Glutathione is a nutrient-like compound that is one of the most versatile and important protective substances in the human body. It’s found in varying degrees in all tissues, body fluids and organs, where it plays a variety of roles, including:

• Elimination of toxic chemicals
• Antioxidant activity
• Regeneration of vitamins C and E
• Immune system stimulation
• Enhancement of liver function and overall detoxification

The body naturally produces glutathione from the amino acids glutamate, cysteine and glycine, or it can be obtained from food. The best dietary sources of glutathione are meat, poultry, fish, and raw and cooked fruits and vegetables. Broccoli and garlic provide phytonutrients that help activate enzymes that assist the body in making glutathione.

According to one of the foremost glutathione experts in the world, Dean P. Jones, PhD, of Emory University School of Medicine, the lungs, intestines, kidneys and some immune cells are able to absorb glutathione directly. At other sites, such as the liver, it is first broken down into its three amino acids, which are absorbed by the liver and then recombined to make glutathione. 

In fact, glutathione is so important for liver function that if the body goes 24 hours without food, it will “steal” the precursor amino acids from muscles to maintain liver glutathione. Supplemental glutathione was once thought to be ineffective since it does not appreciably raise plasma levels.  However, recent studies by John P. Richie, PhD, of the Penn State University College of Medicine and other researchers have demonstrated that glutathione supplements do enhance the glutathione content of critical tissues beyond plasma.

Why is glutathione important?

Glutathione’s primary role may be detoxification, because the highest amounts of the nutrient are found in the liver and kidneys—organs responsible for processing everything we ingest and for eliminating toxic compounds.

High amounts of glutathione are also found in the fluid lining the lungs, which protects against airborne pollutants, and in the mucus lining of the intestine, which prevents the absorption of reactive chemicals.  

In addition, glutathione is a key player in the body’s antioxidant defenses. When vitamins C and E are “spent” as antioxidants, they are regenerated by glutathione. Thus, the nutrient not only acts directly to prevent oxidative damage to cells, it also indirectly supports a powerful antioxidant team within the body.

There is also evidence that glutathione supports the immune system by stimulating the ability of immune cells to kill bacteria in the lungs and by reducing replication of the influenza virus in the airway passages.

“Glutathione promotes the health of the entire airway,” explains Dr. Jones. “It may be very useful for those most at risk of contracting influenza—children, the elderly and those with compromised immune systems.” Studies conducted by Jones at Emory University found that glutathione lessened the viral load in both the lungs and trachea.

Another virtue of the glutathione molecule is its speed. When a cancer-causing chemical threatens to damage a cell’s DNA and cause a mutation, glutathione can react with the invader faster than the invader can react with DNA. In this way, glutathione intercepts and neutralizes many toxic substances. These protective functions occur continually in all major organ systems, including the brain, heart, skeletal muscle, skin, immune system liver, kidneys, intestines and lungs.

In 2009, researchers from the University of Rochester School of Medicine concluded, “Glutathione deficiency manifests itself largely through an increased susceptibility to oxidative stress, and the resulting damage is thought to be a key step in the onset and progression of many disease states.”

A lack of glutathione has also been associated with obesity, type 2 diabetes, cigarette smoking, alcohol abuse and taking multiple prescription and nonprescription medications. Low glutathione levels in the body can impair chemotherapy treatment and contribute to AIDS and cardiovascular, kidney, Parkinson’s and lung diseases. In addition, in a 2008 study published in the journal Nutrition and Cancer, Dr. Richie and his colleagues at Penn State found a link between low glutathione levels and an increased risk of mouth cancer.

How much is needed?

Because levels of glutathione vary throughout the body and throughout the day, determining a single optimal level can be challenging. The amount the kidneys need, for example, is different than the amount the brain needs, and the amount measured in the blood does not reflect that in the tissues. However, research has shown relative changes of glutathione under certain conditions, suggesting that multiple factors affect glutathione status.  

One inescapable factor is age. Young, healthy people with diets rich in fresh foods generally have good glutathione status, but this begins to decline around age 45 and continues to plunge as we age. 

A dosage of 100 mg a day appears to be a reasonable target for most healthy people, but those older than 45 might want to consider more. Research shows glutathione is safe at levels higher than 1,000 mg daily.

For more information on Glutathione interactions, click here.