Complementary medicines can help mild depression and premenstrual syndrome

Not all dietary supplements and "alternative" products are harmless though. German Institute urges consumers to be more critical of health claims.

Many people use "alternative" or complementary products because they see them as a more gentle form of medicine. The German Institute for Quality and Efficiency in Health Care has now analysed the latest research on several products and released the results along with a guide for consumers.

St John's wort (hypericum), for example, could help ease mild depression, but it does not help with severe depression. It also probably cannot help with the symptoms of premenstrual syndrome (PMS). However, calcium and vitamin B6 (pyridoxine) might help relieve PMS. On the other hand, evening primrose oil has not been proven to help.

Herbal medicines and dietary supplements can also have risks

According to the Institute, conflicting research results in recent years have caused confusion and controversy about St. John's wort. It concluded this is partly because the effects vary from product to product, and the effect depends too on how severe depression is. The controversy highlights the importance of looking at all clinical trial results to gain a better picture of health care treatments.

"Consumers need to be more critical of all health claims," according to the Institute's Director, Professor Peter Sawicki. "This is as true of dietary supplements and complementary medicines as it is of prescription medicine. Just because a product is made from a plant or vitamins, it does not mean it is necessarily safe in very high doses or for frequent use. And not all medicinal products can provide as much relief as patients expect." The growing evidence that high doses of some vitamins and antioxidants can cause cancer or earlier death is an important reminder that dietary supplements are not necessarily harmless.

All treatments and products should face the same scientific standards for effectiveness and safety

Patients need to consider several questions before choosing any treatment, including a dietary supplement. Professor Sawicki: "Doctors and patients need to know whether treatments have been proven to work in enough good clinical trials that measured benefits large enough to matter to the patient. Whether a medicine is made from a plant or manufactured in a laboratory, the same scientific standards apply if you want to know which treatment might be the best for you."