HERBAL SMART DRUGS

HERBAL "SMART DRUGS"

The so-called smart drugs may win the contest for ingenious marketing of marginally effective agents. Their popularity has been fueled in part by the general enthusiasm for cleansing and lack of intoxication in a drug-weary culture. The recent explosion of "energy" drinks shows little sign of abating. Although taking a drug to improve mental quickness instead of getting bombed certainly seems innocent, nowhere is superstition more rampant than in the marketing claims for drugs that improve memory and general mental acuity. There is truly a desperate need for such drugs in medicine to retard the memory loss caused by Alzheimer's disease and some other forms of dementia. However, despite years of effort, only a few marginally effective drugs have been developed (this is discussed in the "Nicotine chapter).

The herbal smart drugs are often a concoction of various amino acids

and similar compounds. The most common supplements in energy drinks and herbal "smart" supplements are the sulfur-containing amino acid tau­rine, carnitine, and precursors to neurotransmitters including tyrosine, phenylalanine, and choline. Should you take "smart" nutrients? First, if you are eating a normal American diet with the typical excess of protein, there is more than enough of most of these micronutrients in your diet to maintain optimal levels in your blood and brain. Second, these com­pounds act over hours to days. They don't produce the advertised immedi­ate "energy boost." Finally, even if enough amino acid is provided to boost the production of a neurotransmitter, it doesn't automatically mean the neuron is releasing more to have greater effect. A newly made neurotrans­mitter is simply stored, awaiting the arrival of a nerve impulse to release it. So simply making more adds to the store that is ready for release. Adding more is effective only if stores are truly depleted. This generally happens only after life-threatening stresses (not a had day at work).

Let's look at a couple of examples. Phenylalanine is reputed to have mar­velous pleasurable qualities as the precursor to dopamine. There is some truth to this claim. Tyrosine and phenylalanine are both amino acids that are required for the synthesis of proteins. Tyrosine is the basic building block for the neurotransmitters dopamine and norepinephrine, and it is logical to think that increasing tyrosine might improve mood. However, the average American eats enough protein to provide adequate levels of these amino acids. Taking a pharmacologic (big) dose of tyrosine may be able to boost catecholamine production for a short time, but the benefits are transient, and scientists are just starting to study the behavioral out­comes (if any) of supplementing tyrosine.

There may be more truth to the claims that taking large doses of other neurotransmitter precursors can influence the production of the neu­rotransmitter. Choline supplements can indeed enhance the production of the neurotransmitter acetylcholine, which is important for many aspects of brain function, including memory. The death of acetylcholine neurons may contribute to the disabling memory loss of Alzheimer's dis­ease, and supplementing acetylcholine production can produce slight and temporary improvement in the memory of Alzheimer's patients. The cho­line precursor citicoline actually may improve memory a bit in both healthy people and those who have experienced brain injury and Alzhei­mer's disease, but whether the effect is large enough to overcome the dis­ease process remains to be seen. Similarly, the tryptophan in high-protein foods like milk can enhance the production of serotonin in the brain. Because increases in serotonin are speculated to enhance sleep, there may be some truth to the old wives' tale that warm milk enhances sleep. Another claim that might have some credibility is that ingesting extra tryptophan could help to prevent the loss of serotonin that occurs when a person takes Ecstasy. There is a rapid loss of serotonin in this case, which perhaps can be lessened by providing an extra precursor. Unfortunately, this does not diminish the dangerous side effects of MDMA at all.

Taurine and carnitine are the most common additions to energy drinks. Taurine is a sulfur-containing amino acid and is very abundant in the body, including in the brain, and it seems important for maintaining many body functions including blood pressure and metabolism. It may function as an inhibitory neuromodulator, especially in situations like ischemia or stroke where it may counteract the release of excitatory neurotransmitters. Studies in animals seemed to indicate it was a panacea—it lowered blood pressure, improved glucose tolerance in diabetes, possesses valuable antioxidant properties, and best of all, burns fat. Unfortunately, human studies are fewer, but they offer sonic opposing concerns—it may raise blood pressure in women, does not burn fat, and lowers glucose unless rats also eat fruc­tose (or presumably people drink soft drinks). Clearly, more work is needed to understand the benefits and risks of taurine supplementation. Similarly, carnitine is also an important normal constituent of the body that is neces­sary for the production of energy by mitochondria, and a lack of carnitine caused by a genetic deficiency can have extremely adverse effects on brain function. There are some published studies of carnitine supplements in var­ious neural disorders including Alzheimer's disease and Parkinson's dis­ease with mixed results at best. Does this mean that giving dietary supplements to healthy young adults improves memory? Again, we have no evidence, and many compounds that show marginal effects in impaired populations have even less action in healthy adults. So will these "energy" drinks give you a better edge mentally in studying for exams? Perhaps, but the reason may be the 100 to 280 milligrams of caffeine that they contain! Many other "nutraceuticals" including SAMe (S-adenosylmethionine) and various vitamins often appear in supplements and benefit people who are deficient—not normal, well-nourished adults.

Nevertheless, hope springs eternal that we will find the natural product to optimize mental function or stave off the effects of aging. The findings that resveratrol, a molecule present in red wine, prolongs life and improves functioning in aging mice led to another wave of hope until we learned that the amounts required equal the resveratrol in 750 to 1,500 bottles of

wine a day!