B complex, calcium and potassium from food sources may
protect against stroke
In this recent observational study published in Nutrition Research and Practice, Yongsoon
Park and associates, of the Department of Food and Nutrition at Hangyang
University in Seoul Korea, sought to elucidate which constituents in foods may
account for findings in previous studies associating vegetable and fruit
consumption with a reduction in stroke risk.With regard to specific nutrients, Park acknowledges other research
suggesting that decreased stroke risk has been associated with some, but not
all antioxidants.He also cites two
randomized trials demonstrating no associations with reduced stroke risk and
supplementation with some synthetic vitamins and antioxidant isolates.Park notes that folate and B-vitamins from
food, however, have received attention in recent studies as possibly protecting
against stroke.
Park writes the purpose of this study was to “test the hypothesis that intake of fruits
and vegetables, which are major sources of antioxidant and vitamin B complex
vitamins, reduces the risk of stroke.”
Subjects were recruited among patients admitted to
Hanyang University Seoul Hospital for treatment of first event of stroke (n = 69) over
a 20 month period. The 69 participants
were age, sex, and body mass indexed to healthy controls, and were not taking
dietary supplements during the study period.A semi-quantitative food frequency questionnaire (FFQ) including 117
food items common to Korean meals was administered for baseline dietary
assessment.Despite the statistically
significant findings noted below, Park acknowledges limitations of the study: the small size of the food items accounted
for, the small the number of subjects, and possible, unaccounted for residual
confounding factors (such as socioeconomic status).
To quote, Park, the main results were as follows: “Multivariable-adjusted regression analysis
showed that intakes of total fat, plant fat, calcium, potassium, vitamin B1,
vitamin B2, vitamin B6, niacin, and folate were negatively correlated with the risk of stroke
after adjusting for age, sex, BMI, and family history of stroke (Table 2). However,
intake of antioxidant vitamins, such as carotene, vitamin C, and vitamin E was
not associated with the risk of stroke.”Writing further, Park observed “no
association between intake of
grain, fruits, seafood, milk and meat, and the risk of stroke.”
Citing related findings the author speculated that the
protective effects of vegetables, plants and plant fats (rich sources of B
complex, calcium and potassium) may especially be due to the combined interaction
of four relevant B vitamins needed to metabolize and in turn reduce levels of
homocysteine; which, when elevated may be a risk factor for arterial
endothelial dysfunction.Park notes that
clinical trials are needed to determine causality as well as clarify the actual
mechanisms at work accounting for the inverse association observed between stroke
risk and high vegetable intake.
Study: Park, H., Nutr Res Pract 4(4):303-310 (2010)