Influence of saturated fat and linolenic acid on the association between intake of dairy products and blood pressure
Data on the association between dairy consumption and blood pressure have been inconsistent. We sought to examine the relation between dairy consumption and prevalent hypertension (HTN) among 4797 participants of the National Heart, Lung, and Blood Institute Family Heart Study. We used generalized estimating equations to estimate prevalence odds ratios of HTN across categories of dairy consumption. From the lowest to the highest sex-, age-, and energy-adjusted quartile of dairy consumption, there was an inverse association between dairy intake and prevalent HTN: odds ratios (95% CIs) were 1.0 (reference), 0.82 (0.64 to 1.05), 0.68 (0.53 to 0.89), and 0.62 (0.45 to 0.84), respectively, in a model adjusting for age, sex, energy intake, field center, body mass index, dietary linolenic acid, saturated and monounsaturated fat, sodium intake, potassium, caffeine, fiber, and fruits and vegetables (P for trend = 0.002). This association was independent of calcium intake and was mainly observed among subjects consuming fewer calories from saturated fat (P for interaction = 0.014). Dairy consumption was inversely associated with systolic (P for trend = 0.003) but not diastolic (P for trend = 0.09) blood pressure. Although subjects consuming > or = 2 servings per day of dairy products and higher total linolenic acid had the lowest prevalence odds of HTN, there was no evidence for interaction between linolenic acid and dairy consumption on HTN (P for interaction = 0.65). In conclusion, our data indicate an inverse association between dairy consumption and prevalent HTN that was independent of dietary calcium, mainly among individuals consuming less saturated fat. This suggests that consumption of low-fat dairy products might be more beneficial for preventing HTN.