Higher Plasma Dairy Fat Associated With Lower Incidence Of Diabetes

[Brasica]

Circulating Biomarkers of Dairy Fat and Risk of Incident Diabetes Mellitus Among US Men and Women in Two Large Prospective Cohorts

Abstract
Background—In prospective studies, relationship of self-reported consumption of dairy foods with risk of diabetes mellitus is inconsistent. Few studies have assessed dairy fat, using circulating biomarkers, and incident diabetes. We tested hypothesis that circulating fatty acid biomarkers of dairy fat, 15:0, 17:0, and t-16:1n-7, are associated with lower incident diabetes.

Methods and Results—Among 3,333 adults aged 30-75 years and free of prevalent diabetes at baseline, total plasma and erythrocyte fatty acids were measured in blood collected in 1989-90 (Nurses' Health Study) and 1993-94 (Health Professionals Follow-Up Study). Incident diabetes through 2010 was confirmed by validated supplementary questionnaire based on symptoms, diagnostic tests, and medications. Risk was assessed using Cox proportional hazards, with cohort findings combined by meta-analysis. During mean±SD follow-up of 15.2±5.6 years, 277 new cases of diabetes were diagnosed. In pooled multivariate analyses adjusting for demographics, metabolic risk-factors, lifestyle, diet, and other circulating fatty acids, individuals with higher plasma 15:0 had 44% lower risk of diabetes (quartiles 4 vs. 1, HR=0.56, 95%CI=0.37-0.86; P-trend=0.01); higher plasma 17:0, 43% lower risk (HR=0.57, 95%CI=0.39-0.83, P-trend=0.01); and higher t-16:1n-7, 52% lower risk (HR=0.48, 95%CI=0.33-0.70, P-trend <0.001). Findings were similar for erythrocyte 15:0, 17:0, and t-16:1n-7, although with broader CIs that only achieved statistical significance for 17:0.

Conclusions—In two prospective cohorts, higher plasma dairy fatty acid concentrations were associated with lower incident diabetes. Results were similar for erythrocyte 17:0. Our findings highlight need to better understand potential health effects of dairy fat; and dietary and metabolic determinants of these fatty acids.

 

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great stuff,

J Am Heart Assoc. 2013 Jul 18;2(4):e000092. doi: 10.1161/JAHA.113.000092.
Biomarkers of dairy fatty acids and risk of cardiovascular disease in the Multi-ethnic Study of Atherosclerosis.
de Oliveira Otto MC1, Nettleton JA, Lemaitre RN, Steffen LM, Kromhout D, Rich SS, Tsai MY, Jacobs DR, Mozaffarian D.
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Abstract
BACKGROUND:
Evidence regarding the role of dairy fat intake in cardiovascular disease (CVD) has been mixed and inconclusive. Most earlier studies have used self-reported measures of dietary intake and focused on relatively racially homogeneous populations. Circulating biomarkers of dairy fat in a multiethnic cohort provide objective measures of dairy fat intake and facilitate conclusions relevant to populations with different diets and susceptibility to CVD.

METHODS AND RESULTS:
In a multiethnic cohort of 2837 US adults aged 45 to 84 years at baseline (2000-2002), phospholipid fatty acids including 15:0, 14:0, and trans-16:1n7 were measured using standardized methods, and the incidence of CVD prospectively adjudicated. Self-reported whole-fat dairy and butter intakes had strongest associations with 15:0, rather than 14:0 or trans-16:1n7. In multivariate models including demographics and lifestyle and dietary habits, each SD-unit of 15:0 was associated with 19% lower CVD risk (hazard ratio [95% CI] 0.81 [0.68 to 0.98]) and 26% lower coronary heart disease (CHD) risk (0.74 [0.60 to 0.92]). Associations were strengthened after mutual adjustment for 14:0 and trans-16:1n-7 and were similar after adjustment for potential mediators. Plasma phospholipid 14:0 and trans-16:1n-7 were not significantly associated with incident CVD or CHD. All findings were similar in white, black, Hispanic, and Chinese American participants.

CONCLUSION:
Plasma phospholipid 15:0, a biomarker of dairy fat, was inversely associated with incident CVD and CHD, while no association was found with phospholipid 14:0 and trans-16:1n-7. These findings support the need for further investigation of CVD effects of dairy fat, dairy-specific fatty acids, and dairy products in general.