Personal trainers often advise their clients to take protein supplements as a way of fueling muscle growth. Yet, Julie Katz, clinical nutrition manager at St. Agnes Hospital in Baltimore, warns that popular protein shakes and bars are largely a waste of money. They could even damage a person’s health if used in excess, she said.
“The average American diet already provides more protein than needed for muscle development,” Katz explained, “so when you’re taking all this additional protein, it’s just being excreted. You’re literally flushing it down the toilet.”
Even professional athletes, who require more protein than the average American, don’t need the excess protein that’s found in supplements, Katz said.
Protein supplements come in a wide variety of flavors and are made up of ingredients such as milk proteins, casein whey, soy protein and amino acids. The amount of protein per serving varies from about 15 grams to more than 70.
“Seventy or 80 grams of protein is how much someone who weighs 150 pounds would need for an entire day,” Katz said. “There’s really no need to have that much in one serving.”
Katz acknowledged that those who are exercising need protein, but she said they can get it from a healthy diet that includes lean meats, nuts, seeds, milk and dairy. Vegetarians can turn to tofu and soy products, she said.
“You need some protein after you exercise to help you repair tissue damage,” she said, “but just the small amount in two ounces of meat – 7 to 14 grams of protein – would be plenty.”
Katz said there can be health risks associated with consuming too much protein. It can put stress on the kidneys and cause calcium imbalances in women, she said.
“The excess calories can lead to unwanted weight gain because the protein won’t be stored as protein if your body doesn’t need it,” she said, noting that supplements are often loaded with sugar and carbohydrates. “It will wind up storing it as energy fat instead.”
Katz is similarly dubious of creatine, an amino acid taken by some athletes to improve performance. She warned that if taken in excess, creatine supplements can have negative affects on the liver and kidneys. They can also cause stomach cramping and diarrhea, she said.
“Some believe it can improve muscular performance during activities of short duration,” she said, “but it only really works within the first burst – the first 10 seconds of power and strength as in weight lifting or sprinting.”
Diets rich in meat and fish can provide adequate amounts of creatine, she said.
“The supplement industry is a multi-billion-dollar industry,” Katz said, “and it’s not regulated. It’s not like all our other food products where all the ingredients are checked out and there are recalls if there are problems.”
Katz advised those thinking about using supplements to talk to their doctors first.