Human nutrition. Applied nutrition最新文献

A number of reports have urged a reduction in sugars intake. Implementing this advice depends upon knowledge of sugars intake by target groups. This paper reports the added and natural sugars intake by one target group--young adolescents. The diet of 405 children was recorded using a 3-day diary with interview repeated five times between September 1979 and July 1981. Food tables (Paul & Southgate, 1978) were used and the values for the sugars content of the food items altered to provide both added sugars and natural sugars concentration. The mean daily intake of added and natural sugars respectively, for the 193 boys was 85 g (s.d. 22), 39 g (s.d. 12), and for the 212 girls was 78 g (s.d. 24), 35 g (s.d. 12). Added sugars contributed, on average, 69 per cent of total sugars and 15 per cent of energy intake. Confectionery, table sugar and soft drinks together contained 71 per cent of the added sugars intake, while milk, fruit and their products provided the majority of the natural sugars. It is considered that major reductions of sugars intake would be possible in these children by restricting the intake of a small number of groups of foods of low nutrient density. Food labelling of sugars content would enable consumers to make sensible choices of foods.

The effect of ascorbic acid on the absorption of non-heme iron was studied in 299 subjects. Different meals in which the non-heme iron was labelled with two different radio-iron isotopes were served with and without ascorbic acid to the same subject. Other meals containing foods with a known high content of ascorbic acid were also studied. Studies were also made giving different amounts of ascorbic acid with different meals. Marked differences in the enhancement of iron absorption were seen when ascorbic acid was given in different meals. It is suggested that ascorbic acid promotes iron absorption from the diet by reducing the negative effect on iron absorption of certain ligands such as phytates and tannins present in the diet. This interpretation is supported by observations that the most pronounced effects of ascorbic acid were found in meals with a high content of ligands known to inhibit iron absorption. Crystalline ascorbic acid and native ascorbic acid in foods appeared to have the same effect in promoting absorption of iron. The results indicate that ascorbic acid has a key physiologic role in facilitating the absorption of non-heme iron from the diet and that about 50 mg of the vitamin in each main meal is desirable for optimum effect.

The DHSS special dietary allowance system for those receiving supplementary benefit is explained. The cost of normal and common therapeutic diets are calculated. Inadequacies and shortcomings of the current dietary allowance are identified.

Serum calcium, magnesium, iron, copper and zinc were measured in 117 patients with cystic fibrosis. Apart from serum iron levels, all the other essential element levels were well maintained and there was no evidence of a need for supplementation. Serum iron was frequently low and the need for iron supplements must be considered after further investigation. The subjects studied covered a wide age range, had widely varying fat malabsorption and clinical grading, and also varying degrees of pulmonary involvement. We found no evidence that any of these parameters directly influenced essential element status as assessed by serum levels.

School meals in the USA have been in operation for half a century, yet no associated benefits have been claimed, apart from a slight increase in weight-for-age. In the UK, Netherlands and other European countries, associated benefits have been slight or scarcely apparent. In developing populations, school meals, although little practised, appear less beneficial than expected. In western populations evaluations have been entirely incommensurate with extent and cost of the practice, for, largely, only assessments of dietary intake and anthropometric parameters have been studied. There has been insufficient enquiry into which intakes of nutrients, and which percentiles of growth standards, relate most meaningfully to scholastic prowess, biochemical and clinical parameters in youth, and health experience in later years. Since school meals, a highly emotional subject, are strongly bound up with national agriculture, and clearly are unlikely to discontinue, the authors consider that attempted modifications should be in line with current recommendations of authoritative dietary bodies, i.e. to encourage reduction in fat intake and an increased intake of fibre-containing foods.

The dietary management of a child with intestinal lymphangiectasia complicated by short gut syndrome following surgery at the age of 3 weeks is described. Diets containing amino acids and peptides were not tolerated due to high osmolality. Satisfactory nutrition was achieved by using a feed with low osmolality and containing whole whey protein, maltodextrin, medium-chain triglycerides (MCT) and a small amount of long-chain triglycerides (LCT) to supply essential fatty acids (RD231).

Recently the need for low-fat diets in the treatment of cystic fibrosis has been questioned. Current ideas on the dietary treatment of the disease are discussed and the need to assess each patient individually is stressed. Supplementary feeding may be necessary to promote weight gain.

The mean daily nutrient intakes from dietary sources of 49 pregnant women in the third trimester of normal pregnancy were assessed using a 7-day weighed inventory method and standard food tables. Mean daily intakes of all major nutrients reached DHSS recommended levels, with the exceptions of energy (2065 kcal/8.65 MJ), proportion of energy derived from carbohydrate (48 per cent), calcium (1047 mg), and vitamin D (2.58 micrograms). These results are in agreement with those of comparable published studies and lend support to suggestions that some of the increased requirements in pregnancy may be being met by physiological adaptation, without the need for greatly increased dietary intakes, or for indiscriminate vitamin and mineral supplementation. For seven women with low weight gain (less than 8 kg at 36 weeks; mean 6.97 kg), mean daily intakes of most nutrients were lower, and were below recommended levels for energy (1770 kcal/7.4 MJ), ascorbic acid (47.4 mg), vitamin D (2.18 micrograms), calcium (980 mg), and iron (10.5 mg). Proportional intakes of carbohydrate (50 per cent) and dietary fibre (20.1 g/day) however, tended to be higher in this group.