Diabetes Care, 2017. DOI: 10.2337/dc17-0534