I've heard that creatine helps build muscle. Is this true? Is it safe?
Widely used by athletes, creatine supplements do help build muscle. They are believed to be safe and, unlike other performance-enhancing substances, are allowed by the International Olympic Committee, the National Collegiate Athletic Association and other major sports groups.
Creatine is a natural substance found in meat and fish. "But you don't get any benefit from eating meat unless the meat is raw," said exercise physiologist William J. Evans of the University of Arkansas for Medical Sciences.
And eating raw meat is dangerous because it contains harmful bacteria. Besides, said Evans, to get enough creatine to build muscle, "You would have to eat 10 pounds of fresh, uncooked steak per day. So creatine supplements are the only way to go."
The supplements come in powder, tablet or drink form, all of which are equally effective.
Biochemically, creatine works by combining with phosphate in cells to produce phosphocreatine, which helps create adenosine tri-phosphate, the body's main source of energy, said Dr. George Blackburn, associate director of nutrition at Harvard Medical School.
Interestingly, creatine does not boost performance in aerobic, endurance events such as marathons, according to the American College of Sports Medicine. But it can enhance performance in short, anerobic events such as weight-lifting or sprinting, where muscles work hard for brief periods.
Anecdotal reports suggest creatine may cause stomach cramps and diarrhea, but research on athletes who have taken creatine for longer than a year showed no adverse effects. In large doses, creatine "can adversely affect the kidneys," though this is reversible, said Dr. Doug McKeag, director of the Indiana University Center for Sports Medicine.
Although some researchers have wondered whether creatine might help battle neuromuscular diseases like multiple sclerosis or ALS (amytrophic lateral sclerosis, also known as Lou Gehrig's disease), so far the answer is no.
My daughter is 4 and still uses a pacifier. Is this harming her teeth -- or her psyche?
Sucking a thumb or a pacifier usually does not result in long-term harm to a young child's teeth, or the "bite" that occurs when lower and upper teeth are pressed together, so long as she stops by the time the permanent teeth come in, usually around age 6.
"But sucking a pacifier may have already caused some effect on her bite, depending on the length of time she uses the pacifier and how intensely she sucks," said Dr. Man Wai Ng, dentist-in-chief at Children's Hospital in Boston. Intense sucking can cause narrowing of the palate and affect the growth of the jaws.
In general, pacifiers "are very useful to children," said Dr. Barbara Howard, assistant professor of pediatrics at the Johns Hopkins University. "It provides physiological stabilization. It's been shown to make digestion better, to calm a child down and to help get more oxygen into the system."
But pacifier use is also associated with more ear infections because it creates a vacuum in the ear, which can suck fluid out of the bloodstream into the middle ear. Because pacifiers often fall on the ground, they may also be full of bacteria and viruses. Kids who fall asleep with a pacifier are also more likely to wake up during the night. Even if they put the pacifier back in themselves, their sleep has still been disrupted, said Howard.
In some cases, parents who can't get a child to stop using a pacifier "aren't very good at setting limits in general," said Howard.
These parents "can't tolerate children being in any distress. But part of childhood is to get immunized against increasing stress while you are under the protection of your loving caregivers," she said.
One tactic is to have a ceremony to bury the pacifier in the garden, then focus the child's attention on getting a "grown-up" toy. Or just throw the pacifier away.