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Orthomolecular Medicine

Other common name(s): megavitamin / megamineral therapy, nutritional medicine

Scientific/medical name(s): none


Orthomolecular medicine is the use of high doses of vitamins, minerals, or hormones to prevent and treat a wide variety of conditions. The doses are well above the recommended daily allowance (RDA) and may be used along with special diets and conventional treatment.


Available scientific evidence does not support use of orthomolecular therapy for most of the conditions for which it is promoted. However, vitamins, minerals, and other supplements have been and continue to be studied to see if they can help or prevent many types of illness. While some supplements have been shown to help certain conditions, a few have unexpectedly proven to be harmful. At this time, eating nutritious foods is the best proven strategy to get the vitamins, minerals, and other nutrients that are needed for good health.

How is it promoted for use?

Orthomolecular medicine is promoted to help people with depression, schizophrenia, and other psychiatric illness; Parkinson disease; shingles; irritable bowel syndrome; alcoholism; colds; heart disease; hay fever; pneumonia; bruises; acne; eczema; bug bites; cold sores; chronic fatigue syndrome; and many other health problems. Malnutrition and eating refined foods is considered be at the root of many of these illnesses. Those promoting this therapy believe that conventional medicine is "foreign" to the body and potentially harmful. They believe that vitamins, minerals, enzymes and other substances that they consider to be "natural" are the preferred methods of treatment.

What does it involve?

Based on the diagnosis, high doses of vitamin C, niacin, or other vitamins and minerals may be recommended. These are usually taken by mouth. The patient may be put on a diet free of refined sugar and white flour. The diet may be tailored with other specific guidelines for individuals. In some cases, a person may have hair analysis, blood tests, or urine tests to learn the levels of certain minerals or vitamins in the body.

What is the history behind it?

The concept of orthomolecular medicine dates back to the early 1950s. Nobel Prize winner Linus Pauling, PhD, coined the term in 1968. Proponents believe that taking large doses of vitamins or nutrients could correct "biochemical abnormalities," and thereby reverse a wide variety of conditions such as alcoholism, arthritis, asthma, allergies, cancer, depression, epilepsy, heart disease, high blood pressure, hyperactivity, migraine headaches, mental retardation, and schizophrenia.

What is the evidence?

So far, most studies of supplements have shown that they are not as effective in cancer prevention as eating the foods that contain the vitamins or minerals. This may be because foods have helpful nutrients other than those being studied, or that combinations of nutrients have different effects, or because of other factors.

It has long been known, for instance, that iron supplements can help iron-deficiency anemia and vitamin C supplements can correct scurvy. Both are examples of diseases that are caused by not getting enough of the vitamin or mineral. A few vitamins and minerals have been shown to have physical effects beyond correcting deficiencies. For example, supplements of nicotinic acid (a form of niacin, or vitamin B3) have been shown to help lower cholesterol levels in some people. This has become a standard medical treatment. Research is still going on to find out more about supplement use in treating or preventing specific health conditions. Some of the findings are summarized below.

Several antioxidants have been tested alone or in combinations to find out whether they can help prevent or treat cancer and other diseases. Antioxidants are compounds that hold back chemical reactions with oxygen (oxidation) and are thought to reduce the risk of some cancers. Examples of antioxidants are vitamin C, vitamin E, and beta-carotene (a precursor of Vitamin A). Certain trace minerals such as selenium, copper, and zinc also act as antioxidants. Other studies have looked at minerals in the body such as potassium, magnesium, and calcium. (See Calcium , Copper, Molybdenum, Potassium, Beta Carotene/Vitamin A, Vitamin B Complex, Folic Acid, Vitamin C, Vitamin E.)

The antioxidants vitamin E, vitamin C, beta-carotene, selenium, and zinc were given to French men and women over a 7-year period. Others were given a placebo (sugar pill or sham treatment) over that same time. The men who got the supplement combination seemed to have slightly lower cancer risk than those who got the placebo. However, they tended to have low levels of these vitamins in their bodies at the start of the study. The women who got the supplement had the same cancer risk as those who got the placebo pills.

A large clinical trial looked at whether beta carotene and retinol (a form of vitamin A) could help reduce cancer and deaths in people who were at high risk of lung cancer due to smoking or asbestos exposure. The researchers found in 1996 that the group receiving the vitamins had a higher risk of lung cancer, heart disease, and death. The study was stopped right away because of this surprising effect. The researchers continued to follow the groups to find out if these effects continued. The increased risk of heart disease dropped back to normal risk very quickly, but the cancer risk stayed higher for several years.

One 2005 study looked at whether supplements might help prevent side effects of cancer treatment. Canadian researchers gave "natural" vitamin E and beta carotene to people who were getting radiation therapy for head and neck cancers. They found that those who received the vitamins had fewer side effects of treatment but later on had more recurrences of their cancer. This supports older information suggesting that antioxidant supplements taken during cancer treatment may decrease its effectiveness.

Several studies looked at heart and blood vessel disease. One study of women who ate folate-rich foods, some of whom took folic acid supplements, found that they were at lower risk of high blood pressure than those women who took in less. However, the women who ate at least 400 micrograms of folate per day (the Recommended Daily Allowance) did not have this increased risk, whether or not they used supplements. Supplements appeared to help only those who took in less than recommended daily allowance of folate in foods.

The HOPE TOO study followed up on patients with diabetes or vascular disease who had been studied in the 1990s. It found that those who received vitamin E had no difference in cancer or blood vessel disease in the heart when compared to placebo (sham or sugar pills.) Unexpectedly, those who received vitamin E had more heart failure than those who received the sham pills.

Clinical trials using high doses of vitamins have been done for people with mental illnesses. Schizophrenic patients treated with vitamin C or vitamin B6 (pyridoxine) showed no improvement over those receiving sham treatments. Children with attention deficit disorder who received high doses of vitamins C, B3, B5, and B6 proved no different from those receiving placebo (sham treatment).

A 2007 review of 68 studies of vitamin supplements concluded that people taking vitamin A and vitamin E supplements had a shorter life expectancy than those who did not take these supplements, and that vitamin C had no effect on longevity.

As studies continue, researchers are learning from these surprises. One point is that supplement recommendations cannot be made from studies observing large groups of people. For instance, nearly all of the big studies done before the supplement research showed strong links between low intake of beta carotene in foods and higher rates of cancer. However, giving beta carotene supplements turned out to apparently raise cancer risk—the opposite of what was expected. Also, researchers noted that the effects of some supplements take years to show up, and that some effects take years after the supplements are stopped to wear off. Other findings from these studies will help in future clinical trials.

More nutrients are still being studied in controlled clinical trials, for instance, giving trace minerals to seriously ill patients to see if survival is improved. One preliminary study suggests that the antioxidant lutein may help those with macular degeneration (loss of vision in older people caused by poor circulation to the retina of the eye). More research is needed to find out if this holds true in larger studies.

It is well known that nutrition is important to overall health. Poor nutrition may contribute to illness; for example, obesity is linked to diabetes, heart disease, and it raises the risk of some cancers. Healthy nutrition may contribute to good outcomes from illness. In one study, for example, women who ate low-fat diets after treatment for estrogen-receptor-negative breast cancer were less likely to have recurrence of their cancer. However, vitamin or mineral supplements have not proven to cure any type of cancer. Available scientific studies have not shown that large does of vitamins or minerals can help most of the conditions for which orthomolecular medicine is recommended.

At this time, it is hard to say how each nutrient or nutrient combination affects a person’s risk of cancer. On the other hand, studies of large groups of people have shown that those whose diets are high in vegetables and low in animal fat, meat, and/or calories have lower risks for some of the most common types of cancer.

Until more is known about this, the American Cancer Society recommends eating a variety of healthful foods--with most of them coming from plant sources--rather than relying on supplements. Choose whole grains over refined grains and sugars. Limit high-fat and processed meats. Select foods that help maintain a healthy weight. It is also important to engage in moderate to vigorous physical activity for 30 to 60 minutes 5 or more days per week. For most people, this will help keep weight under control, reduce risk of some cancers, and reap many other health benefits. While it is best to get vitamins and minerals from foods, supplements may be helpful for some people, such as pregnant women, women of childbearing age, and people with restricted food intakes. If a supplement is taken, the best choice for most people is a balanced multivitamin/mineral supplement that contains no more than 100% of the "Daily Value" of most nutrients.

Are there any possible problems or complications?

These products are sold as a dietary supplement in the United States. Unlike drugs (which must be tested before being allowed to be sold), the companies that make supplements are not required to prove to the Food and Drug Administration that their supplements are safe or effective, as long as they don't claim the supplements can prevent, treat, or cure any specific disease.

Some such products may not contain the amount of the herb or substance that is written on the label, and some may include other substances (contaminants). Actual amounts per dose may vary between brands or even between different batches of the same brand.

Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Vitamin A, vitamin D, selenium, iron, magnesium, zinc and other supplements can cause complications if too much is taken. Occasional deaths have been reported from iron or magnesium overdoses, mostly in children. Overdoses of minerals may also cause vomiting, diarrhea, hair loss, rashes, and diseases of the nails. Zinc and molybdenum can cause the body’s copper levels to drop, which may produce anemia and low white blood cell counts.

Reports of pain, numbness in the hands and legs, and trouble walking due to high doses of pyridoxine (vitamin B6) have been noted. Vitamin A overdoses can cause headache, drowsiness, irritability, vomiting, loss of hair and eyebrows, and peeling of the skin. Too much vitamin D can cause poor appetite, nausea, vomiting, weakness, itching, and permanent kidney damage.

As noted above, some supplements can raise the risk of cancer or heart disease. In addition, the potential interactions between supplements and drugs and herbs should be considered. Some of these combinations may be dangerous. Always tell your doctor and pharmacist about any supplements and herbs you are taking.

Antioxidant supplements can interfere with the killing of cancer cells if taken during chemotherapy or radiation treatment. Patients who are in cancer treatment should consult with a knowledgeable physician before taking vitamins, minerals, or other supplements.

Additional Resources

More Information From Your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be ordered from our toll-free number (1-800-ACS-2345).


Bairati I, Meyer F, Gelinas M, Fortin A, Nabid A, et al. Randomized trial of antioxidant vitamins to prevent acute adverse effects of radiation therapy in head and neck cancer patients. J Clin Oncol. 2005 Aug 20;23(24):5805-13.

Bjelakovic, G, et al Mortality in Randomized Trials of Antioxidant Supplements for Primary and Secondary Prevention: Systematic Review and Meta-analysis JAMA 2007; 297:842-857.

Kushi LH, Byers T, Doyle C, et al. American Cancer Society guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity. CA Cancer J Clin 2006;56:254–281.

Galan P, Briancon S, Favier A, Bertrais S, Preziosi P, et al. Antioxidant status and risk of cancer in the SU.VI.MAX study: is the effect of supplementation dependent on baseline levels? Br J Nutr. 2005 Jul;94(1):125-32.

Forman JP, Rimm EB, Stampfer MJ, Curhan GC. Folate intake and the risk of incident hypertension among US women. JAMA. 2005 Jan 19;293(3):320-9.

Haslam RH, Dalby JT, Rademaker AW. Effects of megavitamin therapy on children with attention deficit disorders. Pediatrics. 1984 Jul;74(1):103-11.

Hercberg S, Galan P, Preziosi P, Bertrais S, et al. The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals. Arch Intern Med. 2004 Nov 22;164(21):2335-42.

Goodman GE, Thornquist MD, Balmes J, Cullen MR, et al. The Beta-Carotene and Retinol Efficacy Trial: incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping beta-carotene and retinol supplements. J Natl Cancer Inst. 2004 Dec 1;96(23):1743-50.

Labriola, D., & Livingston, R. (1999). Possible interactions between dietary antioxidants and chemotherapy. Oncology. 13, 1003-1011.

Lerner V, Miodownik C, Kaptsan A, Cohen H, Loewenthal U, Kotler M. Vitamin B6 as add-on treatment in chronic schizophrenic and schizoaffective patients: a double-blind, placebo-controlled study. J Clin Psychiatry. 2002 Jan;63(1):54-8.

Lonn E, Bosch J, Yusuf S, Sheridan P, Pogue J, Arnold JM, et al; HOPE and HOPE-TOO Trial Investigators. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA. 2005 Mar 16;293(11):1338-47.

McGuire JK, Kulkarni MS, Baden HP. Fatal Hypermagnesemia in a Child Treated with Megavitamin/Megamineral Therapy. Pediatrics. 2000 Feb;105(2):E18.

Merck Manual. Available at: http://www.merck.com. Accessed April 24, 2007.

Morris CC. Pediatric iron poisonings in the United States. South Med J. 2000 Apr;93(4):352-8.

Richer S, Stiles W, Statkute L, Pulido J, Frankowski J, Rudy D, Pei K, Tsipursky M, Nyland J. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial). Optometry. 2004 Apr;75(4):216-30.

Taylor PR, Greewald P. Nutritional Interventions and Cancer Prevention. J Clin Oncol. 2005 Jan;23:333-345.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Revised: 06/19/2007

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