Whole Grains May Help Prevent Hypertension In Men

Men who eat whole grains and bran may be lowering the risk of developing hypertension say reserachers from Harvard. 

Under the leadership of project director Alan J. Flint, researchers analysed data on 31,684 men who participated in the Health Professionals Follow-Up Study over an 18 year period and released their findings in the report, “Whole grains and incident hypertension in men,” published in the September issue of the American Journal of Clinical Nutrition.

At the beginning of the study in 1986, none of the men had hypertension, cancer, stroke or coronary heart disease. During the follow-up from 1986 to 2004, researchers found a total of 9,227 cases of hypertension.

Men in the highest quintile of whole grain intake (46 grams per day) accounted for 1,648 of the 9,227 hypertension cases and were deemed to be 19 per cent less likely to develop high blood pressure compared with those men in the lowest quintile (3.3 grams per day), which accounted for 1,826 of the 9,227 cases. Meanwhile, the men in the highest quintile of bran intake (12 grams per day) were found to be 15 per cent less likely to develop high blood pressure compared with those in the lowest quintile (0.3 grams per day).

The intakes of whole grains, bran and germ were calculated by determining the whole grain content of each grain food according to the dry weight of its whole grain ingredients. Nutrient profiles of the various grains were derived by using composite recipes, nutrient data from the U.S. Department of Agriculture, and product labels. For home prepared bakery items, cookbooks were used to estimate whole grain content.

The reasons for whole grain’s influence on hypertension are wide ranging, the researchers noted, including its ability to improve insulin sensitivity, reduce food intake and lower blood sugar.

“There is a growing body of evidence from both observational epidemiologic studies and randomized clinical trials that diet influences blood pressure, particularly intakes of potassium and fiber, both of which are constituent compounds of whole grains.”

The researchers said the inverse association between whole grain intake and hypertension was independent of other healthy lifestyle and diet factors, such as intake of sodium, alcohol, fruit and vegetables, as well as adjustment for physical activity, multivitamin use and cholesterol screening.