Men and women should educate themselves and use caution before taking nutritional supplements to reduce their cancer risks, according to experts at UT MD Anderson Cancer Center.

"Researchers are still unsure about whether or not minerals, herbs and other plants taken in pill, capsule, tablet or liquid form actually prevent cancer," said Sally Scroggs, health education manager at UT MD Anderson's Cancer Prevention Center.

Results from the Women's Health Study and The Physicians' Health Study II found that vitamins E and C do not prevent cancer. The Selenium and Vitamin E Cancer Prevention Trial showed similar results, suggesting these supplements didn't help prevent prostate cancer.

Other studies have suggested that supplements may actually increase cancer risk by tilting the balance of nutrients in the body.

"If you eat lots of vegetables, fruits, whole grains and beans, you should get the nutrients, including fiber, vitamins and minerals, your body needs to lower your chances of getting diseases like cancer," Scroggs said. "Taking a pill can't replace a healthy diet."

Scroggs recommends that men and women fill their diet with foods packed with cancer-fighting nutrients such as beta-carotene, selenium, lycopene, resveratol, and vitamins A, C, and E.

Supplements may benefit some

More research is necessary to truly understand the relationship between supplements and cancer risk. Still, Scroggs said, there are some situations when a person might benefit from taking a supplement. This is especially true for men and women who are not getting enough nutrients because of food allergies, genetics or chronic illnesses.

Here are a few examples of when supplements may be appropriate:

-- Women who are pregnant or breastfeeding

-- People at risk for vitamin D deficiency

-- People at risk for osteoporosis

-- People at risk for B-12 deficiency, including:
- People age 50 or older
- Vegans who consume no animal foods

Get professional advice

Scroggs advises men and women to speak with a doctor or registered dietician before adding supplements to their diet. "Your doctor or dietician can determine which pills you really need and what dose you should take," Scroggs said.

"Keep in mind there's no vitamin or supplement that's good for everyone."

A registered dietician also can also provide advice about what to look for on supplement labels. This is important because some supplement labels can be confusing or misleading. Many companies claim their pills can cure cancer when, in fact, they don't, according to a recent Congressional study.

"Remember, supplements are just that - supplements," Scroggs said. "Even if your doctor recommends them, your top priority should be getting the nutrients you need from the food you eat."