How to Live to Be 100 — 5 Key Factors
This Week’s Research Highlight
Background & Study
Centenarians could be said to be masters of successful aging. But not simply because they have outlived almost everyone else in their birth cohort.
Centenarians are generally much healthier as they age, compared to others who were born in the same year but who did not survive. A majority of centenarians are able to maintain physical independence and postpone the onset of cognitive decline into their 90s and 100s. Indeed, it has been argued that the key to living to one hundred years is escaping disease and disability.
But why exactly are centenarians different? Are they just incredibly lucky?
Well, it is true that a good deal of these lifespan and healthspan advantages can probably be attributed to favorable genetics. However, twin studies suggest that only around 25% of the observed variation in human longevity is explainable entirely by genes. This suggests that lifestyle and environment likely have an overwhelming impact on how long you live — and how well you age over the coming decades. In other words, factors that are within your control.
Importantly, it also means that we might be able to learn from the habits and characteristics of these individuals.
To gain insight into some of these modifiable factors that might promote healthy aging, Australian researchers recently performed a systematic review of epidemiological studies that had been published within the past twenty years. They zeroed in on studies that reported on various dimensions of health-related behaviors among people exhibiting extreme longevity (age 95 or older — basically centenarians and near-centenarians). This screening process produced a total of 34 studies.
From the pooled analysis, five common features emerged.
Key Features of Centenarians
- Healthy Body Weight
The researchers determined that over half (52%) of centenarians had a normal BMI, with 33% being underweight. Only 14% of studied individuals were overweight, and prevalence of obesity among these centenarians was extremely low, with a pooled estimate of 4%. To put those numbers into perspective, 41.9% of American adults currently have obesity, and 73.6% are overweight (including obesity).
The relationship between obesity and mortality can appear somewhat confusing when you look at some of the epidemiological literature. You’ve probably heard before that there is an “obesity paradox,” wherein individuals with a higher BMI are actually at lower risk of dying versus those at a normal weight. However, we have known for some time that unintentional weight loss, especially later in life, is often associated with severe chronic illnesses that may not have even been diagnosed yet. In such cases, these diseases are the actual cause of failing health, rather than being lean per se. On the other hand, randomized controlled trials show that intentional weight loss through healthy lifestyle interventions reduces risk of mortality, and maintaining a stable BMI in the normal range over the course of your life is linked to the lowest cardiovascular risk.
- High Dietary Diversity
In these studies, centenarians were found to have relatively diverse diets, meaning a greater number of different food groups consumed over a given reference period. Among centenarians, higher dietary diversity was linked to a 44% reduced mortality risk, compared to lower.
Nutrition scientists generally prize diversity, because including a wide range of different food types in the diet is robustly associated with adequate intake of essential nutrients, as well as non-essential health-promoting compounds like polyphenols.
Furthermore, dietary diversity may be extra critical as we get older. Older adults tend to eat less food overall, due to a host of physiological changes like slower gastric emptying, changes in taste and smell, and reduced sensitivity to hunger cues. But their demands for essential vitamins and minerals actually go up, due to impairments in absorption and utilization of these nutrients. Aging also leads to reduced capacity to incorporate protein from the diet into skeletal muscle, which contributes to sarcopenia. Taken together, this means that the elderly need, if anything, a higher quality diet than younger counterparts, in order to maintain a healthy body and mind.
- Limited Salt Intake
Most of these centenarians reported avoiding salt. The only study in the review that measured daily sodium intake reported an average of around 1600 mg, which is very low by virtually any standard. Americans currently consume about 3,400 mg of sodium per day, and the Dietary Guidelines recommend less than 2,300 mg per day.
Meanwhile, individuals who did prefer salt or who routinely added extra salt to their food were 3.6 times more likely to suffer significant functional impairment.
This finding lines up with prior epidemiological research revealing that low daily sodium intake is associated with successful aging, as well as the impressive results we’ve seen from recent trials administering salt substitutes to elderly adults in long-term care facilities. It also happens to align with the pattern we tend to observe in hunter-gatherer populations, who consume far less sodium than industrialized people and have relatively low blood pressure even as they get older.
- Lower Medication Use
Perhaps most surprisingly, people who reach age 100 use fewer prescription drugs than other older adults.
Polypharmacy, or the concurrent use of five or more medications, is associated with an array of adverse effects, especially in the elderly. Using multiple drugs has been linked to falls and cognitive impairment, as well as dangerous drug interactions. Even more vexing, drugs prescribed to address one condition can worsen another, or create new problems.
You might think that centenarians, of all people, would have to be on a boatload of drugs. But when the researchers analyzed the pooled data, they found an average of 4.6 medications. So, on average, these subjects were under the threshold for polypharmacy.
How does this compare to other older non-centenarians? In the US, rates of polypharmacy are estimated to be around 65% for adults over the age of 65. In nursing facilities, as many as 95% take 5 or more medications.
- Good Sleep
Finally, the majority of centenarians (68%) reported being satisfied with the sleep that they got, which was similar to younger counterparts who were also surveyed and better than average working Americans. A 2024 Gallup poll showed that just 42% of Americans feel that they are getting as much sleep as they need, and only 26% get at least 8 hours of sleep per night.
Why might sleep be key for healthy aging? Well, sleep, fundamentally, seems to function as a process of restoration — an opportunity for the body to recover from metabolic processes that occur during the waking period, and to repair damage elicited by that activity. Most notably, while we are awake, metabolic activity results in the production of free radicals. To counter this, endogenous antioxidant systems become more efficient while we are asleep, and metabolic waste products of neural activity are cleared from the brain at a faster rate.
On the other hand, when sleep is lost or fragmented, these reactive oxygen species are able to accumulate, and cause damage to DNA. In a trial of older adults, just one night of partial sleep deprivation elicited an increase in DNA damage, which was not reversed by a subsequent night of recovery sleep. These subjects also exhibited an increase in a marker associated with cellular senescence. Senescent cells, which we have discussed previously on our blog, accumulate with age and have been implicated in the chronic systemic inflammation commonly observed in people as they get older.
Unfortunately, sleep quality tends to deteriorate as we get older, and disrupted and/or shortened sleep almost certainly accelerates the aging process at the cellular and molecular level through the mechanisms we just described. It makes sense, then, that centenarians, the most successful agers in the world, manage to maintain healthy restorative sleep, and it is likely that this contributes to their remarkable longevity.
Random Trivia & Weird News
Roman Emperor Domitian was so distressed about his hair loss that he published a book on hair care.
Domitian was profoundly sensitive with respect to his thinning hair, taking any jokes about bald men as a personal insult. He took pains to disguise it using wigs or laurel crowns (you can see the latter strategy being employed in the marble bust shown below).
His obsession with hair so consumed him that he apparently wrote an entire book on the subject (De cura capillorum), in which he speculates about potential cures for the condition.
In this work, he laments:
“And yet the same fate awaits my hair, and I bear with resignation the ageing of my locks in youth. Be assured that nothing is more pleasing than beauty, but nothing shorter-lived."
Bust of Roman Emperor Domitian in the Louvre Museum in Paris (Wikimedia Commons).
Random Trivia & Weird News
- Nicola Twilley: From farm to fridge: The science and history of refrigeration. Via Science Friday.
- George A. Brooks: A masterclass in lactate — Its critical role as metabolic fuel, implications for diseases, and therapeutic potential from cancer to brain health and beyond. Via The Peter Attia Drive.
Products We Like
Cronometer
You don’t have to track your food, of course, but it is probably the surest and more efficient way to optimize your nutrition, especially if you have specific goals (like losing weight).
There are a lot of tracking apps out there, which we have tried, but Cronometer is the one that we keep returning to. It is probably the most comprehensive one around, with the ability to track up to 82 micronutrients, and even individual amino acids. It is free and very easy to use – you can even scan food labels with the barcode scanner and add custom foods and recipes. Strongly recommended for health geeks who enjoy data.
humanOS Catalog Feature of the Week
The How-to Guide to the Mediterranean Diet
It has been known for some time that islands in the Mediterranean region boast an unusually high rate of centenarians. It is thought that one of the keys to their unusual longevity is the dietary pattern characteristic to that part of the world.
In this reference sheet, we go over the fundamental principles of the Mediterranean diet, what components of the diet make it healthy, and what sorts of foods and beverages you should consume in order to achieve the best possible version of this dietary pattern based on the current scientific literature.
For a little bit of a deeper dive, you can refer to our Mediterranean Program, which delves into the background of the Mediterranean diet as well as the clinical research.
Wishing you the best,
