Associations of dairy intake with glycemia and insulinemia, independent of obesity, in Brazilian adults: the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

• Published in: The American journal of clinical nutrition Vol. 101; no. 4; pp. 775 - 782
• Main Authors: Drehmer, Michele, Pereira, Mark A, Schmidt, Maria Inês, Molina, Maria Del Carmen B, Alvim, Sheila, Lotufo, Paulo A, Duncan, Bruce B
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Nutrition 01-04-2015; American Society for Clinical Nutrition, Inc
• Subjects: Adult; adults; Aged; anthropometric measurements; blood glucose; Blood Glucose - metabolism; Brazil; cardiovascular diseases; cities; clinical nutrition; Clinical trials; Cross-Sectional Studies; dairy consumption; Dairy Products; Diabetes; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - prevention & control; Fasting; Female; fermented dairy products; food frequency questionnaires; Glucose; Glycated Hemoglobin - metabolism; glycohemoglobin; homeostasis; Humans; hyperinsulinemia; insulin; Insulin - blood; insulin resistance; Linear Models; Logistic Models; Longitudinal Studies; Male; Middle Aged; Multivariate Analysis; myristic acid; Myristic Acid - blood; noninsulin-dependent diabetes mellitus; Nutrition Assessment; Nutrition research; obesity; Obesity - blood; Prospective Studies; regression analysis; research institutions; risk; Risk Factors; sociodemographic characteristics; Surveys and Questionnaires; universities; Brazil; cohort studies; glycemia; insulinemia; dairy products; obesity
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.114.102152

Background: Inverse associations between dairy intake and the risk of type 2 diabetes have been shown, but more studies are needed, especially from low- and middle-income countries. Objective: The objective was to describe the association between dairy products and direct measures of glycemic status in adults without known diabetes. Design: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) includes 15,105 adults, aged 35–74 y, enrolled from universities and research institutions in 6 Brazilian capital cities. We excluded participants with a known diabetes diagnosis, cardiovascular diseases, and cancer. Dairy consumption was assessed by a food-frequency questionnaire, and we computed servings per day for total and subgroups of dairy. Associations with fasting blood glucose (FG) and fasting insulin, 2-h postload glucose (PG), 2-h postload insulin (PI), glycated hemoglobin (Hb A ₁c), and homeostasis model assessment of insulin resistance (HOMA-IR) were assessed through multivariable linear regression analysis with adjustment for demographic characteristics, behavioral risk factors, other dietary factors, and anthropometric measurements. Results: The sample size after exclusions was 10,010. The intake of total dairy was inversely associated with FG (linear β for dairy servings/d = −0.46 ± 0.2 mg/dL), PG (−1.25 ± 0.5 mg/dL), PI (−1.52 ± 0.6 mg/dL), Hb A ₁c (−0.02 ± 0.0%), and HOMA-IR (−0.04 ± 0.0) after adjustment for all covariates (P < 0.05 for all). The findings were consistent across categories of sex, race, obesity status, and dairy fat amount (reduced-fat vs. full-fat dairy). Fermented dairy products showed particularly strong inverse associations with the outcomes, with adjusted differences for a 1-serving/d increment of −0.24 (95% CI: −0.46, −0.02) mg/dL for FG, −0.86 (−1.42, −0.30) mg/dL for PG, and −0.01% (−0.02%, 0.00%) for Hb A ₁c. Myristic acid was the only nutrient that appeared to mediate the association between dairy intake and glycemia. Conclusion: Dairy intake, especially fermented dairy, was inversely associated with measures of glycemia and insulinemia in Brazilian adults without diagnosed diabetes. This trial was registered at clinicaltrials.com as NCT02320461.