Randomised trial of lipid lowering dietary advice in general practice: the effects on serum lipids, lipoproteins, and antioxidants

Abstract

Objective-To determine the relative efficacy in general practice of dietary advice given by a dietitian, a practice nurse, or a diet leaflet alone in reducing total and low density lipoprotein cholesterol concentration.Design-Randomised six month parallel trial. Setting-A general practice in Oxfordshire. Subjects-2004 subjects aged 35-64 years were screened for hypercholesterolaemia; 163 men and 146 women with a repeat total cholesterol concentration of6*0-8-5 mmol/l entered the trial.Interventions-Individual advice provided by a dietitian using a diet history, a practice nurse using a structured food frequency questionnaire, or a detailed diet leaflet sent by post. All three groups were advised to limit the energy provided by fat to 300/o or less and to increase carbohydrate and dietary fibre.Main outcome measures-Concentrations of total cholesterol and low density and high density lipoprotein cholesterol after six months; antioxidant concentration and body mass index.Results-No significant differences were found at the end of the trial between groups in mean concentrations of lipids, lipoproteins, and antioxidants or body mass index. After data were pooled from the three groups, the mean total cholesterol concentration fell by 1-9a/o (0.13 mmolVI, 95% confidence interval 0*06 to 0*22, P<0.001) to 7*00 mmol/l, and low density lipoprotein cholesterol also fell. The total carotenoid concentration increased by 53 nmol/l (95% confidence interval 3 0 to 103, P=0.039).Conclusions-Dietary advice is equally effective when given by a dietitian, a practice nurse, or a diet leaflet alone but results in only a small reduction in total and low density lipoprotein cholesterol. To obtain a better response more intensive intervention than is normally available in primary care is probably necessary.

Information sources and strategies of nutrition guidance used by primary care physicians

“…Unfortunately, there is probably only one study that determined the relative efficacy of different strategies of giving dietary advice in general practice. Neil et al (33) reported that lipid-lowering dietary advice given by a dietitian or a practice nurse or a diet leaflet alone resulted in equally small effects on lipid concentrations.…”

A transferable programme of nutritional counselling for rehabilitation following myocardial infarction: a randomised controlled study

“…While demonstrating that improvements in diet can be achieved, the deterioration in dietary habits between 12 weeks and 1 y observed in the intervention group suggests the need for a more sustained programme to maintain improvements. Available evidence suggests that delivery of advice must be carefully focused to produce behavioural change (Neil et al, 1995). The present study did not ration advice to individuals assessed as 'ready to change'.…”

A review of recent dietary intervention trials in the United Kingdom to reduce blood cholesterol levels

“…The trials lasted from 3 months (short duration) to over 5 years (long duration). Most of the trials measured changes in total cholesterol and other risk factorsÐ blood pressure, smoking, weight, and dietary habits (Jones, Davies, Dove et al 1988, Bennet, Blackall, Clapham et al 1989, Robertson, Phillips, Mant et al 1992, Gibbins, Riley and Brimble 1993, Oxcheck study 1995, Roderick, Ruddock, Hunt et al 1997, Yasmin, Mascie-Taylor, Brown et al 1998, and two trials also measured lipid pro® les including HDL, LDL and triglycerides (Baron, Gleason, Crowe et al 1990, Neil, Roe, Godlee et al 1995.…”

“…An Oxfordshire trial (Neil et al 1995) involving 163 men and 146 women aged between 35± 64 years examined the extent of reduction in total cholesterol and LDL cholesterol concentrations after dietary advice was given in one of three ways; by a dietician, or a practice nurse, or through a diet lea¯et alone. The adults were randomly assigned to one of the three groups.…”