Inside your body, aging unfolds at remarkably different rates, all the way down to our cells. Academics now call this “organ aging,” which looks at how different parts of our bodies seem to start aging earlier than others, affecting what diseases we develop and how long we live. Today’s post will assist you the next time you and your friends are doing “organ recitals,” an activity that, as we age, becomes as common as talking about the weather.
Aging is much more haphazard than we once thought, starting in different parts of our bodies at different times, possibly long before we’re even thinking about aging. It’s also personal, occurring at a unique molecular level inside each of us, and the process may be partially within our control. Once we know how our own organs are aging, we may be able to slow or speed that process by how we live.
By using advanced molecular biology, genetics and big data to analyze blood samples from people, scientists can tell that some of us are “heart agers,” meaning our hearts appear much older than the rest of our bodies, or we’re “brain agers,” with a relatively old brain in our skulls, or if we’re fortunate, we might be “brain youthers,” with a brain relatively younger than any other organ we possess. Or we could be “muscle agers” or “liver youthers.”
The consequences for our health are considerable. In one of the largest human studies to date of organ aging, Stanford scientists found that heart agers are far more likely to develop heart failure than other people, while brain youthers are about 80 percent less likely to develop dementia in later years than people with average or old brains.
Dozens of at-home tests now promise to estimate biological age from a cheek swab or other sample.
Yet, DIY biological age tests offer a single estimate of how an entire body is aging. It’s increasingly clear aging doesn’t work that way. Aging isn’t linear (I wrote a post about the fact that 44 and 60 were the times we age the most), nor is it singular, meaning your organs age at different paces. Research has shown that the pattern of proteins in one’s bloodstreams is currently the best way to identify organ ages.
About 20 percent of the almost 5,700 men and women researched in a Stanford study harbored at least one organ that was significantly older than their birth age, according to their plasma proteins. These affected organs differed from person to person, creating what the scientists called an “ageotype.” More recently, the researchers expanded their study to tap into 44,530 people in the UK Biobank (not published yet). About 33 percent of the men and women harbored at least one organ that was “extremely” aged, compared with their actual ages. Another 26 percent had two or more extremely aged organs and some as many as eight (maybe those in the UK age their organs faster than in the U.S.?).
The researchers also again found links between organs’ ages and disease and also lifespan. Heart agers risked heart failure and atrial fibrillation; lung agers developed chronic obstructive pulmonary disease; and for liver agers, it was chronic liver disease. But the effects of brain aging were the most striking. People with extremely old brains were 3.4 times more likely to develop Alzheimer’s disease than everyone else, while, on the flip side, those with relatively youthful brains had 81 percent less risk of Alzheimer’s than people with brains the same age as them.
The benefits of a youthful brain also extended to longevity, with brain youthers generally outliving brain agers. In fact, an old brain was, of all organs, “most strongly predictive of mortality,” the study authors wrote, “suggesting that the brain may be a central regulator of lifespan in people.” Perhaps the most important finding in the new study, though, was that organ age appears to be malleable.
When the scientists compared people’s organ ages to their lifestyles in the new study, they found that those who often smoked, drank or ate processed meats were prone to accelerated organ aging, while anyone who regularly exercised or ate oily fish was far more likely to have youthful organs. Interestingly, taking estrogen also noticeably affected organ aging in menopausal women, the researchers found. Women who’d used supplemental estrogen wound up with relatively youthful immune systems, livers and arteries, compared to those who hadn’t.
It’s still impossible to pinpoint precisely why our organs age at different rates. It might be genetics, lifestyle, luck or all or none of those. Still, knowing our ageotype could help guide some of our health decisions. Someone who knows he or she is a heart ager, for instance, even with no current symptoms, should probably consider more-frequent cardiac testing and diet and exercise changes, such as cutting back on ultra-processed foods and walking for at least 30 minutes a day, while a muscle ager could be advised to take up weight training, which is known to build muscular health at a cellular level.
Blood tests to diagnose ageotype could be on the horizon, although it may still be years before they’re validated by the FDA and available as part of standard health testing. The hope is that these tests will show which of our body parts — our heart, brain, kidneys, skin, fat, intestines or something else — is aging fastest and what, if anything, we can do about it.
Today’s post has been partially excerpted from a Washington Post article that appeared two months ago.
-Chip