The Link Between Fruit, Vegetables and Health - Stroke
Data relating to stroke is presented in references 2, 3, and 4. Reference 2 was described on the previous page. Reference 3 involves 75,596 women, ages 34 to 59, 14 years followup, and 38,683 men, ages 40 to 75 with 8 years followup. Reference 4 includes 54,506 men and women, with a total of 168,388 person-years followup.
The results of reference 2 show an RR of 0.73 (0.57 to 0.95 at the 95% confidence level interval) for participants consuming three or more servings a day of fruit and vegetables, compared to those who consume fruit and vegetables less than once a day. Those who ate three times a day, ate on average more than double the weight of fruits and vegetables that those who ate less than once a day - 520 grams compared to 242 grams (19 vs. 9 oz, or 5 vs. 2.5 servings).
In reference 3, an RR of 0.69 (0.52 to 0.92 at the 95% confidence level interval) results, for comsumers in the highest quintile of fruit and vegetable intake, compared to the lowest. Participants in the highest quintile ate approximately 9-10 servings a day, whereas those in the lowest quintile ate 2-3 servings a day.
The result in reference 4 is an RR of 0.72 (0.47 to 1.12 at the 95% confidence level interval). In this study, the participants in the highest quintile ate 673 grams (24 oz) of fruits and vegetables a day, and the lowest quintile - 147 grams (5 oz) per day.
Using the same crude combination we previously described, the combined result is 0.71 (0.57 to 0.85 at the 95% confidence level interval). We conclude that the risk of stroke is reduced by 29% when large quantities of vegetables and fruits are consumed. The intake required to achieve this reduction is around 500 - 700 grams (18 -25 oz), or 9-10 "servings" a day.
References 3 and 4 provide additional information about the types of vegetables that provide the most protection. The statistical precision of reference 4 is insufficient to draw reliable conclusions, but reference 3 contains guidelines worth considering: