Check the label on most energy drinks, and youíll find an ingredient called taurine. Two things come to mind when I hear the word taurine: cats, and bile. So whatís it doing in an energy drink?
Taurine is the most abundant free amino acid in the body, with highest concentrations in brain, heart, retina, skeletal muscle and leukocytes. Itís called a ďfreeĒ amino acid because it does not act as a building block for proteins, but rather works independently performing a variety of important tasks, a testament to its ubiquitous presence.
First isolated in 1827 from ox bile, taurine remained behind the scenes until about 1978 when studies showed it to be an essential nutrient for cats. Cats donít synthesize enough taurine to make up for daily losses and, when deficient, they display many abnormal symptoms, such as dilated cardiomyopathy, retinal degeneration and abnormal platelet function.
Unlike cats, humans can make sufficient taurine from the sulfur-containing amino acids methionine and cysteine as long as we have sufficient vitamin B6. Despite this, taurine is still considered conditionally essential, because although we can synthesize our own, there are times when is it necessary to obtain an outside source, especially for infants and persons on total parenteral nutrition.
||Sobe's fruit punch-flavored Power energy beverage contains a blend of creatine (25 mg), taurine (50 mg) and proline (25 mg). |
The reason taurine can be a desired ingredient in energy drinks is that stressful situations cause the body to lose taurine, and quickly putting it back is beneficial.
Dietary taurine is found mostly in animal proteins, which also contain the methionine and cysteine necessary for its synthesis. Itís not available from vegetable sources other than seaweed. If we choose not to eat animal foods, a mixture of vegetable proteins with sulfur-containing amino acids ó such as nuts and legumes (including soybeans) and a healthy variety of sulfur-rich vegetables, such as onions, garlic, cabbage, Brussels sprouts and turnips ó will do.
Thus, vegetarians may be at risk for a deficiency unless careful to balance their protein intake. There are side benefits to making our own taurine as some of the intermediate compounds created during its synthesis act as antioxidants.
Perhaps the most important roles played by taurine stem from its ability to regulate cell volume, or the passage of water into an out of the cell, a process called osmoregulation. It does this by moving across the cell membrane with the aid of special transporters, and by influencing the movement of sodium, potassium, chloride, and calcium, through specific membrane channels.
This regulation allows cells to adapt to the metabolic stress that alters the cellís water volume, either from disease or the normal wear and tear of nerve impulses and muscle contraction. In this manner, taurine helps to protect the heart from dangerous arrhythmias, ischemia and congestive heart disease. Because of this, taurine holds promise as a therapeutic agent.
In the brain, this action affects the activity of neurotransmitters, and so learning and memory are impacted. In the eye, the same process helps to thwart retinal degeneration and age-related cataracts. Taurine even relieves hypertension, and the osmotic stress caused by the elevated blood glucose levels of diabetes.
The benefits of this versatile amino acid-like compound do not end there. Taurine is synthesized in the liver where it combines with a derivative of cholesterol called cholic acid to from taurocholate, an important bile acid, which along with glycocholate and other bile acids helps to emulsify dietary fats. Bile acids are mostly reabsorbed during digestion, except for about 5 to 10 percent that are excreted with fiber. However, this is an important 10 percent, because bile acid loss is the only way cholesterol is systematically removed from the body.
Since taurocholate is reabsorbed less efficiently than glycocolate, more taurine, favoring a higher proportion of taurocholate may help to lower cholesterol.
Taurine also participates in the immune defense system. Itís found in high concentrations in leukocytes, where it combines with hypochlorous acid to form a compound called N-chlorotaurine. This potent molecule not only serves as an antioxidant and anti-inflammatory, it functions as a powerful bactericide and fungicide, even at low concentrations.
Does taurine give us a burst of energy? Maybe not directly, but by aiding enzymes that control the accumulation and release of calcium in muscle cells, taurine helps stabilize muscle cell contraction and relaxation, reducing muscle fiber excitability.
There could be great potential for its use in the treatment of muscular dystrophy and other diseases of the muscular system. But, taurine enters the brain with difficulty, and a high percentage of the taurine that rapidly enters the blood is quickly excreted by the kidneys. So, rather than a quick-burst energy nutrient, taurine may be thought of more as mentally and physically stabilizing and protective nutrient.
While it may be difficult to distinguish a quick surge of energy from taurine amidst the sugar, caffeine, herbs and other ingredients in most energy drinks, with so many potential benefits, and no reported adverse effects, taurine can be a welcome positive addition to better-for-you beverages and foods.