Dietary change in an intervention trial of wheat bran fiber and colorectal adenoma recurrence

Fiber, sex, and colorectal adenoma: results of a pooled analysis

BACKGROUND

Evidence for an association between dietary fiber and colorectal neoplasia has been equivocal, and some data suggest that there may be sex differences in response to fiber.

OBJECTIVE

We sought to determine whether fiber affects colorectal adenoma recurrence differently in men and women by combining the study populations of 2 large clinical intervention trials: the Wheat Bran Fiber Trial and the Polyp Prevention Trial.

DESIGN

Data from 3209 participants combined from 2 trials were analyzed with logistic regression models to examine the effect of a dietary intervention on colorectal adenoma recurrence in the pooled population as a whole and by sex.

RESULTS

The adjusted odds ratio for adenoma recurrence for those in the intervention group of either the Wheat Bran Fiber Trial or the Polyp Prevention Trial was 0.91 (95% CI: 0.78, 1.06). For men, the intervention was associated with statistically significantly reduced odds of recurrence with an odds ratio of 0.81 (95% CI: 0.67, 0.98); for women, no significant association was observed. Using a likelihood-ratio test, we found a statistically significant interaction between intervention group and sex (P = 0.03).

CONCLUSION

The results of the current analyses indicate that men may experience more benefit from dietary fiber than do women and may help to explain some of the discrepant results reported in the literature.

Nutritional changes among premenopausal women undertaking a soya based dietary intervention study in Hawaii

BACKGROUND

We conducted a 2-year nutritional intervention among premenopausal women. The goal was to incorporate two daily servings of soya into the regular diet. This report describes the dietary modifications and assesses their nutritional adequacy with regard to major nutrients.

METHODS

In this analysis of 100 intervention and 106 control subjects, women completed a validated food-frequency questionnaire at baseline; throughout the study, they participated in at least three unannounced 24-h recalls.

RESULTS

At randomization, both groups were similar in age and body weight, reported low soya intake, and did not differ by intake of major nutrients and foods. According to the 24-h recalls, women in the intervention group consumed nearly two servings of soya per day, while the control women remained at 0.2 servings. In comparison with the control group, the intervention group consumed fewer dairy products, primarily milk, but also less meat, nuts and seeds. As a result of the dietary modification, the intervention women consumed less-saturated fat and cholesterol and more protein, dietary fibre, calcium and vitamins than the control group.

CONCLUSION

These results suggest that women in the intervention group improved the overall quality of their diet by adding two servings of soya per day.