This Cochrane review compared the effective cholesterol-lowering dietary interventions with other forms of dietary intervention in patients with familial hypercholesterolaemia
What is the effectiveness of cholesterol-lowering dietary interventions compared with no dietary treatment or other forms of dietary intervention in children and adults with familial hypercholesterolaemia?
Familial hypercholesterolaemia is a genetic disorder that causes severe elevations in total cholesterol, which is associated with a high risk for premature coronary artery disease.
Changing diet is an important management option for patients with familial hypercholesterolaemia. Nurses play a significant role in providing dietary interventions to children and adults with the disorder, so it is vital for them to know which ones are more effective in these patients.
The review included 11 studies with a total of 331 participants; these were children and adults with familial hypercholesterolaemia (no age limit described).
The intervention of interest was a cholesterol-lowering diet, which could be compared with either other forms of dietary treatment (such as the addition of omega-3 fatty acids, plant sterols or stanols, or soya protein to a cholesterol-lowering diet) or to no dietary intervention.
A cholesterol-lowering diet was described as a reduction in total fat intake and in the intake of saturated fatty acids and dietary cholesterol, and the manipulation of carbohydrate consumption to replace the energy deficit of the low-fat diet.
The authors stated that the methodological quality of the included studies were generally good. For most of the studies, the method of randomisation was not clearly reported, but nine trials reported blinding of assessment of outcomes. Meta-analysis was undertaken where possible.
Only short-term outcomes were assessed in all included studies.
The primary outcomes of interest were incidence of ischaemic heart disease, number of deaths and age at death, although none was reported in any of the included trials.
The secondary outcomes of interest were: fasting serum total cholesterol concentration; fasting serum low-density lipoprotein cholesterol (LDL); fasting serum high-density lipoprotein cholesterol; and fasting serum triglyceride concentration.
Other secondary outcomes included fasting apolipoprotein A-1 concentration, fasting apolipoprotein B-100 concentration, quality of life, compliance and morbidity.
Quality of life, compliance and morbidity were not measured in any of the studies reviewed.
Summary of key evidence
Compared with a cholesterol-lowering diet, no significant differences in any of the secondary outcomes measured were found between no dietary intervention and: nutritional advice; adding omega-3 fatty acids; adding plant stanols; or a high- protein diet.
A significant difference in total cholesterol levels was found when plant sterol was added to a cholesterol-lowering diet and compared with a cholesterol-lowering diet alone at up to two months.
One study on adults indicated a significant reduction in total cholesterol at two months in participants receiving high-dose stanol, participants receiving low-dose stanol, and those receiving sterol at one month. The same study resulted in a significant reduction in LDL cholesterol in the high-dose stanol group only.
Best practice recommendations
No conclusions could be reached about the effectiveness of a cholesterol-lowering diet or any of the other dietary interventions suggested for familial hypercholesterolaemia because the available data was insufficient.
Future research should focus on large, parallel, randomised controlled and long-term trials. Studies measuring a variety of dietary treatment options that have been suggested for the disorder should also be carried out.
Liu Weihua is associate professor; Liu Jing is research student; both at the School of Nursing, TaiShan Medical University, TaiAn City, Shandong Province, PR China, and members of the Cochrane Nursing Care Field
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Shafiq N et al (2010) Dietary treatment for familial hypercholesterolaemia. Cochrane Database of Systematic Reviews; Issue 1, Art no: CD001918. DOI 10.1002/14651858.CD001918.pub2