Most people don’t think about muscle power until the day they reach for a railing going down the stairs or take an extra second to push themselves out of a chair. By then, the slow erosion has already been happening for years. A new clinical trial suggests that eating roughly three tablespoons of peanut butter a day could modestly improve lower-body muscle power over six months among older adults, at least in one widely used mobility test. Individuals who did so showed gains in a physical ability linked in prior research to mobility and fall risk.
Muscle power is not the same as muscle strength. Strength is about how much force your muscles can produce. Power is about how fast they produce it. That split-second burst when you catch yourself before a fall, or stand up quickly from a low couch, runs on power. Research increasingly shows that power fades faster with age than strength does, and that it may matter more for long-term survival and independence than the numbers on a leg press machine. Falls are a major cause of injury in older adults, and weakening muscle power is one important reason why.
The study, published in the Journal of Cachexia, Sarcopenia and Muscle, was the first randomized controlled trial to test whether a daily serving of nuts could improve physical function in older adults already at risk of falling.
It’s worth noting that the research was funded by The Peanut Institute, and the peanut butter used in the experiment was provided by the J.M. Smucker Company. That said, the scientists who completed the study reported no conflicts of interest and said the funders didn’t play a role in the study’s design, data collection or analysis, the decision to publish, or preparation of the paper.
What Researchers Tested, and What They Found
Researchers at Deakin University in Melbourne, Australia enrolled 120 community-dwelling adults aged 65 and older, all screened as being at elevated fall risk. The group averaged 76 years old and was 70 percent female. Half were given 43 grams of peanut butter daily, roughly three tablespoons, at no cost. The other half continued their usual diets and were asked to avoid nuts. Both groups were told to keep their normal exercise routines. After six months, 108 of the 120 participants had completed the study, a 90 percent completion rate that is unusually high for a dietary trial of this length.
Researchers measured walking speed as their primary outcome, and peanut butter did not move it. That was a disappointment on paper, though the researchers noted the group was already walking faster than the clinical threshold for low physical performance at the start, leaving little room to improve.
What did change was how fast participants could get out of a chair. Those eating peanut butter shaved an average of 1.23 seconds off the time it took to stand up and sit back down five times in a row, a standard test used to assess lower-body function and fall risk. That improvement crosses what researchers consider a clinically meaningful threshold, the kind of change researchers associate with better odds of maintaining independence over time.
The Muscle Power Finding That Stands Out
Beyond the chair-stand result, the peanut butter group gained roughly 22 watts of absolute muscle power and about 0.27 watts per kilogram of body weight in relative muscle power compared to the control group. Prior research in older populations suggests that a gain of 0.2 to 0.3 watts per kilogram is enough to shift a person from a lower muscle power category to a higher one, which in practice can mean the difference between struggling to walk without difficulty and managing it comfortably.
None of the other outcomes moved significantly. Grip strength, leg strength, body weight, fat mass, and lean muscle mass were all unchanged. Peanut butter added roughly 250 calories and 10 grams of protein to participants’ daily diets, yet the peanut butter group gained no weight. Previous research suggests that not all the fat in nuts is absorbed, and that the unsaturated fats nuts do contain tend to be burned off rather than stored.
Researchers offered one explanation for why power improved without corresponding strength gains. Power is a function of both force and speed. Participants may have simply moved faster through the chair-stand motion without generating more peak force, which would register as a power gain without touching the strength numbers.
What This Means for Aging Adults
The study has real limitations. The participants were generally well-nourished, with protein intakes already above the standard recommendation for their age group before the trial began. People who are undernourished or more physically limited might see stronger results. Because the Peanut Institute funded the research and the J.M. Smucker Company supplied the peanut butter, independent replication would strengthen confidence in the findings, though the researchers stated the funder had no role in the study design, data collection, analysis, or preparation of the manuscript.
Still, the core result holds up: in a rigorous, controlled trial, older adults who ate three tablespoons of peanut butter a day for six months showed measurable improvements in lower-body muscle power during the five-times sit-to-stand test, a test commonly used to assess lower-body function and mobility risk. Among those who completed the six months, participants in the peanut butter group stuck to the daily serving about 86 percent of the time, and most said they liked the taste. Peanut butter’s soft texture is also a genuine advantage for older adults who find whole nuts difficult to chew.
Source : https://studyfinds.com/three-tablespoons-daily-peanut-butter-improved-muscle-power/
