American Medical Association Family Medical Guide - American Medical Association [77]
Fat-soluble vitamins—such as vitamins A, D, E, and K—are stored in the body’s fat cells. If you take too much of a fat-soluble vitamin, it can build up in your body and cause harm. Most vitamins work together with other nutrients to finely balance the complex chemical processes in your body. Taking too much of one vitamin or mineral without a similar increase in the other nutrients can upset this delicate balance. It is best to get most of your vitamins and minerals from a varied diet that contains plenty of fruits and vegetables, supplemented by a daily multivitamin that contains the recommended doses of vitamins and minerals.
Coenzyme Q-10
Coenzyme Q-10, also known as ubiquinone, is a compound made naturally by the body. It helps cells produce energy and acts as an antioxidant, protecting cells from damaging free radicals (harmful by-products of the body’s normal chemical processes). Naturally made quantities of coenzyme Q-10 in the body decrease as people age. Coenzyme Q-10 is marketed in the United States as a dietary supplement in pill form that protects the heart and stimulates the immune system. Coenzyme Q-10 may also be beneficial as an addition to conventional treatments for cancer and congestive heart failure. No serious side effects have been reported from the use of coenzyme Q-10; it does, however, lower the effectiveness of the anticlotting drug warfarin, so you should not take coenzyme Q-10 if you are taking warfarin.
Melatonin
Melatonin is a hormone produced by the pineal gland in the brain at night, when it is dark, to help regulate the sleep-wake cycle. The level of the hormone falls in the morning, when it is light.
Some people take melatonin supplements to help ease the symptoms of jet lag (brought on by a change in time zone that disrupts the sleep-wake cycle) or as a temporary sleep aid. However, there are no definitive studies proving melatonin’s effectiveness for either jet lag or insomnia, and doctors caution that taking it could reduce the body’s own production of the hormone. Also, because melatonin can interact with other hormones, it should not be taken by women who are pregnant or breastfeeding, or by children. In people with asthma, the supplement may increase asthma symptoms during the night. Possible side effects associated with melatonin include headache, diminished sex drive and fertility, and excessive sleepiness.
If you are thinking about taking melatonin, talk to your doctor. Melatonin may interact with some medications, and the long-term effects of taking melatonin supplements are not known. Also, like all supplements, its manufacture is not regulated by the FDA, and dosages have not been standardized.
Echinacea
Also called purple coneflower, echinacea was initially applied to the skin as a folk remedy to heal wounds. Today it is taken internally to boost the immune system and to treat upper respiratory infections such as colds and the flu. Studies testing its effectiveness in reducing cold symptoms have had mixed results. Echinacea can cause allergic reactions in some people or interfere with immune-suppressing drugs (such as those prescribed to prevent rejection after an organ or tissue transplant).
Ephedra
Also called ma huang, ephedra is a herbal Chinese medicine used for treating asthma and hay fever. Ephedra contains chemicals that have powerful stimulating effects on the nervous system and heart. Because ephedra suppresses appetite and burns fat, it was frequently used as a weight-loss supplement. The supplement was implicated in several deaths, and, for this reason, the FDA banned its use in products in 2004.
Green Tea
Green tea is a drink made from the steamed and dried leaves of the Camellia sinesis plant, a shrub that is native to Asia. The Chinese have been drinking green tea