5.3.1 Evidence statements for cardioprotective dietary advice

5.3.1 Evidence statements for cardioprotective dietary advice

Low fat diet

5.3.1.1.

No randomised controlled trials were identified in people at high risk of CVD that compared low fat diet with usual diet for the outcomes mortality or morbidity.

5.3.1.2.

One small randomised controlled trial in people at high risk of CVD with elevated cholesterol and triglycerides found that advice to reduce consumption of fat, sugar and alcohol was associated with reduction in total cholesterol and fasting triglycerides compared with control.

5.3.1.3.

In patients with suspected CHD, one small randomised controlled trial found that adopting a lipid–lowering diet reduced total cardiac events compared to usual care but did not confer any benefit for the outcomes of cardiovascular mortality, MI, stroke, coronary surgery or angioplasty. Lipid–lowering diet was associated with decreased total and LDL cholesterol compared to baseline levels.

5.3.1.4.

No randomised controlled trials were identified that compared low fat diet with usual diet in patients with peripheral arterial disease or following stroke.

Increased fruit and vegetable diet

5.3.1.5.

No randomised controlled trials were identified that compared increased fruit and vegetables diet with usual diet in people at high risk of CVD.

5.3.1.6.

One randomised controlled trial in patients with angina found that advice to increase consumption of fruit and vegetables was not associated with a reduction in all cause mortality, cardiac death or sudden death compared with advice to eat sensibly.

5.3.1.7.

No randomised controlled trials were identified that compared increased fruit and vegetables diet with usual diet in patients with peripheral arterial disease or following stroke.

5.3.1.8.

One randomised controlled trial in patients with angina found that advice to eat oily fish or take omega 3 fatty acid supplements was not associated with a reduction all cause mortality or cardiac death.

5.3.1.9.

One randomised controlled trial in hypercholesterolemic people without and with coronary artery disease found that omega 3 fatty acid supplements was associated with a reduction in the primary outcome of any major cardiovascular event, and the secondary outcomes of unstable angina and non fatal coronary events (HR 0.81, 95%CI 0.68 to 0.96)

http://www.ncbi.nlm.nih.gov/

Vitamin C supplementation lowers serum low-density lipoprotein cholesterol and triglycerides: a meta-analysis of 13 randomized controlled trials

Review published: 2008.

Bibliographic details: McRae MP.  Vitamin C supplementation lowers serum low-density lipoprotein cholesterol and triglycerides: a meta-analysis of 13 randomized controlled trials. Journal of Chiropractic Medicine 2008; 7(2): 48-58. [PMC free article] [PubMed]

Quality assessment

The review concluded that supplementation with at least 500mg/day of vitamin C for at least four weeks can result in significant decreases in low-density lipoprotein cholesterol and triglyceride; there was a non-significant elevation of serum high-density lipoprotein cholesterol. A lack of study quality assessment and other methodological problems limited the reliability of the author?s conclusions. Full critical summary

Abstract

OBJECTIVE: Vitamin C has been shown to be an effective therapeutic for reducing total serum cholesterol, but epidemiologic studies have determined that low-density lipoprotein (LDL) cholesterol and high-density lipoprotein (HDL) cholesterol are actually better predictive measures of coronary heart disease risk. Therefore, the purpose of this study was to provide a comprehensive meta-analysis of randomized controlled trials to investigate the effect of vitamin C supplementation on LDL and HDL cholesterol as well as triglycerides in patients with hypercholesterolemia.

METHODS: Thirteen randomized controlled trials published between 1970 and June 2007 were identified using Medline and a manual search. From the 13 trials, 14 separate group populations with hypercholesterolemia and who were supplemented with at least 500 mg/d of vitamin C for between 3 and 24 weeks were entered into the meta-analysis. This meta-analysis used a random-effects model; and the overall effect sizes were calculated for changes in LDL and HDL cholesterol, as well as triglyceride concentrations.

RESULTS: The pooled estimate of effect for vitamin C supplementation on LDL and HDL cholesterol was -7.9 mg/dL (95% confidence interval [CI], -12.3 to -3.5; P = .000) and 1.1 mg/dL (95% CI, -0.2 to 2.3; not significant), respectively. The pooled estimate of effect for vitamin C supplementation on triglycerides was -20.1 mg/dL (95% CI, -33.3 to -6.8; P < .003).

CONCLUSION: Supplementation with at least 500 mg/d of vitamin C, for a minimum of 4 weeks, can result in a significant decrease in serum LDL cholesterol and triglyceride concentrations. However, there was a nonsignificant elevation of serum HDL cholesterol.pubmedhealth/PMH0026585/