Ask the experts

Natural Health, Nov, 2007 by Rachel Dowd

[ILLUSTRATION OMITTED]

Q Why can't you take prescription medications with grapefruit?

A Grapefruit is a good source of vitamin C and the antioxidant lycopene. But the citrus fruit also contains chemicals that interfere with the enzymes that normally break down drugs in your digestive system. When those enzymes fail to do their job, the drug enters your bloodstream at higher-than-acceptable levels, increasing your risk of developing side effects.

Until last year, scientists blamed the flavonoids found in grapefruit as the source of interference. But a study published last May in the American Journal of Clinical Nutrition discovered that a group of natural chemicals called furanocoumarins were the likely culprit. The study compared the effects of orange juice, regular grapefruit juice, and furanocoumarin-free grapefruit juice on 18 people taking Plendil, a drug used to treat high blood pressure. Blood levels of Plendil were higher when the drug was taken with regular grapefruit juice, but not with orange juice or furanocoumarin-free juice.

Grapefruit most commonly interacts with drugs taken for blood pressure, high cholesterol, depression, anxiety, allergies, HIV, impotence, and seizures. If you're taking medication for any of these conditions, avoid grapefruit as a snack or juice. To be on the safe side, also stay away from tangelos, which are a hybrid of tangerine and grapefruit.

--Gina L. Nick, N.M.D., Ph.D., medical director at Serenity Wellness Center (serenitywellnessctr.com) in Costa Mesa, Calif.

Q I'm a runner. Is yoga good for me?

A Yoga is not only good for you, it's essential. Unlike sports such as tennis or climbing, which require a variety of movements, running relies on a limited range of motion. As a result, only a few muscles get trained and tight, and the rest of your body goes along for the ride. If you have any kind of structural imbalance--say you spent years carrying a baby on one hip or you fell off a bike as a kid--it will be exacerbated by running. Effective stretching is the only way to lengthen shortened muscles and keep the body in balance.

If you have a serious injury, I recommend one-on-one yoga therapy with a qualified instructor. (See the International Association of Yoga Therapists at iayt.com.) Otherwise, an active yoga program--like Ashtanga, power, Vinyasa, or Iyengar--will help tremendously. Start with a beginner's course, and keep in mind, the fitter you are as an athlete, the more difficult yoga will be for you. So take it slow and easy.

Certain poses offer particular benefits to runners. For example, Downward-Facing Dog (Adho Mukha Svanasana) stretches the back and the back of the legs, as well as the shoulder and intercostal muscles, and strengthens the abdominals and arms. Hero pose (Virasana) loosens the quadriceps, instep, knees, and feet. It's an excellent way to reduce the likelihood of foot and ankle injuries, such as plantar fascitis, Achilles tendinitis, and stress fractures. Warrior I (Virabhadrasana) pose stretches and strengthens the quadriceps, opens the groin and hips, and improves balance and concentration. (A modified Warrior I is shown here.)

[ILLUSTRATION OMITTED]

A word of caution: Never practice yoga in an air-conditioned room. And remember, you don't stretch to warm up; you warm up to stretch. I tell my students, "If yoga seems too difficult at first, it gets easier. If it seems too easy, it gets a lot harder."

--Beryl Bender Birch, founder and director of The Hard & The Soft Yoga Institute (power-yoga.com) and author of Power Yoga (Prion Books, 1995)

Q How can I treat and prevent stretch marks naturally?

A Stretch marks, or striae, are scars created in the skin when it has stretched beyond its ability to recoil. The mark appears as a thin line that starts out red in color and fades to white. Stretch marks are partly hereditary, so if your mother has them, you're more likely to have them, too. But anything that causes the skin to stretch--obesity, puberty, rapid weight gain or loss, pregnancy, or even lifting weights and taking steroids--can cause striae.

To prevent stretch marks, keep your skin hydrated and healthy. Use an oil-based, thick moisturizer (like ShiKai's Borage Dry Skin Therapy, shown below) and drink six to eight 8-ounce glasses of water daffy. Cocoa butter also has a reputation for preventing stretch marks, but there are no studies that show it works better than a regular moisturizer.

More aggressive treatments for stretch marks include topical retinoids like Renova, Retin-A, and Avita, which minimize scars by stimulating the production of collagen in the skin. Laser treatments have also been shown to lighten and smooth stretch marks. Vascular lasers, such as the Vbeam, which are typically used to treat birthmarks and rosacea, target color red and are therefore useful when stretch marks first appear. The Fraxel laser, an infrared resurfacing laser, has been shown to stimulate collagen production, which helps fill in the sunken area beneath the older, white scars. Signs of improvement should be visible after three to six monthly treatments. (It's not cheap: One session can run from $600 to $1,200, depending on the size of the scar, and insurance rarely covers the procedure.)