PubMed Health⌕ Search

Biomedical subjects

C Bolton-Smith

Publications and source records attributed to C Bolton-Smith.

At least 37 records · Page 2Linked to original sources
PubMed2000

Compilation of a provisional UK database for the phylloquinone (vitamin K1) content of foods.

This paper reports the compilation of a food composition database for phylloquinone (vitamin K1) derived from the direct analysis of foods, recipe calculation and the assignment of values based on food similarities. All the basic and other food items used in these calculations had been analysed by HPLC and about 170 of the items had been obtained and assayed in the UK. Recipe calculations took account of the cooking method and changes in water and fat content. Currently, approximately 1501 food items with Royal Society of Chemistry/Ministry of Agriculture, Fisheries and Food food codes have been allocated a vitamin K1 value, and a further 282 new recipe codes are included in the database. Representative values from each food group are reported together with an indication of the potential variation. Detailed examples of some recipe calculations are included, and also the impact of changing the type of fat in recipes. Vitamin K1 is associated with, and most abundant in, photosynthetic tissues of plants. Accordingly, the highest concentrations (3000-6000 micrograms/kg) are found in dark-green leafy vegetables and herbs, such as kale, parsley, spinach and green cabbage. Intermediate concentrations (1000-2000 micrograms/kg) are found in plants with paler leaves such as white cabbage and lettuce or in green, non-leafy vegetables such as broccoli and brussel sprouts. Fats and oils contain variable amounts of vitamin K1 with the highest concentrations (300-1300 micrograms/kg) in soyabean, rapeseed and olive oils and the margarines based on them. Other foods such as dairy products, meat dishes and cereal-based foods (bread, biscuits, cakes, desserts etc.), although not in themselves particularly rich in vitamin K1 (< 200 micrograms/kg), may contribute significantly to intakes when consumption of green vegetables is poor. Within the scope of this present study, it has not been possible to address issues such as inter-sample variability, losses during storage or the bioavailability from different foods and further work on these aspects is needed.

Apiaceae↗
PubMed2000

Seasonal variation in plasma levels of endothelin-1 and nitric oxide.

BACKGROUND: There is a seasonal variation in the incidence of stroke and coronary heart disease with admissions to hospital being higher in the colder months of the year. The mechanism whereby this winter prevalence of vascular disease occurs is still not fully understood. The aim of our study was to measure plasma levels of vasoactive compounds throughout the year to establish whether or not there were any fluctuations which could play a part in the higher winter incidence. METHODS: We measured plasma levels of the vasoconstrictive endothelin-1 (ET) and the vasorelaxant nitric oxide (NO) throughout the year. Blood samples were collected from 176 normal individuals. Samples were collected between 8.00 and 10.00 hours after an overnight fast of at least 12 hours. RESULTS: Results were divided into two-monthly intervals and analysed using a Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests (SPSS). We found a significant seasonal variation in both parameters. Mean levels of endothelin were highest in January/February (4.0 pg/ml) and lowest in May/June (2.3 pg/ml), whereas plasma 5 nitric oxide levels were lowest in January/February (5.7 microM) and highest in September/October (9.9 microM); p values were <0.0001 (Jan/Feb vs May/June) and 0.049 (Jan/Feb vs Sept/Oct), respectively. CONCLUSIONS: The high levels of the vasoconstrictor endothelin combined with low levels of vasorelaxant nitric oxide may account in part for the increased incidence of stroke and coronary heart disease seen in these months.

Aged↗
PubMed1999

Dietary antioxidant vitamins and fiber in the etiology of cardiovascular disease and all-causes mortality: results from the Scottish Heart Health Study.

In this paper, data obtained between 1984 and 1993 from 11,629 men and women as part of the Scottish Heart Health Study (Scotland, United Kingdom) were used to investigate the relation between antioxidant vitamin and fiber intakes and both incident coronary heart disease (CHD) (649 events) and all-causes mortality (591 deaths). All age-adjusted mean intakes tended to be higher in the group that experienced no event. For men, increased fiber intake was associated with decreased risk of CHD even after adjustment for a host of other major coronary risk factors; hazard ratios relative to the lowest quarter were 0.68, 0.70, and 0.64 by increasing quarter. This relation was also observed for mortality (hazard ratios of 0.62, 0.66, and 0.62). Evidence was found that higher intakes of the antioxidants were also beneficial, although the associations were weaker. For women, fiber was the only obviously influential dietary factor, with hazard ratios of 0.94, 0.60, and 0.56 for CHD and 1.25, 0.82, and 0.65 for mortality. These results suggest that the current public health drive to increase the consumption of foods rich in antioxidant vitamins and (particularly) fiber will impact on both CHD risk and the general health of the population.

Adult↗
PubMed1997

Evidence for age-related differences in the fatty acid composition of human adipose tissue, independent of diet.

OBJECTIVE: To test the null-hypothesis that no age difference in adipose tissue fatty acid composition exists independent of dietary fat intake. DESIGN: A cross-sectional survey of coronary heart disease risk factors, the Scottish Heart Health Study, provided needle biopsy adipose tissue fatty acid data and food frequency-derived dietary data. SETTING: Twenty-two Scottish Districts between 1984 and 1986. SUBJECTS: A total of 10,359 men and women aged 40-59 y were randomly recruited in sex and five-year age bands from GP lists. A sub-set of 2308 men and 2049 women (42%) provided satisfactory adipose tissue and dietary data. MAIN OUTCOME AND MEASURES: Multiple regression analysis (adjusting for dietary fats, body mass index and smoking, with and without menopause status for women) of the relationship between individual fatty acids in adipose tissue and age, and between age and the ratio of linoleic acid (C18:2, n-6) to gamma-linolenic acid (C18:3, n-6) as an indicator of delta-6 desaturase activity. RESULTS: Sex-consistent changes with age occurred for linoleate (adjusted regression slope +/- s.e. for men -0.299 +/- 0.1339 and for women -0.504 +/- 0.1731) and gamma-linolenate (adjusted regression slope +/- s.e. for men -0.141 +/- 0.0341 and for women -0.154 +/- 0.0469) both P < 0.0001. These changes gave rise to a significant increase (P < or = 0.005) in the C18:2, n-6 to C18:3, n-6 ratio with age). Dihomo-gamma-linolenic acid (C20:3, n-6) and docosahexa- plus docosapentaenoic acids (C22:5 + C22:6, n-3) also increased significantly with age (P < or = 0.01). For the latter, the adjusted regression slopes were far greater for women (0.596 +/- 0.0575) than men (0.131 +/- 0.0417). CONCLUSIONS: The results show that ageing does influence adipose tissue fatty acid composition independent of diet. The sex differences may partially be due to inadequate adjustment for changes in sex hormone status in males with ageing. Using the current indicator, a decline in the rate limiting step of beta-6 desaturation appeared to occur with age, and was greater in women than in men. These results may indicate that an increase in dietary gamma-linolenic acid (C18:3, n-6) is necessary with age to offset the relative imbalance between PUFA levels which appears to occur. However, any direct health benefit regarding the common diseases of ageing from such a strategy still remain to be clarified.

8,11,14-Eicosatrienoic Acid↗
PubMed1997

Nutritional influences on bone mineral density: a cross-sectional study in premenopausal women.

The association between current and past dietary intake and bone mineral density (BMD) was investigated in 994 healthy premenopausal women aged 45-49 y. BMD was measured with dual-energy X-ray absorptiometry (DXA). Dietary intake was assessed with a food-frequency questionnaire (FFQ). Energy-adjusted nutrient intakes were grouped into quartiles and mean BMD at the lumbar spine (LS), femoral neck (FN), femoral trochanter (FT), and femoral Wards (FW) were calculated. With higher intakes of zinc, magnesium, potassium, and fiber, LS BMD was significantly higher (P < 0.05-0.006), and a significant difference in LS BMD was also found between the lowest and highest quartiles for these nutrients and vitamin C intake (P < 0.05-0.01). These results remained significant after adjustment for important confounding factors. LS BMD and FT BMD were lower in women reporting a low intake of milk and fruit in early adulthood than in women with a medium or high intake (P < 0.01). High, long-term intake of these nutrients may be important to bone health, possibly because of their beneficial effect on acid-base balance.

Absorptiometry, Photon↗
PubMed1996

Does dietary trans fatty acid intake relate to the prevalence of coronary heart disease in Scotland?

Reports of the effects of trans fatty acids on coronary heart disease are inconsistent. Trans fatty acids may particularly influence coronary risk when linoleic acid levels are low, a situation which occurs in Scotland where prevalence of coronary heart disease is also very high. The link between trans fatty acid intake and prevalent coronary heart disease was therefore investigated in the Scottish Heart Health Study population. Trans fatty acid intakes were calculated from 10/359 sets of food-frequency questionnaire data obtained from the cross-sectional survey of men and women aged 40-59 years. Logistic regression analysis was used to calculate the odds ratios for prevalent coronary heart disease by fifths of dietary intake of total, natural and commercial hydrogenation-derived trans fatty acid. The group who had undiagnosed coronary heart disease at the time of survey was the pertinent group for examining the possible causative effects of trans fatty acid intake. After adjustment for the confounding factors (i.e. age, weight, height, smoking, level of physical activity, blood pressure, total energy intake and intakes of saturated fat, linoleic acid and the antioxidant vitamins) the odds of undiagnosed coronary heart disease for men, relative to the lowest intake fifth, did not differ significantly from unity by total or commercially-derived trans fatty acid intake. Odds were around 35% smaller in the higher intake fifths of naturally-derived trans fatty acids. For women, the odds of undiagnosed coronary heart disease tended to be greater in the higher fifths of total (odds ratio 1.36 (95% confidence interval 0.94, 1.89)) and hydrogenated (1.26 (0.92, 1.72)) trans fatty acid relative to the lowest fifth, but only reached significance in the third fifth of total trans fatty acid (1.36 (1.01, 1.83)). Dietary total and commercially-derived trans fatty acids failed to influence the odds of coronary heart disease for men, even though a significant increase in the ratio of low density plus very low density lipoprotein to high density lipoprotein-cholesterol occurred with trans fatty acid intake. The results, therefore, do not support a major effect of dietary trans fatty acid from commercial hydrogenation on coronary heart disease risk in these Scottish men. The results for women are less clear, and the possibility remains that individuals at the high extreme of trans fatty acid intake, who may be essential fatty acid deficient, are at enhanced risk of coronary heart disease.

Adult↗
PubMed1996

Intake of sugars in relation to fatness and micronutrient adequacy.

Dietary sugars have frequently been linked with excess body weight and poor quality diets. A review of the recent research in this area reveals no basis for a causative association between sugar intake and obesity. Rather, a diet which contains a high percentage of energy from carbohydrate (starch and sugars) may assist in weight loss if the proportion of energy from fat is low. Nutrient inadequacies tend to occur in susceptible groups (generally women and children) who have a low total energy intake, and this is compounded by a relatively high contribution from sugars. For general populations with an adequate caloric intake nutrient adequacy can be achieved across a wide range of dietary sugar (4-20% energy). In this respect, intakes at either extreme are sub-optimal.

Adult↗
PubMed1995

Is it necessary to transform nutrient variables prior to statistical analyses?

The distributions of the intakes of many nutrients are skewed, yet this is often overlooked when standard statistical analyses are applied to nutrient data. The nutrient intakes of 5,123 men and 5,236 women, recorded by food frequency questionnaire in the Scottish Heart Health Study, were transformed to achieve approximately symmetric distributions. Power transformations were chosen using letter value analyses. A letter value analysis uses selected order statistics and their position around the median to assess symmetry. The effect that each transformation had on a comparison of nutrient intakes between those with and without prevalent coronary heart disease was determined from t tests on the untransformed and transformed variable. The effects of the logarithm and square root transformation and of the optimum Box-Cox transformation were also determined, and the results were compared with the nonparametric Mann-Whitney test. The conclusion of whether or not to reject the null hypotheses often varied, depending on the transformation and test used. The nonparametric test usually gave a conclusion similar to that of the t test on the letter value-transformed data, the Box-Cox-transformed variable, and after either the logarithm or square root transformation of the data, but not always both. The results from the untransformed variable were sometimes very different. Failure to account for skewness in nutrient variables may thus lead to spurious conclusions.

Aged↗
PubMed1995

An investigation of the relationship between antioxidant vitamin intake and coronary heart disease in men and women using discriminant analysis.

Smoking, high blood pressure and elevated blood cholesterol are the well-established 'classical' risk factors for coronary heart disease (CHD) in men and women. However, it is also well-known that there is a considerable degree of residual variation in CHD after these factors have been taken into account. Consideration of antioxidant vitamin status may help to reduce this unexplained variation. Here, discriminant analysis is applied to the baseline cross-sectional data from the Scottish Heart Health Study. The problem of possible behavioural changes after diagnosis for CHD is addressed by analysing diagnosed and undiagnosed CHD cases separately. Results show that the combined dietary intakes of the antioxidant vitamins C, E and carotene (assessed using a food frequency questionnaire) differentiate CHD prevalence as well as do the classical risk factors. For women, stepwise discriminant analysis shows that the effect of the antioxidant vitamins on CHD is removed by adjustment for the classical risk factors and age. For men, however, the antioxidant vitamins still contribute to the discriminant function. It is concluded that dietary antioxidant vitamins appear to have a significant effect on the prevalence of CHD, especially amongst men. The benefits and problems of using discriminant analysis in this practical context are discussed, including the assumptions that need to be tested.

Adult↗
PubMed1995

An investigation of the relationship between antioxidant vitamin intake and coronary heart disease in men and women using logistic regression analysis.

Antioxidant vitamin intake (C,E and carotene) is assessed from a food frequency questionnaire applied to 10,359 middle-aged men and women participating in the Scottish Heart Health Study. Logistic regression analysis is then used to quantify the relationship between antioxidant vitamin consumption and prevalent coronary heart disease (CHD), analysing diagnosed and undiagnosed cases separately. For men, there is a protective effect of all three antioxidants, before and after adjustment for a comprehensive set of confounding variables. For women the picture is less clear, only vitamin C is negatively associated with CHD, but the effect is removed by adjustment. The logistic regression model is also used to determine classification rules for deciding whether or not an individual has CHD. The classification error rates using the antioxidants are found to be very similar to those found using smoking, blood pressure and serum total cholesterol as classification variables. Significant interactions are found for the antioxidants with smoking, cholesterol and age. It is concluded that antioxidant vitamin intake protects against CHD for men. Logistic regression analysis is compared with discriminant analysis, and is found to have important advantages as an epidemiological tool.

Adult↗
PubMed1995

Trans fatty acids in the Scottish diet. An assessment using a semi-quantitative food-frequency questionnaire.

Trans fatty acids produced during hardening of oils have been associated with higher cholesterol levels and increased risk of heart disease. The potential risk from trans fatty acids may be greater in populations with relatively low intakes of essential fatty acids such as the Scots, who also have a high prevalence of heart disease. Means and ranges of trans fatty acid intakes are reported here for a Scottish population. A semi-quantitative food-frequency questionnaire was used to survey the diet of 10,359 Scottish men and women aged 40-59 years in 1984-6 as part of the baseline Scottish Heart Health Study. Trans fatty acid levels were calculated for each food item on the questionnaire and the total subdivided into that which is derived naturally (primarily by bacterial fermentation in ruminants) and that which is produced during industrial hydrogenation (hardening) of vegetable and fish oils. Means and ranges of intakes of each trans fatty acid variable were calculated by sex, age, smoking and social class groups. Mean total trans fatty acid intakes for men were 7.1 (SD 3.1) g/d, 2.7 (SD 2.9)% energy and for women were 6.4 (SD 2.9) g/d, 3.3 (SD 3.0)% energy. Industrially hydrogenated trans fatty acids made up nearly 58% of the total intake for men and 61% for women, with about 60% coming from cakes, biscuits and sweets, and 20% coming from the cheaper hard margarines. The main sources of the naturally derived trans fatty acids were red meat (27%), milk (20%), butter (18-19%) and cheese (13-16%). Differences between age, smoking and social class groups were apparent. However, apart from the social class differences of up to 1 g/d, these were so small that they are unlikely to be of any biological significance unless compounded by other factors such as marginal essential fatty acid adequacy. The possibility of trans fatty acid intakes up to 48 g/d and 12% total energy (compared with the Department of Health (1991) recommendations of 5 g/d or 2% energy) highlights the need for careful monitoring of the health risks at these high levels of intake.

Adult↗
PubMed1995

Antioxidant vitamin adequacy in relation to consumption of sugars.

OBJECTIVE: To investigate the prevalence of antioxidant vitamin inadequacy and low fibre intakes according to total, intrinsic, extrinsic and milk-sugar consumption groups. DESIGN: Age- and sex-stratified cross-sectional study of coronary risk factors and diet. Based on a personal health and food frequency questionnaire with a clinic attendance for body measurements. SETTING: Ten general practitioners' surgeries from each of 22 Scottish districts (12 Mainland Health Boards) surveyed during 1984-1986. SUBJECTS: 11,626 men and women aged 25-64 years who participated in the baseline Scottish Heart Health (SHHS) and MONICA studies. Overall response rate was 69% after one reminder letter. MAIN OUTCOME MEASURES: Both the mean daily intakes of fibre and vitamins A (retinol and carotenes), C and E, and the percentage of each sex group who fall below the dietary reference values for each nutrient are reported according to fifths of dietary sugars. The percentage of the population variation in vitamin and fibre intake which can be explained by consumption of the different sugars is provided from multiple analysis of variance techniques. RESULTS: Intrinsic sugar intake is positively related to antioxidant vitamin and fibre intake (correlation coefficients, r, between 0.1 and 0.61 apart from retinol, r = -0.06), due to their mutual occurrence in fresh fruits and vegetables, while consumption of milk sugars tends to be weekly inversely related to antioxidant vitamin and fibre intake (apart from vitamin C, r = 0.02-0.06). Both low and high extrinsic sugar intake seems to be associated with poorer antioxidant vitamin and fibre-containing diets compared with a consumption of extrinsic sugar of between 6.5 and 15.6% energy for men and 4.8 and 11.6% energy for women. Intake of different sugar types is related to the antioxidant nutrient adequacy of a diet independent of age, smoking habit, total energy intake, alcohol consumption, weight and height. Fibre intake is below the recommended value at all levels of dietary sugars. CONCLUSIONS: Prevalence of antioxidant vitamin adequacy is significantly related to dietary sugar intake. However, relatively low extrinsic sugar consumption appears equally associated with a poor quality diet as does a relatively high intake. It may be concluded that the dietary reference values for sugars err on the cautions side, with respect to their effect on antioxidant nutrient adequacy.

Adult↗
PubMed1994

Deficient health knowledge, diet, and other lifestyles in smokers: is a multifactorial approach required?

BACKGROUND: Data from the Scottish Heart Health Study, a random cross-sectional sample of middle-aged men and women, are used to compare health knowledge, behavior, and lifestyles between 4896 smokers and 4595 nonsmokers. METHODS: Smokers are identified from self-reports with biochemical validation. They are compared with nonsmokers using analysis of covariance and logistic regression, adjusting for age and social class. RESULTS: Smokers are found to have poorer dietary knowledge than nonsmokers, although both groups are well-informed on some aspects of diet. Knowledge of personal risk modifiers for coronary heart disease and recent intention to improve lifestyle are both worse among smokers. Smokers have lower intakes of the antioxidant vitamins and fiber, but higher intakes of dietary cholesterol and alcohol than nonsmokers. They also tend to have higher salt intake and eat a greater proportion of saturated fat, butter, or hard margarine, and full-fat milk. High-density lipoprotein cholesterol levels are lower, but triglycerides, fibrinogen, and, for women only, total serum cholesterol levels are higher among smokers. On the other hand, body mass index and diastolic blood pressure are lower among smokers. CONCLUSIONS: In addition to advice to give up smoking, smokers should be counseled to improve their diet. The positive message to eat more fresh fruit and vegetables would be particularly helpful.

Adult↗
PubMed1994

Coronary heart disease: prevalence and dietary sugars in Scotland.

STUDY OBJECTIVE: The aim was to investigate the effects of dietary intakes of different types of sugars (extrinsic, intrinsic, and lactose) and the dietary fat to sugar ratio on prevalent coronary heart disease (CHD). DESIGN: This was a baseline cross sectional survey of CHD risk factors. SETTING: Twenty two Scottish health districts were surveyed between 1984 and 1986. PARTICIPANTS: A total of 10,359 men and women aged 40-59 years were screened as part of the Scottish Heart Health Study, and a further 1267 men and women aged 25-39 and 60-64 years were screened as part of the Scottish MONICA (monitoring trends and determinants in cardiovascular disease) Study. The response rates were 74% and 64% respectively. METHODS: Subjects completed a questionnaire which included sociodemographic, health, and food frequency information. Medical history, response to the Rose chest pain questionnaire, and results of a 12 lead ECG recording were used to categorize subjects into CHD diagnosed, previously CHD undiagnosed, or no CHD groups. The chi 2 statistic was used to determine whether the CHD groups differed in their sugar consumption, and multiple logistic regression analysis, with adjustment for other potential coronary risk factors, was used to calculate odds ratios for prevalent CHD by intake fifths of dietary sugars. MAIN RESULTS: Men, but not women, differed in their sugar consumption by CHD group. The odds ratios showed a tendency for a U shaped relationship for extrinsic sugar intake with CHD prevalence, but no significant effect of the fat to sugar ratio (possible marker of obesity) on CHD was seen. CONCLUSIONS: The results suggest that neither extrinsic sugar, intrinsic sugar, nor the fat to sugar ratio are significant independent predictors of prevalent CHD in the Scottish population, when the other major risk factors such as cigarette smoking, blood cholesterol concentration, and antioxidant vitamins intake are accounted for. These new data for different sugar types agree with the consensus view that total sugar intake is not a major marker of coronary heart disease.

Adult↗
PubMed1994

Dietary composition and fat to sugar ratios in relation to obesity.

The aim of this work was to investigate the relationship between dietary composition and prevalent overweight and obesity in a middle-aged Scottish population. An age and sex stratified cross-sectional study was carried out of coronary risk factors and diet. This was based on a personal health and food frequency questionnaire with a clinic attendance for body measurements which included weight and height. The subjects were 11,626 men and women aged 25-64 who participated in the baseline Scottish Heart Health and MONICA studies. Those reporting to be on slimming diets were excluded. The subjects were contacted via ten general practitioners surgeries from each of 22 Scottish districts (12 Mainland Health Boards) surveyed during 1984-1986. The following were measured: (1) the prevalence of overweight (BMI 25-28.6 for women and 25-30 for men) and obesity (BMI > 28.6 for women, and > 30 for men) according to intake fifths of carbohydrates (starch, total, extrinsic, intrinsic and milk sugars) and fat to carbohydrate ratios; (2) the percentage of the variance in BMI explained by multivariate analysis models which included each of the sugar variables and total energy intake. The overall prevalence of overweight and obesity in the Scottish population were 43 and 11% for men and 38 and 14% for women respectively. Their prevalence increased from the lowest to the highest fifth of Fat:ES intake, respectively for men and women, from 5 to 18.5% and from 13 to 26%. The prevalence of overweight and obesity declined from the lowest to the highest fifth of total carbohydrate, total (TS) and extrinsic (ES) sugar intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗