Many studies have found that diets rich in fruits and vegetables may be protective against a number of diseases. But is it the fruits and vegetables themselves, or one or more of the specific nutrients or other compounds they contain, that impart this observed disease protection? Scientists continue to explore that question, but a recent study found that, in the case of high blood pressure, it was fruit and vegetable intake overall, rather than the amount of vitamin C in the diet, that was beneficial. The results are reported in the Annals of Nutrition & Metabolism.
Studying diet and blood pressure
Researchers in Germany studied 1,628 women and 1,340 men aged 18-79 to determine if an association existed between fruit and vegetable intake, vitamin C intake, and high blood pressure.
The participants completed detailed health and lifestyle questionnaires and were given medical exams and dietary interviews. The researchers collected information about the participants' diets and obtained blood pressure readings. Using that information, and controlling for other factors that could affect blood pressure (such as age, physical activity levels, and smoking status), the researchers looked for associations between fruit and vegetable consumption and blood pressure, as well as between vitamin C intake and blood pressure.
Fruits and vegetables more effective than vitamin C
The researchers found a "significant inverse association" between fruit and vegetable intake and systolic blood pressure readings (systolic is the "top" number in blood pressure readings) among the women participating in the study. This means that greater fruit and vegetable intake was associated with lower systolic blood pressure readings. No such association was found between vitamin C intake and blood pressure, and no significant associations were observed in the men.
Benefiting from the "whole package" of nutrients
The results of this study add to existing evidence that the health benefits of diets rich in fruits and vegetables are likely attributable to the whole package of nutrients they contain, rather than to specific, singular nutrients.
Of course, one might also suggest that we just haven't discovered which specific nutrient or nutrients are responsible - clearly it's not vitamin C. Scientists will continue to explore the potential relationships between nutrients and disease states. In the meantime, experts continue to recommend including a variety of brightly colored fruits and vegetables in your diet.
Source
Blood pressure and vitamin C and fruit and vegetable intake. R. Beitz, GBM. Mensink, B. Fischer, Ann Nutr Metab, 2003, vol. 47, pp. 214--220