What’s Taurine?

By Peter Galvin, MD

Amino acids are vital building blocks to life and were an essential part of the “primordial soup” that is thought to have started life on our planet. Some amino acids are used in animals to make proteins. Amino acids that the human body cannot synthesize and must come from dietary sources are known as essential amino acids. Taurine is a naturally occurring amino acid that contains a sulfur molecule (unusual in amino acids) and is found in many foods and is also made in many areas of our body. Therefore, taurine is not an essential amino acid and is not found on lists of nutrients with recommended dietary intakes. Also, taurine is not used for protein synthesis, but it is found in abundant levels in bile salts and human intestines. As an aside, taurine is an essential amino acid for cats, who cannot synthesize it, and is therefore found in pet foods.

For some odd reason, taurine is found in many food supplements and energy drinks yet there is no existing research that justifies this use. It is also found in energy supplements given to people who are undergoing chemotherapy for cancers that include leukemia. A recently published study in the journal Nature may change the way we use taurine. The study, done at the University of Rochester Medical Center, discovered that the use of taurine may inadvertently promote the growth of leukemia cells. The study suggests that leukemia cells cannot produce taurine on their own and instead hijack specialized transporters to snatch this amino acid directly from the bone marrow, where these cancers originate. Once absorbed, unlike normal cells, taurine supercharges the cancer cells’ ability to break down glucose for energy, fueling tumor growth and disease spread.

Dr. Jeevisha Bajaj, the study’s lead author, said “Our work suggests that developing and testing effective inhibitors of the taurine transporter could lead to new therapeutic options for these deadly cancers.” He noted that leukemia cells cannot make taurine themselves, so they have to find it elsewhere. In mice experiments, they found that they were able to slow or block leukemia growth by preventing taurine from entering the cancer cells. Conversely, they found that when they supplemented leukemia cells with extra taurine, tumor growth accelerated dramatically.

These findings may carry immediate implications for the estimated 60,000 Americans diagnosed with leukemia each year. Analysis of human tissue samples found that patients with higher levels of the taurine transporter protein had worse outcomes and greater resistance to treatment, especially those with aggressive leukemia subtypes. Taurine supplements are commonly recommended to help cancer patients deal with chemotherapy-related fatigue. Energy drinks containing taurine are popular among young adults, a demographic that has a relatively high incidence of leukemia. Dr. Hoda Pourhassan, a hematologist-oncologist in Newport Beach, California, who was not involved in the study, said the study results warrant caution. She said it would appear to be reasonable to limit the amount of taurine in leukemia patients. Of course, more study is needed.

As you probably know, the FDA does not regulate dietary supplements and energy drinks, but considering that there has never been any studies or research that has shown any useful effects of taurine supplements, what the heck is taurine doing in them, especially at levels 10 times higher than average daily dietary intake?

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