Many of us get plenty of protein each day. But that’s not a reason to stop paying attention to it, experts say.
Protein is essential for every function in your body, whether it’s building muscle, bone and collagen, digesting food or fighting infections, said Glenda Courtney-Martin, a nutrition scientist at the University of Toronto.
And how much you need fluctuates throughout your life, depending on how old you are, your body size and other circumstances. Sometimes, you may fall short without realising it, said Stuart Phillips, a muscle physiologist and nutrition researcher at McMaster University in Ontario, Canada.
US federal guidelines published in 2005 recommend a daily intake for protein based on your age and weight, though more recent research has suggested that these amounts should be a little higher for optimal health, Dr Phillips said.
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PROTEIN THROUGH THE AGES
We have to eat protein every day, in part because old proteins get damaged or worn out, and new ones must replace them, Dr Phillips said – similar to swapping out old bricks in a crumbling wall.
CHILDHOOD AND ADOLESCENCE
Babies, older children and teenagers are constantly growing, so they need more protein than adults do in proportion to their body weight, Dr Courtney-Martin said.
According to the federal guidelines, for example, infants between 7 and 12 months of age need 0.54 grams of protein per pound of body weight each day, whereas adults require 0.36 grams per pound.
As children age, their protein needs slow along with their growth, Dr Phillips said. For instance, 4- to 8-year-olds need 0.43 grams of protein per pound per day, and 14- to 18-year-olds need 0.39 grams per pound.
Most kids get enough protein with a typical balanced diet, said Christopher Gardner, a nutrition scientist at Stanford University.
An 11kg toddler, for example, needs about 12 grams of protein per day – or the amount in a cup of milk and a slice of whole wheat bread. A 23kg 8-year-old needs about 22 grams of protein, found in one cup of Greek yogurt, and a 54kg teenager needs 46 grams, or the amount in one thick pork chop.
Between 25 and 50 per cent of 14- to 18-year-old girls, however, don’t meet federal recommendations for protein, according to survey data published in 2023. Studies have found that adolescent girls eat less meat than boys do and are more likely to follow restrictive diets, which could explain the protein shortfall in this group.
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YOUNG AND MIDDLE ADULTHOOD
By around age 17 or 18, your body usually stops growing and your protein requirements settle to more of a maintenance level – just enough to replace your worn out “bricks,” Dr Phillips said.
The federal guideline for people ages 19 and older is 0.36 grams of protein per pound. For a 84kg adult, this translates to 67 grams of protein per day – an amount you can get from eating one small salmon filet, a cup of lentils and a half cup of almonds.
Among adults aged 19 to 50 in the United States, less than 10 per cent of men don’t get the recommended amount of protein each day, and between 10 and 25 per cent of women fall short.
Certain people, Dr Phillips said, such as those who do regular strength or endurance training, or those who are pregnant or breastfeeding, may require up to twice as much protein as recommended by federal guidelines.
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OLDER ADULTHOOD
Protein recommendations for older adults are currently the same as those for younger adults, but some evidence suggests that those 65 and older may benefit from consuming more – at least 0.45 to 0.54 grams per 0.45kg, said Denise K Houston, a professor of gerontology and geriatric medicine at Wake Forest University School of Medicine.
For a 84kg adult, this higher recommendation translates to 84 to 101 grams of protein per day; you can get about that much from one cup of cottage cheese, a six-inch tuna salad sandwich on whole wheat bread, and a six-ounce chicken breast. As with younger adults, regularly lifting weights, running or doing other vigorous activities will further increase the protein needs for older adults. You’ll also require more if you’re recovering from an infection, hospitalization, surgery or a period of bed rest, Dr Phillips said.
Once you reach your 50s and beyond, you start to lose muscle mass, Dr Phillips said, which can increase your risk of falling, bone fractures, hospitalisation and earlier death.
A lack of physical activity is the biggest cause of muscle loss, but studies have also shown that ageing muscles are less efficient at using protein to make new muscle fibers, Dr Phillips said. And among those aged 71 and older, about 50 per cent of women and 30 per cent of men aren’t meeting even the lower federal recommendations for protein.
Such a shortfall can occur because older adults usually consume less than they did when they were younger, and may have difficulty chewing or a decreased ability to cook, or afford, protein-rich foods, Dr Houston said.
Foods like yoghurt and eggs are good options, Dr Houston said, because they’re rich in protein and simple to prepare and eat.
And because people often skimp on protein at breakfast, it’s worth paying extra attention to this meal, especially for older adults, said Samaneh Farsijani, an epidemiologist at the University of Pittsburgh School of Public Health.
Instead of having a piece of toast and orange juice (which supplies five grams of protein), you can consider a cup of Greek yoghurt with berries (22 grams); a peanut butter sandwich on whole wheat bread with a glass of milk (23 grams); or a breakfast burrito with eggs, beans and cheese (39 grams).
One caution, Dr Houston said: Those with chronic kidney disease or otherwise impaired kidney function are often advised to watch how much protein they eat because consuming protein makes your kidneys work harder. Such people should work with their health providers to plan a balanced diet, she said.
By Alice Callahan © The New York Times Company
The article originally appeared in The New York Times.
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