Citrus fruit peels may lower cholesterol

We may be throwing away the best part of citrus fruits, which help in lowering cholesterol. A study found that certain compounds in the peels of tangerines and oranges significantly lower "bad" LDL cholesterol in animals (hamsters – a rodent) that had been fed a high-cholesterol diet.The compounds known as polymethoxylated flavones (PMFs) are antioxidants that belong to a group of plant chemicals called flavonoids. Flavonoids exist in a variety of fruits and vegetables, as well as tea and red wine. The research suggests that these compounds help guard against heart diseases and cancer. Two other citrus flavonoids - hesperetin from oranges and naringenin from grapefruit have shown early promise in lowering cholesterol.In the animal study, researchers found that a diet containing one percent PMFs cut the animals' LDL cholesterol by up to 40 percent. The researchers used the two PMFs most commonly found in citrus fruits, tangeretin and nobiletin. For comparison, some of the hamsters were given a diet enriched with hesperetin and naringenin. These flavonoids, also lowered LDL cholesterol, but it took three times as much of them to yield the benefit seen with the PMFs.

Researcher from the Canadian nutraceutical company, KGK Synergize Inc., found that PMFs are not soluble in water, so citrus juice contains only a small amount of the compounds. Orange zest (grated orange peel), used for flavouring, contains PMFs, but it would take eating the zest of about 25 oranges a day to get cholesterol-lowering benefit. The results from a pilot study suggest the benefits may extend to humans, and a larger clinical trial is underway to see whether a supplement combining PMFs and a form of vitamin E can help treat high cholesterol.