Healthy adults who consumed at least five servings of fruit and vegetables
daily--the amount recommended in the US and UK--had lower blood pressure than
adults who consumed fewer servings over 6 months.
On a population level, the reduction in blood pressure observed in the study
would translate into a 17% reduction in the rate of high blood pressure, a 6%
lower risk of coronary heart disease and 15% fewer strokes, the researchers
The findings support previous research showing that a fruit- and vegetable-rich
diet boosts levels of disease-fighting antioxidants in the blood and reduces
blood pressure in the short term.
To investigate the longer-term effects of such a diet, the researchers from
the University of Oxford in the UK assigned nearly 700 adults aged 25 to 64
to follow their regular diet or to eat at least five servings of fruit and vegetables
daily. One serving is equal to 80 grams--about one medium-sized piece of fruit
or half a cup of cooked vegetables. Adults who took vitamin pills were not included
in the study.
Over the next 6 months, levels of certain antioxidants--including vitamin C,
lutein and beta-carotene--increased in the group of adults encouraged to boost
their fruit and vegetable intake but not in the other group. There were no changes
in body weight or cholesterol levels but the systolic blood pressure of adults
who consumed more fruit and vegetables fell by about 4 mm Hg and their diastolic
pressure fell by 1.5 mm Hg.
The systolic blood pressure is the first number in a blood pressure reading,
and the diastolic blood pressure is the second.
The fall in blood pressure achieved in our study is unlikely to be attributable
to reduced fat intake or changes in physical activity," Dr. Andrew Neil
and colleagues report.
They suggest that a higher intake of potassium, which is abundant in many fruits
and vegetables and is associated with lower blood pressure, may underlie the
health benefits. Lower levels of sodium may also contribute to the benefits,
although the researchers did not measure blood sodium.
About half of adults in the UK currently consume at least five servings of
fruit and vegetables daily, according to the study in the May 28th online issue
of The Lancet.
"The effects of the intervention on fruit and vegetable consumption, plasma
antioxidants, and blood pressure would be expected to reduce cardiovascular
disease in the general population," the study authors conclude