DEAR DR. BLONZ: I have a question on behalf of my 15-year-old high school freshman. He took a weightlifting class at school and is now working out at home, along with doing many hours of mountain biking every week. He really enjoys physical fitness, and is a healthy weight for his age.
Friends at school have been telling him about protein shakes and creatine supplements. My son is conscientious and is asking about the safety and long-term consequences of both of these items. Can you please write about how beneficial these things are, as well as their safety for a 15-year-old? -- L.S., via email
DEAR L.S.: Pass on my positive recognition of your son's fitness efforts, and just as important, his interest in finding out the details before he considers taking stuff. I hope that all his coaching, guidance and techniques are respectful of a body in his state of development. As for supplements, advertisements are often accompanied by pictures of ripped bodies with the implied promise that "this can be yours" if you use their product.
Few athletes at age 15 need to add protein to their menus to achieve realistic goals. Adults involved with intensive muscle-building or endurance events sometimes double their protein requirements -- that, however, is only for adults, and only in specific scenarios. But even those athletes might not have to eat more protein than they already were: The typical American diet already contains about twice what the body requires.
To put some numbers to this, adults of average activity level require about 11 grams of protein for every 30 pounds of body weight. A 150-pound adult would need about 55 grams of protein per day. (Note: If you're overweight, calculate using the ideal body weight for someone of your height.) Those over 60 should count on about 15 grams of protein per 30 pounds of body weight; the higher level for older individuals reflects their decreasing digestive efficiency. In contrast to these guidelines, most American adults consume about 100 grams of protein per day.
A 15-year-old of average activity will need about 12 grams for every 30 pounds -- not much different from an adult. A physically active 15-year-old boy will need more protein than one who is sedentary, perhaps as much as 14 to 21 grams for every 30 pounds. Again, these are all estimates, and they can vary according to the source; see articles on teen athlete protein requirements at b.link/smgmr7 and b.link/66ebne.
The theme should be "enough, but not too much." Excess protein has no magical powers to build muscle. The extra gets turned into fat and can put a load on the kidneys, causing dehydration and a possible loss of minerals in the urine.
As for creatine, it is made by the body and is not an essential nutrient. It is a popular supplement among adult athletes, and there is some research to support specific uses. But again, this is for adults. (For more, see b.link/2qjtsp.) Research studying the effects of creatine on adolescents is limited. The American Academy of Pediatrics and the American College of Sports Medicine say that athletes under 18 should not use creatine and other performance-enhancing supplements. Don't dismiss this.
Avoid tossing supplements with unknown consequences into a body that may not have reached its full adult status, especially one being stressed with hefty workouts. And avoid social pressures to find a short-term metabolic "cheat," as the last thing you want to do is raise the risk of a negative payback in the long term.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to questions@blonz.com. Due to the volume of mail, personal replies cannot be provided.