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Biomedical subjects

A R Leeds

Publications and source records attributed to A R Leeds.

At least 19 recordsLinked to original sources
PubMed1992

Mycoprotein reduces blood lipids in free-living subjects.

Mycoprotein is a food produced by continuous fermentation of Fusarium graminearum (Schwabe). A previous metabolic study showed that mycoprotein decreased total and low-density-lipoprotein (LDL) cholesterol and increased high-density-lipoprotein (HDL) cholesterol. This study was undertaken to determine the effects of mycoprotein under free-living conditions. Two groups of subjects with slightly raised cholesterol concentrations participated in the 8-wk study. The experimental group was fed cookies containing mycoprotein and the control group was fed a nutrient-balanced cookie without mycoprotein. After 8 wk of treatment total cholesterol was reduced by 0.46 mmol/L in the control group and 0.95 mmol/L in the mycoprotein group, and LDL was reduced by 0.34 mmol/L in the control group and 0.84 mmol/L in the mycoprotein group. All analysis of variance differences were statistically significant. This study confirms the metabolic-study results and we are now relatively confident that mycoprotein exerts a beneficial effect on blood lipids.

Adult↗
PubMed1992

The antihypertensive effect of dietary supplementation with a 6-desaturated essential fatty acid concentrate as compared with sunflower seed oil.

There is increasing evidence that the type of fat in the diet may play a role in the control of blood pressure and development of hypertension. The purpose of the present study was to investigate the effect of a concentrated preparation of the 6-desaturated essential fatty acids gamma-linolenic acid (C18:3n-6), eicosapentaenoic acid (C20:5n-3) and docosahexaenoic acid (C22:6n-3) on individuals with raised BP. Eighteen volunteers from our College staff with elevated BP on several occasions but otherwise healthy, were divided into two groups following a two-week baseline period. One group received 4g sunflower seed oil daily and the other 4g of an oil preparation rich in C18:3n-6, C20:5n-3 and C22:6n-3 for six weeks. Major measurements included BP and fatty acids in phospholipids and cholesteryl esters. Dietary intakes and urinary fluid and electrolyte excretion were also monitored during baseline and intervention periods. The subjects' office diastolic BP showed a significantly greater effect of the concentrate over the sunflower seed oil, both overall (P = 0.03) and in interaction with time (P = 0.012). Fatty acids in plasma cholesteryl esters underwent mild alterations following the administration of the concentrate. There were no important changes in nutrient intakes or in sodium, potassium and fluid excretion during the trial period.

Antihypertensive Agents↗
PubMed1990

Alterations in rat intestinal mucin patterns following luminal infusion of acetylsalicylic acid and prostaglandin derivatives.

The secretion of gastrointestinal mucin and/or the formation of mucoid caps have been implicated in cytoprotective or repair mechanisms related to mucosal injury models. In this study, rats were treated with acetylsalicylic acid (ASA) or prostaglandins (PG), and their effects on the synthesis and secretion of small intestinal mucin were examined. A newly developed polyclonal antibody to rat intestinal mucin was used for immunoassay of rat intestinal luminal and tissue mucin. The mucin antigen source was obtained by vacuum aspiration of luminal mucus. A high-molecular-weight glycoprotein (2 x 10(6) Da) fraction injected into rabbits produced a primary mucin antibody. A sensitive and quantitative enzyme-linked immunosorbent assay (ELISA) was developed that yielded a highly reproducible and linear response with mucin aliquots containing 0-20 ng of protein/ml. Incorporation of the plasma tracers ([3H]glucose and [35S]sodium sulfate) into mucin derived from hexadecyltrimethylammonium bromide precipitation after treatment with ASA (100 mg/kg body wt) decreased, although administration of dimethylprostaglandin E2 (100 micrograms/kg body wt) significantly increased the specific tracer incorporation values for the sialomucin and sulfomucin indices in luminal mucin fractions. The immunoassay data pattern for the ELISA technique was virtually identical to the results of the radiolabeled tracer method obtained for the same pharmacologic treatments. These experiments demonstrate that the estimation of synthesized mucin (tissue source) or secreted mucin (luminal source) as determined by the ELISA technique is similar to that obtained by the time-consuming and labor-intensive tracer incorporation methodology.

16,16-Dimethylprostaglandin E2↗
PubMed1990

Effect of mycoprotein on blood lipids.

This metabolic study was designed to investigate the effects of mycoprotein on blood lipids. Mycoprotein is a food produced by continuous fermentation of Fusarium graminearum (Schwabe) on a carbohydrate substrate. Two groups of subjects with slightly raised cholesterol concentrations took part in the 3-wk study. The experimental group was fed mycoprotein in place of meat and the control diet contained meat. There was no change in plasma cholesterol in the control group but there was a 13% reduction in the mycoprotein group. Low-density lipoprotein (LDL) increased in the control group by 12% and decreased by 9% in the mycoprotein group. High-density lipoprotein (HDL) decreased by 11% in the control group but increased by 12% in the mycoprotein group. In each case the group ANOVA differences between variables were statistically significant. It is clear from these results that lipid variables are advantageously altered by mycoprotein consumption.

Adult↗
PubMed1990

Alteration of gastrointestinal mucin by fiber feeding in rats.

Alterations in gastrointestinal mucin induced by dietary fiber may affect nutrient bioavailability, cytoprotection of the mucosa or other aspects of gastrointestinal function. To allow quantitative study of gastrointestinal mucin, a polyclonal antibody to the mucin of the rat small intestine was produced by injecting rabbits with a high-molecular-weight subfraction (MW 2 x 10(6)) of purified mucin glycoprotein derived from rat intestinal mucin. An enzyme-linked immunosorbent assay was developed and used for the mucin assay. Three groups of male Wistar rats consumed 5% guar gum, 5% citrus fiber or a fiber-free control diet ad libitum for 4 wk. After an overnight fast, luminal and tissue mucin antibody reactivities were determined in the rat stomach, colon and small intestine. In all groups, total (luminal and tissue) mucin reactivity was greater in the small intestine than in the colon or stomach. The group fed 5% citrus fiber had significantly greater mucin reactivity in luminal samples from stomach and intestine than did the fiber-free control group. Fiber-induced increments in gastrointestinal mucin production or availability may be responsible for several reported consequences of fiber feeding, such as more rapid transit times and delayed or impaired nutrient absorption.

Animals↗
PubMed1979

The dietary management of diabetes in adults.

The ultimate object of all types of dietary management before the introduction of insulin was to prevent emaciation and death: the consequences of metabolic derangements due to lack of insulin. Now, while dietary therapy continues to be important in minimizing the requirement for endogenous insulin or in balancing administered insulin, the major objects are changing to prevention of large vessel and microvascular disease. The next decade will probably see a more widespread introduction of diets containing a lower proportion of energy derived from fat. The increased carbohydrate intake will almost inevitably result in increased dietary fibre intake. Whether David Jenkins' Lente carbohydrate foods (those containing viscous unabsorbable polysaccharides) will prove to be of lasting value is not yet known. Since galactomannans occur in legumes perhaps we should consider the possibility of diets containing large proportions of legumes: a twentieth century 'Legume cure'? If this should prove of value it would not have excited ancient Indian physicians who wrote (in the Caraka-Samita) of their use of legumes in the treatment of glycosuria, at least as early as the first century AD, before Aretaeus had applied the term diabetes.

Adult↗
PubMed1979

Dietary fiber and blood lipids: reduction of serum cholesterol in type II hyperlipidemia by guar gum.

Guar gum, a storage polysaccharide galactomannan and a form of dietary fiber, was administered to 10 patients with type II a or b hyperlipidemia for 2 weeks. Five grams of gum was given before each of three meals daily, either in a specially prepared soup or mixed with fruit juice or milk. No other deliberate change of diet was made. Three patients had been taking 12 to 16 g/day of cholestyramine for more than 2 years and one had been taking 1000 mg of clofibrate daily. These drugs were continued throughout the trial. Serum cholesterol levels of all 10 patients had been stable for 6 to 18 months before the trial at the start of which the mean level was 345 +/- 15 mg/dl. After 2 weeks of guar gum the mean was 308 +/- 16 mg/dl, a fall of 10.6% (P less than 0.01). Serum triglyceride was not changed significantly. Guar gum, which can be incorporated into foods, merits further study as a potential hypocholesterolemic agent.

Anticholesteremic Agents↗
PubMed1979

Hypocholesterolemic action of dietary fiber unrelated to fecal bulking effect.

Twenty-two healthy volunteers took approximately 20 g/day of concentrated dietary fiber from either carrot, cabbage, apple, bran, or guar gum or 31 g from pectin, added for 3-week periods to controlled diets. Total serum cholesterol fell by 13% on both guar and pectin (P less than 0.01) with no significant change in high density lipoprotein cholesterol. Over the 3-week supplementation period, the other fibers were without effect with the exception of carrot, where both control and test high density lipoprotein levels fell (P less than 0.05 and less than 0.01, respectively). If, however, the 3rd week of the control was compared with the 3rd test week, the values for total cholesterol were 7% lower after apple (P less than 0.02) while after carrot the high density lipoprotein cholesterol level was 10% lower than the control (P less than 0.01). No significant change was seen in serum triglyceride or body weight either as judged by differences over the 3-week periods or by comparing test and control values at 3 weeks. Comparison of stool weights obtained in this study indicate that the fecal bulking action of dietary fiber is independent of its hypocholesterolaemic effect.

Adult↗
PubMed1979

High-fibre foods: a feasibility study using guar gum.

Guar gum at different concentrations was incorporated into foods from six groups to establish some principles to aid the production of high-viscosity therapeutic foods. The amounts of gum that could be incorporated into a food, without major loss of acceptability, were higher in products with low final water content than those with high final water content. The domestic preparation of these recipes should be possible provided that recipe modifications are carefully followed.

Cellulose↗
PubMed1978

Dietary fibres, fibre analogues, and glucose tolerance: importance of viscosity.

To define the type of dietary fibre of fibre analogue with the greatest potential use in diabetic treatment, groups of four to six volunteers underwent 50-g glucose tolerance tests (GTT) with and without the addition of either guar, pectin, gum tragacanth, methylcellulose, wheat bran, or cholestyramine equivalent to 12 g fibre. The addition of each substance significantly reduced blood glucose concentration at one or more points during the GTT and generally reduced serum insulin concentrations. The greatest flattening of the glucose response was seen with guar, but this effect was abolished when hydrolysed non-viscous guar was used. The reduction in the mean peak rise in blood glucose concentration for each substance correlated positively with its viscosity (r = 0.926; P less than 0.01), as did delay in mouth-to-caecum transit time (r = 0.885; P less than 0.02). Viscous types of dietary fibre are therefore most likely to be therapeutically useful in modifying postprandial hyperglycaemia.

Adult↗