Query: Stool Size and Breast Cancer Risk

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Ability of a high-total antioxidant capacity diet to increase stool weight and bowel antioxidant status in human subjects. <=SEP=> There is limited knowledge about the possible effect of unabsorbed dietary antioxidants that reach the large intestine on bowel habits. The aim of the present study was to investigate whether a dietary recommendation directed to increase diet total antioxidant capacity (TAC) is able to affect gut function in human subjects. In this cross-over intervention, nineteen subjects followed a high-TAC (HT) and a low-TAC (LT) diet for 2 weeks, which were comparable for energy, macronutrient, total dietary fibre and alcohol contents. At the end of each intervention period, the 48 h stool output was recorded. In the faecal samples obtained from a subset of nine subjects, moisture, pH, ammonia content, Lactobacillus and Bifidobacterium counts, faecal water antioxidants and genotoxicity were measured. A 3 d weighed food record was used to assess the diet composition during HT and LT diet intake. Significant increases in the intake of TAC, vitamins E and C and phenolic compounds were observed during the HT diet intake. The higher intake of antioxidants led to increased 48 h stool output (324 (SD 38) g in HT v. 218 (SD 22) g in LT), and to higher TAC and total phenolic concentrations in faecal water. No significant variation in the other measured parameters was observed between the diets. In conclusion, a diet selected to raise the intake of dietary antioxidants is able to increase stool bulk and antioxidant content of faeces.

Fecal weight, colon cancer risk, and dietary intake of nonstarch polysaccharides (dietary fiber) <=SEP=> Low fecal weight and slow bowel transit time are thought to be associated with bowel cancer risk, but few published data defining bowel habits in different communities exist. Therefore, data on stool weight were collected from 20 populations in 12 countries to define this risk more accurately, and the relationship between stool weight and dietary intake of nonstarch polysaccharides (NSP) (dietary fiber) was quantified. In 220 healthy U.K. adults undertaking careful fecal collections, median daily stool weight was 106 g/day (men, 104 g/day; women, 99 g/day; P = 0.02) and whole-gut transit time was 60 hours (men, 55 hours; women, 72 hours; P = 0.05); 17% of women, but only 1% of men, passed < 50 g stool/day. Data from other populations of the world show average stool weight to vary from 72 to 470 g/day and to be inversely related to colon cancer risk (r = -0.78). Meta-analysis of 11 studies in which daily fecal weight was measured accurately in 26 groups of people (n = 206) on controlled diets of known NSP content shows a significant correlation between fiber intake and mean daily stool weight (r = 0.84). Stool weight in many Westernized populations is low (80-120 g/day), and this is associated with increased colon cancer risk. Fecal output is increased by dietary NSP. Diets characterized by high NSP intake (approximately 18 g/day) are associated with stool weights of 150 g/day and should reduce the risk of bowel cancer.

Antioxidant activity in human faeces. <=SEP=> Scarcely-absorbed antioxidants might reach the large bowel and exhibit antioxidant activity, opposing the action of reactive O species by bacterial and cellular metabolism and thus contributing to protection from oxidative damage-induced gastrointestinal diseases. This study was carried out to evaluate the antioxidant activity in the faeces of a group of healthy subjects on a freely-selected diet, and to look for possible associations with the intake of some macro- and micronutrients and food groups. Fourteen subjects recorded their food intake three times for a period of 2 d, each time collecting all the faeces passed during the next 24 h. Total antioxidant activity (TAA; mmol 6-hydroxy-2,5,7,8 tetramethylchroman-2-carboxylic acid (Trolox)/kg) of faecal suspensions was measured using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS(.+)) decolorisation assay. The average TAA value of faeces was 26.6 (sd 10.2) mmol Trolox/kg wet faeces (range 7.5-50.5). The total amount of antioxidant equivalents excreted over 24 h, derived by multiplying the TAA by the amount of faeces passed over 24 h, was 3.24 (sd 1.51) mmol Trolox (range 0.92-5.82) and this was significantly correlated with the average 24 h intake of coffee red wine and particularly to the sum of coffee and red wine In conclusion, the faeces of healthy subjects show detectable capacity to scavenge radical cations, suggesting that antioxidant activity occurs in the colonic lumen. Moreover, such activity seems at least in part to be related to dietary habits.

Food selection based on high total antioxidant capacity improves endothelial function in a low cardiovascular risk population. <=SEP=> BACKGROUND AND AIMS: Oxidative stress has been advocated as a major cause for cardiovascular disease (CVD), and low plasma antioxidant concentrations are associated with endothelial dysfunction, the first step towards atherosclerosis. However, although the antioxidant content in fruits and vegetables may explain at least in part their protective effect against CVD, supplementation with antioxidant vitamins fails to improve endothelial function and reduce CVD risk. The aim of this study was to investigate the impact of a diet rich in antioxidants on endothelial function measured by flow-mediated dilatation (FMD) in volunteers at low cardiovascular risk. METHODS AND RESULTS: In a crossover trial, 24 subjects (13 women, mean age 61 ± 3 years), received, in a randomised order, a 14-day high (HT) and a 14-day low (LT) antioxidant diets, with a 2-week wash-out (WO) in between. Both diets were comparable in daily portions of fruits and vegetables, and in alcohol, fibre and macronutrient intake, but differed in their total antioxidant capacity. Before and after each diet, anthropometrics, blood pressure, fasting plasma glucose, lipid profile, hepatic enzymes, circulating antioxidant concentrations, high sensitivity C-reactive protein (hs-CRP) and FMD were assessed. FMD increased significantly during the HT diet compared to the LT (p < 0.000). FMD values were 2.3% higher after HT compared with LT (p < 0.001) after adjustment for age, gender and diet order. α-tocopherol increased significantly (p < 0.05) and hs-CRP and of γ-glutamyltranspeptidase decreased significantly (p < 0.05 and p < 0.01, respectively) during the HT diet, compared with the LT diet. CONCLUSIONS: A short-term HT diet improves endothelial function in volunteers at low cardiovascular risk, which may further reduce their risk of CVD. Copyright © 2010 Elsevier B.V. All rights reserved.

Globalization, diet, and health: an example from Tonga. <=SEP=> The increased flow of goods, people, and ideas associated with globalization have contributed to an increase in noncommunicable diseases in much of the world. One response has been to encourage lifestyle changes with educational programmes, thus controlling the lifestyle-related disease. Key assumptions with this approach are that people's food preferences are linked to their consumption patterns, and that consumption patterns can be transformed through educational initiatives. To investigate these assumptions, and policies that derive from it, we undertook a broad-based survey of food-related issues in the Kingdom of Tonga using a questionnaire. Data on the relationships between food preferences, perception of nutritional value, and frequency of consumption were gathered for both traditional and imported foods. The results show that the consumption of health-compromising imported foods was unrelated either to food preferences or to perceptions of nutritional value, and suggests that diet-related diseases may not be amenable to interventions based on education campaigns. Given recent initiatives towards trade liberalization and the creation of the World Trade Organization, tariffs or import bans may not serve as alternative measures to control consumption. This presents significant challenges to health policy-makers serving economically marginal populations and suggests that some population health concerns cannot be adequately addressed without awareness of the effects of global trade.

PASSCLAIM--gut health and immunity. <=SEP=> BACKGROUND: The gut and immune system form a complex integrated structure that has evolved to provide effective digestion and defence against ingested toxins and pathogenic bacteria. However, great variation exists in what is considered normal healthy gut and immune function. Thus, whilst it is possible to measure many aspects of digestion and immunity, it is more difficult to interpret the benefits to individuals of variation within what is considered to be a normal range. Nevertheless, it is important to set standards for optimal function for use both by the consumer, industry and those concerned with the public health. The digestive tract is most frequently the object of functional and health claims and a large market already exists for gut-functional foods worldwide. AIM: To define normal function of the gut and immune system and describe available methods of measuring it. RESULTS: We have defined normal bowel habit and transit time, identified their role as risk factors for disease and how they may be measured. Similarly, we have tried to define what is a healthy gut flora in terms of the dominant genera and their metabolism and listed the many, varied and novel methods for determining these parameters. It has proved less easy to provide boundaries for what constitutes optimal or improved gastric emptying, gut motility, nutrient and water absorption and the function of organs such as the liver, gallbladder and pancreas. The many tests of these functions are described. We have discussed gastrointestinal well being. Sensations arising from the gut can be both pleasant and unpleasant. However, the characteristics of well being are ill defined and merge imperceptibly from acceptable to unacceptable, a state that is subjective. Nevertheless, we feel this is an important area for future work and method development. The immune system is even more difficult to make quantitative judgements about. When it is defective, then clinical problems ensure, but this is an uncommon state. The innate and adaptive immune systems work synergistically together and comprise many cellular and humoral factors. The adaptive system is extremely sophisticated and between the two arms of immunity there is great redundancy, which provides robust defences. New aspects of immune function are discovered regularly. It is not clear whether immune function can be "improved". Measuring aspects of immune function is possible but there is no one test that will define either the status or functional capacity of the immune system. Human studies are often limited by the ability to sample only blood or secretions such as saliva but it should be remembered that only 2% of lymphocytes circulate at any given time, which limits interpretation of data. We recommend assessing the functional capacity of the immune system by: measuring specific cell functions ex vivo. measuring in vivo responses to challenge, e. g. change in antibody in blood or response to antigens. determining the incidence and severity of infection in target populations during naturally occurring episodes or in response to attenuated pathogens.

Fibre and bowel transit times. <=SEP=> 1. Bowel transit time has been investigated in vegetarians and non-vegetarians and related to dietary fibre intake and the presence of diverticular disease. 2. Vegetarians who have less diverticular disease than non-vegetarians have more rapid transit times. 3. Subjects with total dietary fibre intake of more than 30 g/d all had transit times of less than 75 h whereas 38% of those eating less had transit times exceeding 75 h and varying up to 124 h. 4. Individuals with diverticular disease were found to have faster transit times than those without the disease. 5. The colon may respond to a fibre-depleted diet either by becoming hyperactive and prone to diverticular disease or by becoming hypoactive leading to constipation.

Bowel movement and constipation frequencies and the risk of colorectal cancer among men in the Netherlands Cohort Study on Diet and Cancer. <=SEP=> The authors investigated the associations between bowel movement and constipation frequencies and colorectal cancer (CRC) endpoints among men in the Netherlands Cohort Study on Diet and Cancer (n = 58,279) and explored whether dietary fiber intake may modify associations. After 13.3 years (1986-1999), 1,207 CRC cases and 1,753 subcohort members were available for case-cohort analyses. Multivariate analyses showed a significantly increased hazard ratio for CRC overall and rectal cancer in men who reported having a bowel movement 1-2 times per day (second-highest category) as compared with once a day (CRC: hazard ratio (HR) = 1.29, 95% confidence interval (CI): 1.09, 1.53 (P(trend) < 0.001); rectal cancer: HR = 1.50, 95% CI: 1.15, 1.95 (P(trend) = 0.001)). Hazard ratios for CRC overall and rectal cancer were significantly decreased and lowest in men who reported suffering from constipation sometimes or more often versus never (CRC: HR = 0.76, 95% CI: 0.58, 0.98 (P(trend) = 0.02); rectal cancer: HR = 0.57, 95% CI: 0.35, 0.90 (P(trend) = 0.01)). No trends in the associations with proximal or distal colon cancer risk were observed. Interactions with dietary fiber intake were not significant. In this study, frequent bowel movements were associated with an increased risk of rectal cancer in men, and constipation was associated with a decreased risk.

Fecal weight, colon cancer risk, and dietary intake of nonstarch polysaccharides (dietary fiber) <=SEP=> Low fecal weight and slow bowel transit time are thought to be associated with bowel cancer risk, but few published data defining bowel habits in different communities exist. Therefore, data on stool weight were collected from 20 populations in 12 countries to define this risk more accurately, and the relationship between stool weight and dietary intake of nonstarch polysaccharides (NSP) (dietary fiber) was quantified. In 220 healthy U.K. adults undertaking careful fecal collections, median daily stool weight was 106 g/day (men, 104 g/day; women, 99 g/day; P = 0.02) and whole-gut transit time was 60 hours (men, 55 hours; women, 72 hours; P = 0.05); 17% of women, but only 1% of men, passed < 50 g stool/day. Data from other populations of the world show average stool weight to vary from 72 to 470 g/day and to be inversely related to colon cancer risk (r = -0.78). Meta-analysis of 11 studies in which daily fecal weight was measured accurately in 26 groups of people (n = 206) on controlled diets of known NSP content shows a significant correlation between fiber intake and mean daily stool weight (r = 0.84). Stool weight in many Westernized populations is low (80-120 g/day), and this is associated with increased colon cancer risk. Fecal output is increased by dietary NSP. Diets characterized by high NSP intake (approximately 18 g/day) are associated with stool weights of 150 g/day and should reduce the risk of bowel cancer.

Cytological abnormalities in nipple aspirates of breast fluid from women with severe constipation. <=SEP=> The relation between epithelial dysplasia in nipple aspirates of breast fluid and frequency of bowel movements was studied in 1481 white women. There was a significant positive association with dysplasia (risk ratio 4.5; 95% confidence interval 1.9-11.9) in women reporting severe constipation, i.e., two or fewer bowel movements weekly, which was not seen in women reporting more than one bowel movement daily. Women who had one bowel movement daily or one every other day had increased risk ratios. Cytological abnormalities in breast epithelium associated with severe constipation may be relevant to studies of diet and breast disease since the intestinal flora has been reported to metabolism bile salts and oestrogens secreted by the liver into the gastrointestinal tract-a process which may be enhanced by severe constipation.

Diets and hormonal levels in postmenopausal women with or without breast cancer. <=SEP=> The role of diet in breast cancer (BC) risk is unclear. Fiber could reduce BC risk, through the enterohepatic circulation of estrogens. We examined the relationship between diet and sex hormones in postmenopausal women with or without BC. Thirty-one postmenopausal women (10 omnivores, 11 vegetarians, and 10 BC omnivores) were recruited. Dietary records (5 days) and hormone levels (3 days) were evaluated on 4 occasions over 1 yr. Vegetarians showed a lower fat/fiber ratio, a higher intake of total and cereal fiber (g/d)/body weight (kg), a significantly lower level of plasma estrone-sulfate, estradiol, free-estradiol, free-testosterone, and ring D oxygenated estrogens, and a significantly higher level of sex-hormone-binding-globulin than BC subjects. Fiber was consumed in slightly larger amounts by omnivores than by BC subjects. Omnivores had significantly lower plasma testosterone and estrone-sulfate but higher sex-hormone-binding-globulin than BC subjects. No difference was found for the urinary 16-oxygenated estrogens. However, the 2-MeO-E1/2-OH-E1 ratio was significantly lower in omnivores than in BC group. This ratio is positively associated with the fat/fiber ratio. In conclusion, testosterone may contribute to causing alterations in the levels of catechol estrogens and 16-oxygenated estrogens. The fat/fiber ratio appears to be useful in evaluating dietary effects on estrogen metabolism.

Dietary habits and breast cancer incidence among Seventh-day Adventists. <=SEP=> Breast cancer incidence was monitored in a cohort of 20,341 California Seventh-day Adventist women who completed a detailed lifestyle questionnaire in 1976, and who were followed for 6 years. There were 215 histologically confirmed primary breast cancer detected among some 115,000 person-years of follow-up. Mean age at diagnosis was 66 years, indicating a primarily postmenopausal case series. Established risk factors for breast cancer showed strong relationships to risk in these data. Age at first live birth, maternal history of breast cancer, age at menopause, educational attainment, and obesity were all significantly related to risk. However, increasing consumption of high fat animal products was not associated with increased risk of breast cancer in a consistent fashion. Nor were childhood and early teenage dietary habits (vegetarian versus nonvegetarian) related to subsequent, adult risk of developing breast cancer. Also, a derived index of percent of calories from animal fat in the adult years was not significantly related to risk. These results persisted after simultaneously controlling for other, potentially confounding variables, utilizing Cox proportional hazard regression models.

Estrogen excretion patterns and plasma levels in vegetarian and omnivorous women. <=SEP=> We studied 10 vegetarian and 10 nonvegetarian premenopausal women on four occasions approximately four months apart. During each study period, the participants kept three-day dietary records, and estrogens were measured in plasma, urinary, and fecal samples. Vegetarians consumed less total fat than omnivores did (30 per cent of total calories, as compared with 40 per cent) and more dietary fiber (28 g per day, as compared with 12 g). There was a positive correlation between fecal weight and fecal excretion of estrogens in both groups (P less than 0.001), with vegetarians having higher fecal weight and increased fecal excretion of estrogens. Urinary excretion of estriol was lower in vegetarians (P less than 0.05), and their plasma levels of estrone and estradiol were negatively correlated with fecal excretion of estrogen (P = 0.005). Among the vegetarians the beta-glucuronidase activity of fecal bacteria was significantly reduced (P = 0.05). We conclude that vegetarian women have an increased fecal output, which leads to increased fecal excretion of estrogen and a decreased plasma concentration of estrogen.