Vitamin supplements have taken a beating lately. And plenty of people who use them to help ensure their good health are now left wondering whether these pills should be dumped in the trash.

But before you do that, there’s another side to the vitamin question that you should know—most of the negative findings are misreported and/or the studies are flawed. After decades of research (backed by more than 26,000 medical journal articles and 19 years of clinical practice treating thousands of patients), I am confident that supplements can and often do work. The question is, which supplements?

What Everyone Needs

In an ideal world, we’d get all our nutrients from foods—there’s a powerful synergistic effect when vitamins and minerals are found in foods. But the reality is, most people don’t get enough of these crucial nutrients. That’s why certain individual supplements can help.

  • B-complex.

The B vitamins—thiamine, riboflavin, niacin and several others—are a must for the body’s production of energy. They also play a key role in the health of the brain and nervous system.

But when foods are refined—for example, when kernels of whole wheat are stripped of their outer covering of fibrous bran and inner core of wheat germ and turned into white flour, as commonly occurs in American manufacturing practices—B vitamins are lost.

New scientific evidence: A study of 104 middle-aged and older adults, published this summer, showed that taking three B vitamin ­(folic acid, B-6 and B-12) lowered levels of the amino acid homocysteine in people with very high levels (such elevations are linked to heart disease) and improved several measurements of mental functioning, such as memory.

Typical dose of B vitamins: Look for a B-complex supplement that contains at least 20 mg of most of the B vitamins, including B-6, thiamine and niacin…and at least 50 micrograms (mcg) each of B-12 and biotin.

  • Magnesium.

Without this mineral, your body couldn’t produce energy, build bones, regulate blood sugar or even move a muscle. But most Americans don’t get enough of this mineral in their diets.

Magnesium is used by nutritionally oriented clinicians to treat many health problems, including insomnia, chronic muscle pain, headache, heart disease, diabetes, osteoporosis and hearing loss. Overall, magnesium is the most beneficial supplement I have seen in my patients.

Typical dose of magnesium: 200 mg, twice a day. A capsule or a chewable or liquid form is preferable to a tablet, because it is more easily absorbed. But all types of magnesium—including magnesium oxide, magnesium citrate and magnesium aspartate—are equally effective for most conditions. If you develop diarrhea, reduce the dose until diarrhea eases.

  • Vitamin C.

This vitamin is an antioxidant—a nutrient that protects you from oxidation, a kind of inner rust that destroys cells. A low level of oxidation is normal, but it’s increased by many factors—such as stress and chronic disease.

Recent finding: A review of 13 studies involving nearly 4,000 people with colorectal adenoma (a benign tumor that can turn into colon cancer) found that people with the highest levels of vitamin ­C­­ were 22% less likely to develop colon cancer.

Typical dose of Vitamin C: 100 mg to 500 mg daily, for general nutritional support. If you have a family history of colon cancer (for example, in a first-degree relative, such as a parent or sibling), consider taking 1,000 mg, three times daily.

“Add-On” Supplements You May Need…

Certain people may need additional supplements to protect or improve their health. Two key “add-on” supplements…

  • Fish oil.

A large body of scientific research shows that fish oil can help prevent and treat heart disease. Typical dose: About 1 g daily for people who want to reduce heart disease risk…and 2 g to 6 g daily for people diagnosed with the condition. People with coronary heart disease need 360 mg to 1,080 mg daily of eicosapentaenoic acid (EPA) and 240 mg­­ to 720 mg of docosahexaenoic acid (DHA). Talk to a health practitioner before taking fish oil—it may increase bleeding risk.

  • Vitamin D.

Vitamin D deficiency is common, and it can increase risk for bone loss (osteoporosis), falls in older people (frailty), the flu, autoimmune diseases (such as rheumatoid arthritis, lupus and multiple sclerosis) and even cancer.

New thinking: 400 international units (IU) daily was once thought to preserve bone and prevent falls, but studies now show that 800 IU daily is preferable. An even higher dose (up to 1,200 IU daily) may be needed, depending on age (older people may need more)…weight (the obese are at greater risk for deficiency)…and skin color (people with dark skin produce less vitamin D when exposed to the sun). Ask your doctor for advice on the best dose for you, and use vitamin D-3 (the type derived from sunlight and animal sources).

*Be sure to check with a nutrition-savvy health practitioner before taking any supplements. To find one near you, consult the American Holistic Medical Association, ­HolisticMedicine.org, or the American Association of Naturopathic Physicians, Naturopathic.org.