Human nutrition. Applied nutrition最新文献

The variation from day to day, between individuals and within individuals, in the consumption of energy and a variety of nutrients is presented for two groups of executive grade civil servants aged 40-49, numbering 83 and 68 and working in London in 1970-1971, and for 98 drivers and 83 conductors aged 30-67 of London's double decker buses in 1958-1967, a total of 332 men. Each man weighed and recorded his food for at least a week. The reliability with which these men could be classified into extreme thirds of the distribution of individual consumption of the various 'nutrients' or foods on the basis of a single day's or of several days' measurement was calculated. The number of days of measurement required to achieve a given reliability of classification into extreme thirds of the distribution was also estimated. The key is the ratio of the 'between-person' to the 'within-person' variance for the particular nutrient. A diagram is presented of how this ratio is related to the number of days of survey required for a given reliability. Nutrients fall into three main groups--those consumed in relatively large amounts each day (eg protein, fat), those found in moderate amounts in many or most foods but in very large quantities in a few foods (eg dietary cholesterol, calcium), and those which may not be consumed at all by some people but are taken in large quantities by others (eg alcohol). The number of days of survey required for 80 per cent reliable classification of individuals varies from 2 or 3 days for some nutrients like sugar or total carbohydrates to 2 or 3 weeks for others like dietary cholesterol or the ratio of polyunsaturated fatty acids to saturated fatty acids. One day's survey classified no nutrients with 80 per cent reliability in our data, whereas one week's survey classified most nutrients with this reliability or better, although for a few the figure is lower. The precision of a week's survey is also shown in absolute quantities such as grams as distinct from thirds of the distribution. The relevance of these observations to the use of the results of 24-hour surveys in population surveys and correlation and regression analysis is discussed.

Four hundred and seventy-two dietitians and adult members of their households took part in a research project carried out by the British Dietetic Association's Community Nutrition Group. They first kept 7-day weighed food diaries of their normal eating habits. These were analysed and compared with the dietary goals set by the study. The participants who did not 'achieve' the goals were then asked to keep a second 7-day weighted diary while trying to eat a diet conforming to the dietary goals which were based on the NACNE long-term guidelines; 351 people did so. Mean nutrient intakes on first diaries were within the short-term goals recommended by the NACNE report except for fat and when participants were consciously altering their diets they achieved all the long-term goals. Average intakes were: fat, 30 per cent of energy; saturated fat; 10 per cent of energy; added sugar, 7 per cent of energy; alcohol, 4 per cent of energy; dietary fibre, 38 g; and sodium 2690 mg. The goals for total fat and saturated fat were the hardest to achieve. There was a significant drop in energy intake between the first and second diaries from 7.99 (s.d. +/- 1.54) MJ to 7.05 (s.d. +/- 1.25) for women (P less than 0.001) and 10.92 (+/- s.d. 1.76) MJ to 9.42 (s.d. +/- 1.54) MJ for men (P less than 0.001). The percentage of energy from fat and added sugars and the amount of sodium and fibre in the diet tended to increase with energy intake. None of the men in the highest energy band (12.56 MJ) achieved the goal for sodium. The diet which achieved the goals was more nutrient-dense than the diet which did not with significant increases in 14 vitamins and minerals despite the drop in energy. Participants experienced some problems in achieving the goals but not as many as had been anticipated.

Nine subjects (four women and five men) consumed the energy required to maintain body weight for 3 weeks (control) and 1000 kcal per day less than the energy required to maintain body weight for 6 weeks (undereating). Ordinary foods were used to provide a mixed diet which was standardized as to composition and analysed by bomb calorimetry and by proximate analysis. During the third week of the control period and the third and sixth weeks of the undereating period, food, faecal and urine samples were collected for calculations of the metabolizable energy of the diets. The mean coefficients of availability of the three energy nutrients were lower than predicted by the Atwater method, between 83.8 and 88.3 for protein, between 91.6 and 93.2 for fat and between 92.5 and 94.7 for carbohydrates. The calorie to nitrogen ratio of the urine of these subjects during the balance periods varied from 4.96 to 19.05. The metabolizable energy of these mixed diets was 12 to 24 per cent less than the energy calculated from US food tables. Formulas proposed to calculate the metabolizable energy of diets differed from our analysed metabolizable energies by 6.4 per cent (Miller & Payne, 1959), 6.8 per cent (Southgate, 1975) and 0.7 per cent (Miller & Judd, 1984).

Publications are reviewed which give detailed nutritional analyses of a wide range of representative samples of UK foods that have been undertaken since the publication of the fourth edition of McCance and Widdowson's 'The composition of foods'. These include trace elements, vitamin A, immigrant foods, cereals, milk and milk products and potatoes. Typographical corrections to the fourth edition are also given as well as the weight loss on cooking the recipe dishes.

Data are presented from the results of 46 dietary assessments on 13 children on continuous ambulatory peritoneal dialysis (CAPD). The results demonstrate that even with dietary supplements, energy and protein intakes are generally inadequate. Nutritional requirements and possible reasons for suboptimal intake are discussed and potential methods for improving nutritional intake are suggested.

A representative sample of 49 women (40-59 years) in Caerphilly, South Wales, completed a seven-day weighed dietary record and a similar sample of 48 women photographed all food and drink consumed for seven days. Mean nutrient intakes calculated for the two methods were very similar, indicating that the photographic method is reliable. Mean energy intake for the 97 women was 6.6 MJ/d (1568 Kcals). Mean intakes of protein fat and carbohydrate were 56 g, 72 g and 179 g per day respectively. Intakes were comparable with those reported from another survey in South Wales, but considerably lower than those reported from a study in Cambridgeshire. Possible reasons for these differences were discussed.

We have studied the glycaemic response to 50 g of carbohydrate (CHO) within a standard meal in order to ascertain the usefulness of the glycaemic index of food high in CHO for planning the diabetic diet. Carbohydrate was given in the form of three kinds of food: rice, potatoes and lentils, each having a different glycaemic index. Four types of standard meals were prepared with different energy distributions. A1,2,3: 60 per cent CHO, 10 per cent protein, 30 per cent fat and 1.35 MJ (322 kcal); A4,5,6: 60 per cent CHO, 30 per cent protein, 10 per cent fat and 1.37 MJ (327 kcal); B1,2,3: 40 per cent CHO, 20 per cent protein, 40; per cent fat and 2.08 MJ (498 kcal); B4,5,6: 40 per cent CHO, 40 per cent protein, 20 per cent fat and 2.08 MJ (499 kcal). The increase in postprandial blood glucose levels at 30 min was lower when lentils were given than with rice or potatoes in all four types of energy distribution used (P less than 0.01). No differences were found at the other times studied. The slope from time 0 to maximal increase of glycaemia was lower with lentils in meals B1,2,3 (P less than 0.006) and B4,5,6 (P less than 0.007) but not in A1,2,3 or A4,5,6. Areas under the curve of the glycaemic responses elicited by the foods studied were similar with all four types of energy distribution used. These similar glycaemic responses were unexpected since the three foods used have different glycaemic indices.(ABSTRACT TRUNCATED AT 250 WORDS)

During recent years much evidence has accumulated indicating that diet and nutrition may be important in the aetiology of human cancer. This paper discusses some of the components of diet that have been implicated as both causative and protective agents. Total calorie intake and overnutrition have been associated with breast and uterine cancers, high fat intake with cancer of the breast and large bowel and nitrates with gastric cancer. High fibre intakes are suggested to protect against colo-rectal cancer, and vitamin A, selenium and vitamin E have been inversely associated with various cancers.