The promise of health benefits from soy has contributed to the recent increase in the availability of soy-containing foods. Since 1995, sales of soy-based products have increased 20% per year, with a large boost in 1999 when the US Food and Drug Administration (FDA) approved a health claim for soy's cardiovascular benefits. Large-scale dietary trends toward vegetarianism and ready-to-eat meals are also driving an increase in the consumption of soy-based meat alternatives. As a result, soy foods are moving rapidly from a niche market to mainstream acceptance. Given recent studies reporting an inverse relationship between soy intake and breast cancer risk, awareness and use of soy foods may be particularly high among women at increased risk for breast cancer. Likewise, beliefs about the benefits of soy in reducing menopausal symptoms may motivate women at risk for breast cancer who are perimenopausal or postmenopausal to try alternatives to estrogen to treat menopausal symptoms.

However, despite the widespread promotion of soy and evidence of its health benefits with respect to heart disease risk, its effects on breast health, especially in non-Asian women, are unknown. Indeed, studies of soy effects on breast density and fluid suggest the possibility that high levels of intake might actually increase breast cancer risk in US women, of particular concern among women already at increased risk for the disease. The objectives of the present study were to: (a) examine sociodemographic and lifestyle correlates of soy food consumption among women at increased risk for breast cancer, (b) describe primary reasons for consumption or nonconsumption of soy foods, and (c) identify sources from which at-risk women obtain information about soy food.

Questionnaires were sent to 893 women enrolled in a family risk assessment program, an education/counseling program for first- and second-degree relatives of cancer patients. A sample of 452 respondents (54% response rate) took part in the study. A self-report questionnaire was used to elicit information about the frequency of consumption of soy and other isoflavone-containing foods, reasons for consumption or nonconsumption, and sources of information about soy foods.

Thirty-two percent reported soy food consumption. Commonly consumed soy foods were vegetable burgers, tofu, and soymilk. Consumers of soy foods were more likely to have higher levels of education and report eating five or more daily servings of fruits and vegetables. The primary reason for consumption of soy foods was eating a healthful diet, whereas insufficient knowledge about soy food preparation was the primary reason stated for nonconsumption. Both consumers and nonconsumers reported obtaining information about soy foods from magazines, friends, and newspapers. Consumers also indicated using the Internet to seek information. Overall, 43% (n=193) of participants reported eating at least one soy food per month, regardless of how they classified themselves with respect to soy food consumption. The majority (123 of 193, 64%) consumed soy foods more than twice a month. One hundred and eighteen women categorized themselves as consumers, and 283 women categorized themselves as nonconsumers. The remaining 51 women who described themselves as both (n=l 5) or neither (n=36) were categorized as consumers or nonconsumers based on their soy food consumption. Mean frequency of soy food intake among consumers was 18.35 servings per month. The soy food items eaten by the highest percentages of consumers were vegetable burgers, tofu, soymilk, soynuts, and green soybeans. The most frequently consumed soy foods on average were soymilk, soynuts, vegetable burgers, and tofu.

This is one of the first studies to evaluate soy food intake among women at increased risk for breast cancer. Interestingly, although 32% of respondents self-reported being consumers of soy food, 43% recounted consuming some soy food at least once per month. Thus, a significant proportion of respondents were getting soy in their diets, even without making concerted efforts to consume soy. It is also notable that compared with other studies in which consumers incorporated soy foods into their diets only once or twice per month, the majority of consumers (64%) in the present sample reported consumption in a frequency more than twice per month. The higher prevalence and frequency of soy consumption in the present sample suggests that at-risk women may be more inclined to incorporate soy foods into their diets, perhaps in an effort to establish healthful dietary behaviors. Women cited several reasons for consuming soy foods, with the majority of consumers being motivated to eat a more healthful diet. In addition, nearly half of the consumers cited cancer risk reduction as motivating their soy food consumption. Notably, a greater proportion of women reported consuming soy to reduce cancer risk than to reduce their risk of heart disease, even though the only health claim for soy permitted by the FDA is related to heart disease.