Study participants with the highest average intake of low-fat dairy were found to have significantly lower systolic and diastolic blood pressure (BP), than participants in with the lowest average low-fat dairy intakes, according to results published in the British Journal of Nutrition,
“To our knowledge, the present study is the first large prospective cohort observing an inverse association between low-fat dairy products and BP in an older population at high cardiovascular risk during a 12-month follow-up,” wrote lead author Estefania Toledo from University of Navarra.
Biological plausibility
Despite being the first such study, the results do compliment others in the literature. Animal studies have reported that milk proteins, including both caseins and whey proteins, can reduce blood pressure, with the effects being linked to angiotension converting enzyme (ACE) inhibitory peptides in the proteins.
ACE inhibitors work by inhibiting the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, thereby improving blood flow and blood pressure.
Companies are active in this area, with Spain’s Puleva looking at hydrolysed caseins from goat's milk as a potential anti-hypertensive ingredient.
A potential role for calcium has also been mooted by researchers. A study by Harvard researchers noted that the mineral may inhibit the constriction of vascular smooth muscle cell, while also improving the sodium-potassium balance. High calcium intakes have also been linked to weight loss and enhanced insulin sensitivity, which could also contribute to blood pressure improvements (Hypertension, Vol. 51, pp. 1-7).
There are an estimated 10m people in the UK with hypertension, defined as having blood pressure higher than 140/90 mmHg. High fat diets have long been identified as a prime factor in increasing the risk of hypertension. This has led to a switch by many consumers to lower fat products.
Study details
Toledo and her co-workers recruited 2290 elderly volunteers at high cardiovascular risk, including 1845 with hypertension. Dietary intakes was assessed using a food frequency questionnaire (FFQ) and blood pressure was measured by trained personnel. The participants were followed for 12 months.
The systolic and diastolic blood pressures of those with the highest average level of low-fat dairy intake (631 grams per day) were 4.2 and 1.8 mmHg lower than for participants with the lowest average intakes (3.1 grams per day).
“In conclusion, low-fat dairy products could play an important role in the prevention of hypertension and may be helpful in the control and reduction of BP levels,” wrote the researchers.
“The current study fills one gap in the available evidence about the effects of dairy products in elderly high-risk populations, suggesting that low-fat dairy products could also be potentially beneficial in this group.
“To confirm our findings, large clinical trials designed specifically to assess the role of low-fat dairy products on BP levels or on the incidence of hypertension should be conducted,” they added.
Source: British Journal of NutritionVolume 101, Pages 59-67 “Low-fat dairy products and blood pressure: follow-up of 2290 older persons at high cardiovascular risk participating in the PREDIMED study”Authors: E. Toledo, M. Delgado-Rodriguez, R. Estruch, J. Salas-Salvado, D. Corella, E. Gomez-Gracia, M. Fiol, R.M. Lamuela-Raventos, H. Schroder, F. Arosa, E. Ros, V. Ruiz-Gutierrez, J. Lapetra, M. Conde-Herrera, G. Saez, E. Vinyoles, M.A. Martinez-Gonzalez