There's no great demand for most potential human enhancements. Only a few daredevils, for example, would risk surgery to upgrade their vision from normal to extraordinary. But when it comes to sports—higher, faster, stronger—no such restraint exists. Athletes, enticed by fat contracts, Olympic medals, and fan adulation, will accept almost any health risk to steal an advantage. And eventually, some of their cheats will cross over to a mass audience. Steroids and nutritional supplements—certified by home-run records and 350-pound offensive linemen—have already found their way to every major high-school sports program in the United States.
But current sports enhancements don't appeal broadly, for two reasons. First, they take too much work: Anyone who injects steroids can get very strong, but only if he lifts weights regularly. And second, they're dangerous. Steroids raise cancer risk, promote impotence, and cause mood changes. EPO (erythropoietin)—a red blood cell booster often used by endurance athletes (especially cyclists and cross country skiers)—can thicken the blood, increasing the possibility of blood clots, heart attacks, and strokes.
For 9-to-5 supermen and superwomen who want the free lunch—stronger without effort, faster without danger—here's what the future may offer.
1) Bodybuilding for Couch Potatoes
Muscle weakness is a great unacknowledged enemy of our aging society. As you get older, you lose muscle mass. (The medical term for this is sarcopenia.) Shrinking muscle mass leads to more falls, more broken bones, more disability, and a declining quality of life. Low muscle mass also makes it harder for old people to survive trauma since muscles are reservoirs of proteins and metabolites needed in an emergency. In recent years, doctors have been virtually dragging seniors to the weight room to get them buffed up.
But maybe your grandmother won't have to pump iron, and neither will you. There's a treatment that could boost muscle mass without (much) work: a gene for something called Insulin-like Growth Factor.
The IGF gene is a multitasker. It makes different proteins, depending on the circumstances. When a muscle is exercised by a long-distance runner, the gene manufactures something called IGF-1. But when a muscle is intensely stretched or contracted, as by a weight lifter, the gene produces Mechano Growth Factor. MGF, which was discovered by University of London professor of anatomy Geoffrey Goldspink, instigates muscle growth by activating the "satellite cells" in the muscle, causing them to divide and fuse, creating the nuclei for new muscle cells.
Both MGF and IGF-1 encourage muscles to grow. (IGF-1 seems to activate protein synthesis necessary for new muscle cells.) Scientists have created mighty mice using both compounds. When Goldspink injected a gene for MGF into mouse muscles, he recorded a 20 percent increase in muscle mass in two weeks and a 25 percent increase in muscle strength—without the mouse hitting the weight room and without apparent side effects. Similar tests have been done on mice using IGF-1. They, too, became supermice, though it took longer.
Goldspink hopes MGF could be a therapy for the sick and frail: Muscular dystrophy and age-related muscle loss are the obvious targets. But he has no doubt "there will be misuse of MGF" by athletes and bodybuilders. (In fact, the International Olympic Committee has already commissioned him to develop a test for MGF, IGF-I, and human-growth hormone abuse.) But it won't just be hard-core muscleheads who experiment with MGF; if it turns out that MGF is safe and effective in 65-year-olds with sarcopenia, 50-year-olds will start asking for it, then all the rest of us. If you could get 25 percent bigger pecs without a visit to the gym, wouldn't you consider it?
No clinical trials of MGF have started yet. The technique for inserting the gene into muscles is not complicated, but gene therapy is never easy. Although Goldspink's experiment resulted in Schwarzenegger mice, that doesn't mean that MGF will successfully pump up normal humans. Goldspink saw no side effects in his mice tests but wonders if prolonged application of the gene would cause damage. (Goldspink expects a single dose of the gene would last about a year.) And as for IGF-1, it may have health risks that MGF does not. For example, it could damage the heart if it is injected directly into the bloodstream.