Full-fat versus fat-free yogurt improves postprandial markers of glucose homeostasis and fasting markers of glucose and lipid homeostasis in individuals with prediabetes
Authors: Taormina Victoria , Eisenhardt Simonne , Devine Derek , Gilbert Matthew , Poynter Matthew , Kien C , Kraft Jana 
Published: May 2023

While many national health authorities, such as the American Heart Association, have long recommended low-fat (1%) or fat-free dairy products over those with full fat (≥3.25%), recent epidemiological research suggests beneficial health effects of full-fat dairy products. The objective of this pilot study was to determine the effect of substituting full-fat (3.25%) yogurt for fat-free yogurt on glucose and lipid metabolism in individuals with prediabetes. We hypothesized that short-term consumption of three daily servings of full-fat yogurt would improve glucose and lipid homeostasis. We conducted an 8-week randomized, double-masked, controlled crossover study in six men and seven women aged 45-75 years old to compare two diets, i) a lower-fat (30%) diet containing non-fat yogurt (NFY diet) and ii) a higher-fat diet (38%) consisting of full-fat yogurt (FFY diet), consumed for three weeks each. Dairy fat in the full-fat yogurt accounted for the arithmetic difference in fat (8% energy) between diets. At the end of each diet, blood was collected and an oral glucose tolerance test (OGTT) and mixed meal tolerance test (MMTT) were performed. The FFY diet resulted in a lower blood fructosamine concentration ( P=0.01). During the OGTT, fasting blood glucose and insulin concentrations were both lower in response to the FFY diet ( P=0.05 and P=0.03, respectively), but there was no change in the C-peptide concentration. In addition, no differences between the diets for the area under the curve for glucose or insulin concentrations were observed. At the 120-minute time point, there was no difference between the diets for glucose or insulin concentrations; however, C-peptide concentrations were lower in response to the FFY diet ( P=0.05). Though the Matsuda index did not differ between diets, the Homeostatic Model Assessment for Insulin Resistance value was lower in response to the FFY diet on the day of the OGTT ( P=0.03). During the MMTT, the area under the curve was lower for glucose ( P=0.02) and higher for insulin ( P=0.01) in response to the FFY diet. Blood triacylglycerol concentration and the total cholesterol to HDL cholesterol ratio were lower in response to the FFY diet ( P=0.01 and P<0.01, respectively). The FFY diet improved postprandial markers of glucose homeostasis and fasting markers of glucose and lipid homeostasis. Collectively, our pilot study indicates that short-term consumption of three daily servings of full-fat yogurt elicits beneficial effects on metabolic health in individuals with prediabetes. This project was funded by National Dairy Council Nutrition Research Funding and a USDA Agriculture and Food Research Initiative National Institute of Food and Agriculture Predoctoral Fellowship. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.