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Biomedical subjects

D A Southgate

Publications and source records attributed to D A Southgate.

At least 19 recordsLinked to original sources
PubMed1995

Digestion and metabolism of sugars.

Many factors potentially influence the digestion, absorption, and metabolism of the various species of sugars occurring in the human diet. Experimental evidence indicates that the source of sugars in foods does not in itself affect the rate of absorption or the metabolism of the sugars. However, the form in which the sugars are ingested and the physical and chemical properties of the food matrices do have significant effects on the rates of absorption. Food matrices influence gastric emptying and through their physical properties affect the rate of transport across the small intestinal mucosa. Disaccharides form the major proportion of ingested carbohydrates in the small intestine and the digestion and transport systems for these sugars, except for lactose, are the most efficient. After absorption, the pathways of the different dietary sugars converge and the original dietary source has only minimal effects on metabolism.

Dietary Carbohydrates↗
PubMed1993

Intercomparison of methods for the determination of vitamins in foods. Part 1. Fat-soluble vitamins.

An intercomparison of methods involving 18 European laboratories was organized to assess the state-of-the-art of vitamin determination in foods. Each laboratory received identical samples of dry food reference material (homogeneous powders, milk powder, pork muscle and haricot vert beans), which were recently certified for major dietary components and elements. Each laboratory was requested to perform the analyses by its own methods. Results for fat-soluble vitamins are reported. All participants isolated the fat-soluble vitamins by alkaline saponification. For retinol, only high-performance liquid chromatography (HPLC), reversed- or normal-phase, was applied, with both ultraviolet (UV) and fluorescence detection. Results in milk powder showed a relative standard deviation of reproducibility (RSDReprod) of only 10%. Carotene was determined by HPLC (reversed- and normal-phase) and with open-column chromatography at atmospheric pressure. For beta-carotene results in milk powder agreed very well; the RSDReprod was 14%. The values reported for haricot vert beans showed poor agreement; the RSDReprod was 52%. A major part of this variability was due to differences in methodological principles. The results for alpha-tocopherol in milk powder and haricot vert beans agreed very well, with RSDSReprod of 16 and 15%, respectively. Only HPLC (reversed- and normal-phase) with UV and fluorescence detection was applied.

Animals↗
PubMed1993

Intercomparison of methods for the determination of vitamins in foods. Part 2. Water-soluble vitamins.

An intercomparison of methods involving 18 European laboratories was organized to assess the state-of-the-art of vitamin determination in foods. Each laboratory received identical samples of dry food reference material (homogeneous powders, milk powder, pork muscle and haricot vert beans), which have recently been certified for major dietary components and elements. Each laboratory was requested to perform the analyses by its own routine methods. The results for water-soluble vitamins are reported. The reproducibility for the determination of vitamin B1 in milk powder, pork muscle and haricot vert beans with high-performance liquid chromatography (HPLC), fluorimetric and microbiological methods was good, with the relative standard deviation of reproducibility (RSDReprod) ranging from 11 to 18%. Differences between laboratories for the determination of the vitamin B2 content of milk powder, pork muscle and haricot vert beans determined using HPLC and microbiological methods were very high, with RSDReprod ranging from 28 to 74%. The extraction and hydrolysis procedures were probably the most important sources of variation. For vitamin B6 various HPLC and microbiological methods were used. The variation in the results for vitamin B6 was high, except in milk powder. The RSDReprod ranged from 18 to 51%. A major part of this variability was due to differences in the extraction and hydrolysis procedures and problems with the identification of the vitamin B6 vitamers by HPLC. Variation in the results for niacin obtained with the microbiological methods in milk powder, pork muscle and haricot vert beans, was small; RSDReprod = 9-15%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Nature and variability of human food consumption.

The early human diet was characteristically extremely varied, and a wide range of plant species and plant organs were consumed. Foods of animal origin included those taken opportunistically, such as invertebrates, amphibians, reptiles, small mammals, birds and their eggs, and the scavenging and hunting of larger mammals. Each of these types of food have characteristic nutritional compositions. Comparison of these compositional features shows that an adequate diet could be obtained in many different ways. The selection of food providing fat had substantial advantages in reducing the amount of plant foods to be gathered, in the satiety provided and in supplying essential micronutrients. Obtaining adequate water and energy would probably be the main physiological drives. Many plant foods contain natural toxicants, and would only have been suitable as major items in the diet once cooking had been developed, and the preference for sweet tastes would have protected humans from eating bitter, toxic plants.

Animals↗
PubMed1991

Coronary heart disease: seven dietary factors.

The dietary factors believed to be linked with the incidence of coronary heart disease are reviewed in the light of evidence with regard to their functional role, either in protection or in promotion. Detailed analysis of the evidence shows that the relations are more complex than the current lipid hypothesis suggests. It is proposed that, in particular, the polyunsaturated/saturated ratio as a measure of the propensity of the diet to influence the incidence of coronary heart disease should be replaced by indices of atherogenicity and thrombogenicity.

Coronary Disease↗