A lot of noise gets made about aging well. Supplements, cold plunges, mitochondria, fasting windows — the wellness industry generates new protocols faster than scientists can test them. But four recent research papers reinforce what actually moves the needle on optimal aging.

The most actionable finding: you need to get stronger. Especially if you're an older woman.

Stronger older women die at significantly lower rates, even when their aerobic fitness and exercise habits are identical, according to a new study from researchers at the University of Buffalo. Just being active isn't enough: It wasn't enough to walk regularly or meet the recommended 150 minutes of weekly exercise.

What mattered was muscle density: The women whose muscles were stronger lived longer.

The study tracked more than 5,000 women aged 63 to 99 over eight years, controlling for fitness, activity levels, inflammation and a long list of other variables. Muscle strength predicted survival on its own. And the strength involved wasn't elite — about 53 pounds of grip force, which is actually slightly below average for women of all ages. The study, published in JAMA Network Open, can't prove causation. But the lead researcher believes the findings extend to men and younger adults and the pattern is consistent enough to take seriously.

Second finding: Eating less, done right, actually works.

When you restrict calories, your cells kick on repair and cleanup processes that would otherwise sit idle. Studies in animals show calorie restriction, aka CR, delays cancer, heart disease and cognitive decline. In humans, two years of moderate caloric restriction measurably slowed biological aging. A major review published in Nature Aging synthesizes 30 years of evidence across species from yeast to primates and the case is genuinely strong.

There are a couple of major catches, though. One is that CR, in its most effective, life-prolonging form, is a hard way to live and it counteracts muscle building, because you're not getting enough nutrients to fuel aging muscle growth.

The second catch is that genetics matter a lot.

Caloric restriction helps some people significantly, does nothing for others and in rare cases may actually be harmful. The review also notes it increases vulnerability to infection and slows wound healing — tradeoffs you won't hear about from whoever's selling you a fasting app. Though the science is serious, this is not a universal prescription.

Third: Your gut bacteria may have more to do with how long you live than you realize.

People who reach 100 consistently maintain a gut microbiome with strong anti-inflammatory properties, suggesting the microbiome is a contributor to survival and not just a byproduct of good health. A review published in Nature Reviews Endocrinology documents how the gut ecosystem deteriorates with age — less diverse, more inflammatory, more linked to the frailty and disease that ultimately kill people.

Diet and exercise move the needle here.

Some probiotic supplements show early promise, but the science is still young and nobody has agreed on what a healthy aging gut even looks like. Every person's microbiome responds differently and the biology is real and worth watching. But my advice for the time being is that products claiming to fix it are mostly getting ahead of themselves.

Fourth: Though mitochondria is a popular longevity topic nowadays, you should remain slow and skeptical on this topic.

The mitochondria-aging axis is real — mitochondria, after all, are your cells' power generators and their gradual decline is a big part of aging.

Konstantin Khrapko, a Northeastern University professor who studies mitochondrial mutations, makes a useful point in a March 2 piece from Northeastern's news office: Mitochondrial dysfunction and aging happen together, Khrapko says, but that's a long way from proving that a supplement or an infrared sauna will help you live longer.

Exercise genuinely improves mitochondrial health. The rest is mostly marketing dressed up in biology. Khrapko's advice is to be physically active and eat in moderation. Though that won't sell many products, it's the right answer.

The wellness industry's business model depends on making early-stage biology sound like a reason to buy a specific supplement. Most of the time, the science isn't there yet. That's why my advice, which is informed but free, has always been to default to common sense:

Pick up something heavy a few times a week and break a sweat.

To find out more about Paul Von Zielbauer and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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