Plasma Branched-Chain Fatty Acids Reflect Dairy-Fat Intake in a Pilot Clinical Trial in Individuals with Prediabetes

Abstract

Epidemiological studies often rely on fatty acid (FA) biomarkers of dairy-fat intake to represent diet history and to establish associations with cardiometabolic risk factors. However, a more robust body of direct research is needed to validate the currently utilized FA biomarkers as accurate representations of dairy-fat intake. Thus, our objectives were to i) compare the plasma FA profile of individuals with prediabetes following the consumption of a diet with full-fat (3.25%) yogurt (FFY diet) or non-fat yogurt (NFY diet) to evaluate their validity of currently utilized biomarkers and ii) identify additional FAs to serve as potential biomarkers. We hypothesized that the proportion of the unique dairy-derived FAs including odd-chain FAs (13:0, 15:0, 17:0, 19:0, 21:0, 23:0), branched-chain FAs ( iso-13:0, anteiso-13:0, iso-14:0, iso-15:0, anteiso-15:0, iso-16:0, iso-17:0, anteiso-17:0, iso-18:0), and the trans-FAs 16:1 trans-9 and 18:1 trans-11 would increase in plasma total lipids following the consumption of three daily servings of full-fat yogurt for three weeks. Our 8-week randomized, double-masked, controlled crossover study included six men and seven women aged 45-75 years old. Each experimental diet period, NFY diet and FFY diet, was three weeks in length. The arithmetic difference in fat (8% energy) between the NFY diet (30% fat) and the FFY diet (38% fat) was solely due to the dairy fat in the full-fat yogurt. Following each experimental diet period, fasting plasma samples were taken and analyzed for FA composition of plasma total lipids using gas-liquid chromatography. Consumption of the FFY diet resulted in no change in the proportion of total odd-chain FAs or the individual FAs 16:1 trans-9 and 18:1 trans-11, but the proportion of total branched-chain FAs was greater in response to the FFY diet ( P < 0.01). For individual odd-chain and branched-chain FAs, the proportions of iso-17:0 and anteiso-17:0 were greater in response to the FFY diet ( P < 0.01 for both); however, there were no differences in anteiso-15:0 or iso-15:0 proportions by diet. Results from this pilot trial suggest that commonly utilized FA biomarkers may not be suffciently robust to represent dairy-fat intake. Branched-chain FAs should be further explored for alternatives. Funding for this project was provided by National Dairy Council Nutrition Research Funding, a USDA Agriculture and Food Research Initiative National Institute of Food and Agriculture Predoctoral Fellowship, and a fellowship from the University of Vermont’s Food Systems Research Center. This is the full abstract presented at the American Physiology Summit 2024 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.