Do Amino Acids Really Stack Up?

By Catherine Guthrie

Amino acid supplements used to be the stuff of gym rats: ordinary Joes yearning for Incredible Hulk-like physiques, who gobbled down the protein precursors like candy. Today amino acids are not only sold alongside vitamins, they also appear on grocery store shelves in the form of “functional foods.” The amino acid taurine, for example, puts the pep in Red Bull, an energy drink popular among college students. And baby boomers nibble on HeartBars, nutritional bars boasting arginine, an amino acid purported to lower cholesterol and tame hypertension. Between supplements and food additives, the market for amino acids in the United States is climbing at a steady 5 percent a year with sales expected to near $600 million by 2004.

Some people swear by them. Dan Delaney, a 34-year-old computer programmer in Louisville, Kentucky, takes them for insomnia. “The quality of my sleep has improved exponentially with 5HTP,” says Delaney, who can barely remember a time when sleep was an effortless affair. Between long workdays and helping to care for two young sons, he spent many a night in bed ticking off to-do lists and stewing over various worries. When sleep finally came, it was thick and leaden, leaving him groggy in the morning. But once Delaney began taking 5HTP, which he read about in a diet book, he started having deep and restful slumber, and feeling refreshed by morning. “Working with your body’s own biochemistry just makes sense,” he says.

Indeed, considering the critical role amino acids play in the body, it’s tempting to think that tossing one or two into your daily supplement mix won’t hurt. But some practitioners think that may be overdoing it. Taking too many amino acids, they say, or even too much of a single one, can create a biological imbalance, hindering the body’s ability to build protein, fight disease, and absorb vitamins and minerals.

Even proponents agree there’s a right way and a wrong way to use amino acids. Most recommend a targeted strategy. “I don’t see any reason to take them for prolonged periods,” says Ray Sahelian, a general practitioner and nutritionist in Marina Del Rey, California, and author of Mind Boosters and Natural Sex Boosters. “But people with specific medical conditions can benefit from taking amino acids temporarily to ease symptoms.”

So, when can amino acid supplements help? And how do we take them without throwing a wrench into our biochemistry? First of all, it helps to know why they’re so important—and why there’s so much conflicting opinion about whether you even need them at all.

Amino acids are most often described as building blocks of protein. Better yet, picture an erector set with 20 distinct pieces, each with its own specific shape. Imagine how many hundreds of structures you could build just by combining those pieces in different ways. By stringing together the different aminos, the body constructs roughly 50,000 unique proteins, which are responsible for a jaw-dropping 75 percent of your body mass—everything from a strand of hair on your scalp to the nerve endings in your pinkie toe. Indeed, every single organ, tooth, and bone in your body depends on amino acids to stay healthy.

The human body is ingeniously designed to keep its stock of amino acids full. Of the 20 the body needs, the liver manufactures 11. These are called nonessential—not because they aren’t important but because the body churns them out on its own. The other nine, known as essential amino acids, are gleaned from plant and animal proteins in our diet—and some people take them as supplements.

So what are the odds that your diet is lacking one of the essential nine? Not high, say many medical experts. They point to America’s love of meat and dairy as evidence that we’re getting enough. Even vegetarians, if they eat eggs, and vegans, if they eat soy, take in loads of the stuff. “If you eat a basically healthy diet, it’s difficult to be deficient in amino acids,” says Cynthia Sass, a spokesperson for the American Dietetic Association.

Still, even in the land of plenty, amino acid deficiencies do occur. Those who tend to fall short are people who undereat—the critically ill, crash dieters, and extreme athletes who eat too little and overtrain—and those with digestive problems such as irritable bowel syndrome and ulcerative colitis, which can inhibit amino acid absorption. Signs of deficiency include fatigue, a weakened immune system, and injuries that refuse to heal. But Sass still thinks the best approach is to eat more protein rather than rely on supplements. “Even in rare cases when a health problem might lead to a deficiency,” she says, “it’s not so easy to tell which amino acid might be lacking.”

Some practitioners, though, think supplements are a good idea not only for people with signs of a deficit but for some healthier types as well. In some cases, they view single amino acids as viable alternatives to prescription drugs, especially for certain tenacious conditions. Sahelian encourages his patients to try a short course of amino acid supplements to increase sex drive (arginine), boost the immune system (glutamine), and induce sleep (5HTP). Others have used arginine to treat hypertension and taurine for congestive heart failure.

The importance of amino acids to brain function makes the nutrients of particular interest to practitioners who deal with mental disorders. While the majority of amino acids make protein, a few work in the brain as neurotransmitters. Jay Lombard, an assistant clinical professor of neurology at Cornell Medical School in New York, uses some for patients who spurn traditional drug therapy. “Single amino acid supplements, such as taurine and 5HTP, can be extremely helpful for people with mild to moderate problems like anxiety and insomnia,” he says.

But nagging questions remain. On top of the fact that scientific evidence of the benefits of amino acid supplementation is in short supply—and long-term analysis of side effects doesn’t exist—physicians worry that consumers lack the know-how to determine accurate dosage. “Swallowing an amino acid supplement is not the same as taking a multivitamin,” says James Dillard, assistant clinical professor at Columbia University’s College of Physicians and Surgeons and author of The Chronic Pain Solution. “It’s a medical intervention. Whether you’ve got insomnia or heart disease, you need the advice of a professional, not the guy in the health food store.”

The concern is not unfounded. Overloading the body with one amino acid can crowd out one or more of the remaining 19. A special molecule carries amino acids from the gut to the liver, explains Phil Harvey, a nutritional biochemist and chief science officer of the National Nutritional Foods Association, based in Newport Beach, California. “That molecule is like a bus with only so many seats. Put in too many of any one ‘passenger,’ and there is less room for the others,” he says. Without ready pools of all 20 amino acids, the body isn’t able to create proteins needed to keep things running smoothly. Indeed, a deficiency of one amino acid may force the body to tear down muscle protein to glean enough aminos for basic metabolic functions—a condition called negative nitrogen balance. Signs of a long-term imbalance include weight loss and muscle wasting. More severe symptoms of a protein deficit include depression, digestive ills, and growth problems.

Here’s the scoop on six popular amino acid supplements that have shown promise either in scientific studies or clinical practice. Even with these, you should always consult a physician or a naturopath before trying one. And bear in mind several precautions. Many experts recommend alternating two months on, two months off, to avoid developing an imbalance. Food inhibits absorption, so wait at least an hour between taking an amino acid and eating. And always follow recommended dosages unless otherwise instructed, since several amino acids, including aspartic acid, glutamic acid, and homocysteine, are toxic when taken in large quantities.

Arginine
Protecting Hearts and Perking Up Libido
This amino acid is most often associated with heart health. It raises blood levels of nitric oxide, a compound that expands blood vessels, keeps arteries pliable, and enhances blood flow. Three small trials have found that taking supplemental arginine improved symptoms of congestive heart failure; other preliminary studies suggest it may reduce cholesterol, and also lower blood pressure in those with mild hypertension.

Hoping to cash in on Americans’ ailing hearts, one company has marketed an arginine-laced nutritional bar. But the HeartBar, packed with 3 grams of arginine, has failed to live up to its name. In a study published last March in the American Heart Journal, researchers divided 47 high-cholesterol patients into two groups. One gobbled two HeartBars a day for two weeks; the other ate placebo bars. At the end of the study, neither group saw any change in their cholesterol numbers.

Some researchers are experimenting with arginine as an alternative to Viagra for treating impotence in men and sexual dysfunction in women. In one study of 50 men with erection problems, half swallowed 5 grams of arginine daily while their counterparts took a dummy pill. Six weeks later, a greater number of men in the amino acid group than in the placebo group reported enhanced “sexual performance.” In a similar study of postmenopausal women with lackluster libidos, those taking 6 grams of arginine noted a greater improvement in sexual response than their counterparts on placebos.

Dosage: For heart disease, take 2 to 3 grams per day. For sexual performance, take 5 to 10 grams an hour before activity no more than once a week.
Cautions: Heart disease is a serious condition that shouldn’t be treated solely with an amino acid. If you have cardiac disease, consult with your doctor before adding any supplement to your diet. People with kidney disease or cancer should steer clear of arginine; raising nitric oxide levels can be dangerous for these conditions. Also, arginine may trigger outbreaks in people with herpes.

5HTP
Easing Insomnia and Depression
Until 1989, the amino acid tryptophan was considered helpful in treating insomnia and mild depression, but the popular supplement was banned in the United States after it was linked to a life-threatening blood disorder. Experts eventually traced the problem to contamination during manufacturing, but the supplement has yet to come back into favor with the Food and Drug Administration.

Many consider 5HTP, which is derived partly from tryptophan, to be the next best thing. Made from the seeds of the griffonia plant, 5HTP is used as a weight loss aid and mood lifter as well as a sleep inducer. Research on the amino acid is still in its infancy—in two recent reviews of more than 200 clinical studies, researchers concluded that the lack of quality trials made it impossible to support or refute 5HTP-related claims—but it may be worth a try if you don’t want to use prescription antidepressants or sleep aids.

Dosage: Up to 50 milligrams daily for depression; for insomnia, take the same amount, but at night.
Cautions: Don’t mix 5HTP with prescription antidepressants. High doses of 5HTP (more than 50 milligrams per day) may cause nausea, stomach cramps, and decreased sex drive.

GABA
Taming Anxiety
The body generates GABA, or gamma-aminobutyric acid, from another amino acid called glutamic acid. It works by muffling neuronal activity in the brain and soothing frazzled nerve cells.

However, the notion that GABA’s brain-pacifying powers can be instigated by tossing back a supplement is contested. At the crux of the debate is whether or not GABA supplements elbow past the blood-brain barrier, the body’s shield that protects the brain from blood-borne diseases and toxins. Studies are lacking, but Sahelian sees enough improvement in his patients to suggest that people with anxiety issues should consider it.

Dosage: For anxiety, 1 to 2 grams daily.
Cautions: Side effects from too much GABA include increased anxiety, shortness of breath, and tingling in the hands and feet.

Glutamine
Protecting Muscles
This nonessential amino acid is credited with building, repairing, and maintaining the body’s thousands of muscles. However, new research shows that sports enthusiasts who use it may be wasting their money. Two trials found no difference between the muscle mass of athletes who gulped glutamine and those who abstained.

That’s not to say no one can benefit from the amino acid. In addition to fortifying muscles, glutamine is used by white blood cells that help the immune system ward off disease. A few small studies show that supplementing with glutamine may help prevent the post-race infections that plague professional athletes. Another promising application is for HIV patients; studies have shown that those taking glutamine supplements were better able to maintain a healthy weight.

Dosage: To prevent post-exercise infection, take 1.5 to 6 grams daily. If you have HIV, consult your physician before adding glutamine supplements to your routine.
Cautions: Don’t take glutamine if you are sensitive to MSG (monosodium glutamate) because the body metabolizes the amino acid into glutamate. Also, be aware that high doses of glutamine may interfere with anti-seizure drugs, such as those taken to control epilepsy.

Taurine
Boosting Energy
Taurine helps shore up cell membranes in body parts with multiple neuronal connections, such as the brain and heart. For years, scientists noticed a correlation between lagging levels of taurine and heart attack deaths. As a result, in Japan, where much of the research originates, cardiologists regularly give heart attack victims up to 6 grams of taurine a day to buttress wounded heart muscles. Taurine supplements also appear to mellow symptoms of congestive heart failure (CHF). However, experts are calling for more research before the amino acid can be sanctioned as a routine treatment.

A more common use for taurine is perking up sleep-deprived students and groggy office workers. In a review of three studies of Red Bull Energy Drink, which relies partially on taurine to deliver a jolt, researchers found Red Bull drinkers had quicker reaction times, longer attention spans, and better short-term memories than those who consumed ersatz brews.

Dosage: For an energy boost, 1.5 grams a day; for heart health, up to 6 grams a day.
Cautions: Too much taurine may cause diarrhea and peptic ulcers.

Carnitine
Promoting Weight Loss and Enhancing Memory
There seems to be some confusion about whether or not carnitine is technically an amino acid. But it looks and acts enough like one that it is often lumped in with the aminos for discussion’s sake. It’s gleaned primarily from meat and dairy foods and is best known as a fat catalyst, meaning it hauls molecules from the body’s fat stores to cells looking for energy to burn.
Carnitine has long piqued researchers’ interest as both a weight loss enhancer and stamina booster, particularly in patients suffering from long-term ailments. The National Center for Complementary and Alternative Medicine is currently studying whether or not carnitine can boost energy levels of patients undergoing treatment for cancer.

Carnitine also holds promise as a memory enhancer, especially when paired with acetic acid, a substance that resembles a brain chemical used for memory. Numerous studies show that the duo, called acetyl-L-carnitine or ALCAR, eases symptoms of early Alzheimer’s disease, especially in patients under 65.

Dosage: If you’re looking to boost memory, try 500 milligrams of either L-carnitine or acetyl-L-carnitine twice a day; people with early Alzheimer’s disease can take up to 1,500 mg a day.
Cautions: At the store, you may see the supplement sold as D-carnitine or DL-carnitine, but most experts recommend L-carnitine; it’s the closest match to what your body makes, so it’s safer and more easily absorbed. Acetyl-L-carnitine is also fine, but you’ll pay a lot more for it.