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Biomedical subjects

S A Bingham

Publications and source records attributed to S A Bingham.

At least 55 records · Page 3Linked to original sources
PubMed1997

Validation of dietary intakes of protein and energy against 24 hour urinary N and DLW energy expenditure in middle-aged women, retired men and post-obese subjects: comparisons with validation against presumed energy requirements.

OBJECTIVES: To compare validation of reported dietary intakes from weighed records against urinary nitrogen excretion and energy expenditure measured by DLW, and to examine the utility of the Goldberg cut-off for EI:BMR in the identification of under-reporters. DESIGN: Energy (EI) and nitrogen (protein) intake (NI) were measured by 16 d of weighed diet records collected over 1 y. They were validated against urinary nitrogen excretion in 5-8 (mean 6.0) 24 h urine collections and total energy expenditure (EE) measured by doubly labelled water (DLW). Basal metabolic rate (BMR) as measured by whole body calorimetry in women or bedside ventilated hood (Deltatrac) in men. Individual subjects were identified as under-reporters if Urine N:NI was > 1.00 or if EI:EE was < 0.79. The agreement between the two ratios in detecting under-reporting was examined. The results from the direct validation by DLW were also compared with validation using the Goldberg cut-off for EI:BMR (Goldberg et al, 1991). SUBJECTS: Eighteen women aged 50-65 y and 27 men aged 55-87 y were selected from participants in two larger dietary surveys as representing the full range of dietary reporting as measured by Urine N:NI. Data from a previous study of 11 post-obese subjects were also included. RESULTS: The two ratios, Urine N:NI and EI:EE, were significantly related (r = -0.48, P < 0.01). Using the above cut-offs, seven (4F, 3M) subjects were identified as under-reporters by both methods, one (1M) by Urine N:NI only and 8 (3F, 5M) by EI:EE only. There was close agreement in post-obese subjects where 6 subjects showed a substantial degree of under-reporting by both methods (r = -0.87, P < 0.001). The correlation between direct validation by DLW and EI:BMRest was 0.65 (P < 0.001). Some limitations of the Goldberg cut-off for identifying individual under-reporters were demonstrated. CONCLUSIONS: EI:EE provides an estimate of the degree of under-reporting of energy at the group and individual level. Urine N:NI identifies under-reporting of protein intake and the most obvious under-reporters of energy, but is probably of lesser value in estimating the overall degree of under-reporting of energy at group level. Good validation by EI:BMR depends on knowledge of physical activity at both group and individual level. However, the correlation of 0.65 between EI:EE and EI:BMRest suggests that EI:BMR could be usefully incorporated into analysis of data from epidemiological studies. Validation measures consisting of at least predicted EI:BMR ratios and urinary measures should be incorporated into dietary surveys. SPONSORSHIP: This work was funded by the Ministry of Agriculture Fisheries and Food, the Medical Research Council, the Cancer Research Council and the Swedish Medical Research Council and the Henning and Johan Throne-Holst Foundation.

Aged↗
PubMed1997

Dietary assessment in Whitehall II: the influence of reporting bias on apparent socioeconomic variation in nutrient intakes.

OBJECTIVE: To assess socio-economic differences in nutrient intake, giving particular consideration to the influence of reporting bias. DESIGN: Cross-sectional study. Three methods of data analysis (inclusion of all subjects, exclusion of low energy reporters, and regression-based energy adjustment) were evaluated against biomarkers of fatty acid and antioxidant intakes. SETTING: London-based Civil Servants. SUBJECTS: Age and employment grade stratified random sub-sample of 459 men and 406 women aged 39-61 y who completed 7 d diet diaries at Phase 3 follow-up (1991-93) of the Whitehall II Study. DIETARY MEASURES: Mean daily intakes by employment grade (6 levels) of dietary energy, total fat, saturated fatty acids, polyunsaturated fatty acids (PUFA), linoleic acid, carbohydrate excluding fibre, dietary fibre, protein, alcohol, vitamin C, vitamin E, carotenes, potassium and calcium. Biomarkers: serum cholesterol ester fatty acids (CEFA), total cholesterol, plasma alpha-tocopherol and beta-carotene. RESULTS: Low energy reporting (LER), defined as a reported energy intake below 1.2 times calculated basal metabolic rate, was strongly associated with employment grade (top grade: men 17.3%, women 19.3%, bottom grade: men 45.7%, women 49.2% trend P < 0.0001 both sexes). This association is only to a small extent accounted for by the relative weight distribution across grades. The direct associations with grade--high status, high intakes--of total fat, saturated and polyunsaturated fatty acids seen in the results overall were greatly reduced or abolished when LER were excluded or when energy adjustment was used. Direct associations between grade and intakes of vitamin C and potassium in both sexes were evident regardless of data presentation method. Spearman correlations between biomarkers and reported intakes, for example CEFA and dietary linoleate (men 0.46, women 0.61), plasma beta-carotene/cholesterol ratio and dietary carotenes (men 0.16, women 0.21) together with theoretical considerations indicate that energy adjustment may be the preferred method for reducing the influence of reporting bias. CONCLUSIONS: Low energy reporting is a major source of bias in dietary surveys and its prevalence shows a marked inverse association with socio-economic status. The energy adjustment method provides an approach which reduces this bias without exclusion of low energy reporters. Intakes of micronutrients including vitamin C, rather than fatty acids, showed associations with socio-economic status consistent with a dietary explanation for social inequalities in cardiovascular disease.

Adult↗
PubMed1997

Effect of black tea drinking on blood lipids, blood pressure and aspects of bowel habit.

Thirty-one men (47 (SD 14) years) and thirty-four women (35 (SD 13) years) took part in a 4-week randomized cross-over trial to compare the effect of six mugs of black tea daily v. placebo (water, caffeine, milk and sugar) on blood lipids, bowel habit and blood pressure, measured during a run-in period and at the end of weeks 2, 3 and 4 of the test periods. Compliance was established by adding a known amount of p-aminobenzoic acid (PABA) to selected tea bags, and then measuring its excretion in urine. Mean serum cholesterol values during run-in, placebo and on tea drinking were 5.67 (SD 1.05), 5.76 (SD 1.11) and 5.69 (SD 1.09) mmol/l (P = 0.16). There were also no significant changes in diet, LDL-cholesterol, HDL-cholesterol, triacylglycerols, and blood pressure in the tea intervention period compared with placebo. Compared with placebo, stool consistency was softened with tea (P = 0.04), and no other differences were found in bowel habit. Results were unchanged when fifteen 'non-compliers', whose PABA excretion indicated that fewer than six tea bags had been used, were excluded from the analysis, and when differences between run-in and tea periods were considered separately for those who were given tea first or second.

4-Aminobenzoic Acid↗
PubMed1997

Effect of meat and resistant starch on fecal excretion of apparent N-nitroso compounds and ammonia from the human large bowel.

N-nitroso compounds are produced in the human large intestine, but little is known about the dietary modulation of their synthesis at this site. The effects of meat and resistant starch on the fecal excretion of N-nitroso compounds, measured as apparent total N-nitroso compounds (ATNC), were therefore investigated in a crossover study involving eight healthy men. Three controlled diets that differed in the amount of meat (40 or 600 g) and resistant starch (37 g added to 600 g meat diet) were fed in random order, and fecal ATNC, as well as fecal ammonia and parameters of bowel function, were measured after 19 days of dietary adaptation. Mean ATNC excretion during the high-meat period was 114 micrograms/day, three times that during the low-meat period of 35 micrograms/day (p = 0.02); ammonia excretion was twice that during the low-meat period: 2.9 vs. 1.4 mmol/day (p = 0.03). The fecal ATNC were dissolved in the fecal water, and 45% had a molecular weight < 3,000. The addition of readily fermentable resistant starch to the high-meat diet significantly increased stool output from 118 to 153 g/day and decreased fecal pH from 7.2 to 6.6 but had no significant effect on fecal ATNC (151 micrograms/day), ammonia (3.7 mmol/day), whole gut transit time, urinary nitrate, or plasma urea. ATNC produced in the large bowel in association with a high-meat intake could represent an important source of DNA-damaging alkylating agents in the human large bowel.

Adult↗
PubMed1997

Using biochemical markers to assess the validity of prospective dietary assessment methods and the effect of energy adjustment.

The validity of dietary assessment methods in a group of women aged 50-65 y was evaluated with use of biochemical markers. Estimates of nitrogen, potassium, and carotene intakes from weighed-food and estimated records yielded higher correlations with urinary nitrogen, urinary potassium, and serum concentrations of carotenoids than did estimates from food-frequency questionnaires and 24-h recalls. When the residuals method of energy adjustment was used, the correlations between intakes of nitrogen and potassium estimated from food-frequency questionnaires and 24-h recalls and intakes derived from weighed-food records improved, and the high correlations between biochemical markers and estimates from weighed-food records were maintained. In addition, with use of this method, estimates for nitrogen and potassium intakes from food-frequency questionnaires showed the most improvement in comparison with the biochemical markers; however, the correlations of crude nitrogen and potassium with crude energy intake were highest. Carotene intake was not related to energy intake, so that correlations between the intake of carotene assessed by any method and the plasma beta-carotene concentration did not improve with energy adjustment and between-person variability was not reduced. Energy adjustment with either the energy density or residuals method did not alter the ranking of accuracy of various dietary assessment methods in comparison with weighed-food records or biochemical markers in either the total group of subjects or those who were identified as having provided valid weighed-food records.

Aged↗
PubMed1997

Validation of dietary assessment methods in the UK arm of EPIC using weighed records, and 24-hour urinary nitrogen and potassium and serum vitamin C and carotenoids as biomarkers.

BACKGROUND: In the UK EPIC validation studies, the accuracy of several methods was assessed by comparison with to-day weighed records and the biomarkers, 24-hour urine nitrogen (N) and potassium (K), plasma carotenoids and plasma vitamin C. METHODS: Comparisons between methods were made on 156 women, studied over 1 year at 3-monthly intervals at home. On each of four occasions, volunteers completed 4 days of weighed records and provided two 24-hour urine collections and a fasting blood sample. RESULTS: In comparison with the 16 days of weighed records, a food frequency questionnaire (FFQ) yielded higher values mainly due to greater reported consumption of milk and of vegetables. A 24-hour recall was as good as the FFQ in placing individuals in the distribution of habitual diet from weighed records. Results obtained from a 7-day estimated record were closest to those obtained from the weighed record. Correlations between 24-hour urine excretion and dietary N intake from weighed records were high (0.78-0.87) as were those with estimated food diaries (0.60-0.70). Correlations between urine N and the FFQ and 24-hour recall were lower (0.10 to 0.27), but improved by energy adjustment using residuals for N and K which are correlated with total energy intake. Comparisons between dietary estimates and urinary K and serum carotenoids and vitamin C showed broadly similar results. Limited biomarker information amongst 200 UK EPIC participants supported the findings of the validation study. CONCLUSIONS: UK EPIC uses three methods (the 7-day diary, an improved FFQ, and the 24-hour recall) to assess diet. 93% of first food diaries are returned completed by participants. Repeated diaries are the main dietary assessment method for nested case-control analyses.

Aged↗
PubMed1997

Dietary assessments in the European prospective study of diet and cancer (EPIC).

Biomarkers of nutrition intake were used to validate the dietary assessments proposed for use in the European prospective study of diet and cancer (EPIC). In the UK validation studies, the accuracy of several tested methods was assessed with weighed food records and biomarkers, 24 h urine nitrogen, potassium and plasma carotenoids and vitamin C. Correlations between dietary nitrogen intake from weighed food records and 24 h urine excretion were high (0.78-0.87). The correlations between nitrogen from estimated food diaries and urinary nitrogen were r = 0.60-0.70. Correlations with other methods were lower, but improved by energy adjustment, using residuals for those nutrients correlated with total energy, such as nitrogen and potassium, but not for nutrients not correlated with energy intake--for example, beta-carotene. Hence, the correlation between urinary nitrogen and unadjusted nitrogen from a food frequency questionnaire (FFQ) was 0.24 but improved with energy adjustment to 0.49. UK EPIC uses three methods (diary, improved FFQ and 24 h recall) to assess diet, with repeated measures from the food diary at 18 months and four years. Ninety-three percent of first food diaries are returned completed by participants. Results from 200 subjects randomly selected from the first 2,000 recruits suggest that differences between methods with improved FFQ design are less obvious than in the initial validation study. Results from the diary are more closely correlated with plasma carotenoids and vitamin C than other methods, although supplements of vitamin C are the main determinant of the magnitude of correlations. More detailed biomarker studies are in progress among EPIC participants.

Aged↗
PubMed1996

The correlation between the intake of lutein, lycopene and beta-carotene from vegetables and fruits, and blood plasma concentrations in a group of women aged 50-65 years in the UK.

The correlations between the mean of 4 d weighed intakes of lutein, lycopene and beta-carotene and mean plasma concentrations during each of the four seasons were lutein r 0.64, lycopene r 0.47 and beta-carotene r 0.45. Intake was not significantly correlated with plasma concentrations during every seasonal time-point. There was a significantly higher intake of lutein during the spring compared with summer and autumn, lycopene intake was significantly higher during the summer and autumn and there were no significant seasonal differences in beta-carotene intake. There were, however, significant seasonal differences in plasma carotenoid concentrations, the highest levels occurring between May and October. There were large inter- and intra-individual variations in intake and plasma concentrations of carotenoids. BMI was inversely correlated with plasma beta-carotene (r-0.41). The findings suggest that plasma carotenoid concentrations are indicative of dietary intake, but the large intra-individual variation in plasma concentrations indicates that any assessment of longer-term status from data at any one time-point should be treated with caution.

Aged↗
PubMed1996

Digestion and physiological properties of resistant starch in the human large bowel.

The digestion of four sources of resistant starch (RS) has been studied in twelve healthy volunteers who ate controlled diets for 15 d periods. RS from potato, banana, wheat and maize (17-30 g/d) was compared with a starch-free diet, a diet containing wheat starch that was fully digested in the small intestine, and with 18.4 g NSP from brand/d. RS increased stool wet weight by 1.6 g/d per g RS fed for potato, 1.7 for banana, 2.5 for wheat and 2.7 for maize, but this was significantly less than bran NSP at 4.9 g/g. RS was extensively digested in twenty-seven of thirty-four diet periods but five subjects were unable to break down one or two of the RS sources. Faecal N and energy excretion were increased. RS decreased NSP breakdown and RS2 (resistant starch granules) tended to prolong transit time. All forms of RS increased faecal total short-chain fatty acid excretion. RS2 (from potato and banana) gave greater proportions of acetate in faeces, and RS3 (retrograded starch from wheat and maize) more propionate. We have concluded that RS2 and RS3 are broken down in the human gut, probably in the colon although in 26% of cases this breakdown was impaired. RS exerts mild laxative properties, predominantly through stimulation of biomass excretion but also through some sparing of NSP breakdown.

Adult↗
PubMed1996

Does increased endogenous formation of N-nitroso compounds in the human colon explain the association between red meat and colon cancer?

High red meat diets have been linked with risk of sporadic colorectal cancer; but their effects on mutations which occur in this cancer are unknown. G-->A transitions in K-ras occur in colorectal cancer and are characteristic of the effects of alkylating agents such as N-nitroso compounds (NOC). We studied th effect of red meat consumption on faecal NOC levels in eight male volunteers who consumed diets low or high in meat (60 or 600 g/day), as beef, lamb or pork, whilst living in a metabolic suite. Increased intake of red meat induced a significant (P<0.024) 3-fold increase from 40 + or - 7 to ab average of 113 + or - 25 microgram/day NOC, a range of exposure in faeces similar to that from tobacco-specific NOC in cigarette smoke. THe diets were isoenergetic and contained equal amounts of fat, but concentrations of heterocyclic amines were low. Faecal excretion of the promotor ammonia was significantly increased to 6.5 + or - 1.08 mmol/day. When the high red meat diets were supplemented with 20 g phytate-free wheat bran in six volunteers there was no reduction in NOC levels (mean 138 + or - 41 microgram/day NOC), but faecal weight increased. Higher starch and non-starch polysaccharide intakes reduced intraluminal cross-linking in microcapsules (r=-0.77) and reduced faecal pH (r=-0.64). In two volunteers there was no effect of 600 g white meat and fish o faecal NOC (mean low white meat diet 68 + or - 10 microgram/day, high white meat 56 + or -6 microgram/day nor on faecal nitrate, nitrite and iron. Faecal nitrite levels increased on changing from a white to red meat diet (mean high white meat diet 46 + or - 7 mg/day, high red meat diet mean 80 + or - 7 mg/day.) Increased endogenous production of NOC and precursors from increased red meat, but not white meat and fish, consumption may be relevant to the aetiology of colorectal cancer.

Adult↗
PubMed1995

Validation of weighed records and other methods of dietary assessment using the 24 h urine nitrogen technique and other biological markers.

Results from analysis of 24 h urine collections, verified for completeness with para-amino benzoic acid, and blood samples collected over 1 year were compared with 16 d weighed records of all food consumed collected over the year, and with results from 24 h recalls, food-frequency questionnaires and estimated food records in 160 women. Using the weighed records, individuals were sorted into quintiles of the distribution of the urine N excretion:dietary N intake ratio (UN:DN). UN exceeded DN in the top quintile of this ratio; mean ratio UN:DN = 1.13. Individuals in this top quintile were heavier, had significantly greater body mass indices, were reportedly more restrained eaters, had significantly lower energy intake:basal metabolic rate ratios (EI:BMR), and had correlated ratios of UN:DN and EI:BMR (r -0.62). Those in the top quintile reported lower intakes of energy and energy-yielding nutrients, Ca, fats, cakes, breakfast cereals, milk and sugars than individuals in the other quintiles but not lower intakes of non-starch polysaccharides, vitamin C, vegetables, potatoes or meat. Correlations between dietary intake from weighed records and 24 h urine K were 0.74 and 0.82, and between dietary vitamin C and beta-carotene and plasma vitamin C and beta-carotene 0.86 and 0.48. Correlations between dietary N intake from weighed records and 24 h urine excretion were high (0.78-0.87). Those between N from estimated food records and urine N were r 0.60-0.70. Correlations between urine N and 24 h recalls and food-frequency questionnaires were in the order of 0.01 to 0.5. Despite problems of underreporting in overweight individuals in 20% of this sample, weighed records remained the most accurate method of dietary assessment, and only an estimated 7 d diary was able to approach this accuracy.

Basal Metabolism↗
PubMed1994

Starch intake and colorectal cancer risk: an international comparison.

Intakes of starch, non-starch polysaccharides (NSPs), protein and fat have been compared with colorectal cancer incidence in 12 populations worldwide. There were strong inverse associations between starch consumption and large bowel cancer incidence (large bowel r = -0.70, colon r = -0.76). There was no significant relation with NSPs, although the association with large bowel cancer incidence was still significant when NSP was combined with resistant starch (RS) to give an estimate of fermentable carbohydrate (large bowel r = -0.52, colon r = -0.60). The relationships between starch, RS and NSPs and cancer incidence remained statistically significant after adjusting for fat and protein intakes. The strong inverse associations found here suggest a potentially important role for starch in protection against colorectal cancer and correspond with the hypothesis that fermentation in the colon is the mechanism for preventing colorectal cancer. Measures of both starch and NSPs need to be included in future epidemiological studies of diet and bowel cancer.

Age Factors↗
PubMed1994

Comparison of dietary assessment methods in nutritional epidemiology: weighed records v. 24 h recalls, food-frequency questionnaires and estimated-diet records.

Women (n 160) aged 50 to 65 years were asked to weigh their food for 4 d on four occasions over the period of 1 year, using the PETRA (Portable Electronic Tape Recorded Automatic) scales. Throughout the year, they were asked to complete seven other dietary assessment methods: a simple 24 h recall, a structured 24 h recall with portion size assessments using photographs, two food-frequency questionnaires, a 7 d estimated record or open-ended food diary, a structured food-frequency (menu) record, and a structured food-frequency (menu) record with portion sizes assessed using photographs. Comparisons between the average of the 16 d weighed records and the first presentation of each method indicated that food-frequency questionnaires were not appreciably better at placing individuals in the distribution of habitual diet than 24 h recalls, due partly to inaccuracies in the estimation of frequency of food consumption. With a 7 d estimated record or open-ended food diary, however, individual values of nutrients were most closely associated with those obtained from 16 d weighed records, and there were no significant differences in average food or nutrient intakes.

Diet Records↗