Taurine and the Sulfur-Based Amino Acids

Sulfur-containing amino acids contribute substantially to the maintenance and integrity of cellular systems by influencing cellular redox state and cellular capacity to detoxify toxic compounds, free radicals and reactive oxygen species. Methionine and cysteine are the two primary sulfur-containing amino acids in mammals. Methionine is an essential amino acid, obtained by dietary intake while cysteine is non-essential and a metabolite of methionine metabolism.

Methionine, cysteine, homocysteine, and taurine are the four common sulfur-containing amino acids, but only the first two are incorporated into proteins. Sulfur belongs to the same group in the periodic table as oxygen but is much less electronegative. This difference accounts for some of the distinctive properties of the sulfur-containing amino acids. Methionine is the initiating amino acid in the synthesis of virtually all proteins in green plants. Cysteine, by virtue of its ability to form disulfide bonds, plays a crucial role in protein structure and in protein-folding pathways. Cysteine may be converted to such important products as glutathione and taurine.

Taurine is a powerful nutrient that is not widely publicized or understood among the general population. Nevertheless, its importance to our health and well-being should not be overlooked. Taurine is found in many foods and can be synthesized in the body from two sulfur-based amino acids: cysteine and methionine. While numerous Internet articles refer to taurine as an amino acid, biochemists don’t define it as such because it contains chemical bonds that make it behave a little differently.

What does Taurine do?

• Taurine detoxifies the liver.
• Taurine protects the kidneys from free radical damage.
• Taurine is used to regulate the heartbeat.
• Taurine increases the action of insulin.
• Taurine inhibits lipid and cholesterol synthesis that are linked to hardening of the arteries.
• Taurine is an important neurotransmitter that the nervous system uses to inhibit adrenal stress responses.
• Taurine reduces the risk of seizures caused by the build-up of too much glutamic acid in the brain.
• Taurine helps the body synthesize vitamin B12 and absorb potassium, magnesium, sodium, and calcium which are essential for building and maintaining healthy bone density.

Individuals who have low levels of taurine may be more susceptible to heart arrhythmias, skipped beats, and palpitations. Low amounts can also reduce the liver’s ability to eliminate toxic waste products through the bile and out through the colon.

Newborn infants cannot synthesize their own taurine and must obtain it from dietary sources. Human breast milk provides an excellent supply. As we age, the need for dietary taurine increases. Just like essential amino acids, taurine levels tend to be low among those who do not obtain enough of it from their diet.

What foods contain Taurine? Natural sources of taurine can be found in animal-based foods, especially seafood and meat. Here are several foods that have the highest taurine content:

• Whole mackerel (9.295 grams of taurine per kilogram of dry weight)
• Chicken liver (6.763 grams per kilogram)
• Alaskan salmon fillets (4.401 grams per kilogram)
• Lamb (3.676 grams per kilogram)
• Raw shrimp (almost 50 milligrams per ounce (28 grams))
• Plain yogurt
• Cottage cheese
• Chocolate
• Wheat germ
• Granola
• Eggs
• Avocado

Because taurine is heat-sensitive, much of it is lost by cooking. For instance, to maximize your intake of taurine from meat, consider eating it either rare or medium-rare. While crop vegetables grown on land do not contain taurine, sea algae does, according to a 1997 study reported in the journal “Plant Physiology.” Since taurine is not considered an essential nutrient, there are no established dietary guidelines. It’s believed that most Americans who eat meat consume about 200 milligrams of taurine daily, with 3,000 milligrams considered to be the safe upper limit by many researchers. Consumers can now find taurine as an addition to baby formulas and energy drinks.