Protein Needs Help from Carbs, Magnesium and Iron to Build Muscle

Protein builds muscles–but not on its own.

That’s the conclusion of a new report from Harvard’s T.H. Chan School of Public health listing six other nutrients that make muscles muscular.

“Protein plays in tandem with other macronutrients, micronutrients, antioxidants, hydration status, activity level, and more,” says Meghan Salamon, a preventive medicine and obesity medicine dietitian at Harvard-affiliated Massachusetts General Hospital.

Losing muscle as the body ages, a process known as sarcopenia, is a natural fact of life. As a result, since muscles protect bones, health stats show that as many as 50 percent of women and 40 percent of men older than 50 will break a bone due to osteoporosis. But as the Harvard study leader and Department of Nutrition chair Frank Hu notes, there are six key nutrients in America’s everyday diet that can work along with protein to protect bone and prevent the breaks.

Surprise: Carbs are Number One on the list. As the body’s primary source of energy they replenish glycogen, the stored fuel that muscles burn during activity. Lacking healthful carbs from fresh fruit and veggies, the body turns to muscle tissue for energy instead.

Next up, magnesium a mineral prominent in leafy greens, beans, nuts, seeds, and whole grains. Day after day, this nutrient powers an astounding 300-plus biochemical reactions including muscle contractions and relaxation, while complimenting reducing inflammation and leading to faster recovery from injury. Best yet: three years ago, a study at TAIUWAN National Defense Medical Center, CHINA found that sufficient magnesium intake may protect against sarcopenia.

Third: No surprise here. Iron, which supports the production of energy by helping to deliver oxygen to muscles. Americans who consume animal foods such as red meat, poultry, and fish, plus bens and fortified breakfast cereals are likley to get the iron they need, but, the incidence of anemia tends to rise later in life, often due to medications, difficulties absorbing iron, or internal bleeding from health conditions like ulcers.

On to Omega-3 fatty acids, the “good fats” found primarily in fish. These well-known anti-inflammatories that protect the heart and benefit muscles as well, reducing chronic low-grade inflammation that can drive muscle loss. In 2021, nutrition researchers at Saudi Arabia’s College of Food and Agriculture Sciences, King Saud University found that middle-age and older adults who ate a measly-sounding two weekly servings of fish for two months increased their muscle mass, handgrip strength, and how fast they were able to move.

Of course, vitamins also count. Muscle cells contain vitamin D receptors, and the Harvard piece noes that and low levels of the vitamin have been consistently linked to weaker muscles, slower walking speed, and a higher risk of falls. Vitamin D is also involved in the body’s absorption of calcium - a mineral vital to muscle contraction. In that regard, Dr. Salamon says,

“Vitamin D levels are known to decrease with age, so it’s crucial to ensure proper intake of vitamin D, whether from food, sunlight, or supplements.”

Finally, who would have guessed that robust solid-seeming muscle tissue is actually 76% water. Alas, dehydration is common in older adults because thirst sensation naturally weakens with age. A Spanish study of 190 older adults published on the National Institutes of Health website found that dehydration was significantly linked with greater levels of breakdown of muscle protein. How much water changes the picture? The old rule of eight cups a day comes and goes in popularity but the simpler idea currently in favor is about six cups a day.