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Biomedical subjects

M Skeaff

Publications and source records attributed to M Skeaff.

10 recordsLinked to original sources
PubMed2005

Cholesterol lowering effects of nuts compared with a Canola oil enriched cereal of similar fat composition.

BACKGROUND AND AIM: Small quantities of nuts protect against subsequent cardiovascular risk. There is speculation that the cholesterol lowering effect associated with nut consumption arises primarily from the fatty acid composition of nuts but may be caused by some other component. To evaluate this possibility we compared the effect of various nuts, against a Canola oil based cereal with a comparable fatty acid profile, on lipids, lipoproteins and fatty acids to determine whether the fatty acid profile of nuts explains their cholesterol lowering effects. METHODS AND RESULTS: Twenty-eight men and women with mean (s.d.) levels of total and low density lipoprotein cholesterol of 6.0 (1.1) mmol/L, and 4.1 (1.0) mmol/L, respectively and a mean body mass index (BMI) of 26.9 (3.2) kg/m2 took part in a randomised cross over trial. For two periods of six weeks, separated by a four-week washout, participants were asked to consume a low saturated fat diet, which included either 30 g/d nuts (nut diet) or one serving of a cereal containing Canola oil (cereal diet). There were no significant differences in the lipids, lipoproteins, plasma fatty acids or other variables between the two diets at the end of the study. Total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) were lower on both experimental diets than at baseline, 0.51 mmol/L and 0.40 mmol/L (p<0.001, p<0.01), respectively on the nut diet and 0.42 mmol/L and 0.37 mmol/L (p<0.001, p<0.01), respectively on the cereal diet. CONCLUSION: A 30 g serving of nuts, or a serving of a Canola oil enriched cereal with a similar fatty acid composition reduced total and LDL cholesterol to a similar extent when consumed as part of a lipid lowering diet. Results suggest that foods with a similar fatty acid composition to nuts can produce comparable decreases in lipoprotein mediated cardiovascular risk.

Cholesterol↗
PubMed2000

Interrelationship of indices of body composition and zinc status in 11-yr-old New Zealand children.

Serum zinc and hair zinc concentrations of some New Zealand children aged 11 yr, were examined in relation to selected anthropometric indices. Serum zinc concentrations (n = 453) in boys and girls were similar and were unrelated to anthropometric indices and hair zinc concentrations. Mean hair zinc concentration (n = 620) of the girls was higher than that for the boys (2.95+/-0.49 vs 2.46+/-0.47 micromol/g; p < 0.001). Correlation analysis demonstrated that, for the boys, all the studied anthropometric indices, with the exception of height, were significantly related to hair zinc concentration and that the confounding effects of mid-parent height and the timing of the adolescent growth spurt was small. Results for the girls were similar but less significant. Dichotomizing the hair zinc results divided both the boys and girls into two groups: those with hair zinc < 2.44 micromol/g were heavier (girls, 39.0 vs 35.2 kg; boys, 36.6 vs 34.7 kg) and fatter (mid-upper-arm fat area: girls, 15.2 vs 12.0 cm2; boys, 11.1 vs 9.5 cm2) compared to their counterparts with hair zinc > 2.44 micromol/g. The results demonstrate that in these healthy New Zealand children, those with lower hair zinc concentrations are fatter and heavier than their high-hair-zinc counterparts.

Algorithms↗
PubMed1998

A diet rich in walnuts favourably influences plasma fatty acid profile in moderately hyperlipidaemic subjects.

OBJECTIVE: To compare two low fat diets one rich in walnuts on parameters of lipid metabolism in a group of hyperlipidaemic subjects. DESIGN: A randomised cross over study. SETTING: Department of Human Nutrition, University of Otago, Dunedin, New Zealand SUBJECTS: Twenty one men with mean (s.d.) levels of total and LDL cholesterol of 6.58 (0.60) and 4.63 (0.58) respectively. INTERVENTIONS: For two periods of four weeks subjects were asked to consume two low fat diets (fat 30% total energy), one containing, on average, 78 g/d walnuts. Walnuts obtained through Lincoln University and the Walnut Growers Group (South Canterbury). RESULTS: Participants reported a higher total fat intake on the walnut diet (38% compared with 30% on the low fat diet P < 0.01) The most consistent change in fatty acid profile of triacylglycerol, phospholipid and cholesterol ester on the walnut diet was a significant (P < 0.01) increase in linoleic acid. Triacylglycerol linolenate also increased significantly (P < 0.01). Total and LDL cholesterol were lower on both experimental diets than at baseline, 0.25 mmol/l and 0.36 mmol/l respectively on the walnut diet and 0.13 mmol/l and 0.20 mmol/l respectively on the low fat diet. High density lipoprotein cholesterol was higher on both the walnut and low fat diets when compared to baseline (0.15 mmol/l and 0.12 mmol/l, respectively). When comparing the walnut and low fat diets only apo B was significantly lower (P < 0.05) on the walnut diet. CONCLUSIONS: Despite an unintended increase in the total fat intake on the walnut diet, fatty acid profile of the major lipid fractions showed changes which might be expected to reduce risk of cardiovascular disease. The reduction of apolipoprotein B suggests a reduction in lipoprotein mediated risk, the relatively low myristic acid content of both diets perhaps explaining the absence of more extensive differences in lipoprotein levels on the two diets.

Adult↗
PubMed1998

Effects of dietary coconut oil, butter and safflower oil on plasma lipids, lipoproteins and lathosterol levels.

OBJECTIVE: The aim of this present study was to determine plasma levels of lathosterol, lipids, lipoproteins and apolipoproteins during diets rich in butter, coconut fat and safflower oil. DESIGN: The study consisted of sequential six week periods of diets rich in butter, coconut fat then safflower oil and measurements were made at baseline and at week 4 in each diet period. SUBJECTS: Forty-one healthy Pacific island polynesians living in New Zealand participated in the trial. INTERVENTIONS: Subjects were supplied with some foods rich in the test fats and were given detailed dietary advice which was reinforced regularly. RESULTS: Plasma lathosterol concentration (P < 0.001), the ratio plasma lathosterol/cholesterol (P=0.04), low density lipoprotein (LDL) cholesterol (P<0.001) and apoB (P<0.001) levels were significantly different among the diets and were significantly lower during coconut and safflower oil diets compared with butter diets. Plasma total cholesterol, HDL cholesterol and apoA-levels were also significantly (P< or =0.001) different among the diets and were not significantly different between buffer and coconut diets. CONCLUSIONS: These data suggest that cholesterol synthesis is lower during diets rich in coconut fat and safflower oil compared with diets rich in butter and might be associated with lower production rates of apoB-containing lipoproteins.

Adult↗
PubMed1997

Randomised controlled trial of effect of fruit and vegetable consumption on plasma concentrations of lipids and antioxidants.

OBJECTIVES: To determine the extent to which plasma antioxidant concentrations in people with habitual low intake of fruit and vegetables respond to increased intakes of these foods. To examine whether advice to increase fruit and vegetables will result in reduction of concentrations of total and low density lipoprotein cholesterol. DESIGN: Randomised controlled trial in which intervention and control groups were followed up for eight weeks. The intervention group was asked to consume eight servings of fruit and vegetables a day. SETTING: Dunedin, New Zealand. SUBJECTS: Eighty seven subjects with normal lipid concentrations who ate three or fewer servings of fruit and vegetables daily. MAIN OUTCOME MEASURES: Plasma concentrations of vitamin C, retinol, alpha and beta carotene, alpha tocopherol, lipids, and lipoproteins. Dietary intake assessed with diet records over four days. RESULTS: The mean plasma vitamin C, alpha carotene, and beta carotene concentrations increased in parallel with increased dietary intake of fruit and vegetables in the intervention group. Concentrations of retinol, alpha tocopherol, lipids, and lipoproteins remained unchanged despite some increase in dietary vitamin E and a small reduction in saturated fat intake. CONCLUSIONS: Following a recommendation to increase fruit and vegetable consumption produces change in plasma concentrations of vitamin C, alpha carotene, and beta carotene likely to reduce incidence of cancer. More specific dietary advice to modify fat intake may be necessary to reduce the risk of cardiovascular disease mediated by lipoprotein and vitamin E.

Adult↗
PubMed1996

Effect on lipoprotein profile of replacing butter with margarine in a low fat diet: randomised crossover study with hypercholesterolaemic subjects.

OBJECTIVE: To examine the effect on lipid and lipoprotein concentrations when butter or an unsaturated margarine is used for cooking or spreading in a reduced fat diet. DESIGN: Randomised crossover study with two intervention periods of six weeks' duration separated by a five week washout. SETTING: Community setting in New Zealand. SUBJECTS: 49 volunteers with polygenic hypercholesterolaemia and baseline total cholesterol concentration in the range 5.5-7.9 mmol/l. MAIN OUTCOME MEASURES: Concentrations of total and low density lipoprotein, Lp(a) lipoprotein, high density lipoprotein, apolipoprotein B 100, and apolipoprotein A I. RESULTS: Concentrations of low density lipoprotein cholesterol and apolipoprotein B were about 10% lower with margarine than with butter. Lp(a) lipoprotein and high density lipoprotein cholesterol concentrations were similar with the two diets. CONCLUSION: Despite concerns about adverse effects on lipoproteins of trans fatty acids in margarines, the use of unsaturated margarine rather than butter by hypercholesterolaemic people is associated with a lipoprotein profile that would be expected to reduce cardiovascular risk.

Apolipoprotein A-I↗
PubMed1995

Trans fatty acids: a cause for concern?

The recommendation to reduce total and saturated fat is incorporated into the dietary guidelines for the general population in many western countries. In addition, dietary modification to reduce substantially the intake of saturated fats is a cornerstone of treatment in the hyperlipidaemias. Concern has recently been expressed regarding possible deleterious effects of trans isomers of unsaturated fatty acids on the lipoprotein profiles of both normo and hypercholesterolaemic persons. This review seeks to examine recent research in this area with a view to considering possible changes in the present dietary recommendations.

Coronary Disease↗
PubMed1995

Effects of coconut oil, butter, and safflower oil on lipids and lipoproteins in persons with moderately elevated cholesterol levels.

The physiological effects of coconut oil, butter, and safflower oil on lipids and lipoproteins have been compared in moderately hypercholesterolemic individuals. Twenty eight participants (13 men, 15 women) followed three 6-week experimental diets of similar macronutrient distribution with the different test fats providing 50% total dietary fat. Total cholesterol and low density lipoprotein cholesterol were significantly higher (P < 0.001) on the diet containing butter [6.8 +/- 0.9, 4.5 +/- 0.8 mmol/l] (mean +/- SD), respectively than on the coconut oil diet (6.4 +/- 0.8; 4.2 +/- 0.7 mmol/l) when levels were significantly higher (P < 0.01) than on the safflower diet (6.1 +/- 0.8; 3.9 +/- 0.7 mmol/l). Findings with regard to the other measures of lipids and lipoproteins were less consistent. Apolipoprotein A-I was significantly higher on coconut oil (157 +/- 17 mg/dl) and on butter (141 +/- 23 mg/dl) than on safflower oil (132 +/- 22 mg/dl). Apolipoprotein B was also higher on butter (86 +/- 20 mg/dl) and coconut oil (91 +/- 32 mg/dl) than on safflower oil (77 +/- 19 mg/dl). However gender differences were apparent. In the group as a whole, high density lipoprotein did not differ significantly on the three diets whereas levels in women on the butter and coconut oil diet were significantly higher than on the safflower oil diet. Triacylglycerol was higher on the butter diet than on the safflower and coconut oil diets but the difference only reached statistical significance in women. Cholesteryl ester transfer activity was significantly higher on butter than safflower oil in the group as a whole and in women.(ABSTRACT TRUNCATED AT 250 WORDS)

Butter↗