Protein: The Mortality Protector. Are You Getting Enough?
We’ve long known that we need sufficient protein to live.
But now, research reveals that we need more protein as we age—to live healthfully and longer.
Why Protein Matters
Proteins are considered the building blocks of life. These long chains of amino acids, found almost everywhere in the body, create new cells and repair others, and help build bone, muscles, cartilage, and skin.
Our bodies naturally create some but not all of the proteins we need; we have to get the rest through diet. In particular, we need to consume what are called essential amino acids, the ones our bodies cannot produce alone. They are commonly found in a variety of proteins, some of which contain more amino acids and some of which the body absorbs better than others.
Typically, consuming enough protein daily is not difficult, especially for meat eaters. But emerging research shows that the amount we consume when we are younger is not sufficient when we get older."As we age, our ability to synthesize protein from foods declines."As we age, our protein metabolism changes. Our ability to synthesize protein from foods declines. There’s a reduction in total body protein.
For those who are not consuming enough to compensate, there can be detrimental consequences.
Poor Protein Predicts…
"The importance of dietary protein cannot be underestimated in the diets of older adults," R. Chernoff writes in the Journal of American College of Nutrition. "Inadequate protein intake contributes to a decrease in reserve capacity, increased skin fragility, decreased immune function, poorer healing, and longer recuperation from illness…[and] an inability to fight infection."
"Older people… also need more protein to offset inflammatory and catabolic conditions associated with chronic and acute diseases that occur commonly with aging, " writes J. Bauer in the 2013 PROT-AGE Study Group position paper. "Protein deficits have adverse consequences, including impairment of muscular, skeletal, and immune function."
Ultimately, insufficient protein is so problematic because of a word only doctors seem to know: Sarcopenia.
What is Sarcopenia?
Sarcopenia is the loss of muscle mass. It’s believed to be caused mostly by loss of skeletal muscle fibers and atrophy.
It happens naturally over time. Our muscle mass increases through childhood,"Muscle mass increases through childhood, peaks in middle adulthood, and then begins to decline around age 45 — 55."peaks in middle adulthood, and then begins to decline around age 45 — 55. Then, from each decade on, there’s a 3−8% reduction. At the beginning, small decreases in muscle mass or function may not show, but in time, advanced sarcopenia may set in. By age 60, it affects about 30% of the population, and by age 80, more than half.
Health hazards surface. People with sarcopenia are more likely to fall, to suffer a fall-related fracture, and to lose their independence. They’re three to four times more likely to become disabled. They have a significantly increased risk of being unable to perform routine activities of daily living.
And they’re more likely to die. Among the research pointing to this conclusion is a 2012 study which followed 197 people age 80 — 85 living in the Sirente region of central Italy. After seven years, those with sarcopenia had a significantly higher risk of death from all causes: 67% of the sarcopenia group died, compared to 41% of those without sarcopenia.
There’s good news, though: Age-related loss of muscle mass can be counteracted. A body of good scientific evidence shows that both nutrition—especially protein consumption— and exercise can ward off and even reverse sarcopenia.
The Protein Prescription Problem
How much protein is optimal to preserve health in older adults?
Unfortunately, it is not the widespread RDA (recommended daily allowance) number:"The RDA guidelines for protein were originally derived from short-term studies in young men."0.8 grams of protein per kilogram or 0.36 grams per pound of body weight. These RDA guidelines were originally derived from short-term studies in young men, and were not adjusted for adults in different life circumstances. Here’s what that general RDA looks like for different weights:
Protein RDA (Based on Studies of Young Men)
100 lbs: 36 grams
120 lbs: 43 grams
140 lbs: 50 grams
160 lbs: 58 grams
180 lbs: 65 grams
200 lbs: 72 grams
Rethinking this RDA
In 2013, the PROT-Age Study Group, consisting of world experts in various specialties—"World experts in various medical specialties declared that the RDA for protein is not sufficient for older adults."geriatric medicine, internal medicine, endocrinology, nutrition, exercise physiology, gastroenterology, and renal medicine—declared that the RDA for protein is not sufficient for older adults.
They cited such evidence as:
- An association between protein consumption at RDA levels and muscle decreases in the mid-thigh area. In a small but tightly controlled study, 10 healthy men and women aged 55−77 received meals based on RDA-guideline protein allowances. After 14 weeks, their mid-thigh muscle area had significantly decreased. The PROT-Age Study Group remarked: "This suggests… the RDA for protein was not adequate to meet the metabolic and physiological needs of these individuals. "
- An association between older adults' greater protein intake and maintenance of healthy body mass. After three years, researchers divided nearly 2,100 men and women age 70−79 into five equal groups on a scale from least to most protein consumed (as measured by food frequency questionnaires). Participants in the highest quintile (group of five) of protein consumption lost approximately 40% less lean mass than those in the lowest quintile.
Newer studies also pinpoint a relationship between inadequate protein consumption and muscle loss:
- An association between less protein consumption and loss of knee muscle strength in older adults with inflammation. Researchers studied some 600 adults age 65+ living near Florence, Italy. After three years, those with inflammation who ate less protein (as measured by a food frequency questionnaire) had a significant decline in knee muscle strength.
- A correlation between increased protein intake and reduced frailty in women. Researchers followed nearly 25,000 women age 65−79 who were initially free of frailty (defined by muscle weakness/slowness, poor endurance/exhaustion, low physical activity, and unintentional weight loss). Over three years, 13.5% of the women developed frailty. A 20% increase in protein (as measured by urinary nitrogen levels) was associated with a 32% lower risk of frailty. The women in the upper fifth of protein consumption were on average consuming 50% more protein than the current RDA.
The researchers concluded: "Optimal protein intake may be above current recommended guidelines."
New Protein Guidelines for Older Adults
After a thorough literature review, the PROT-AGE Study Group recommended that healthy adults 65+ consume in the range of .45 grams/pound to .54 grams/pound each day. Adults who exercise were advised to eat at the higher range. This translates to:
PROT-AGE Recommendations, Healthy Adults 65+
100 lbs: 45 grams - 54 grams
120 lbs: 54 grams - 65 grams
140 lbs: 63 grams - 76 grams
160 lbs: 72 grams - 86 grams
180 lbs: 81 grams - 97 grams
200 lbs: 90 grams - 108 grams
If You Have Acute or Chronic Disease
For older adults who have acute or chronic diseases, however, the PROT-AGE Group recommended a higher range of protein consumption: .54 -.68 grams/pound:
PROT-AGE Recommendations, Adults 65+ with Disease
100 lbs: 54 grams — 68 grams
120 lbs: 65 grams — 82 grams
140 lbs: 76 grams — 95 grams
160 lbs: 86 grams — 109 grams
180 lbs: 97 grams — 122 grams
200 lbs: 108 grams — 136 grams
The one exception to these guidelines, the PROT-Age group noted, is an older person with severe kidney disease (estimated GFR <30 mL/min/1.73 m (2)), who may need to limit protein consumption.
Time Your Protein
Beyond having enough daily protein, the PROT- AGE Study Group found that timing one’s protein consumption is also important. They cited research showing that how older adults reached the optimum amount of daily protein also mattered—specifically, that eating at least 25−30 grams of protein at one meal (if not more) was necessary for optimal protein synthesis. Medical experts who convened at the Protein Summit 2.0 and published a 2015 paper summarizing their hypotheses came to the same recommended protein range for at least one meal a day.
Underlying the 25−30 gram recommendation is the fact that most studies of meal distribution have shown that older adults who get their daily protein in one or more large meals (30 grams/meal) have more muscle protein synthesis than when the same total daily protein is spread over multiple small meals.
Consuming additional protein at a meal may not add more benefits. "Older adults who get their daily protein in one or more large meals (30 grams/meal) have more muscle protein synthesis than when the same total daily protein is spread over multiple small meals."In one small study, researchers gave both young and older volunteers either 30 grams or 90 grams of protein consisting of 90% lean beef. Hours later, they calculated muscle synthesis. Both young and older volunteers who consumed the lean beef with 30g protein had an approximately 50% increase in muscle protein synthesis, and there was no further increase in protein synthesis for younger and older volunteers who had the 90-gram protein portion.
Look for Leucine
Why might 25−30 grams of protein at a meal be optimal for protein synthesis? One hypothesis, supported by initial research, relates to the critical role of the essential amino acid leucine. A few studies show that when eating protein without enough leucine, healthy older adults don’t synthesize skeletal muscle protein from their protein diets as well as younger adults. For example, one small study pointed to differences in leg muscle protein response among elderly and young people after both ingested protein containing 1.72 grams of leucine. Generally, the more protein is consumed, the more leucine is as well. E. Volpi writes: "The threshold dose of leucine for stimulation of muscle protein synthesis in older adults appears to be approximately 3g, corresponding to approximately 25−30g of a high quality protein."
Exercise—The Other Essential Element
The research is consistent: Older adults can best protect themselves from age-losses in muscle mass and many conditions that follow with properly timed additional protein consumption:
- .45 — .54 grams per pound of body weight daily (higher end for exercisers)
- .54 — .68 grams per pound for older adults with acute or chronic diseases
- 25 — 30 grams of protein containing about 3 grams leucine at least once a day
(And very early research indicates that some of this may also be true for middle-aged adults.)
However, protein alone is not the ultimate muscle mass/ mortality protector for older adults. For truly healthy aging, exercise is just as vital. As an expert panel convened by the Society for Sarcopenia, Cachexia, and Wasting Disease concluded: "Both resistance and aerobic exercise in combination with adequate protein and energy intake is the key component of the prevention and management of sarcopenia."
In short, protein and physical activity are synergistic, protecting muscle mass and advancing long-term health best in combination."Protein and physical activity protect muscle mass and advance long-term health best in combination."To learn how best to integrate both—for example, how much protein to consume before and after exercise for optimal protein synthesis in older adults—read "Part II: Exercise + Protein—Perfect Partners in Mortality Protection."