Dietary supplements hormones

Dietary Supplements. In the past 10 years, melatonin, available as a dietary supplement from health food stores or over the Internet, has become a popular sleep agent. Melatonin is a hormone produced by the pineal gland at peak levels during the night. It is believed to help regulate the 24 hour circadian sleep-wake cycle. 

Martini and Wood (2002) tested the bioavailability of 3 different sources of Ca in 12 healthy elderly subjects (9 women and 3 men of mean SEM age 70 3 and 76 6 years, respectively) in a 6-week crossover trial conducted in a Human Study Unit. Each Ca source supplied 1000 mg Ca/day and was ingested for 1 week with meals (as 500 mg Ca 2x/day), thus contributing to a high-Ca intake (1300 mg Ca/day). A low-Ca intake (300 mg Ca/day strictly from the basal diet) was adhered to for 1 week in-between each treatment. The Ca sources included skim milk, CCM-fortified OJ, and a dietary supplement of CaCOa. Assessment parameters were indirect measures predicted to reflect the relative bioavailability of Ca postprandially via an acute PTH suppression test (hourly for 4h). Longer-term responses to Ca supplementation were assessed via a number of urinary and serum hormone, mineral, and bone resorption biomarkers (i.e., vitamin D, Ca, phosphorus, and collagen t) e 1 N-telopeptide cross-links). 

The methyl transferases (MTs) catalyze the methyl conjugation of a number of small molecules, such as drugs, hormones, and neurotransmitters, but they are also responsible for the methylation of such macromolecules as proteins, RNA, and DNA. A representative reaction of this type is shown in Figure 4.1. Most of the MTs use S-adenosyl-L-methionine (SAM) as the methyl donor, and this compound is now being used as a dietary supplement for the treatment of various conditions. Methylations typically occur at oxygen, nitrogen, or sulfur atoms on a molecule. For example, catechol-O-methyltransferase (COMT) is responsible for the biotransformation of catecholamine neurotransmitters such as dopamine and norepinephrine. A-methylation is a well established pathway for the metabolism of neurotransmitters, such as conversion of norepinephrine to epinephrine and methylation of nicotinamide and histamine. Possibly the most clinically relevant example of MT activity involves 5-methylation by the enzyme thiopurine me thy Itransf erase (TPMT). Patients who are low or lacking in TPMT (i.e., are polymorphic) are at... 

Errors of omission. The major causes of cancer (other than smoking) do not involve exposures to exogenous chemicals that cause cancer in high-dose tests rather, the major causes are dietary imbalances, hormonal factors, infection and inflammation, and genetic factors. Insufficiency of many vitamins and minerals, which is preventable by supplementation, causes DNA damage by a mechanism similar to radiation. 

While legally speaking melatonin is a dietary supplement, biologically speaking it is a hormone. Other types of hormones include estrogen and testosterone. Hormones are known to have major effects on the human body. Only one other hormone can be sold over the counter in the United States. All other hormones require a doctor s prescription. Many other countries do not allow over-the-counter sales of melatonin because it is a hormone and has not been studied well enough to know if it is safe to take. 

Another issue is the dietary supplements commonly referred to as prohormones, which are touted as muscle builders and available legally at health food stores. In 1998 during the homerun race between baseball stars Mark McGuire and Sammy Sosa these supplements were propelled into the media spotlight. Mark McGuire announced he was quitting his use of the most popular prohormone, androstenedione (or andro ) to help boost his performance. DHEA is another popular one. Now under scrutiny by the DEA, FDA, and Federal Trade Commission, these prohormones are intermediates in the synthesis of testosterone, and can be converted to testosterone and other hormones in the body. 

Lemay, A., Dodin, S., and Kadri, N. 2002. Flaxseed dietary supplement versus hormone replacement therapy in hypercholesterolemic menopausal women. Obstet. Gynecol. 100, 495-504. 

Many herbal drugs, amino acids, and hormones are marketed as dietary supplements. They include areca, DHEA, ephedra, ginkgo biloba, kava, melatonin, SAMe, Salvia divinorum, St. John s wort, and valerian. 

When ingested, GHB stimulates dopamine release, leading to pleasurable effects such as euphoria, muscle relaxation, and heightened sexual desire. It also has CNS depressant effects resulting in sedation and hypnosis. Because GHB was reported to enhance grovrth hormone release, it has been used as a steroid alternative by body builders and athletes. Athletes also have used GHB as a sleep aid because they believe it promotes rapid recovery from vigorous repetitive competition. These properties and the availability of GHB in dietary supplements led to growing recreational abuse of the... 

Postmenopausal hormone therapy is a subject of major interest in the field of women s health. Treatment of menopausal symptoms can be managed effectively in some women with lifestyle modifications, including exercise, weight control, smoking cessation, and a healthful diet. More recently, however, dietary supplements and nonpharma-cologic therapies have been promoted as complementary medicine alternatives to hormone therapy. To date, there is little to support the use of such nonprescription products, which include various herbal remedies and soy-based supplements. 

However, while they were researching GHB, scientists noticed that it caused the body to release human growth hormone. This hormone helps the muscles develop. This discovery made GHB appealing to weight lifters and body builders. Many athletes began to use GHB, which was then available as a dietary supplement, to increase their muscle mass. 

Case Reports A few case reports showed only a transitory increase of TSH during soy-based food consumption. Jabbar et al. (1997), Conrad et al. (2004), and Bell and Ovalle (2001) report on higher thyroxine substitution required by hypothyroid children consuming soy-based formulas. The latter authors concluded that concurrent administration of thyroid hormone with a soy dietary supplement leads to decreased absorption of levothyroxine and the need for higher oral doses to attain therapeutic thyroid hormone levels. 

Hormones are not typically considered to be part of the diet, yet hormonal products represent an important segment of the dietary supplement market. Hormone supplements are promoted for maintaining or restoring physiological levels of hormones that decline with aging. Some preparations contain meat animal by-prodncts such as ovaries, uteri, and testes. Plant-derived ingredients include phytoestrogens and other compounds that mimic mammalian hormones. 

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