A high consumption of dairy products, in particular milk products and low-fat dairy products, could play a role in the prevention of high blood pressure in a general older population, concludes a recent article published in the American Journal of Clinical Nutrition.
The researchers from Wageningen University and the Erasmus Medical Centre in Rotterdam wanted to determine whether hypertension in older subjects is associated with the intake of different types of dairy products. A total of 2,245 Dutch adults aged 55 years or older were included in the study and had their dietary and blood pressure data recorded during 3 visits: the first between 1990 and 1993, a second follow-up between 1993–1995 and a final follow-up after 6 years between 1997–1999.
Study participants were then split into four equal-sized groups with average dairy intakes of 164 g/d, 325 g/d, 472 g/d, and 691g/d, respectively. In order to decipher the impact of different milk products, the scientists defined the following dairy subgroups:
- Milk and milk products - all kinds of milk, yogurt, coffee creamer, curd, pudding, porridge, custard, and whipped cream
- Cheese - all kinds of cheese products, i.e. soft cheese, hard cheese, and cheese spreads
- Low fat dairy products - fat content <2g/100g for milk and milk products and <20g/100g for cheese
- High fat dairy products - fat content >3.5g/100g for milk and milk products and >20g/100g for cheese
Statistical analysis revealed that the risk of developing high blood pressure decreased with increasing dairy intake. Risk reduction was 7% for each additional 150 ml serving of dairy. When looking at the dairy subgroups, subjects consuming milk and milk products and low-fat dairy products at the high end of the spectrum had a decreased risk for developing hypertension compared to participants with lower intakes. No such impact was found for cheese or high-fat dairy intakes in general. Risk reduction was higher after 2 years than after 6 years of follow-up and more pronounced among subjects with overweight.
The authors raised various hypotheses to explain why the observed associations were weaker after 6-years follow-up than after 2 years: 1) dairy product intake may slow the progression rather than prevent the development of hypertension in certain individuals and thus dairy product intake may better predict short-term (2 years) than long-term (6 years) onset of hypertension; 2) participants could have changed their diet between 2 and 6 years of follow-up; 3) individuals who are most susceptible to a beneficial effect of dairy products may already benefit after 2 years, whereas individuals who do not respond within 2 years will also not respond after 6 years. The mechanism(s) by which dairy products reduce blood pressure remain(s) to be established, but the minerals calcium, magnesium and potassium may have a role as well as antihypertensive peptides produced upon digestion of milk protein.
For more information
Engberink MF et al (2009). Inverse association between dairy intake and hypertension: the Rotterdam Study. American Journal of Clinical Nutrition 89(6):1877-83. doi:10.3945/ajcn.2008.27064
