Does Dairy Fat Lower Risk of Diabetes?
Title: Circulating Biomarkers of Dairy Fat and Risk of Incident Diabetes Mellitus Among US Men and Women in Two Large Prospective Cohorts
Author: Yakoob et al
Objective: To test the hypothesis that circulating fatty acid biomarkers of dairy fat, 15:0, 17:0, and t-16:1n-7, are associated with lower incidence of diabetes mellitus
CDC data from 2014 on Diabetes shows that:
- 29.1 million Americans have diabetes
- 86 million Americans have prediabetes,
- Total medical costs for treating diabetes is $245 billion
- Having diabetes increases your risk of death by 50% compared to non-diabetics and will shave years off your life expectancy
The most common recommendations for treating diabetes beyond medications is:
- Dietary changes
- Weight loss
The association between dairy and dairy-based products and diabetes is unclear. Some early studies have suggested that yogurt or cheese may have protective effects, despite these food products having high fat content. Most research is based on questionnaires.
This study sought to use blood biomarkers of dairy consumption, namely the odd-chain saturated fats pentadecanoic acid (15:0) and heptadecanoic acid (17:0), and the natural ruminant trans fat trans-palmitoleate (t-16:1n-7). These fats are obtained exclusively from dairy consumption and blood levels can be tested.
Early laboratory research suggests these types of fat may improve muscle uptake of glucose and prevent new synthesis of glucose by the liver. The authors of this study wanted to measure these lab tests both in the blood and in red blood cells (erythrocytes) and see if they are associated with a lower incidence of diabetes.
This study included 3,333 adults, aged 30-75 who were diabetes free at baseline.
Plasma and erythrocyte fatty acids were measured in blood collected in a couple of well known studies from the 1990s (Nurses’ Health Study, Health Professionals Follow-Up Study).
Incident diabetes through 2010 was confirmed by validated supplementary questionnaire based on symptoms, diagnostic tests, and medications.
With an average follow up of 15 years, 277 new cases of diabetes were diagnosed.
They adjusted their results for metabolic risk factors, lifestyle, diet and other circulating fatty acids.
What they found was individuals with
- Higher plasma pentadecanoic acid (15:0) levels were associated with a 44% lower risk of diabetes (quartiles 4 vs. 1, HR=0.56, 95%CI=0.37-0.86; Ptrend= 0.01);
- Higher plasma heptadecanoic acid (17:0) levels were associated with a 43% lower risk (HR=0.57, 95%CI=0.39-0.83, P-trend=0.01);
- Higher trans-palmitoleate (t-16:1n-7) levels were associated with a 52% lower risk (HR=0.48, 95%CI=0.33-0.70, P-trend <0.001).
Findings were similar for erythrocyte (which are red blood cells) 15:0, 17:0, and t-16:1n-7, although with broader CIs that only achieved statistical significance for 17:0.
Higher plasma dairy fatty acid concentrations were associated with lower risk of developing diabetes.
These findings suggest that dairy may have a protective effect on the development of diabetes.
These findings also highlight need to better understand dietary and metabolic effects of these dairy fatty acids as well as to potential health effects of dairy fat on other disease processes.
Yakoob, M. Y., Shi, P., & Willett, W. C. (2016). Circulating Biomarkers of Dairy Fat and Risk of Incident Diabetes Mellitus Among Men and Women in the United States in Two Large Prospective CohortsCLINICAL PERSPECTIVE. Circulation,133(17), 1645-1654. doi:10.1161/circulationaha.115.018410