Consumption Of Soy Products Research Articles

Hypogonadism and erectile dysfunction associated with soy product consumption

Previous research has focused on the beneficial effects of soy and its active ingredients, isoflavones. For instance, soy consumption has been associated with lower cardiovascular and breast cancer risks. However, the number of reports demonstrating adverse effects of isoflavones due to their estrogenlike properties has increased. We present the case of a 19-y-old type 1 diabetic but otherwise healthy man with sudden onset of loss of libido and erectile dysfunction after the ingestion of large quantities of soy-based products in a vegan-style diet. Blood levels of free and total testosterone and dehydroepiandrosterone (DHEA) were taken at the initial presentation for examination and continuously monitored up to 2 y after discontinuation of the vegan diet. Blood concentrations of free and total testosterone were initially decreased, whereas DHEA was increased. These parameters normalized within 1 y after cessation of the vegan diet. Normalization of testosterone and DHEA levels was paralleled by a constant improvement of symptoms; full sexual function was regained 1 y after cessation of the vegan diet. This case indicates that soy product consumption is related to hypogonadism and erectile dysfunction. To the best of our knowledge, this is the first report of a combination of decreased free testosterone and increased DHEA blood concentrations after consuming a soy-rich diet. Hence, this case emphasizes the impact of isoflavones in the regulation of sex hormones and associated physical alterations.

Tracing distant environmental impacts of agricultural products from a consumer perspective

Globally, trade flows of agricultural products are increasing. While value is typically added along the whole production chain, certain environmental impacts, such as land and water use, biomass appropriation, and soil degradation, are intrinsically linked to where the primary products originate from. When taking a consumer oriented approach on environmental problems, bilateral trade statistics can help in providing a clearer picture about the location of impacts caused by consumption elsewhere. However, in today's increasingly globalized world, consumer goods are often imported from countries other than where the primary product originated from. For instance, soybeans are transported from Brazil to the Netherlands, where they are processed into soy oil, which is shipped to Austria, where it is consumed. Utilizing bilateral trade matrices and matrix algebra, we present a method that allows to clearly link consumption patterns to the origin of primary products. In this, the method can help to provide information about consumption related, distant environmental impacts. We employ the case of land and water use linked to Austria's soy product consumption to demonstrate the approach's relevance. Finally, we outline some possible applications of this method to show its potential in enhancing understanding for informed consumer based environmental decision making.

Nutrition Concerns and Health Effects of Vegetarian Diets

Vegetarians exhibit a wide diversity of dietary practices, often described by what is omitted from their diet. When a vegetarian diet is appropriately planned and includes fortified foods, it can be nutritionally adequate for adults and children and can promote health and lower the risk of major chronic diseases. The nutrients of concern in the diet of vegetarians include vitamin B(12), vitamin D, ω-3 fatty acids, calcium, iron, and zinc. Although a vegetarian diet can meet current recommendations for all of these nutrients, the use of supplements and fortified foods provides a useful shield against deficiency. A vegetarian diet usually provides a low intake of saturated fat and cholesterol and a high intake of dietary fiber and many health-promoting phytochemicals. This is achieved by an increased consumption of fruits, vegetables, whole-grains, legumes, nuts, and various soy products. As a result of these factors, vegetarians typically have lower body mass index, serum total and low-density lipoprotein cholesterol levels, and blood pressure; reduced rates of death from ischemic heart disease; and decreased incidence of hypertension, stroke, type 2 diabetes, and certain cancers than do nonvegetarians.

FORMULATION OF A SOY–COFFEE BEVERAGE BY RESPONSE SURFACE METHODOLOGY AND INTERNAL PREFERENCE MAPPING

ABSTRACT Coffee consumers (n = 60) tasted and rated samples of a new soy–coffee beverage made from instant coffee, soymilk powder and sugar. Ingredient concentrations (independent variables) varied according to a 23central composite design for overall degree of acceptance. Data were analyzed by analysis of variance (ANOVA), least square difference and response surface methodology, followed by internal preference mapping (IPM) with cluster analysis. ANOVA from the consumers' acceptance data revealed that samples differed significantly (P ≤ 0.05). Although soymilk content did not influence significantly the consumers' acceptance in the tested range, IPM with cluster analysis indicated that at least part of the acceptance differences was based on the soy beverage consumption habit. The final beverage formulation was evaluated cold and hot for overall acceptability (9‐point structured hedonic scale) by 112 coffee consumers and the cold beverage reached a good acceptability mean score (6.2) among the participants.PRACTICAL APPLICATIONSThe consumption of soy products has been reported to reduce the risk of several diseases and a number of recent studies have found beneficial health properties attributed to coffee. Considering the current consumer trend for healthier alternatives in food products, we decided to combine the health benefits of these two important Brazilian commodities in a functional beverage. In order to optimize the formulation and maximize sensory acceptance, we performed consumers' tests using response surface methodology. Internal preference mapping and cluster analyses were also applied to provide information on the variability of the consumer individual opinions and segment them in groups of similar preference criteria.

Effect of dietary soy intake on breast cancer risk according to menopause and hormone receptor status

Although high soy consumption may be associated with lower breast cancer risk in Asian populations, findings from epidemiological studies have been inconsistent. We investigated the effects of soy intake on breast cancer risk among Korean women according to their menopausal and hormone receptor status. We conducted a case-control study with 358 incident breast cancer patients and 360 age-matched controls with no history of malignant neoplasm. Dietary consumption of soy products was examined using a 103-item food frequency questionnaire. The estimated mean intakes of total soy and isoflavones from this study population were 76.5 g per day and 15.0 mg per day, respectively. Using a multivariate logistic regression model, we found a significant inverse association between soy intake and breast cancer risk, with a dose-response relationship (odds ratios (OR) (95% confidence interval (CI)) for the highest vs the lowest intake quartile: 0.36 (0.20-0.64)). When the data were stratified by menopausal status, the protective effect was observed only among postmenopausal women (OR (95% CI) for the highest vs the lowest intake quartile: 0.08 (0.03-0.22)). The association between soy and breast cancer risk did not differ according to estrogen receptor (ER)/progesterone receptor (PR) status, but the estimated intake of soy isoflavones showed an inverse association only among postmenopausal women with ER+/PR+ tumors. Our findings suggest that high consumption of soy might be related to lower risk of breast cancer and that the effect of soy intake could vary depending on several factors.

Cultural differences in food description and preference: Contrasting Vietnamese and French panellists on soy yogurts

This study investigated the cultural differences in description and preference of soy yogurts formulated for French market between French and Vietnamese panellists, two cultures with important differences in soy and dairy product consumption habits. Two trained panels assessed the in-mouth perceptions of eight soy yogurts and four milk yogurts, using a conventional descriptive analysis method. Three soy and two cow milk yogurts, representing the sensory space of the product set were then assessed by two consumer panels in a hedonic test. A multiple factor analysis (MFA) showed that the two sensory profiles are highly similar. The two panels agreed on texture and taste attributes but cultural specificities were revealed for aroma attributes: French panellists used two times more attributes than Vietnamese panellists (10 vs. 5). While the Vietnamese attributes are related to soy-based products (“ raw soybean”, “ soy milk” and “ tofu”) the French attributes were more diverse and even included references to non-food products (“ wood”, “ earthy” and “ chalk”). The result of the hedonic test showed that soy yogurts were worst appreciated by both panels. In general, the soy and dairy product consumption data of the panellists helped to explain their preferences towards soy or milk yogurts. However this is not the case of a Vietnamese consumer subgroup who consumes soy products frequently. Their hedonic ratings on soy yogurts suggest that they expected the authentic soy-related sensory properties in tasting soy yogurts and these properties might not be found in this new product.

Abstract B107: The association of soy consumption and lung cancer among Japanese women: Analyses stratified by smoking status and reproductive factors

Abstract Soybean products intake has been suggested to have protective effects against breast cancer. As for lung cancer, we previously reported that soy consumption showed inverse association with the risk of non-small cell lung cancers (NSCLC) with epidermal growth factor receptor mutations among Japanese. However, other possible heterogeneity of its effect on the etiology of NSCLC by background characteristics is still unclear. In this study, we investigated the impact of soy consumption on the development of NSCLC among larger number of Japanese women, with the association of smoking status, reproductive factors, as well as histology. We conducted a case-control study with 420 NSCLC women cases and 840 age-sex matched control subjects. Dietary exposures were evaluated based on a semi-quantitative food frequency questionnaire, including items on lifestyles, menstrual and reproductive history. Soy consumption was categorized into two groups: a lower third group, “Low consumption group (LCG)” which intake of soy was less than 30.3 mg/day, and others, “High consumption group (HCG)” which intake of soy were 30.3mg/day or more. We assessed the impact of soy consumption on lung cancer by calculating odds ratios (ORs) and their 95% confidence intervals (CIs) of HCG, relative to LCG with adjustment for potential confounding factors using logistic regression model. In the overall analysis, we observed inverse association with high consumption of soy products [OR: 0.87, 95%CI: 0.65–1.16]. When stratified by smoking status, HCG in never smokers showed significantly inverse association showed an OR below unity [OR: 0.69, 95%CI: 0.50–0.96] in spite of the increased OR among HCG in ever smokers [OR: 2.02, 95%CI: 1.11–3.68]. As for reproductive factors, ORs of HCG were consistently below unity among women with pre-menopause [OR: 0.55, 95%CI: 0.29–1.04], menopause after 50 years old [OR: 0.57, 95%CI: 0.34–0.94], and no delivery [OR: 0.57, 95%CI: 0.15–1.06]. It is interesting to note that on histology based analysis, we found inverse association between high consumption of soy products and adenocarcinoma [OR: 0.57, 95%CI: 0.34–0.94] among never smokers, despite the increased ORs were seen among ever smokers [OR: 3.35, 95%CI: 0.17–67.7]. In this study, consumption of soybean products generally demonstrated an inverse association with NSCLC. In addition, the results indicated the interaction between soy consumption and smoking status for the impact on the development of NSCLC. We also found associations among soy consumption, reproductive factors and lung cancer, which indicated that female hormonal factors might be involved in the etiology of NSCLC. Further epidemiological evaluation is warranted. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B107.

女子短大生の時間帯別の食品群及び栄養素等摂取量と朝食欠食等に関する実態調査

Young female students were divided into two groups, those who living at home and the others living away from home, and their consumption of food groups on different time zones and intake of various nutrients were compared. To find the relationship between the habit of skipping breakfast and time zones of meal intake, the subjects of the study-193 students majoring in food and nutrition or enrolled in a nutrition course at a junior college in Tokyo were requested to respond to “meal menu and intake time-based food frequency questionnaire (MMITQ).” Compared with those students living at home (n=133), the students living away from home (n=60) were found to consume significantly less quantities of seafood and vegetables. Among the nutrients, the intake of vitamins C and D by the latter group was significantly lower (p<0.05). The habit of breakfast-skipping was noted in 11.3% (n=15) of those students living at home and 13.3% (n=8) of those living away from home, with no significant difference between the two groups. Among the breakfast-skippers who lived away from home, 68.9% of the daily energy was taken exclusively in the time zone after 4 : 00 pm. In the same time zone, their consumption of soy beans and soy products was greater than that of those living at home, and their intake of total lipids and magnesium was also high. There was no significant difference between the groups vis--vis the habits of snacking at night. Of 54.9% who habitually snacked at night, many consumed more than 2 types of food at night (20.7%). This study indicated the status of the diet that needs to be improved even for students who major in nutrition. Attention should be directed to the potential risk of nutrient deficiency that threatens those who live away from home and those habitually skip breakfast.

Continuous hydrolysis of raffinose family oligosaccharides in soymilk by fluidized bed reactor

Soybean is an important pulse crop for human and animal nutrition. However, raffinose family oligosaccharides (RFOs) found in soybean seeds specifically hinder its consumption as it is not digested by normal human carbohydrases and is fermented by intestinal microflora, leading to flatulence. Immobilized spores of Aspergillus oryzae were grown for 5 days in calcium alginate gel beads, then harvested and employed in RFOs hydrolysis in batch mode, repeated batch and continuous mode in a fluidized bed reactor. Effective hydrolysis of 244.4 mg/60 ml was obtained after 6 h incubation. And in continuous mode 465.6 mg/100 ml was obtained at a flow rate of 25 ml/h. The use of immobilized A. oryzae cells for hydrolysis of RFOs is a promising solution to overcome flatulence and to increase the consumption of soy products.

South African consumers' opinions and consumption of soy and soy products

AbstractInterest in soy foods has increased with consumer awareness of its health benefits, especially with soy‐related ingredients being utilized as one of the major sources of high‐protein fortification. The aim of the present study was to assess South African (SA) consumers' opinion of soy and soy products through different statements on consumption, taste, protein value and healthiness. The respondents (n = 3001) for this randomized cross‐sectional study were randomly selected from metropolitan and rural areas in South Africa. Trained fieldworkers administered questionnaires by conducting face‐to‐face interviews. Fourteen statements from four sections of the questionnaire (consisting of 17 food‐related topics in total), probing information on consumers' opinion on soy and soy products, were used. Data on 81% of the respondents (n = 2437), who had heard of soy before, were used for statistical analyses. The data were weighted to be representative of the total SA population based on gender, age and race. No practically significant differences among metropolitan and rural respondents' opinion, gender or age variables regarding any statement were found. A practically significant higher percentage (&gt;60%) of respondents in the total population and within all race groups were positive about soy and agreed that soy is a good source of protein, has many health benefits, associated soy with meat substitutes, were aware of a number of meat substitutes and agreed that soy can replace meat in their diet. Medium to large practically significant differences were found between racial groups regarding certain statements. More Blacks and Indians (76% and 68% respectively) than Whites (25%) use soy. Almost two‐thirds of Indians (65%) and Blacks (64%) eat or drink soy products, compared with only 22% for Whites, indicating that the potential target market for soy products should be chosen accordingly. Higher percentages of Blacks than Whites also indicated that they liked the taste of soy, would use more soy if it was readily available and if a bigger product range existed and would replace cow's milk with soy milk, confirming that Blacks are more positive about soy and would use even more soy if a bigger range of soy products were available. The findings from the current study indicated that more than 70% of SA consumers believe that soy has many health benefits and more than 60% already use soy. Insight gained from this first study of its kind in SA provided valuable information to developers and marketers, and signified that consumer segmentation should be taken into consideration to focus on developing more acceptable soy products that appeal to these consumer segments that are more positive towards the taste of soy and might consume soy regularly. Within the discipline of Consumer Science, efforts to inform consumers about the advantages of soy in terms of its health benefits, and to support it in terms of a greater availability of more acceptable soy products at reasonable prices, would support the ideal of informed, responsible buying decisions across all socio‐economic groups.

Soja – ein unterschätztes Pollen assoziiertes Nahrungsmittelallergen!?

Einhergehend mit einem steigenden Konsum wurden in den letzten Jahren in Deutschland zunehmend teils schwere allergische Reaktionen auf Sojaprodukte, insbesondere auf Sojagetränke, beobachtet. Birkenpollenallergiker haben ein besonderes Risiko, eine solche Reaktion zu erleiden, denn das Hauptallergen der Birke Bet v 1 zeigt eine hohe Homologie mit dem Soja-Allergen Gly m 4. Hierdurch kann es bei entsprechend Sensibilisierten zu einer immunologischen Kreuzreaktion im Sinne einer Pollen assoziierten Nahrungsmittelallergie kommen. Genaue Daten zur Prävalenz dieses Krankheitsbildes sind nicht bekannt. In Deutschland könnten allerdings bei geschätzten 5 – 10 % (4 – 8 Mio.) Birkenpollenallergikern bis zu 2,9 Mio. Menschen von einer Kreuzsensibilisierung auf Soja betroffen sein. Eine sichere Allergenmeidung ist schwierig, da Soja vielfach versteckt in Nahrungsmitteln enthalten sein kann. Besondere Hinweise für Birkenpollenallergiker, die insbesondere vor dem Verzehr proteinreicher, nicht-fermentierter Sojaprodukte (z. B. Drinks) gewarnt werden sollten, scheinen gerechtfertigt. Inwieweit auch durch eine spezifische Immuntherapie gegen Bet v 1 die Birken assoziierte Sojaallergie beeinflusst werden kann, ist nicht bekannt.

Isoflavone consumption and subsequent risk of hepatocellular carcinoma in a population‐based prospective cohort of Japanese men and women

The incidence of hepatocellular carcinoma (HCC) is much higher in men than in women. Several experiment and epidemiological studies have suggested that estrogen might play an inhibitory role in the development of HCC. Because isoflavones have a similar structure as 17beta-estradiol and appear to have an anti-estrogenic effect in women and estrogenic effect in men, we hypothesized that the effect of isoflavones on HCC differs by sex. We investigated the association between isoflavones (genistein and daidzein) and soy products and HCC in Japan in a population-based prospective study in 19,998 Japanese (7,215 men and 12,783 women) aged 40-69 years. During 11.8 years of follow-up, 101 subjects (69 men and 32 women) were newly diagnosed with HCC. Case patients were grouped according to consumption of isoflavones and soy products and stratified by hepatitis virus infection. Hazard ratios (HRs) and 95% confidence intervals (CIs) for HCC were calculated by Cox proportional-hazards modeling. In women, genistein and daidzein were dose-dependently associated with an increased risk of HCC, with multivariable HRs for the highest versus lowest tertile of 3.19 (95%CI = 1.13-9.00, p(trend) = 0.03) and 3.90 (95% CI = 1.30-11.69, p(trend) = 0.01), respectively. No association between isoflavones and HCC was observed in men. These results persisted when analysis was restricted to subjects positive for either or both hepatitis C and B virus. In conclusion, isoflavone consumption may be associated with an increased risk of HCC in women. Women with hepatitis virus infection may be advised to abstain from isoflavone consumption. Further studies are warranted to confirm these findings.

Identification of Several gy4 Nulls from the USDA Soybean Germplasm Collection Provides New Genetic Resources for the Development of High-Quality Tofu Cultivars

Tofu, a cheese-like food made by curdling soy milk, is a major dietary staple of Asian countries. Consumption of tofu and other soy products is steadily increasing in North America due to its well-known health benefits. Soybean A(5), A(4), and B(3) peptide null lines 'Enrei' and 'Raiden' are commonly utilized in breeding programs to develop high-quality tofu cultivars. To expand the genetic diversity it is desirable to identify and utilize other A(5), A(4), and B(3) null genotypes in the development of improved tofu cultivars that are adapted to North American conditions. In this study were screened diverse soybean accessions from the USDA Soybean Germplasm Collection to identify Gy4 mutants, the locus that controls A(5), A(4), and B(3) peptide production. Analysis of total seed proteins from 485 soybean lines by SDS-PAGE enabled the identification of 38 accessions that lacked the A(5), A(4), and B(3) peptides. These accessions showed marked differences in seed size and seed coat color and represented different maturity groups ranging from 0 to IX. To ascertain the molecular basis for the lack of A(5), A(4), and B(3) peptides in the newly identified Gy4 mutants, the nucleotide sequence of a portion of the Gy4 gene was determined from eight soybean accessions representing different maturity groups. These eight Gy4 mutants revealed a single point mutation that changed the translation initiation codon ATG to ATA, resulting in the A(5), A(4), and B(3) null phenotype. The newly identified Gy4 mutants from this study will enable plant breeders to expand the genetic diversity of North American food-quality soybeans and also aid in the development of hypoallergenic soybeans.

Early Life and Adult Exposure to Isoflavones and Breast Cancer Risk

Soy and red-clover isoflavones are commonly consumed within the diet or as a dietary supplement due to a range of presumed beneficial health benefits. These isoflavones are thought to protect against heart diseases as well as breast and other types of cancer. Isoflavones are structurally similar to estrogens and may act as estrogen agonists or antagonists by binding to estrogen receptors. Because of an increased use of isoflavones in processed foods and dietary supplements as well as the greater consumption of soy products, dietary intakes of isoflavones are increasing in children and adolescents in North America. Estrogens are a known component of numerous hormone related cancers including breast cancer. It is with these facts in mind that we review the existing epidemiological and experimental animal studies for a resolution to a proposed correlation between increased isoflavone consumption and breast cancer. There is conflicting evidence from epidemiological, intervention and experimental animal studies regarding the chemopreventing effects of soy isoflavones in breast cancer. Isoflavones are weak estrogens and their effect depends upon the dose, time of exposure and species involved. It would, therefore, not be safe to indisputably accept soy or red-clover as a source of isoflavone resource to prevent breast cancer.

Health Effects of Soy Protein and Isoflavones in Humans

Epidemiological investigations suggest that soy consumption may be associated with a lower incidence of certain chronic diseases. Clinical studies also show that ingestion of soy proteins reduces the risk factors for cardiovascular disease. This led to the approval of the food-labeling health claim for soy proteins in the prevention of coronary heart disease by the U.S. FDA in 1999. Similar health petitions for soy proteins have also been approved thereafter in the United Kingdom, Brazil, South Africa, the Philippines, Indonesia, Korea, and Malaysia. However, the purported health benefits are quite variable in different studies. The Nutrition Committee of the American Heart Association has assessed 22 randomized trials conducted since 1999 and found that isolated soy protein with isoflavones (ISF) slightly decreased LDL cholesterol but had no effect on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure. The other effects of soy consumption were not evident. Although the contributing factors to these discrepancies are not fully understood, the source of soybeans and processing procedures of the protein or ISF are believed to be important because of their effects on the content and intactness of certain bioactive protein subunits. Some studies have documented potential safety concerns on increased consumption of soy products. Impacts of soy products on thyroid and reproductive functions as well as on certain types of carcinogenesis require further study in this context. Overall, existing data are inconsistent or inadequate in supporting most of the suggested health benefits of consuming soy protein or ISF.

Social and behavior factors related to aged Chinese women with osteoporosis

Background. Women aged ≥65 years are screened routinely for osteoporosis in the developed world and identifying risk factors for osteoporosis should be highlighted in developing countries such as the People's Republic of China. In the present study, possible factors related to the occurrence of primary osteoporosis in aged Chinese women were explored.Methods. On appointed attendance at a menopausal outpatient clinic, generally healthy Chinese women aged ≥65 years were requested to complete a self-administered questionnaire. Bone mineral density at the left femur region was assessed using dual-energy X-ray absorptiometry, by which subjects were categorized as osteoporotic (group A), osteopenic (group B) or normal (group C). If a prevalent spinal fracture was affirmed, patients in group B were reclassified into group A. Non-conditional logistic regression analysis was applied to the calculate odds ratio (OR) of being in group A against the other two groups in terms of social and behavior factors (including education, past occupation, work quality, marriage status, income, self-rated health status, amount of daily physical activity, cigarette smoking, time watching television, and consumption of milk, soy products and tea).Results. Three hundred and twenty-four participants were eligible (77 in group A, 137 in group B, 110 in group C). There were significant differences in age, height, weight, menopausal age and years since menopause among groups. Compared with subjects with amount of daily physical activity <0.5 h in group A, the OR for women in group C was 0.357 (95% confidence interval (CI) 0.144–0.889) for 0.5–1 h, 0.314 (95% CI 0.126–0.780) for 1–2 h and 0.278 (95% CI 0.080–0.968) for >2 h of daily physical activity. When adjusted for age and weight, however, the difference was not significant. Other factors did not reach statistical significance.Conclusion. The development of osteoporosis in aged women was affected by both menopause and aging. The known related factors could help to identify susceptible subjects in aged Chinese women for either further assessment or treatment.

Soy intake and breast cancer: elucidation of an unanswered question

Soy intake and breast cancer: elucidation of an unanswered question

Soy Product Consumption and the Risk of Colon Cancer: A Prospective Study in Takayama, Japan

: The relationship of the intake of soy products and the incidence of colon cancer was prospectively evaluated in a population-based cohort study in Japan. The total intake of soy products and isoflavones in a daily diet was estimated from a validated questionnaire administered at the baseline. The participation rate of the questionnaire was 92.0%. The participants were followed from 1992 to 2000, and colon cancer diagnoses were identified at the main hospitals in the study area. In the analysis, 13,894 men and 16,327 women were included. The medians for energy-adjusted soy product intake were 85.52 g/day for men and 79.60 g/day for women. During follow-up, 111 men and 102 women were diagnosed with colon cancer. A Cox-proportional hazard model was applied to assess the risk of colon cancer incidence. Among women, the risk was reduced with an increased soy product consumption; the hazard ratio in the highest tertile was 0.56 (95% CI 0.34–0.92) compared as the lowest tertile (trend: P = 0.04), after adjusting for multiple potential confounders. Among men, no significant association was observed. Our results exhibited the weak benefit of soy foods only among women. Further research to confirm our results may be beneficial.

Diet and breast cancer

The role of diet for the risk of breast cancer is of great interest as a potentially modifiable risk factor. The evidence from prospective observational studies was reviewed and summarized on selected dietary factors, gene-diet interactions, and breast cancer incidence. Dietary factors were considered that, based on their nutritional constituents, are of particular interest in the context of breast cancer: fat intake, biomarkers of fat intake, fruit and vegetable consumption, antioxidant vitamins (vitamins A, C, E, and beta-carotene), serum antioxidants, carbohydrate intake, glycemic index and glycemic load, dairy consumption (including vitamin D), consumption of soy products and isoflavones, green tea, heterocyclic amines, and adolescent diet. The PubMed database was searched for all prospective studies that relate these dietary items to the incidence of breast cancer or consider gene-diet interactions. Among the prospective epidemiologic studies conducted on diet and breast cancer incidence and gene-diet interactions and breast cancer incidence, to date there is no association that is consistent, strong, and statistically significant, with the exception of alcohol intake, overweight, and weight gain. The apparent lack of association between diet and breast cancer may reflect a true absence of association between diet and breast cancer incidence or may be due to measurement error exceeding the variation in the diet studied, lack of sufficient follow-up, and focus on an age range of low susceptibility. The risk of breast cancer can be reduced by avoidance of weight gain in adulthood and limiting the consumption of alcohol.

Soy Product and Isoflavone Consumption in Relation to Prostate Cancer in Japanese Men

The incidence of prostate cancer is much lower in Asian than Western populations. Environmental factors, such as dietary habits, may play a major role in the causation of prostate cancer. Although isoflavones have been suggested to show a preventive effect against prostate cancer in animal experiments, the results of epidemiologic studies are inconsistent. Here, we conducted a population-based prospective study in 43,509 Japanese men ages 45 to 74 years who generally have a high intake of isoflavones and low incidence of prostate cancer. Participants responded to a validated questionnaire, which included 147 food items. During follow-up from 1995 through 2004, 307 men were newly diagnosed with prostate cancer, of which 74 cases were advanced, 220 cases were organ localized, and 13 cases were of an undetermined stage. Intakes of genistein, daidzein, miso soup, and soy food were not associated with total prostate cancer. However, these four items decreased the risk of localized prostate cancer. In contrast, positive associations were seen between isoflavones and advanced prostate cancer. These results were strengthened when analysis was confined to men ages >60 years, in whom isoflavones and soy food were associated with a dose-dependent decrease in the risk of localized cancer, with relative risks for men in the highest quartile of genistein, daidzein, and soy food consumption compared with the lowest of 0.52 [95% confidence interval (95% CI), 0.30-0.90], 0.50 (95% CI, 0.28-0.88), and 0.52 (95% CI, 0.29-0.90), respectively. In conclusion, we found that isoflavone intake was associated with a decreased risk of localized prostate cancer.