The Second Most Important Single Supplement

Jun 12, 2004 12:16 AM EDT

In an earlier article, I stated that selenium was the most important single supplement to take because studies have shown that 200 micrograms per day could cut the risk of most cancers by 50%. The nutrient that ranks a close second is sulfur, and the reason is that both selenium and sulfur are integral to one particular enzyme—glutathione peroxidase.

This enzyme is found throughout your body especially in your liver, thyroid and immune system. Malfunction of this enzyme can result in anything from mild allergies, eczema, asthma and indigestion, to damaged arteries that can lead to heart attack or stroke or to damaged DNA that can result in cancer, plus the myriad of diseases that fall between these extremes.

The name glutathione peroxidase tells you a lot about this enzyme. ‘Peroxidase’ refers to its ability to chop deadly peroxides into harmless water, while ‘glutathione’ refers to its protein that consists of three amino acids: alanine, glycine and the critical sulfur-containing amino acid cysteine. Glutathione is obviously a very important protein, mainly due its sulfur content obtained from cysteine but also due to the fact that it contains selenium.

Glutathione is absorbed intact into your small intestine but is then digested into its three amino acid components that have to be reassembled inside your body, so supplementation with glutathione hasn’t been very successful. German research found a way to reduce the digestion of glutathione by binding it to an extract from prunes, but it is still questionable as to how well this reduced glutathione works.

Since cysteine is the source of beneficial sulfur, it has been used as a supplement but has shown toxicity levels that make it impractical. N-acetylcysteine (NAC) is a variant on cysteine that has improved absorption with minimal toxicity. However, animal studies show that NAC has a tendency to bind to heavy metals that may then be transported into the brain, making it potentially dangerous to use.


The sulfur substance that has proven to improve glutathione levels the most is whey. Whey is the protein that is left over after the casein protein in milk has been curdled to make cheese. Whey is high in cystine, which is two cysteine amino acids bound together. This binding of two cysteines together reduces its toxicity and doubles the amount of cysteine entering your body. Most health stores carry whey protein powders as bodybuilding supplements, though its greater importance is its ability to aid in detoxification by activating glutathione peroxidase enzyme. However, it’s critical that the whey is processed under low heat so as not to denature the delicate sulfur compounds; many companies now process it this way.

Much of the research on the medicinal benefits of whey was done at McGill University in Montreal where they produce a highly effective whey extract known as Immunocal® in the US and HMS 90® in Canada. HMS 90® has been well documented to improve all the chronic diseases mentioned in the first paragraph of this article by improving glutathione enzyme activity.

While glutathione peroxidase enzyme is your internal invisible superhero, gallantly chopping deadly peroxides into harmless water as fast as they form, like all superheroes it has a weakness. Superman lost his super powers when exposed to Kryptonite, Achilles was vulnerable in his heel and glutathione peroxidase’s powerful sulfur is where heavy metals, particularly mercury, prefer to bind, depleting and draining this valuable ally of its vitality and vigor.

If adding whey to your supplement schedule reduces your symptoms and improves your energy, suspect that you may have heavy metals bound to this superhero enzyme. Consider working with a naturopath or other healthcare practitioner to evaluate heavy metal toxicity and discuss a proper treatment program for removing toxic metals from your body.