Featured article in the July, 2017 Issue of Nutrition Research Update; written by Kevin C Maki, PhD and Orsolya M. Palacios, PhD, RDN from MB Clinical Research and Consulting.
Consuming a healthful diet and participating in an adequate amount of physical activity are key tools for managing metabolic abnormalities that can increase risk for both cardiovascular disease and type 2 diabetes mellitus. A growing body of evidence supports the view that a diet high in refined starches and added sugars exacerbates disturbances in carbohydrate (CHO) metabolism. Replacement of these macronutrients with protein and/or unsaturated fatty acids (UFA) may help to improve the cardiometabolic risk factor profile. The research team from the Midwest Biomedical Research: Center for Metabolic & Cardiovascular Health, Glen Ellyn, IL and Great Lakes Clinical Trials, Chicago, IL conducted a trial to evaluate the effects of a combination of egg protein (Epro) and UFA, substituted for refined starches and added sugars, on insulin sensitivity and other cardiometabolic health markers in adults with elevated (?150 mg/dL) triglycerides (TG).1
Participants (11 men, 14 women) with elevated TG were randomly assigned to consume test foods prepared using Epro (~8% of energy) and UFA (~8% of energy) for the Epro/UFA condition, or using refined starch and sugar (~16% of energy) for the CHO condition. Each diet was low in saturated fat and consumed for 3 weeks in a controlled feeding (all food provided) crossover trial, with a 2-week washout between diets. Insulin sensitivity, assessed by the Matsuda insulin sensitivity index, increased 18.1 ± 8.7% from baseline during the Epro/UFA condition, compared to a change of -5.7 ± 6.2% during the CHO condition (p < 0.001). The disposition index, a measure of pancreatic beta-cell function, increased during the Epro/UFA condition compared to the CHO condition (net difference 40%, p = 0.042), and low-density lipoprotein (LDL) peak particle size increased during the Epro/UFA condition compared to the CHO condition (net difference 0.27 nm, p = 0.019). TG and very low-density lipoprotein cholesterol (VLDL-C) levels were lowered more following the Epro/UFA (~16% differences, p < 0.002) versus the CHO diet condition. LDL-C was lowered by 9-10% with both diets, compared with baseline, but the response did not differ between diets.
The results of this study are consistent with those from a previous study by our group, where daily consumption of three servings of sugar-sweetened products reduced insulin sensitivity by 18%, as assessed by the homeostasis model assessment of insulin sensitivity, compared to a habitual diet baseline.2 Three daily servings of dairy products produced no change in insulin sensitivity.2 Reductions in TG and VLDL-C may reduce cardiovascular disease risk, and are often accompanied by a shift toward larger, more buoyant LDL particles, which may be less atherogenic. A shift toward larger LDL particles was observed in the current trial. The findings from this study support the Dietary Guidelines for Americans recommendations to limit intakes of refined starches and added sugars, and to emphasize UFA intake as replacements for both dietary saturated fatty acids and refined CHO.3
Find the full study online (linked here).
- Maki KC, Palacios OM, Lindner E, Nieman KM, Bell M, Sorce J. Replacement of refined starches and added sugars with egg protein and unsaturated fats increases insulin sensitivity and lowers triglycerides in overweight or obese adults with elevated triglycerides. J Nutr. 2017;May 17 [Epub ahead of print].
- Maki KC, Nieman KM, Schild AL, Kaden VN, Lawless AL, Kelley KM, Rains TM. Sugar-sweetened product consumption alters glucose homeostasis compared with dairy product consumption in men and women at risk of type 2 diabetes mellitus. J Nutr. 2015; 145:459-466. Available at http://jn.nutrition.org/content/145/3/459.full.pdf+html.
- U.S. Department of Health and Human Services and U.S. Department of Agriculture. 2015-2020 Dietary Guidelines for Americans 2015-2020. Eighth Edition. December 2015. Available at http://health.gov/dietaryguidelines/2015/guidelines/.