Fruit and vegetable intake and ischaemic stroke

Can fruit and vegetables reduce the risk of ischaemic stroke?

Eating fruit and vegetables is one of the mainstays of healthy living. They reduce the risk of heart disease and cancer. What about stroke? Bandolier 20 has previously reported that fruit and vegetables reduce the risk of stroke in men. This study examines the same association, but focuses on ischaemic stroke and looks at both men and women.

Message

Eating fruit and vegetables reduces the risk of ischaemic stroke in men and women. Eating a minimum of six servings of fruit and vegetables a day reduces the risk of ischaemic stroke by approximately 30%.

Reference

K Joshipura et al. Fruit and vegetable intake in relation to risk of ischemic stroke. JAMA 1999 282: 1233-1239.

Study

Participants for this study were 75,596 women, aged 34 to 59 years, from the US Nurses Health Study with 14 years of follow-up (1980-1994) and 38,683 men, aged 40 to 75 years, from the US Health Professionals Follow-up Study with eight years of follow-up (1986-1994). They were free of cardiovascular disease, cancer and diabetes at the start of the study. Questionnaires, completed every two years, provided information on medical history, new conditions and health behaviours. Cases of stroke were confirmed by physicians (unaware of participants dietary status) using medical records and imaging results.

Food frequency questionnaires assessed diet: for women in 1980, 1984, 1986 and 1990; and for men in 1986 and 1990. Average daily servings of fruit and vegetables were calculated from responses to average intake over the previous year. (Although a serving is not defined, generally it equals one piece of fruit, e.g. an apple, or one portion of vegetables, e.g. a carrot, and does not include potatoes.) Average daily intake was categorised into quintiles (1 = lowest intake, 5 = highest).

There were 366 cases of ischaemic stroke among women and 204 among men.

Results

Compared with men and women in the lowest quintile (less than 3 servings a day), those in the highest quintile (more than 6 servings a day) reduced the risk of ischaemic stroke by 31% (relative risk 0.69, 95% confidence interval 0.52 to 0.92). The results were adjusted for age, smoking, alcohol consumption, history of heart disease, body mass index and other possible cardiovascular risk factors.

Comment

This large study provides another valuable reason to eat fruit and vegetables and supports the current recommendation to eat at least five to six servings of fruit and vegetables a day.