The Importance of Selenium
Selenium is one of the most important mineral. It is considered heart protective mineral. Deficiency of selenium is very common. Most people are deficient of this mineral due to depleted soil quality in farming. One of the obvious sign is pigmentation on the face in adults, so called aging spots. Masking by cosmetic creams does not solve deficiency of this mineral. If more than six months, the pigmentation tend to be permanent or unlikely to go away. Nevertheless the supplementation should continue to protect heart.
It requires for at least 22 enzymes (selenoenzymes atau selenoproteins). There are two major families of selenoenzymes — glutathione peroxidases and deiodinases. The metabolic function of the glutathione peroxidases is to convert oxidized fat (lipid hydroperoxides), which is generated as the result of normal metabolism and contributes to heart disease and stroke, to less harmful compounds.
SOD is considered first-line defense against reactive oxygen species. The H2O2 produced in the reaction, which can potentially react to yield other reactive oxygen species, is degraded to water and oxygen by enzymes such as catalase, which catalyzes the reaction
And glutathione peroxidase, which uses glutathione (GSH) and the reducing agent:
The latter enzyme also catalyzes the breakdown of organic hyperoxide. Some types of glutathione peroxidase require selenium for activity; this is one reaction why selenium appears to have antioxidant activity.
Selenium is essential to the proper functioning of one of the heart’s most extensively studied protective mechanisms against oxidative stress – an enzyme called glutathione peroxidase. This enzyme is 100% dependent on having a selenium atom at its core for proper function. In fact, selenium is what gives the enzyme its potency in preventing and cleaning up after destructive oxygen free radicals.
Decreased selenium in the blood leads to decreased glutathione peroxidase (GSH-Px in the above chemistry pathway) activity, which in turn makes heart tissue more vulnerable to the damage that can impair its function. This situation is especially grave in older adults.
In a particularly impressive study, 81 heart attack survivors were treated with either 200 micrograms per day of selenium or a placebo for six months (all other cardiovascular drug treatment was continued). The real difference between the two groups showed up in the number of patients who either had heart attacks or died of heart disease. Four patients who did not receive the selenium supplements died of cardiac disease, while 100% of the patients in the selenium group survived.
A human disease known to be caused by selenium deficiency and found in various regions of China is Keshan disease, a cardiomyopathy (disease of the heart muscle) in children.
Extensive data from studies in China have been used to establish the required and safe levels of selenium for humans. These studies revealed significant correlations between daily selenium intake and the selenium content of blood, breast milk, and urine. Significant correlations were also observed between urinary, plasma, hair, fingernail, and toenail selenium levels.
The majority studies showed anticancer effects of selenium. Three human trials on selenium and cancer have been completed, and all of them showed positive results. In one trial, the addition of selenium to table salt significantly reduced the incidence of liver cancer in a Chinese population. After 5 years of supplementation with selenium, vitamin E, and beta-carotene, the incidence of stomach and esophageal cancer in another Chinese population was significantly reduced. A study in the U.S. showed that 970 men supplemented with 200 mcg of selenium daily (as selenium-enriched yeast) for 4.5 years had a 63% reduction in the incidence of prostate cancer, as well as a significantly reduced incidence of colorectal, lung, and total cancers. These supplementation studies are consistent with a recent study showing one-half to two-thirds reduction in the risk of prostate cancer among men with the highest selenium status, as assessed by toenail levels of selenium that indicate long-term selenium intake.
Infusion drip of selenium is used by doctors in Europe to treat cancers.
It is estimated that Americans consume about 100 mcg/day of dietary selenium. In the aforementioned prostate cancer study, subjects were given 200 mcg supplements daily, which boosted their estimated daily intake to about 300 mcg. To prevent selenium deficiency symptoms, a daily intake of 55 mcg is required. For maximal protection against certain cancers, a total daily intake of 200-300 mcg is probably necessary.
I recommend minimum of 120 mcg daily with empty stomach for better absorption.
It is one of the most cost effective supplementation that I consider as a must for everybody who want to prevent heart disease and cancers. Enough evidence to support the notion with sound bio-chemistry or scientific basis.