More than half of the 17 cholesterol-lowering supplements tested recently by ConsumerLab failed to contain their listed ingredients and many could not be adequately broken down for use by the body, reported the agency last week.
One product contained less than 10 per cent of its claimed ingredient. Tablets of another product costing over $80 per month were so hard that only a hammer could break them, said ConsumerLab, an independent testing agency.
The review covered products containing the plant-derived guggulsterones, policosanol, or sterols - all shown in clinical studies to reduce total cholesterol and LDL by about 10-15 per cent, and most backed by strong scientific evidence. But while there is significant proof of their efficacy, it appears that many manufacturers of cholesterol-lowering supplements market the products with insufficient ingredients to produce the desired effect.
With around 50 per cent of American adults suffering from elevated blood cholesterol levels, a key risk factor for heart disease, sales of such products have exploded in recent years, increasing 37 per cent in the past year in the natural foods market, according to SPINS, and 20 per cent in mainstream sales, according to ACNielsen.
"After diet and exercise, supplements are a viable option to lower cholesterol levels before considering drug therapy," said Dr Tod Cooperman, president of ConsumerLab.com. "To provide their full benefit, however, these supplements must contain and deliver all of their ingredients - otherwise the only thing they are sure to reduce is your bank account."
The problems revealed by the survey reflect a combination of poor manufacturing and the use of low quantity or low quality ingredients, suggested Cooperman.
Only one out of five guggulsterone products, produced from tree sap, passed testing - the other four contained from 4-74 per cent of the expected ingredient.
Only three of seven supplements containing policosanol, derived from sugar cane, passed testing - the other four contained from 23-79 per cent of the expected ingredient.
Sterol supplements seemed to be the most reliable - of four sterol supplements tested, three passed but one failed for containing only 77 per cent of the expected ingredient and also could not fully break apart.Sterols have been shown to prevent cholesterol absorption in the gut and they are recognised as safe when taken in supplement or food form.