Whole grain breakfast cereals, fruits and vegetables are all important dietary sources of antioxidants.

Whole grains are nutrient rich and may protect against chronic disease. To study this, we previously reviewed 14 case-control studies of colorectal, gastric, and endometrial cancers and found consistently lower risk in those with high than in those with low whole-grain intake. Questions remained concerning other cancers, dietary assessment, quantity consumed, confounding, and differential study quality. Here we expand the review to 40 case-control studies of 20 cancers and colon polyps. Odds ratios are < 1 for 46 of 51 mentions of whole-grain intake and for 43 of 45 after exclusion of 6 mentions with design/reporting flaws or low intake. The pooled odds ratio for high vs. low whole-grain intake among the 45 mentions was 0.66 (95% confidence interval = 0.60-0.72); they range from 0.59 to 0.78 across four types of dietary questionnaires. Odds ratios were < 1 in 9 of 10 mentions of studies of colorectal cancers and polyps, 7 of 7 mentions of gastric and 6 of 6 mentions of other digestive tract cancers, 7 of 7 mentions of hormone-related cancers, 4 of 4 mentions of pancreatic cancer, and 10 of 11 mentions of 8 other cancers. Most pooled odds ratios for specific cancers were in the range of 0.5-0.8, notable exceptions being breast (0.86) and prostate (0.90). The pooled odds ratio was similar in studies that adjusted for few and many covariates. Dose-response associations were stronger in studies using food-frequency questionnaires than in more quantitative questionnaires. The case-control evidence is supportive of the hypothesis that whole-grain intake protects against various cancers.

Dietary guidance recommends consumption of whole grains to reduce the risk of chronic diseases including cancer and cardiovascular disease. Epidemiologic studies support the belief that whole grains are protective against cancers, especially gastrointestinal cancers such as gastric and colonic, and cardiovascular disease. Components in whole grains that may be protective are diverse and include compounds that affect the gut environment, i.e., dietary fiber, resistant starch, and other undigestible compounds in whole grains, compounds that function as antioxidants such as trace minerals and phenolic compounds, and compounds that are phytoestrogens with potential hormonal effects. Many of the protective compounds in whole grains are also in fruits and vegetables, but some plant compounds are more concentrated in whole grains, such as phenolic compounds including ferulic and caffeic acid. Other potential mechanistic effects of whole grains include binding of carcinogens and modulation of glycemic index. Clearly, the range of protective substances in whole grains is impressive, and advice to consume additional whole grains is justifiable.

Vitamintmineral supplements are often used by athletes as ergogenic aids to improve performance. This paper reviews studies of the prevalence, patterns, and explanations for vitamintmineral supplement use among athletes. Fifty-one studies provided quantitative prevalence data on 10,274 male and female athletes at several levels of athletic participation in over 15 sports. The overall mean prevalence of athletes' supplement use was 46%. Most studies reported that over half of the athletes used supplements (range 6% to loo%), and the larger investigations found lower prevalence levels. Elite athletes used supplements more than college or high school athletes. Women used supplements more often than men. Varying patterns existed by sport. Athletes appear to use supplements more than the general population, and some take high doses that may lead to nutritional problems. Sport nutritionists should include a vitaminlmineral supplement history as part of their dietary assessment so they can educate athletes about vitamintmineral supplements and athletic performance.Key Words: nutrition, sports, diet, ergogenic aids Vitamin/mineral supplements are often used by athletes as ergogenic aids to improve performance. Considerable physiological work has been done on the need for and effects of supplement use in athletes (33,36,56,63,78). By contrast, less attention has been given to the prevalence, patterns, and explanations for athletes' supplement consumption behavior. In this paper we will review and integrate the literature on athletes' supplement use by quantitatively analyzing studies on the prevalence and patterns of athletes' supplement use, examining research that offers explanations for their supplement use, and discussing applications of this information. Studies of the Prevalence of Supplement UseStudies of the prevalence of vitamin/mineral supplement consumption by athletes published as papers, chapters, and books were compiled using computerized bibliographic searches, our files and those of colleagues, and references in the J.

The epidemic of type 2 diabetes among children, adolescents and adults is increasing along with the increasing prevalence of overweight and obesity. Overweight is the most powerful modifiable risk factor for type 2 diabetes. Intake of wholegrain foods may reduce diabetes risk. Three prospective studies in 160 000 men and women examined the relationship of whole-grain or cereal-fibre intake with the risk of type 2 diabetes. Each study used a mailed Willett foodfrequency questionnaire and similar methods of quantifying wholegrain foods and cereal fibre. The self-reported incident diabetes outcome was more reliably determined in the two studies of health-care professionals than in the study of Iowa women. Risk for incident type 2 diabetes was 21-27 % lower for those in the highest quintile of whole-grain intake, and 30-36 % lower in the highest quintile of cereal-fibre intake, each compared with the lowest quintile. Risk reduction persisted after adjustment for the healthier lifestyle found among habitual whole-grain consumers. Observations in non-diabetic individuals support an inverse relationship between whole-grain consumption and fasting insulin levels. In feeding studies in non-diabetic individuals insulin resistance was reduced using whole grains or diets rich in whole grains. Glucose control improved with diets rich in whole grains in feeding studies of subjects with type 2 diabetes. There is accumulating evidence to support the hypothesis that whole-grain consumption is associated with a reduced risk of incident type 2 diabetes; it may also improve glucose control in diabetic individuals. Although several risk factors for the development of type 2 diabetes among children, adolescents and adults (Rosenbloom, 2002) are well recognized, there is a growing epidemic of type 2 diabetes. Several of the risk factors for type 2 diabetes are non-modifiable, including family history, age and ethnicity, while other factors are modifiable, including obesity (Rosenbloom, 2002), central adiposity (Franz et al. 2002), and a sedentary lifestyle (Engelgau et al. 2000). The results of three randomized clinical trials showed that changes in these modifiable risk factors could alter the incidence rate of type 2 diabetes (Pan et al. 1997;Hu et al. 2001;Tuomilehto et al. 2001; Knowler et al. 2002). In the USA a lifestyle intervention of increasing physical activity and a low-energy low-fat diet, without specific mention of an increase in fibre or whole-grain intake, reduced the risk of diabetes by 58 %; use of the medication metformin was associated with a 31 % reduction in risk. In China a diet that focused on increasing the consumption of vegetables and reducing the intake of alcohol and simple sugars reduced the risk of type 2 diabetes in individuals with impaired glucose tolerance by 31 % after adjustment for baseline glucose and BMI (Pan et al. 1997). A lifestyle intervention aimed at increasing physical activity and fibre intake and decreasing body weight and total and saturated fat intake was associated with a 58 % reduc...