Besides aiding digestion and staving off constipation, a high-fiber diet may reduce a woman’s risk for breast cancer. Harvard researchers found that women who consumed the most fiber overall were 8 percent less likely to develop breast cancer than those who consumed the least, according to a report in the journal Cancer, based on analysis of data involving more than 8.5 million women. They found that the risk reduction applied to women of all ages, both pre- and postmenopausal, although studies that focused solely on premenopausal women revealed a greater effect, with risk 18 percent lower for women who consumed the most fiber, compared with those who consumed the least. The researchers noted that the risk-reduction benefit was similar for all fiber-containing foods that had been tracked, including cereals, fruits, vegetables and legumes such as beans and peas. Health experts tend to believe that the beneficial effects of dietary fiber on breast cancer risk relate to the ability of fiber to help control blood sugar and decrease estrogen levels. Current dietary guidelines call for the average adult woman to consume about 25 grams of fiber a day to achieve the most benefit (38 grams a day for men), although people often fall short of that goal — a situation described as America’s “fiber gap.” People adding dietary fiber to their daily menu are advised to do so gradually and to drink plenty of water, to avoid the gas, bloating and cramping that can develop as the digestive system adjusts to the change.