Most people know that antioxidants are important for health. These compounds, including beta-carotene, selenium and vitamins C and E, reduce the harmful effects of free radicals, molecules that damage cells and the DNA within cells) and increase the risk for serious diseases, including heart disease and cancer.

What's new: Scientists are investigating a molecule that might be the most powerful antioxidant of all. It's called glutathione. Like other antioxidants, it helps neutralize free radicals—but it also has benefits that other antioxidants don't.

The Master Antioxidant

Glutathione has been called the master antioxidant because it performs so many functions that are critical for good health...

  • Neutralizes free radicals. Oxidation—the same process that causes iron to rust-occurs whenever atoms in our body's cells lose an electron. To regain their chemical balance, these atoms, known as free radicals, rip electrons from other atoms-including the atoms that make up DNA and the tissues of important structures, such as the lungs and the walls of blood vessels.

Glutathione is a "donor" molecule. It donates its electrons to free radicals, which prevents free radicals from damaging healthy tissues.

  • Revitalizes other antioxidants. Glutathione also donates electrons to vitamin C and other antioxidants. It recharges these protective compounds and allows them to work harder and longer.
  • Removes toxins. An important component of the glutathione molecule is sulfur, which acts "sticky." It binds to toxins, such as mercury and phthalates (found in many plastics), and neutralizes them before they enter the bloodstream.

Of the roughly 15 grams (g) of glutathione that normally are present in the body, about four grams are found in the liver. One of the liver's main jobs is to metabolize (break down) and eliminate toxins. High levels of glutathione are essential for the liver to do this job.

Patients who overdose on acetaminophen are routinely treated with N-acetylcysteine (NAC), which increases the body's production of glutathione. In Japan, glutathione routinely is used to treat patients with excessive levels of heavy metals, pesticides and other toxins.

Important Findings

Preliminary studies suggest that glutathione potentially could be used to prevent some of the most serious chronic diseases, including cancer, cardiovascular disease and possibly even Alzheimer's disease.

One study, published in Annals of Oncology, looked at women with ovarian cancer. Those who were treated with glutathione had fewer side effects from chemotherapy and better survival rates than those who didn't get glutathione.

Other research has shown that glutathione increases the activity of the immune system, important for preventing—and possibly treating—colds and flu. It's also thought to be involved with depression and other psychiatric illnesses. Patients who have these conditions typically are low in glutathione.

Falling Short

We don't know exactly how much glutathione is necessary, but we do know that most Americans don't produce enough of it. This is partly because of dietary factors. Many of us are not eating enough of the nutritious foods, such as fruits, vegetables and fresh meat, that contain the amino acids (cysteine, glycine and glutamic acid) needed to produce glutathione.

Also, we are routinely exposed to 80,000 chemical compounds, many of which greatly increase the levels of free radicals in the body. The amount of glutathione that might have protected us in the past can't keep up with the modern chemical burden.

Important: Smokers and those who are exposed to high levels of air pollution (such as road workers) should do everything possible to increase glutathione. It can help offset some of the damage from these pollutants.

What To Eat

To increase glutathione, aim for five servings of fruits and vegetables and two servings of animal protein a day. Include the following…

  • Sulfur-containing foods, such as garlic and onions. The sulfur provides one of the building blocks of glutathione.

Also helpful: Cruciferous vegetables, such as broccoli, cauliflower and cabbage.

  • Amino acids. All animal proteins, including fish, turkey, beef, chicken and eggs, contain the amino acids that are needed to produce glutathione. A three-and-a-half-ounce serving of steak, for example, provides the amino acids that convert to 13.4 milligrams (mg) of glutathione. A four-ounce hamburger provides 17.5 mg
  • Fruits and vegetables. All plant foods, including nuts, help increase glutathione. But certain fruits and vegetables, besides the cruciferous vegetables mentioned earlier, are particularly rich in glutathione.

Examples: Avocados and asparagus have about 28 mg per three-and-a-half-ounce serving. Tomatoes have about 9 mg for the same size serving.

Important: Opt for fresh foods as opposed to processed foods. The preservatives and high-heat processing that are used to package foods deplete glutathione. Frozen foods are fine—freezing actually preserves glutathione.


Someone who eats a nutritious diet might produce about 250 mg of glutathione daily. Supplements still may be needed to achieve optimal levels, especially when you're at risk for colds or flu, if you have frequent infections or are stressed. You can take one or all of the following supplements…

  • Glutathione. I recommend products made by the company Setria, which has done the most research. Brands I like include GNC and Vitamin Shoppe.

Typical dose: 500 mg once a day. If you are sick, take 500 mg twice a day.

Some experts believe that liquid glutathione is absorbed more readily than capsules, but this hasn't been proven. A typical dose of liquid glutathione is one teaspoon (about 422 mg) daily. The liquid is expensive relative to capsules-per gram of glutathione absorbed, capsules are a better deal.

  • N-acetylcysteine (NAC). It contains sulfur and cysteine, both of which increase glutathione in the body. This supplement is particularly important if you take acetaminophen regularly for arthritis or another condition.

Dose: 500 mg to 1,000 mg daily.

  • Alpha-lipoic acid is another high-sulfur supplement that increases glutathione.

Dose: 100 mg to 200 mg daily.

Helpful: Take a supplement first thing in the morning. That's when the body's levels of glutathione are lowest.

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