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Biomedical subjects

E M Widdowson

Publications and source records attributed to E M Widdowson.

At least 19 recordsLinked to original sources
PubMed1992

Physiological processes of aging: are there special nutritional requirements for elderly people? Do McCay's findings apply to humans?

Aging is characterized by shrinkage of muscle fibers and loss of protein from them. Bone is also lost, and matrix and mineral are lost together. The predominance of breakdown over synthesis is probably the fundamental cause of both muscle and bone loss. Little can be done to prevent this by dietary means, but physical activity is of vital importance in helping to maintain the integrity of both muscle and bone. McCay's finding that rats underfed from weaning lived longer than those that had adequate food has been confirmed by others, but this is only true if the rats remain free of infections and other hazards, particularly during growth. The mechanisms by which underfeeding delays the aging process in rats may apply to the human body but, if so, this is completely offset by other considerations. For their present and future well-being, children should be fed in the best possible way.

Aged↗
PubMed1991

Contemporary human diets and their relation to health and growth: overview and conclusions.

Contemporary human diets are probably as diverse now as they have ever been in the history of mankind. The abundance of food in the western world is in stark contrast to the lack of food and near starvation in parts of Africa, the continent where Homo sapiens evolved. The development of agriculture has enabled the population of the world to expand and to colonize almost the whole of its land surface, but the dependence on one staple food has introduced problems. If the staple crop fails, for example because of drought, there may be no alternative, and undernutrition and starvation are the result. Further, if the rest of the diet does not provide the nutrients that the staple food lacks, diseases due to specific nutrient deficiencies become widespread. Vitamin deficiencies among adults are less common now than they were 50 years ago, but even today millions of children in the poor rice-eating areas of the world are blind because their diets were deficient in vitamin A. For physiological reasons infants and young children will suffer most wherever there is a scarcity of food, of water, or of specific nutrients.

Animals↗
PubMed1979

Response of the organs of rabbits to feeding during the first days after birth.

An experiment described previously showed a large increase in weight and protein of the intestinal mucosa of suckling piglets during the first 24 h after birth. This did not take place in piglets that were starved. The results might have been partly due to the inclusion of protein molecules in the mucosa in process of absorption. Rabbits do not absorb large quantities of protein after birth, and the experiment has now been repeated on them. The gastrointestinal tract of suckled rabbits also grew rapidly in the first 24 h, but again not in those that were given only water, which is in line with the suggestion that colostrum contains a factor which stimulates the growth of the gastrointestinal tract. The brain gained weight in the suckled animals, due to incorporation of lipid and protein. It gained weight too in the starving rabbits, demonstrating its high priority for nutrients at a time when its growth velocity is at its peak.

Adipose Tissue↗
PubMed1979

Nutritional requirement and its assessment, with special reference to energy, protein and calcium.

If food is plentiful the requirement for energy is met by an accurate system of control so that intake balances expenditure. Energy requirements are therefore often assessed by measuring energy intakes. Intakes of protein, however, are no measure of protein requirements and the amounts customarily taken in Western diets are considerably more than man needs. The requirements for calcium are difficult to assess, for they are affected not only by age, but by other constituents of the diet, by the time of year, by individual peculiarities and by the previous intake. There is a physiological loss of calcium from the body starting in middle age which is not prevented by a high calcium intake.

Calcium, Dietary↗
PubMed1978

Preparations used for the artificial feeding of infants.

Cow's milk differs from human milk in a number of important ways, and manufactures of dried milk preparations for infants have used various methods to make the composition of the diluted product more like that of human milk. The first was to add lactose, or to recommend the mother to add sucrose. This not only increased the carbohydrate, but also 'diluted' the protein and inorganic constituents which are more concentrated in cow's than in human milk. The second was to replace all or part of the cow's milk fat with animal and vegetable fats, and so make the fatty acid composition more like that of human milk fat. In particular the proportion of linoleic acid was increased and that of stearic acid decreased, and this made the fat more easily digested and absorbed by the young infant. The third modification of cow's milk has been more fundamental. Its aim has been to make a product containing less sodium and phosphorus than cow's milk and with a higher lactalbumin: casein ratio. Whey, which contains lactalbumin but not casein, is used as the starting material. This is dialysed to remove soluble inorganic constituents. Some skimmed milk is then added to supply casein and some minerals, and the composition is adjusted as required with further minerals and vitamins. Lactose is added and a mixture of animal and vegetable fats. Dried milks on sale in Britain contain added vitamins A,D, and C and also iron. Some have added copper and zinc.

Animals↗
PubMed1977

Vitamin-D in human milk.

The vitamin-D concentration in human milk is reported to be very low, yet breast-fed infants do not develop rickets. All the earlier assays of vitamin D were made on the lipid fraction of milk, and the aqueous phase was discarded. It is now clear that most of the vitamin D in human milk is present as a water-soluble conjugate of vitamin D with sulphate. The concentration of vitamin-D sulphate in the aqueous fraction of human milk collected at different stages of lactation has been chemically measured. Milk was collected from twenty-two women 3-8 days post partum and fourteen women 4-6 weeks post partum. The vitamin-D sulphate concentration in milk collected between the 3rd and 5th days was 1-78 mug/dl, significantly higher that the 1-00 mug/dl for milk collected between the 6th and 8th days. After the 8th day there was no significant change.

Breast Feeding↗
PubMed1977

Fat.

Fat has been a menace to longevity since biblical times, but detailed studies of its deposition and function in the perinatal period only began comparatively recently. The function of brown fat in thermogenesis as distinct from that of white fat as a reserve of energy is now clear, but not why the guinea pig and the human baby should be two of the very few land mammals to lay down white fat in their bodies before birth. How much of this fat crosses the placenta and how much is synthesized by the fetus? There is evidence that the amounts and timing of the two events may not be the same in the two species but the reasons behind the differences are not at all clear. Genetic obesity in many forms is well known in rodents. None of them have contributed much to paediatrics as yet, but the Egyptian sand rat has promising similarities to persons who develop obesity and diabetes in adult life and a comparison of their metabolism in early life might be a profitable exercise.

Adipose Tissue↗
PubMed1976

Changes in the body and its organs during lactation: nutritional implications.

Lactation makes considerably greater demands on the mother's body than pregnancy does in species where the young are helpless at birth and depend on mother's milk for a comparatively long time. These species include many rodents and carnivores and also man. The requirements for the production of milk are met partly from within, by the mobilization of the mother's body tissues, and partly from without, by an increased food intake. Both ways lead to alterations in the composition of the mother's body which may or may not be permanent. Fat laid down in the body during pregnancy is used and there may also be losses of calcium from the skeleton, especially if the calcium intake is low. Whether extra protein is deposited during human pregnancy and lost again during lactation still remains an open question. In rats, the answer depends partly on the intake of protein and energy. The increase in food intake during lactation in some species is so great that the gastrointestinal tract grows considerably to deal with it. In the rat, the small intestine more than doubles its weight. The intestinal wall dilates and the area of mucosa almost doubles. The liver also increases considerably in size owing to an increase in both number and size of cells. After lactation, the liver becomes smaller again, and so does the amount of protein in it, but there is no loss of cells, so that rats that have reared litters have more cellular livers than those that have not. There is no indication whether similar changes occur in women.

Animals↗
PubMed1976

Diets and living conditions of Asian boys in Coventry with and without signs of rickets.

1. The diets and living conditions of nin Asian boys with biochemical, and in most instances also radiological, signs of rickets were compared with those of nine other boys who appeared to be normal. The groups were matched according to age, religion, place of father's origin and boy's own place of birth. 2. There were no outstanding differences between the diets of the boys with, and of those without signs of rickets. All had adequate to high calcium intakes. Most of the boys had low intakes of vitamin D, and those withsigns of rickets generally had lower intakes than the normal boys. The food tables used for making the calculations of vitamin D intakes report the amount of the vitamin in the lipid fraction of milk. If it proves to be true that most of the vitamin D activity of milk is in the aqueous fraction, the boys would have been getting considerably more vitamin D than the results suggested, and their average intake may have been about 3-5mug/d. 3. It was not possible to make any quantitative measure of the exposure of the boys to sunlight. All Asian boys studied appeared to have their bodies more completely covered than British or West Indian boys. 4. The problem of why nine boys had signs of rickets and nine had none has not been solved. It is suggested that those with signs of rickets may have had higher requirements for vitamin D than others. When the intake of vitamin D is low and exposure to sunlight is minimal, those with high requirements will be the ones to develop signs of rickets.

Adolescent↗
PubMed1976

Body lipids of guinea pigs exposed to different dietary fats from mid-gestation to 3 months of age.

Pregnant guinea pigs were fed one of three diets: a control low-fat diet, or a high-fat diet containing maize oil or beef dripping. At birth some animals were killed and the remainder reared on the same diet as their mothers till 3 months old. Body weight, weight of various adipose tissue depots, size and number of fat cells were measured. Animals fed high-fat diets were fatter than control animals. On all diets females were fatter than males. In both instances the increase in adipose tissue mass was attributable to enlargement of fat cells. The composition of dietary fat had little influence on the cellularity of adipose tissue.

Adipose Tissue↗
PubMed1976

Body lipids of guinea pigs exposed to different dietary fats from mid-gestation to 3 months of age. II. The fatty acid composition of the lipids of liver, plasma, adipose tissue, muscle and red cell membranes at birth.

Pregnant guinea pigs were fed one of three diets: a commercial low-fat diet, or a high-fat diet containing maize oil or beef dripping. The young were killed at birth and the fatty acid composition of the lipids of the liver, plasma, adipose tissue, quadriceps muscle and red cell membranes was determined. Compared with those fed the commercial diet the tissue of the young of mothers fed maize oil had an increased percentage of linoleic acid whereas in those of the young of mothers fed beef dripping, the percentage of oleic acid was significantly higher. These changes occurred both in the triglycerides and in the membrane phospholipids (with the exceptin of sphingomyelins) of all tissues examined. These results demonstrate that the fatty acid composition of the tissue lipids of the newborn guinea pig can be influenced by the fatty acid composition of the maternal diet. Changes in the fatty acid composition of membrane phospholipids can be as great as those in storage lipids. This raises the question of long-term physiological significance for the animal.

Adipose Tissue↗