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Biomedical subjects

B M Margetts

Publications and source records attributed to B M Margetts.

70 records · Page 4Linked to original sources
PubMed1986

Vegetarian diet in mild hypertension: a randomised controlled trial.

In a randomised crossover trial 58 subjects aged 30-64 with mild untreated hypertension were allocated either to a control group eating a typical omnivorous diet or to one of two groups eating an ovolactovegetarian diet for one of two six week periods. A fall in systolic blood pressure of the order of 5 mm Hg occurred during the vegetarian diet periods, with a corresponding rise on resuming a meat diet. The main nutrient changes with the vegetarian diet included an increase in the ratio of polyunsaturated to saturated fats and intake of fibre, calcium, and magnesium and a decrease in the intake of protein and vitamin B12. There were no consistent changes in urinary sodium or potassium excretion or body weight. In untreated subjects with mild hypertension, changing to a vegetarian diet may bring about a worthwhile fall in systolic blood pressure.

Adult↗
PubMed1986

Nutrient intake, blood pressure, serum and urinary prostaglandins and serum thromboxane B2 in a controlled trial with a lacto-ovo-vegetarian diet.

Fifty-nine healthy omnivores volunteered for a randomized crossover trial with a lacto-ovo-vegetarian (L-O-V) diet. Twenty-one 1-day diet records were kept throughout the project as a means of assessing food and nutrient intakes, and samples of serum and urine were assayed to evaluate change in prostanoid metabolism. While on the L-O-V diet subjects ate more vegetable protein, wholegrain cereals, polyunsaturated oils, fruits and vegetables, and avoided eating meat, fish or poultry. The L-O-V diet contained significantly more polyunsaturated fatty acids, fibre, vitamin C, vitamin E, magnesium, calcium and potassium, and less total protein, saturated fat, monounsaturated fat and vitamin B12 than the control omnivore diet. Changes in nutrient intakes were subjected to principal components analysis to identify dimensions of change in nutrient intakes. Three Factors accounted for 83% of the total variation in dietary intake. Blood pressure changes were significantly and negatively (F = 17.4, P less than 0.001 for systolic; F = 6.09, P = 0.02 for diastolic pressure) related to individual scores for only one Factor--that representing an increase in intake of polyunsaturated fat, fibre, vitamin C, vitamin E, calcium and magnesium, and a fall in intake of protein and vitamin B12. Blood pressure changes were unrelated to change in body weight or sodium intake. Serum and urinary prostanoids were not affected by eating the L-O-V diet.

Blood Pressure↗
PubMed1985

Blood pressure and dietary polyunsaturated and saturated fats: a controlled trial.

Fifty-four healthy, omnivore normotensive volunteers aged 20-59 years were randomly allocated either to a control group eating a low polyunsaturated to saturated fat ratio (P/S ratio) diet (0.3) throughout, or to one of two experimental groups eating a high P/S ratio diet (1.0) for one of two 6-week experimental periods. Changes in other components were avoided. Twenty-four hour diet records showed substantial changes in the P/S ratio for experimental groups when on the high P/S ratio diet (0.3 to 1.0). There were significant increases in relative concentrations of linoleic acid in plasma phospholipids when on the high P/S ratio diet. There was no consistent effect of dietary P/S ratio elevation from 0.3 to 1.0 on group mean systolic and diastolic blood pressures. Adjustment of blood pressure changes for changes in electrolytes, other dietary components, plasma lipids, weight and other lifestyle variables did not alter this result. It was concluded that the blood pressure lowering effect of a vegetarian diet reported previously was unlikely to have been due to changes in dietary P/S ratio.

Adult↗
PubMed1985

Vegetarian diet in the treatment of mild hypertension: a randomized controlled trial.

The effect on blood pressure of an ovo-lacto-vegetarian (OLV) diet was assessed in a randomized controlled crossover trial. Fifty-eight mild untreated hypertensive subjects recruited from the Perth Centre for the 1983 National Heart Foundation (NHF) Risk Factor Prevalence Survey were randomly allocated to one of three groups: the first maintained their usual diet throughout 12 weeks; the other two were given an OLV diet for either the first or second 6 weeks of the 12-week trial. A significant fall in systolic blood pressure, on average of the order of 5 mmHg, was associated with eating an OLV diet. Blood pressure change was unrelated to change in urinary sodium, potassium or body weight, but was related to initial blood pressures. Although an OLV diet may have an adjunctive role in control of mild hypertension, in view of likely problems with acceptability the dietary components responsible for the blood pressure changes need to be identified.

Diet, Vegetarian↗
PubMed1984

Dietary-induced changes in the fatty acid composition of human cheek cell phospholipids: correlation with changes in the dietary polyunsaturated/saturated fat ratio.

Healthy normotensive volunteers aged 20 to 59 yr were randomly allocated either to a control group or to one of two experimental groups. The control group ate a low P/S ratio diet for 12 wk while the first experimental group ate a high P/S ratio diet for 6 wk followed by a low P/S ratio diet for the next 6 wk. The second experimental group ate a low P/S ratio diet in the first 6 wk followed by a high P/S ratio diet for the next 6 wk. Dietary P/S ratio, plasma linoleic acid (18:2), and cheek cell phospholipid 18:2 levels were compared in each dietary group at the end of the 1st and 2nd 6 wk. On change from a low to a high P/S ratio diet, there was a 36% increase in the proportion of 18:2 in the cheek cell phospholipids in comparison with the proportion existing before the change. This was associated with an increase in the proportion of 18:2 in the plasma lipids of this group. No reduction in the proportion of 18:2 in the cheek cell phospholipids was apparent in the control group or the group which changed from a high to a low P/S ratio diet, although in the latter group there was a reduction in the proportion of 18:2 in the plasma lipids. As the phospholipid fatty acid composition of human cheek cells reflects dietary lipid status under certain conditions, this observation may be useful in dietary and nutritional studies, particularly as human cheek cells can be obtained in a noninvasive manner.

Adult↗
PubMed1984

Dietary fats and blood pressure.

The blood pressure lowering effect of elevating the dietary polyunsaturated/saturated (P/S) ratio has been assessed in a randomised, controlled trial in normotensive volunteers. Subjects were allocated either to a control group who ate a low P/S ratio diet throughout, or to one of two experimental groups who ate a high P/S ratio diet for one of two six week experimental periods. There were significant changes in estimated dietary P/S ratio and measured changes in plasma fatty acids and buccal mucosal cell phospholipids. Changes in blood pressure were not related to changes in P/S ratio. There were no changes in other factors which may have confounded the relationship between blood pressure and P/S ratio change. This study suggests that P/S ratio change, without changing other nutrients, does not affect blood pressure in normotensive subjects.

Adult↗
PubMed1984

Dietary fat intake and blood pressure: a double blind controlled trial of changing polyunsaturated to saturated fat ratio.

The effect on blood pressure of elevating the dietary polyunsaturated/saturated fat (P/S) ratio was assessed in a double-blind, randomized control trial. Fifty-four healthy, normotensive volunteers aged between 20 and 59 years were randomly allocated either to a control group who ate a low P/S ratio diet throughout, or to one of two experimental groups who ate a high P/S ratio diet for one of two six-week experimental periods. Other nutrient changes were avoided. Twenty-four-hour diet records showed substantial changes in the P/S ratio when on the high P/S ratio diet, and no change in the control group or either experimental group when on the low P/S ratio diet. Relative concentrations of linoleic acid in plasma and cheek cell phospholipids were significantly increased when on the high P/S ratio diet. Changes in blood pressure, before and after adjustment for other possible confounding factors, were not related to changes in P/S ratio. It was concluded that an increase in P/S ratio per se cannot account for the previously reported blood pressure lowering effect of a vegetarian diet.

Adult↗
PubMed1983

Coronary risk factors in Italian migrants to Australia.

Coronary risk factor levels (height, weight, blood pressure, serum total cholesterol, high density lipoprotein (HDL) cholesterol, serum apo-HDL, physical activity, and smoking and drinking habits) were measured in 177 Italian migrants to Australia aged 20-79 years and 176 age-matched native-born Australians of Australian, British or New Zealand parentage. The Italian men had a lower mean systolic and diastolic blood pressure (125.0/79.8 mmHg) than the Australian men (129.4/82.3 mmHg), but Italians of both sexes had higher mean body mass indices (2.8 and 2.9 g/cm2) than Australians (2.4 and 2.5 g/cm2) and Italian women had a significantly lower mean serum HDL cholesterol concentration (1.16 mmol/liter) than Australian women (1.34 mmol/liter). The blood pressure differences between Italians and Australians were increased by adjustment of the means for differences between the two groups in age and obesity. There were slightly more current smokers and drinkers in Italian men than in Australian men; the opposite was true in women. Risk factor levels in Italians were influenced little by duration of residence in Australia. Mortality from ischemic heart disease in Italians in Italy and Italian migrants to Australia is between one third and two thirds that in native-born Australians. The small differences in coronary risk factors observed in this study appear insufficient to explain differences in ischemic heart disease mortality of this size.

Adult↗
PubMed1981

Summarizing dietary patterns using multivariate analysis.

Data on the frequency of consumption of 76 foods were collected from 142 native-born Australians of Australian or British parentage, 26 of Italian parentage and 140 Italian migrants to Australia. Clear separation of the three groups was achieved, using a few as 27 food items in a discriminant function analysis. Potatoes, cauliflower, pumpkin and salt were consumed more by Australians, while salad dressings and grapes were eaten more by Italians. Australian-Italians fell between the two groups, although they tended to be more like Italians. The discriminant score derived for each person was used as an overall food score and this was then related to the serum cholesterol level. There was no consistent relationship between food score and serum cholesterol level.

Australia↗
PubMedDate not supplied

Water sodium and blood pressure in rural school children.

Blood pressures were measured in 326 boys and 309 girls, 12 to 14 yr of age, who attended schools in six rural towns with water sodium levels ranging from 1.46 to 9.69 mmol/L. Although there were significant differences between mean blood pressure levels in children living in the six towns, they did not appear to result from differences in water sodium levels. Children who lived on farms and who drank low-sodium rain water did not have lower blood pressures than children who lived in the towns. The estimated intake of sodium from drinking water in the towns varied between 1.5 and 11.6 mmol/day and represented between 1.2% and 10.4% of the estimated daily sodium intake. No effect of water sodium level on urinary sodium excretion was found. Blood pressure levels showed significant positive relationships with pulse rate, body height and weight, Quetelet's index, mid-upperarm circumference, and triceps skinfold thickness. Diastolic blood pressures in girls were inversely related to the measure of physical activity. Control of these variables, where relevant, by covariance analysis did not uncover any relationship between water sodium level and blood pressure.

Adolescent↗
PubMedDate not supplied

A randomized control trial of a vegetarian diet in the treatment of mild hypertension.

The effect of an ovo-lacto-vegetarian (OLV) diet on blood pressure was assessed in a randomized, controlled, crossover trial in 58 mild untreated hypertensive subjects recruited from the Perth Centre for the 1983 NHF Risk Factor Prevalence Survey. Subjects were randomly allocated to one of three groups; the first maintained their usual diet throughout 12 weeks; the other two were given an OLV diet for either the first or second 6 weeks of the 12-week trial. Introduction of an OLV diet was associated with a significant fall in systolic blood pressure, on average of the order of 5 mmHg, which was unrelated to change in urinary sodium, potassium or body weight. It was concluded that a vegetarian diet may have an adjunctive role in control of mild hypertension, but that in view of likely problems with acceptability those dietary components responsible for the blood pressure differences need to be identified.

Adult↗