Taking B vitamins may have a favourable effect on blood pressure, according to a statistical study (1) published by the American Heart Association.
Hypertension, also called high blood pressure, is a leading cause of heart disease worldwide (2). Heart disease and stroke risk rises across blood-pressure levels; even high-normal pressure carries appreciable risk (1). Dietary habits involving salt are known to raise blood pressure (3), but despite research, the effects of many other nutrients remain unclear (1).
A broad nutrient-based study offers a more comprehensive statistical approach to investigating hypertension than studying one nutrient at a time.
Two large studies, INTERMAP (4) and NHANES (National Health and Nutrition Examination Survey) (5), provided databases for this broad nutrient investigation. INTERMAP was a collaborative study of macronutrients and micronutrients, reported in 2003. It used cross-sectional data on 4,680 men and women aged 40–59 from 17 countries, including China, Japan and the United States, as described in the source. Participant interviews recorded food and supplement intake, from which 82 different nutrients were derived.
To validate these findings, NHANES conducted extensive ongoing observations in the United States in 1999–2006 in a population similar to INTERMAP’s. The aim was to confirm earlier findings and identify previously unreported associations between nutrients and hypertension. Alcohol intake was again associated with higher pressure. The link between greater sodium intake relative to potassium and higher pressure was also reinforced (4,5).
People consuming phosphorus, magnesium and non-haem iron were more likely to have lower blood pressure. New findings not identified in earlier studies concerned B vitamins: thiamine (B1), folic acid (B9) and riboflavin (B2) were inversely associated with higher blood pressure, like the minerals above.
Identifying an association between a nutrient and blood pressure does not establish causation, but can guide future studies.
Further clinical evaluation is needed to determine whether B vitamins can help prevent cardiovascular disease caused by high blood pressure (1).
Reference:
1. Tzoulaki, Ioanna , et al. A Nutrient-Wide Association Study on Blood Pressure, Circulation. 2012;126:2456-2464; originally published online October 23, 2012; doi: 10.1161/CIRCULATIONAHA.112.114058 Circulation is published by the American Heart Association.
2. Hajjar I, Kotchen JM, Kotchen TA. Hypertension: trends in prevalence, incidence, and control. Annu Rev Public Health. 2006;27:465-9
3. Sacks, Frank MD et al. Effects on Blood Pressure of Reduced Dietary Sodium and the Dietary Approaches to Stop Hypertension (DASH) Diet. N Engl J Med 2001; 344:3-10. DOI: 10.1056/NEJM200101043440101
4. Stamler J, Elliott P, Dennis B, Dyer AR, Kesteloot H, Liu K, Ueshima H, Zhou BF; INTERMAP Research Group. INTERMAP: background, aims, design, methods, and descriptive statistics (nondietary). J Hum Hypertens. 2003;17:591– 608.
5. Centers for Disease Control and Prevention (CDC). National Health and Nutrition Examination Survey. http://www cdc gov/nchs/nhanes/ 2011; Accessed 03/06/2012.