Instruct: Given a question, retrieve relevant passages that answer the question.
Query: television
OBJECTIVES: The aim of this study was to examine the independent relationships of television viewing or other screen-based entertainment ("screen time") with all-cause mortality and clinically confirmed cardiovascular disease (CVD) events. A secondary objective was to examine the extent to which metabolic (body mass index, high-density lipoprotein and total cholesterol) and inflammatory (C-reactive protein) markers mediate the relationship between screen time and CVD events. BACKGROUND: Although some evidence suggests that prolonged sitting is linked to CVD risk factor development regardless of physical activity participation, studies with hard outcomes are scarce. METHODS: A population sample of 4,512 (1,945 men) Scottish Health Survey 2003 respondents (≥35 years) were followed up to 2007 for all-cause mortality and CVD events (fatal and nonfatal combined). Main exposures were interviewer-assessed screen time (<2 h/day; 2 to <4 h/day; and ≥4 h/day) and moderate to vigorous intensity physical activity. RESULTS: Two hundred fifteen CVD events and 325 any-cause deaths occurred during 19,364 follow-up person-years. The covariable (age, sex, ethnicity, obesity, smoking, social class, long-standing illness, marital status, diabetes, hypertension)-adjusted hazard ratio (HR) for all-cause mortality was 1.52 (95% confidence interval [CI]: 1.06 to 2.16) and for CVD events was 2.30 (95% CI: 1.33 to 3.96) for participants engaging in ≥4 h/day of screen time relative to <2 h/day. Adjusting for physical activity attenuated these associations only slightly (all-cause mortality: HR: 1.48, 95% CI: 1.04 to 2.13; CVD events: HR: 2.25, 95% CI: 1.30 to 3.89). Exclusion of participants with CVD events in the first 2 years of follow-up and previous cancer registrations did not change these results appreciably. Approximately 25% of the association between screen time and CVD events was explained collectively by C-reactive protein, body mass index, and high-density lipoprotein cholesterol. CONCLUSIONS: Recreational sitting, as reflected by television/screen viewing time, is related to raised mortality and CVD risk regardless of physical activity participation. Inflammatory and metabolic risk factors partly explain this relationship. Copyright Â© 2011 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.
A historical view on how our agricultural systems evolved and how they are contributing to obesity and disease.
Tea (Camellia sinensis, Theaceae) and tea polyphenols have been studied for the prevention of chronic diseases, including obesity. Obesity currently affects >20% of adults in the United States and is a risk factor for chronic diseases such as type II diabetes, cardiovascular disease, and cancer. Given this increasing public health concern, the use of dietary agents for the prevention of obesity would be of tremendous benefit. Whereas many laboratory studies have demonstrated the potential efficacy of green or black tea for the prevention of obesity, the underlying mechanisms remain unclear. The results of human intervention studies are mixed and the role of caffeine has not been clearly established. Finally, there is emerging evidence that high doses of tea polyphenols may have adverse side effects. Given that the results of scientific studies on dietary components, including tea polyphenols, are often translated into dietary supplements, understanding the potential toxicities of the tea polyphenols is critical to understanding their potential usefulness in preventing obesity. In this review, we will critically evaluate the evidence for the prevention of obesity by tea, discuss the relevance of proposed mechanisms in light of tea polyphenol bioavailability, and review the reports concerning the toxic effects of high doses of tea polyphenols and the implication that this has for the potential use of tea for the prevention of obesity. We hope that this review will expose areas for further study and encourage research on this important public health issue.
Epidemiological evidence suggests a role for tea catechins in reduction of chronic disease risk. However, stability of catechins under digestive conditions is poorly understood. The objective of this study was to characterize the effect of common food additives on digestive recovery of tea catechins. Green tea water extracts were formulated in beverages providing 4.5, 18, 23, and 3.5 mg per 100 mL epicatechin (EC), epigallocatechin (EGC), epigallocatechin-gallate (EGCG), and epicatechin-gallate (ECG), respectively. Common commercial beverage additives; citric acid (CA), BHT, EDTA, ascorbic acid (AA), milk (bovine, soy, and rice), and citrus juice (orange, grapefruit, lemon, and lime) were formulated into finished tea beverages at incremental dosages. Samples were then subjected to in vitro digestion simulating gastric and small intestinal conditions with pre- and post-digestion catechin profiles assessed by HPLC. Catechin stability in green tea was poor with <20% total catechins remaining post-digestion. EGC and EGCG were most sensitive with less, not double equals 10% recovery. Teas formulated with 50% bovine, soy, and rice milk increased total catechin recovery significantly to 52, 55, and 69% respectively. Including 30 mg AA in 250 mL of tea beverage significantly (p<0.05) increased catechin recovery of EGC, EGCG, EC, and ECG to 74, 54, 82, and 45% respectively. Juice preparation resulted in the highest recovery of any formulation for EGC (81-98%), EGCG (56-76%), EC (86-95%), and ECG (30-55%). These data provide evidence that tea consumption practices and formulation factors likely impact catechin digestive recovery and may result in diverse physiological profiles.
BACKGROUND: The present analysis was conducted in response to inconsistent epidemiologic studies on the relation between consumption of tea and cardiovascular diseases. OBJECTIVE: We undertook a literature review of the consistency and strength of the associations between tea and cardiovascular diseases on the basis of published observational studies and meta-analyses addressing tea or tea flavonoids and cardiovascular disease risk. DESIGN: We performed a search in 3 databases for meta-analyses and compared them with studies they subsumed. We performed an additional search for subsequent studies to determine whether the conclusions were consistent. RESULTS: Many epidemiologic studies have been conducted and summarized in 5 meta-analyses on either tea consumption or flavonoid consumption and cardiovascular disease or the subset of stroke. Heterogeneity of effect was seen when the outcome included all cardiovascular diseases. In the case of stroke, a consistent, dose-response association with tea consumption on both incidence and mortality was noted with RRs of 0.80 (95% CI: 0.65, 0.98) for flavonoids and 0.79 (95% CI: 0.73, 0.85) for tea when high and low intakes were compared or the addition of 3 cups/d was estimated. CONCLUSION: Thus, the strength of this evidence supports the hypothesis that tea consumption might lower the risk of stroke.
OBJECTIVE: To investigate the efficacy and cost effectiveness of an herbal tea, Smooth Move, in nursing home residents with chronic constipation. DESIGN: Double-blind, placebo-controlled, 2-armed, parallel-group clinical trial. SETTING: A 483-bed nursing home in Allentown, Pennsylvania, operated by Lehigh County Government. PARTICIPANTS: A total of 86 nursing home residents with chronic constipation. INTERVENTIONS: Participants (n = 86) were randomly assigned to receive Smooth Move (n = 42) or a placebo (n = 44), once daily, in addition to standard treatment for chronic constipation. The study period was 28 days. MEASUREMENTS: The primary efficacy parameter was the difference in total number of bowel movements. Secondary parameters included the difference in average number of standard treatment doses dispensed, and the difference in total medication costs. RESULTS: Compared to placebo, in the intention to treat (ITT analysis) there was a statistically significant increase in the number of bowel movements in the Smooth Move group. The Smooth Move group (n = 42) compared with the placebo group (n = 44) experienced an average of 4.14 more bowel movements during the 28-day study period versus the 28-day pre-study period (P = .017). CONCLUSION: Smooth Move herbal tea, when added to the standard treatment regimen for nursing home residents with chronic constipation, increased the average number of bowel movements compared to the addition of a placebo tea.
The thermal stability of virulent hepatitis E virus (HEV) and hepatitis A virus (HAV) was compared. Fecal suspensions of virus were heated to temperatures between 45 degrees C and 70 degrees C, and residual infectivity was determined in a cell culture system that was permissive for both viruses. Although HEV was less stable than was HAV, some HEV would most likely survive the internal temperatures of rare-cooked meat.
In 2011, the protease inhibitors boceprevir and telaprevir were approved in the United States and European Union for the treatment of hepatitis C infection. While remarkably effective, the newly approved therapies are also accompanied by additional side effects and considerable costs. Understanding the balance between costs and effectiveness is critical to making decisions about the optimal use of these new agents, especially for health care systems constrained by rising costs. Our goal for this review is to facilitate an understanding of the importance of cost-effectiveness analyses in guiding policy decisions about the use of newly approved drugs as well as future therapies for hepatitis C.
Background Tea consumption is associated with a lower risk of cardiovascular disease including stroke. Direct effects of tea components on the vasculature, particularly the endothelium, may partly explain this association. Objective We performed a meta-analysis of controlled human intervention studies on the effect of tea on flow-mediated dilation (FMD) of the brachial artery, a measurement of endothelial function, which is suggested to be associated with cardiovascular risk. Methods Human intervention studies were identified by systematic search of the databases Medline, Embase, Chemical s and Biosis through March 2009 and by hand-searching related articles. Studies were selected based on predefined criteria: intervention with tea as the sole experimental variable, placebo-controlled design, and no missing data on FMD outcome or its variability. A random effects model was used to calculate the pooled overall effect on FMD due to the intake of tea. The impact of various subject and treatment characteristics was investigated in the presence of heterogeneity. Results In total, 9 studies from different research groups were included with 15 relevant study arms. The overall absolute increase in FMD of tea vs. placebo was 2.6% of the arterial diameter (95% CI: 1.8-3.3%; P-value <0.001) for a median daily dose of 500 mL of tea (2–3 cups). This is a relative increase of approximately 40% compared to the average FMD of 6.3% measured under placebo or baseline conditions. There was significant heterogeneity between studies (P-value <0.001) that might partly be explained by the cuff position either distal or proximal to the area of FMD measurement. No indication for publication bias was found. Conclusion Moderate consumption of tea substantially enhances endothelial-dependent vasodilation. This may provide a mechanistic explanation for the reduced risk of cardiovascular events and stroke observed among tea drinkers.
Recent evidences have highlighted an influence of micronutrients in the maintenance of telomere length (TL). In order to explore whether diet-related telomere shortening had any physiological relevance and was accompanied by significant damage in the genome, in the present study, TL was assessed by terminal restriction fragment (TRF) analysis in peripheral blood lymphocytes of 56 healthy subjects for which detailed information on dietary habits was available and data were compared \with the incidence of nucleoplasmic bridges (NPBs), a marker of chromosomal instability related to telomere dysfunction visualised with the cytokinesis-blocked micronucleus assay. To increase the capability to detect even slight impairment of telomere function, the incidence of NPBs was also evaluated on cells exposed in vitro to ionising radiation. Care was taken to control for potential confounding factors that might influence TL, viz. age, hTERT genotype and smoking status. Data showed that higher consumption of vegetables was related with significantly higher mean TL (P = 0.013); in particular, the analysis of the association between micronutrients and mean TL highlighted a significant role of antioxidant intake, especially beta-carotene, on telomere maintenance (P = 0.004). However, the diet-related telomere shortening did not result in associated increased spontaneous or radiation-induced NPBs. The distribution of TRFs was also analysed and a slight prevalence of radiation-induced NPBs (P = 0.03) was observed in subjects with higher amount of very short TRFs (<2 kb). The relative incidence of very short TRFs was positively associate with ageing (P = 0.008) but unrelated to vegetables consumption and daily intake of micronutrients, suggesting that the degree of telomere erosion related with low dietary intake of antioxidants observed in this study was not so extensive to lead to chromosome instability.
Scope Observational studies have evaluated the relationship between green tea intake and cancers of the ovary and endometrium, but we are not aware of the published studies on green tea intake and risk of human papillomavirus (HPV)-related cancers of the cervix, vagina, or vulva. Methods and results A critical review of the published literature on tea intake and risk of ovarian and endometrial cancers was conducted. In meta-analyses, we report inverse associations for green tea intake and risk of ovarian cancer (odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.54, 0.80), and for green tea and risk of endometrial cancer (OR = 0.78, 95% CI: 0.62, 0.98). There was no association for black tea and ovarian cancer risk (OR = 0.94, 95% CI: 0.87, 1.02) and a positive association with endometrial cancer risk (OR = 1.20, 95% CI: 1.05, 1.38). We summarized the experimental evidence supporting the antiviral and immunomodulatory activities of green tea catechins, and results from randomized clinical trials that demonstrated green tea catechin efficacy on treatment of cervical lesions and external genital warts. Conclusion Observational data support a protective role of green tea on risk of ovarian and endometrial cancers. Observational data are needed to evaluate whether green tea reduces risk of human papillomavirus-related cancers.
Epidemiologic studies suggest that tea consumption decreases the risk for cardiovascular events. However, there has been no clinical report examining the effects of tea consumption on coronary circulation. The purpose of this study was to evaluate the effects of black tea on coronary flow velocity reserve (CFVR) using transthoracic Doppler echocardiography (TTDE). This was a double-blind crossover study of 10 healthy male volunteers conducted to compare the effects of black tea and caffeine on coronary circulation. The coronary flow velocity of the left anterior descending coronary artery was measured at baseline and at hyperemia during adenosine triphosphate infusion by TTDE to determine CFVR. The CFVR ratio was defined as the ratio of CFVR after beverage consumption to CFVR before beverage consumption. All data were divided into 2 groups according to beverage type: group T (black tea) and group C (caffeine). Two-way analysis of variance showed a significant group effect and interaction in CFVR before and after beverage consumption (p = 0.001). CFVR significantly increased after tea consumption in group T (4.5 +/- 0.9 vs 5.2 +/- 0.9, p <0.0001). The CFVR ratio of group T was larger than that of group C (1.18 +/- 0.07 vs 1.04 +/- 0.08, p = 0.002). Acute black tea consumption improves coronary vessel function, as determined by CFVR.
In vitro studies show Hibiscus sabdariffa L., an ingredient found in many herbal tea blends and other beverages, has antioxidant properties, and, in animal models, extracts of its calyces have demonstrated hypocholesterolemic and antihypertensive properties. Our objective in this study was to examine the antihypertensive effects of H. sabdariffa tisane (hibiscus tea) consumption in humans. A randomized, double-blind, placebo-controlled clinical trial was conducted in 65 pre- and mildly hypertensive adults, age 30-70 y, not taking blood pressure (BP)-lowering medications, with either 3 240-mL servings/d of brewed hibiscus tea or placebo beverage for 6 wk. A standardized method was used to measure BP at baseline and weekly intervals. At 6 wk, hibiscus tea lowered systolic BP (SBP) compared with placebo (-7.2 +/- 11.4 vs. -1.3 +/- 10.0 mm Hg; P = 0.030). Diastolic BP was also lower, although this change did not differ from placebo (-3.1 +/- 7.0 vs. -0.5 +/- 7.5 mm Hg; P = 0.160). The change in mean arterial pressure was of borderline significance compared with placebo (-4.5 +/- 7.7 vs. -0.8 +/- 7.4 mm Hg; P = 0.054). Participants with higher SBP at baseline showed a greater response to hibiscus treatment (r = -0.421 for SBP change; P = 0.010). No effects were observed with regard to age, gender, or dietary supplement use. These results suggest daily consumption of hibiscus tea, in an amount readily incorporated into the diet, lowers BP in pre- and mildly hypertensive adults and may prove an effective component of the dietary changes recommended for people with these conditions.
A microwave-assisted acid digestion procedure coupled with a graphite furnace atomic absorption method has been applied in the determination of aluminum (Al) in urine to verify the correlation of free forms of Al in tea infusions and urinary excretion of Al. Significant urinary Al excretion has been found in 24-h urine of four volunteers after tea drinking. However, the difference in amount of Al excretion in urine between the consumption of Oolong (black tea) and Long-Jin (green tea), each of them with unique Al contents and species, was not significant. These findings indicated that the high levels of free Al species in tea infusions did not result in significant change in urinary excretion of the metal, possibly owing to the transformation by ligands present in food and the gastrointestinal tract (GIT). However, it could not be assumed that there was no big difference in absorption of the metal in the human body if fractions of consumed Al retained in the body or excreted by bile or feces were considered.
Tea leaves produce organic compounds that may be involved in the defense of the plants against invading pathogens including insects, bacteria, fungi, and viruses. These metabolites include polyphenolic compounds, the six so-called catechins, and the methyl-xanthine alkaloids caffeine, theobromine, and theophylline. Postharvest inactivation of phenol oxidases in green tea leaves prevents oxidation of the catechins, whereas postharvest enzyme-catalyzed oxidation (fermentation) of catechins in tea leaves results in the formation of four theaflavins as well as polymeric thearubigins. These substances impart the black color to black teas. Black and partly fermented oolong teas contain both classes of phenolic compounds. A need exists to develop a better understanding of the roles of polyphenolic tea compounds in food and medical microbiology. This overview surveys and interprets our present knowledge of activities of tea flavonoids and teas against foodborne and other pathogenic bacteria, virulent protein toxins produced by some of the bacteria, virulent bacteriophages, pathogenic viruses and fungi. Also covered are synergistic, mechanistic, and bioavailability aspects of the antimicrobial effects. Further research is suggested for each of these categories. The herein described findings are not only of fundamental interest, but also have practical implications for nutrition, food safety, and animal and human health.
12 healthy volunteers on a controlled aluminium (Al) diet each consumed a tea infusion (500 ml/70 kg body weight), with either milk or lemon juice as additives, or mineral water, following a three-way crossover design. The concentrations of Al were determined in the diet, mineral water and tea infusions, and in plasma samples collected before and up to 24 hr after consumption of tea or water, using graphite-furnace atomic absorption spectrophotometry or inductively coupled plasma emission spectrometry. Consumption of up to 1.60 mg Al from tea with milk or lemon juice did not increase plasma Al levels compared with consumption of approximately 0.001 mg Al from mineral water. The results suggest that, in the short-term, drinking tea does not contribute significantly to the total body burden of Al.
The in vitro speciation of aluminium (Al) in black tea infusion (pH 4.8) was assessed using 3000, 10,000 and 30,000 Da cut-off ultrafilters, and the effect of adding human gastric juice (pH 2.3) and then raising the pH to 6.5 were also studied. 78% Al in the tea infusion passed through the 3000-Da ultrafilter; this percentage increased to more than 90% with the addition of gastric juice at pH 2.3, but then reduced to approximately 5% when the incubate was adjusted to pH 6.5. The breakdown of tea-derived polyphenols to low molecular weight phenols in vivo was measured using high-resolution 1H nuclear magnetic resonance spectroscopic analysis of ileostomy effluent, but there was no evidence of low molecular weight breakdown products from the polyphenols of ingested tea in this effluent. These results suggest that only a small proportion of Al in tea is potentially available for absorption throughout the small bowel. It may be misleading to estimate systemic Al absorption from tea drinking simply from total urinary aluminium excretion as has been done previously.
OBJECTIVE: To investigate the association between cooking behaviour and long-term survival among elderly Taiwanese. DESIGN: Cohort study. The duration of follow-up was the interval between the date of interview and the date of death or 31 December 2008, when censored for survivors. Information used included demographics, socio-economic status, health behaviours, cooking frequencies, physical function, cognitive function, nutrition knowledge awareness, eating out habits and food and nutrient intakes. These data were linked to death records. Cox proportional-hazards models were used to evaluate cooking frequency on death from 1999 to 2008 with related covariate adjustments. SETTING: Elderly Nutrition and Health Survey in Taiwan, 1999-2000. SUBJECTS: Nationally representative free-living elderly people aged ≥65 years (n 1888). RESULTS: During a 10-year follow-up, 695 participants died. Those who cooked most frequently were younger, women, unmarried, less educated, non-drinkers of alcohol, non-smokers, without chewing difficulty, had spouse as dinner companion, normal cognition, who walked or shopped more than twice weekly, who ate less meat and more vegetables. Highly frequent cooking (>5 times/week, compared with never) predicted survival (hazard ratio (HR) = 0·47; 95 % CI, 0·36, 0·61); with adjustment for physical function, cognitive function, nutrition knowledge awareness and other covariates, HR was 0·59 (95 % CI, 0·41, 0·86). Women benefited more from cooking more frequently than did men, with decreased HR, 51 % v. 24 %, when most was compared with least. A 2-year delay in the assessment of survivorship led to similar findings. CONCLUSIONS: Cooking behaviour favourably predicts survivorship. Highly frequent cooking may favour women more than men.
Among the many known health benefits of tea catechins count anti-inflammatory and neuroprotective activities, as well as effects on the regulation of food intake. Here we address cannabimimetic bioactivity of catechin derivatives occurring in tea leaves as a possible cellular effector of these functionalities. Competitive radioligand binding assays using recombinant human cannabinoid receptors expressed in Chem-1 and CHO cells identified (-)-epigallocatechin-3-O-gallate, EGCG (K(i)=33.6 microM), (-)-epigallocatechin, EGC (K(i)=35.7 microM), and (-)-epicatechin-3-O-gallate, ECG (K(i)=47.3 microM) as ligands with moderate affinity for type 1 cannabinoid receptors, CB1. Binding to CB2 was weaker with inhibition constants exceeding 50 microM for EGC and ECG. The epimers (+)-catechin and (-)-epicatechin exhibited negligible affinities for both CB1 and CB2. It can be concluded that central nervous cannabinoid receptors may be targeted by selected tea catechins but signaling via peripheral type receptors is less likely to play a major role in vivo.
Total aluminum, chromium, copper, iron, manganese, and nickel were determined in black tea, green tea, Hibiscus sabdariffa, and Ilex paraguariensis (mate) by electrothermal atomic absorption spectrometry after nitric/perchloric acid digestion. In each case, one ground sample of commercially available leafy material was prepared and three 0.5-g subsamples were run in parallel. The infusions were also analyzed and the percentage of each element leached into the liquor was evaluated. The obtained results indicated that hibiscus and mate contained lower levels of aluminum (272+/-19 microg/g and 369+/-22 microg/g, respectively) as referred to black tea (759+/-31 microg/g) or green tea (919micro29 microg/g) and suggested that mate drinking could be a good dietary source of essential micronutrient manganese (total content 2223+/-110 microg/g, 48.1% leached to the infusion). It was also found that the infusion of hibiscus could supply greater amounts of iron (111+/-5 microg/g total, 40.5% leached) and copper (5.9+/-0.3 microg/g total, 93.4% leached) as compared to other infusions. Moreover, it was found that the percentage of element leached to the infusion was strongly related to the tannins content in the beverage (correlation coefficients > 0.82 with the exception for nickel); for lower tannins level, better leaching was observed.
To determine the presence of Shiga toxin-producing Escherichia coli (STEC) and other potentially diarrheagenic E. coli strains in retail meats, 7,258 E. coli isolates collected by the U.S. National Antimicrobial Resistance Monitoring System (NARMS) retail meat program from 2002 to 2007 were screened for Shiga toxin genes. In addition, 1,275 of the E. coli isolates recovered in 2006 were examined for virulence genes specific for other diarrheagenic E. coli strains. Seventeen isolates (16 from ground beef and 1 from a pork chop) were positive for stx genes, including 5 positive for both stx1 and stx2, 2 positive for stx1, and 10 positive for stx2. The 17 STEC strains belonged to 10 serotypes: O83:H8, O8:H16, O15:H16, O15:H17, O88:H38, ONT:H51, ONT:H2, ONT:H10, ONT:H7, and ONT:H46. None of the STEC isolates contained eae, whereas seven carried enterohemorrhagic E. coli (EHEC) hlyA. All except one STEC isolate exhibited toxic effects on Vero cells. DNA sequence analysis showed that the stx2 genes from five STEC isolates encoded mucus-activatable Stx2d. Subtyping of the 17 STEC isolates by pulsed-field gel electrophoresis (PFGE) yielded 14 distinct restriction patterns. Among the 1,275 isolates from 2006, 11 atypical enteropathogenic E. coli (EPEC) isolates were identified in addition to 3 STEC isolates. This study demonstrated that retail meats, mainly ground beef, were contaminated with diverse STEC strains. The presence of atypical EPEC strains in retail meat is also of concern due to their potential to cause human infections.
There is strong evidence indicating that elevated plasma total homocysteine (tHcy) levels are a major independent biomarker and/or a contributor to chronic conditions, such as CVD. A deficiency of vitamin B₁₂ can elevate homocysteine. Vegetarians are a group of the population who are potentially at greater risk of vitamin B₁₂ deficiency than omnivores. This is the first systematic review and meta-analysis to appraise a range of studies that compared the homocysteine and vitamin B₁₂ levels of vegetarians and omnivores. The search methods employed identified 443 entries, from which, by screening using set inclusion and exclusion criteria, six eligible cohort case studies and eleven cross-sectional studies from 1999 to 2010 were revealed, which compared concentrations of plasma tHcy and serum vitamin B₁₂ of omnivores, lactovegetarians or lacto-ovovegetarians and vegans. Of the identified seventeen studies (3230 participants), only two studies reported that vegan concentrations of plasma tHcy and serum vitamin B₁₂ did not differ from omnivores. The present study confirmed that an inverse relationship exists between plasma tHcy and serum vitamin B₁₂, from which it can be concluded that the usual dietary source of vitamin B₁₂ is animal products and those who choose to omit or restrict these products are destined to become vitamin B₁₂ deficient. At present, the available supplement, which is usually used for fortification of food, is the unreliable cyanocobalamin. A well-designed study is needed to investigate a reliable and suitable supplement to normalise the elevated plasma tHcy of a high majority of vegetarians. This would fill the gaps in the present nutritional scientific knowledge.
There is no recognized definition of what constitutes a high fiber diet. Intakes of dietary fiber in different populations internationally vary widely from less than 20 g to more than 80 g per day. The types of foods contributing fiber also vary; in some countries cereals contribute the most fiber, in others leafy or root vegetables predominate. Vegetables have the highest fiber content per Kcal, and in most populations with fiber intakes over 50 g, vegetables contribute over 50% of total fiber intake. In rural Uganda, where the fiber hypothesis was first developed by Burkitt and Trowell, vegetables contribute over 90% of fiber intake. An experimental diet, the "Simian" diet, has been developed to mimic as closely as possible using human foods, the diet consumed by our simian ancestors the great apes. It is also similar to the Ugandan diet in containing large amounts of vegetables and 50 g fiber/1000 Kcal. Though nutritionally adequate, this diet is very bulky and not a suitable model for general recommendations. Dietary guidelines are that fat intake should be < 30% of energy, with a fiber intake of 20-35 g/d. These recommendations are inconsistent with a high fiber diet because, for people consuming more than about 2400 Kcal, low fiber choices for fruits and grains must be selected to keep dietary fiber intake within the range of 20-35 g. In a 30% fat, 1800 Kcal omnivorous diet, selection of wholemeal bread and whole fruit, results in a fiber intake over 35 g/d, and for and 1800 Kcal vegetarian diet, with substitution of modest amounts of peanut butter and beans for meats, dietary fiber intake goes up to 45 g/d. Thus, if it is desirable to promote the use of unrefined foods, the recommended dietary fiber intake should be a minimum of 15-20 g/1000 Kcal.
Hepatitis E, which is caused by hepatitis E virus (HEV), may now be considered a zoonosis as well as an anthroponosis. Pigs, boars and deer have been identified as reservoirs, and their flesh and entrails--as meat and offal--as vehicles of HEV transmission. Shellfish also act as vehicles. Dietary, gastronomic and culinary preferences influence how extensively HEV conveyed by these vehicles can be inactivated before their ingestion by the host. Another route of infection is paved by HEV that is enterically shed by humans and by live animals into the environment. Although anthroponotic transmission of HEV is primarily environmental, zoonotic transmission may proceed along both foodborne and environmental routes.
There is increasing evidence that obesity in humans is associated with infection with human adenovirus-36 (Adv36). Infection of experimental animals with Adv36 demonstrates that this virus causes obesity. Human studies have shown a prevalence of Adv36 infection of 30% or greater in obese adult humans, but a correlation with obesity has not always been demonstrated. In contrast, three published studies and one presented study with a total of 559 children all show that there is an increase in prevalence of Adv36 infection in obese children (28%) compared to non-obese children (10%). The explanation for the apparently more robust correlation of Adv36 infection with obesity in children vs. adults is not clear. The data in animals and people suggests that Adv36 has contributed to the worldwide increase in childhood obesity. More research is needed to identify prevalences and consequences of Adv36 infection in people of all age groups and geographic locations.