Effects of a low-fat dietary intervention on glucose, insulin, and insulin resistance in the Women's Health Initiative (WHI) Dietary Modification trial

Division of Preventive Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
American Journal of Clinical Nutrition (Impact Factor: 6.77). 07/2011; 94(1):75-85. DOI: 10.3945/ajcn.110.010843
Source: PubMed


Glycemic effects of the Women's Health Initiative (WHI) low-fat dietary intervention are unknown.
Our objective was to analyze the effects of the WHI low-fat dietary intervention on serum glucose and insulin and insulin resistance up to 6 y after random assignment.
Postmenopausal WHI Dietary Modification trial intervention (DM-I) and comparison (DM-C) participants with blood measures at least at baseline and year 1 (n = 2263) were included. Anthropometric measures, dietary assessments, serum glucose and insulin concentrations, homeostasis model assessment of insulin resistance (HOMA-IR) measures, and quantitative insulin sensitivity check index (QUICKI) values were obtained at baseline, year 1, year 3, and year 6. Changes in measures were compared between groups at years 1, 3, and 6 overall and within stratified analyses.
Mean (±SD) differences in changes at year 1 between the DM-I and DM-C groups were as follows: glucose, -1.7 ± 17.9 mg/dL; insulin, -0.7 ± 5.1 μIU/mL; HOMA-IR, -0.2 ± 1.9; and QUICKI, 0.004 ± 0.019 (all P < 0.05). Similar findings resulted from repeated-measures analyses comparing the intervention and comparison groups over the 6 y. Whereas normoglycemic women at baseline had a decrease in glucose at year 1 that was 1.9 ± 17.2 mg/dL greater in the DM-I than in the DM-C group, diabetic women had an increase in glucose that was 7.9 ± 20.3 mg/dL greater in the DM-I than in the DM-C group (P for interaction <0.001).
A low-fat diet was not significantly associated with adverse glycemic effects up to 6 y after random assignment in postmenopausal women. However, diabetic women experienced adverse glycemic effects of the low-fat diet. This trial is registered at as NCT00000611.

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    • "However, in these studies the separate effect of exercise versus diet could not be elucidated [11]. Data from systematic reviews regarding the role of food in the prevention and treatment of T2DM indicates that there are some uncertainties with respect to the optimal dietary intervention [11,12], and results from one large interventional dietary study suggest that targeting macronutrient composition by lowering total fat intake and increasing carbohydrate intake from whole grains, may have detrimental effects in women with pre-existing T2DM [13]. A recent intensive diet and exercise program in patients with T2DM was stopped because the intervention did not reduce cardiovascular risk, despite significant weight loss at four years, compared to the control group [14]. "
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    ABSTRACT: Research on the role of nutrition in type 2 diabetes has largely focused on macro/micronutrient composition and dietary fiber intake, while fewer studies have tested the effects of differing food choice. Some observational studies and short-term intervention studies suggest that a food pattern mimicking the diet with which humans evolved positively influences glucose control and associated endocrine systems. Such a food pattern mainly differs from other common healthy food patterns in its absence of cereal grains and dairy products. The primary aim of this pilot study is to determine the effect of two healthy diets with or without cereal grains and dairy products on glucose control, while keeping participants' weight stable and other food parameters, such as macro/micronutrient composition, dietary fiber and glycemic load, the same in both diets.Methods/design: We intend to include 15 adult patients with a medical diagnosis of type 2 diabetes mellitus with or without medication and with an increased waist circumference (>= 80 cm for women and >= 94 cm for men) in a random-order cross-over diet intervention study during two periods of four-weeks separated by a six-week washout period. Patients will be instructed to eat two healthy diets according to official dietary guidelines with respect to macro/micronutrient composition and fiber content, but differing in the type of food included, with one diet being without cereal grains and dairy products. Lunch will be served in a hospital kitchen for control of nutrient intake, while the rest of the meals will be eaten at home according to specific directions. The energy content of the diets will be individually adjusted to maintain a stable body weight during the two four-week intervention periods. Primary outcomes will be change in fasting plasma glucagon and fructosamine, while secondary outcomes include change in fasting glucose and glycated hemoglobin, glucose and glucagon response during oral glucose tolerance test, blood lipids, blood pressure, C-reactive protein, body composition, quality of life, subjective experience with the two diets, satiety scores and changes in medication. Using these results, we will assess the need to conduct larger and longer studies with similar design.Trial registration: This trial was registered at as NCT01891955 and Spanish Agency of Medication and Sanitary Products (AEMPS) registration code: MFV-ADI-2013-01.
    Trials 01/2014; 15(1):2. DOI:10.1186/1745-6215-15-2 · 1.73 Impact Factor
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    • "The association of weight loss among overweight or obese individuals with increases in insulin sensitivity has been extensively studied (18–20). For example, in an analysis of participants in the Women’s Health Initiative, a similar increase in QUICKI to what was observed on the UNSAT diet in our results was seen in women who lost an average of 1 kg of body weight (21). In the OmniHeart Trial, weight change during the three feeding periods was small and not significantly different between intervention diets. "
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    Metabolism: clinical and experimental 05/2012; 61(11):1572-81. DOI:10.1016/j.metabol.2012.04.007 · 3.89 Impact Factor
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