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Two ounces of prevention

Three recent e-Alerts about mammography prompted a batch of member comments that could be called a “heated debate” – some arguing that mammograms are necessary, while others offered experiences that would make anyone think twice about signing on for the procedure when less problematic screening tools are available.

Today, however, I’ll calm the waters with a subject we can all agree on: An effective way to prevent breast cancer would be a welcome addition to any screening process a woman might choose. Fortunately, new evidence shows that an important amino acid may provide significant breast cancer prevention.

Something in the blood

At last month’s American Association for Cancer Research meeting, researchers from Brigham and Women’s Hospital and Harvard School of Public Health released the results of a new study using data from the Nurses’ Health Study.

Researchers wanted to find out if there was any correlation between breast cancer risk and blood serum levels of cysteine – an amino acid and precursor of glutathione, the intracellular antioxidant that I’ve told you about many times; most recently, just this past Monday in “Seeing Triple.”

Taking the lead from previous studies that have shown glutathione to be capable of detoxifying carcinogens, the Brigham researchers examined blood sample data from more than 700 breast-cancer patients. All patient records were matched with records of subjects who were healthy and of similar age.

The most dramatic results were recorded among pre-menopausal women. In this group, women who had the highest levels of cysteine were more than 75 percent less likely to develop breast cancer than those with the lowest cysteine levels. And the risk was reduced even more among women who had normal body weight.

Post-menopausal women with the highest cysteine levels also fared well, reducing their breast cancer risk by almost half compared to women with the lowest levels.

In the conclusions to the Brigham study, lead author Shumin Zhang named a specific supplement, known to boost cysteine levels. Zhang wrote: “N-acetylcysteine, a synthetic precursor of cysteine, might have the potential to be chemopreventive against breast cancer.”

The glutathione factor

In “Seeing Triple,” I told you how N-acetylcysteine (NAC) enhances the production of glutathione, one of the body’s most powerful antioxidant enzymes.

Glutathione is found in every cell of the body (most notably in immune system cells), which is one of the reasons why its antioxidant action is so effective in protecting against disease and repairing damage throughout the body. In addition, glutathione is believed to protect other antioxidants (among them, vitamins C and E), prolonging and enhancing their effectiveness. It also acts directly against certain carcinogenic substances by binding to these toxins and eliminating them through urine or bile.

But all of this effectiveness comes at a price. Because when the immune system is taxed (by everything from pollution, to poor diet, infection, radiation, emotional stress, and all types of trauma), stores of glutathione become depleted. Drugs can also take their toll. In fact, acetaminophen has been shown to deplete glutathione stores in the liver. And as if all of that weren’t enough, our glutathione levels tend to steadily drop as we grow older.

Miss Muffet was right

Fortunately there are good food sources that deliver glutathione precursors, including meats and fresh fruits and vegetables. But even with a diet high in the proteins that supply glutathione amino acids, one of those amino acids – cysteine – is more difficult than the others to come by. And that’s why N-acetylcysteine (note the “cysteine”) is so important as an effective glutathione booster.

There’s also a natural food component with high concentrations of glutathione precursors (including cysteine) called milk-serum-protein concentrate – more simply known as whey. For those who avoid dairy in their diets, whey will not be an answer. For others, however, the proteins found in milk whey (serum albumin, alpha lactalbumin, and lactoferrin) all contribute to the effectiveness of the glutathione precursors.

In a Members Alert we sent you several years ago (“How Whey Can Keep Your Immune System From Failing” 10/1/97), we told you about a Canadian product called Immunocal which is more concentrated in cysteine than other whey products. And Immunocal (easily found through various Internet sources) contains no milk sugars, so is far less likely to trigger a lactose-intolerance reaction.

Unfortunately, Immunocal is a little on the expensive side, so daily use as a preventive measure may not be practical for everyone. But even if you don’t take it daily, it can still be effective as a standby for those times when your immune system needs replenishment.

More to come

The Brigham breast cancer study calls for the next logical step in research: a double-blind placebo trial in which a large group of women, both menopausal and pre-menopausal, are tested with supplements known to boost cysteine levels. In an interview with BioMedNet News, Mr. Zhang mentioned only two cysteine precursors, NAC and Immunocal.

Hopefully researchers will take the hint and focus on these two agents that could impact the prevention of breast cancer for years to come. I’ll watch for further research, and will report to you as soon as the studies are published.

To Your Good Health,

Jenny Thompson
Health Sciences Institute

“A Prospective Study of Plasma Cysteine and Risk of Breast Cancer” Proceedings of the AACR, Volume 44, 2nd ed., July 2003, Abstract Number: LB-3,
“Cysteine Supplements to Battle Breast Cancer?” Dan Ferber, BioMedNet, 8/5/03,
“AACR: High Cysteine Levels Linked to Lower Rates of Breast Cancer” Brian Reid, Doctor’s Guide, 7/15/03,
“Glutathione: New Supplement on the Block” Alison Palkhivala, WebMD, 7/30/01,