Cox News Service

ATLANTA - Every month Sydney Ferguson, 40, spends about $70 on specialty vitamins and dietary supplements because she wants to avoid the heart disease and diabetes that run in her family.

Although she eats well and exercises regularly, she feels like that regimen is an investment in her health.

"My philosophy now is, you either pay for your health up front, which for me is taking vitamins and supplements, or you pay for it in the end, taking medications with a lot of different side effects (and that cost) exorbitant amounts of money," Ferguson says.

As a result, she says, she has more energy, she gets fewer colds, and her husband says her memory has improved.

But how much credit the contents of those bottles deserve for her current well-being remains a big unknown.

For while dietary supplements are a booming business - as of 2006, the industry was worth almost $23 billion annually ($4.6 billion from herbs and other botanicals), according to the Nutrition Business Journal - we don't have a lot of research about them.

According to 1994's Dietary Supplement Health and Education Act, dietary supplements are foods, even though they can be used like drugs. But, unlike drug companies, manufacturers traditionally haven't had to test their formulas or prove the supplements even work.

Even medical studies of supplements often show conflicting results. "All studies aren't created equal," says Dr. Mark Ebell, associate professor of family medicine at the Medical College of Georgia. "If the study isn't well-designed biases can creep in. A poorly designed study may give you the wrong answers."

Despite those unknowns, many health experts also acknowledge it's possible to find a supplement that benefits you if you do your homework. "It's kind of empowering when you can make some choices about your own health - if you do it with education, if you do it with some guidance from your health care team," says Dr. Brent Bauer, director of the Mayo Clinic's Complementary and Integrative Medicine Program in Rochester, Minn., and editor of "The Mayo Clinic Book of Alternative Medicine."

Judith Klose, 50, believes that has been the case for her. She didn't like the side effects of her arthritis medicine, so she says she switched to tuna omega-3 oil and black-currant-seed-oil supplements instead. "If I couldn't do the traditional (medications), I wanted to try at least the alternative because I knew just ignoring [the pain] wouldn't make it better," she said. After a few weeks of treatment, she says the pain was reduced, although she remains under her rheumatologist's supervision.

How can you tell exactly what's in the supplement you're taking? Manufacturers are responsible for the purity of their products, but it's still difficult to tell how strong a supplement is or how you'll react to it. (As of 2010, the government will require supplement manufacturers to prove their "Good Manufacturing Practices," or GMPs, which refer to purity and accurate labeling.)

You should consult your doctor before you try any supplements. Some plants can interfere with medicines, and some can even be harmful when taken incorrectly.

"It behooves every consumer to do some research. It's hard to just go into a store and pick (a supplement)," says Christine A. Rosenbloom, professor of nutrition at Georgia State University, who recommends finding supplement data on the Web before you shop.

"I think there is merit for some supplements for some people, but it isn't a one-size-fits all approach," she says. "For example, people with knee or hip arthritis might want to try supplementing with glucosamine and chondroitin, but they should buy a good-quality supplement - not a discount brand." And be patient, she adds; in some cases it may take months to know if it works. "It is unlikely you will go ballroom dancing after a week's worth of glucosamine for your arthritis."

Nor should supplements ever be used to replace a healthy diet. "If you are eating on the run and eating poorly and not getting enough sleep," Rosenbloom points out, "a supplement that claims to boost your immune system is unlikely to have any effect."

Dietary supplements may be appropriate if: • You don't eat well. If you eat less than five total servings of fruits and vegetables daily, it may be difficult to get all of the vitamins and minerals your body needs. Also, if you eat only one or two times a day, you may be limiting the number and variety of servings you eat from the various food groups. • You're a vegetarian. If you're a vegetarian, you may not consume enough calcium, iron, zinc and vitamins B-12 and D. You can get these nutrients naturally from nonmeat sources, such as fortified soy products, green leafy vegetables, legumes, whole-grain products and nuts. If you aren't able to regularly consume these foods, dietary supplements may be necessary. • You consume less than 1,200 calories a day. Low-calorie diets limit the types and amounts of foods you eat and, in turn, the types and amounts of nutrients you receive. Unless monitored by a doctor, a low-calorie diet isn't usually recommended. • You have a medical condition that affects how your body absorbs, uses or excretes nutrients. If your diet has limited variety because of food allergies or intolerance to certain foods, such as dairy products, you may benefit from a dietary supplement. Also, if you have a disease of your liver, gallbladder, intestines or pancreas, or if you've had surgery on your digestive tract, you may not be able to digest and absorb nutrients properly. In such cases, your doctor may recommend that you take dietary supplements. • You're a postmenopausal woman. After menopause, women experience a sudden drop in estrogen levels, which increases bone loss. To keep bones strong and to decrease bone loss, you need calcium as well as vitamin D - the vitamin essential for absorbing calcium. Women who don't obtain enough calcium and vitamin D through foods could benefit from taking a calcium supplement with vitamin D. • You're a woman who has heavy menstrual bleeding. If you have heavy menstrual bleeding, you may need additional iron to replace the iron depleted by blood loss. Iron deficiency can lead to anemia, a condition in which blood is low in hemoglobin, the substance which carries oxygen to tissues. • You're pregnant or trying to become pregnant. During this time, you need more of certain nutrients, especially calcium, folate and iron. Folate is needed very early in pregnancy to help protect your baby against neural tube birth defects, such as incomplete closure of the spine (spina bifida). Iron helps prevent fatigue by helping you make the red blood cells necessary to deliver oxygen to you and your baby. Your doctor can recommend a dietary supplement. It's important to start taking a supplement before becoming pregnant. • You smoke. Tobacco decreases the absorption of many vitamins and minerals, including vitamin C, folate, magnesium and calcium. But dietary supplements won't make up for the major health risks caused by smoking. The safest option is to avoid all tobacco products. • You drink excessively. Long-term excessive alcohol consumption can impair the digestion and absorption of several vitamins and minerals, including vitamin B-1, iron, zinc, magnesium and folate. In addition, you may substitute alcohol for food, resulting in a diet lacking in essential nutrients. Excessive drinking is defined as more than two drinks a day for men under age 65 and more than one drink a day for men over 65 and women. Taking dietary supplements, however, won't make up for the major health risks caused by excessive alcohol consumption. - Source: Mayo Clinic