A helpful guide to getting the most out of grapefruit

Flavourful and nutritious — it's easy to understand why grapefruits are no longer just a breakfast option. Here are some of the nutritious benefits that grapefruits have to offer.

• Half a grapefruit provides more than 45 percent of the adult Recommended Daily Allowance (RDA) of vitamin C; it also has 175 milligrams of potassium and one milligram of iron.
• The pink and red varieties are high in beta carotene, which the body then converts to vitamin A.A serving of 250 millilitres (one cup) of unsweetened grapefruit juice has 95 milligrams of vitamin C (which is more than 100 percent of the RDA) and most of the other nutrients found in the fresh fruit.
• In the past, many people shunned unsweetened grapefruit juice because of its tartness, but a naturally sweet juice can be made from the red or pink grapefruits.

• Grapefruits are especially high in pectin, a soluble fibre that helps lower blood cholesterol. In addition, recent studies indicate that grapefruits contain other substances that prevent disease.
• Pink and red grapefruits, for example, are high in lycopene, an antioxidant that appears to lower the risk of prostate cancer.
• Re­searchers have not yet identified lycopene's mechanism of action, but a six-year Harvard study involving 48,000 doctors and other health professionals has linked 10 serv­ings of lycopene-rich foods a week with a 50 percent reduction in prostate cancer.
• Other protective plant chemicals found in grapefruits include: phenolic acid, which inhibits the formation of cancer-causing nitro­samines; limonoids, terpenes and mono­terpenes, which induce the production of enzymes that help prevent cancer; and bio­flavonoids, which inhibit the action of hormones that ­promote tumour growth.
• Some people with rheumatoid arthritis, lupus and other inflammatory disorders find that ­eating grapefruit daily seems to alleviate their symptoms. This may occur because plant chemicals block the prosta­glandins that cause inflammation.

Over the years a number of fad diets have promoted the grapefruit as possessing a unique ability to burn away fat. There is no truth to these claims; no food can do this.

• People following grapefruit diets lose weight because they eat little else — a practice that can lead to nutritional deficiencies.
• Even so, grapefruits are a good food to include in a sensible weight-loss diet; a serving contains less than 100 calories, and its high-fibre content satisfies hunger.

Those people who are allergic to other citrus fruits are likely to react to grapefruits, too. The sensitivity may be to the fruit itself or to an oil in the peel.

• Caution: Grapefruit juice should not be used to take certain medications. Compounds in the juice enhance the effects of some drugs, possibly resulting in adverse effects. Drugs to watch out for include the blood-pressure lowering medication felodipine, as well as drugs for anxiety, depression, elevated lipids and more.

Grapefruit offers many health benefits but as a precaution, it is best to avoid taking any drug with grapefruit juice until you have asked your doctor or pharmacist if it is safe to do so.