(These are the notes for a talk I gave to the Austin Prime Timers monthly meeting on Jan. 14, 2018. Here is a Spanish translation of the talk)
And, this page has been translated into
How Much Can We Change Our Aging?
The content of this talk comes from a blog that I have been publishing since 2006, http://mindblog.dericbownds.net. It reports new work on mind, brain, and behavior, as well as random curious stuff. By now it has several hundred posts describing research on aging. Many of the paragraphs below are paraphrases of sections from those blog posts. They are a list of facts and ideas that I have found interesting.
Aging is a fairly recent topic. For most of the several hundred thousand years humans like us have been around -all but the past several hundred years - the average life span has been thirty years or less. Evolution did not design us to last as long as we do today.
The average life span in developed countries now is almost eighty years. We’re defining a new category of old old age. The statistics say that half of the babies born in developed countries in 2007 will live to be 104.
The number of Americans 65 or older could reach 108 million by 2050, like adding three more Floridas inhabited entirely by seniors.
Life expectancy has increased dramatically since 1900 for all ages up to one hundred, but this rise in expectancy is hitting a wall soon, if it hasn’t already. Expectancy for those over 100 has increased much less, and there seems to be a cut or cliff at around 120.
The way you look at aging is like you look at any complicated system…say like a power plant, a car, or a large organization. It has to survive and function despite having thousands of critical components. An engineer (or in our case, evolution) designs these systems with multiple layers of redundancy: with backup systems, and backup systems for the backup systems.
Our backups may not be as efficient as the first-line components, but they allow our machine to keep going even as damage accumulates within the parameters established by our genes. We have an extra kidney, an extra lung, an extra gonad, extra teeth. The DNA in our cells is frequently damaged under routine conditions, but our cells have a number of DNA repair systems. If a key gene is permanently damaged, there are usually extra copies of the gene nearby. And, if the entire cell dies, other cells can fill in.
Nonetheless, as the defects in a complex system increase, the time comes when just one more defect is enough to impair the whole, resulting in the condition known as frailty. It happens to power plants, cars, and large organizations. And it happens to us: eventually, one too many joints are damaged, one too many arteries calcify. There are no more backups. We wear down until we can’t wear down anymore.
How do we measure aging? Number of years isn’t really sufficient. There is no physiological marker that reliably predicts the age of a given individual. 75 year old avid cyclists can have younger peoples’ physiology, and some people in midlife show declines characteristic of people twice their age.
By almost any measure, people get happier as they get older, for reasons that are not clear. On average, people in their early 80s are happier than those in their 20s. Gerontologists call this the paradox of old age: that as people’s minds and bodies decline, instead of feeling worse about their lives, they feel better.
In memory tests, they recall positive images better than negative. During functional magnetic resonance imaging, their brains respond more mildly to stressful images than the brains of younger people. They focus not on their declining abilities but on things that they can still do and that they found rewarding.
Most of us become wiser, peer pressure loses its sting. We have better decision-making, more control of emotions,
Older healthy adults not only are better than young adults at answering general-information questions in the first place, but also, when they do make a mistake, they are more likely than young adults to correct those errors. Correcting errors is the quintessential new-learning task.
To correct mistakes, one needs to supplant entrenched responses with new ones. The fact that older adults display greater facility at error correction than young adults goes against the view that aging necessarily produces cognitive rigidity and an inability to learn.
Extensive research has described how our brains change with aging. Brain decline mirrors brain development in reverse, the frontal areas that continue to develop through our 20’s and are involved in our most advanced cognitive operations are the first to go. Brain connections become more sparse and sharp with aging, long range connections increase while short range connections decrease. Risk taking for potential gains is reduced during aging as dopamine (the reward molecule) levels drop.
It’s surprising that given the deteriorations of brain structures we see that we maintain such a high level of cognitive ability. It is an ability, however, that does not have the same robustness as that of a younger person, it is more fragile, more easily perturbed by changes in environment or routine, and takes longer to recover when perturbed.
Older brains are more noisy, there is more spontaneous background nerve activity, they become more distractible as frontal lobe attentional circuits weaken.
OK, this is enough on a general description of aging. I should get to the title of the talk. How much can we influence our aging?
I’ll start with a list of things we don’t influence.
First would be our genetics. 50% of the odds of your dying in a given year is determined by your genetics, how long people in your family lineage have lived.
Second is disease. 50% of the chance that you will get a debilitating or terminal disease, especially cancer, is a throw of the dice, good or bad luck on whether particular genes randomly mutate to a bad place when cells divide, we get to influence only 30% of the risk of our getting cancer by changing lifestyle, diet, supplements, whatever.
Third would be our early life situation. 50% of what determines your cognitive vitality and intelligence in later life depends on how you started out - your intelligence when you were 11 years old. Your general cognitive ability with respect to your peers remains constant over your life course.
Many studies are now showing that early adversity and stress in life - with the effects starting in utero, before birth - have unfortunate life long effects relevant to longevity. People in the lowest socioeconomic quintile can have less total brain gray matter (fewer nerve cells), greater stress responses, compromised immune responses, more perceived helplessness. For people born in 1960, those in the top quintile in income on average live 12.5 years longer than those in the bottom quintile in income.
To wrap this up, The bottom line is that ~2/3 of the odds of whether we are going go bonkers or croak at a given age is random chance, genetics, or early life experience over which we had no control.
So, let’s take the 30% or so of the odds we can influence and run with that, talk about what we eat and drink, how we move, how we think.
What about diet? I’ll start with booze. I am very attached to my daily happy hour, so I’m always glad to see an article that describes an experiment showing that little bit of alcohol doesn’t hurt, even helps a bit.
A single study doesn’t do the job in proving the point. A large number of studies must be examined and averaged (meta-analysis). This kind of analysis shows that compared with abstainers, male drinkers reduce their risk for dementia by 45 percent, and women by 27 percent. The death rate among non-drinkers is twice that of moderate drinkers.
Other studies show that moderate alcohol consumption can increase HDL, or “good cholesterol,” improve blood flow to the brain and decrease blood coagulation, and increase the size of the hippocampus in our brain that is important for memory.
An interesting factoid…exercising increases the urge to drink alcohol, and drinkers are more likely to exercise more.
What about how much we eat? Health risks go up with obesity, so you would think that the death rate should go up with obesity. Well, a study has been done on that, looking at 97 other studies including 2.88 million people … those deemed 'overweight' by international standards were 6% less likely to die than were those of 'normal' weight over the same time period. But, it turns out the normal weight group included formerly obese people who turn out to have a higher mortality rate, so when you factor in that, the difference disappears, and there doesn’t seem to be a significant difference in the longevity of obese versus normal weight people.
What about eating way less, rather than more? In animals, from worms, through to mice to monkeys, restricting calories slows down aging. A west coast group started up on a calorie restricted diet a few years ago. What happened?…They got very cranky and grumpy!
What about what we eat in our ordinary diet?
What’s the proper balance of fat, carbohydrate, protein, salt in a normal diet? People can feel very passionate about this. It turns out the science behind USDA dietary guidelines is contradictory and in disarray. Looking at lots of studies suggests that evidence against sodium, salt, and saturated fats is not strong.
Replacing fats with carbohydrates doesn’t reduce the risk of cardiovascular events and mortality. Vegetables, grains, unsaturated fats, complex rather than simple carbohydrates, fine, but butter, meat and cheese belong in a healthy diet too.
A recent book on flip-flops in medical advice and practice estimates that about 40 percent of what we consider state of the art health care is likely to turn out to unhelpful or actually harmful. Extremely stringent diets prescribed for diabetes turn out to be unnecessary. Surgical repair of the meniscus in the knee turns out to be no more effective than physical therapy alone. The book lists almost 150 disproved common treatments.
What about going beyond our normal diet with supplements? A lot of us do this, I take pills of five of the more common supplements, based by articles I’ve read here and there saying they are good for brain or body health.
What I probably didn’t see, however, were articles describing experiments that failed to show an effect of the supplements. Studies with negative results seem kind of boring and are less likely to get published that ones with positive results. It is clearly documented that journals show this bias.
One of the supplements I take is a fish oil pill with omega-3 fatty acids. Almost nobody argues against the idea that omega 3 fatty acids and other antioxidants are good for your brain. People who eat lots of fish have better brain health.
So, there is a correlation: eating more fish = better brain health. But remember, just because two things happen together doesn’t mean one causes the other. A correlation is not a cause. We have to remain aware of our tendency to alway want to assign reasons and causes to things, even when they are not there.
So, I was not happy to see a recent massive NIH study of ~3,500 subjects, recruited from 82 academic and community medical centers that finds no cognitive effects of dietary supplementation with omega-3, other long-chain polyunsaturated fatty acids, and many other compounds for which effects are claimed in smaller individual studies, things like, lutein, zeaxanthin, vitamins D, C, E, beta carotene, and zinc.
Southern Florida, where I was recently living, is an epicenter of the national life extension and life enhancing supplement industry, peddling life extending elixirs. Several magazines report recent studies and sell pills. The usual article starts with “A new study has shown that…” Just fill in the blank with names like theanine, piracetam, galantamine, metformin, dopamine, riluzole, resveratrol, ginko-biloba, DHEA, testosterone, etc.
We have to remember that one, or a few, studies don’t get you there, we need a lot of studies involving lots of subjects that reach a conclusion. Skepticism is growing about claims of the wonders of special diets, anti-aging dietary supplements and brain exercise. When you look closely, the scientific evidence is not there.
If you want to get into this you should tread very cautiously. Dietary supplements are responsible for more than 20,000 emergency room visits each year. Until the FDA issued a warning letter to 14 companies, at least a dozen supplements sold in the United States for weight loss, enhanced brain function, and improved athletic performance contained a synthetic stimulant similar to dimethylamylamine or DMAA. It had never been tested in people, only in two animal studies from the 1940s.
Other supplements with proprietary unnamed ingredients have been found to have prozac, viagra, the corticosteroid dexamethasone, and so on. A recent investigation found that 30-50 percent of the herbal supplements, like ginko-baloba, being sold by CVS and Walgreens contained filler starch, sawdust, and little or none of the advertised herbal ingredient.
I’ve actually tried, after researching their components, the magic elixirs that three different companies have sent me, hoping I would promote their product on my blog.
I’ve sometimes felt a mental lift, increase in clarity, attentional focus. But I have to ask “Was this real, or was it a placebo effect, my believing they might work leading me to decide they had?” My experience was that over time, the clarity of the effects I initially experienced went away, I felt less and less effect of taking them, and I began to notice unpleasant side effects. Really bad hand arthritis with resveratrol, for example.
Something very basic happens when you give your system a jolt, maybe you rev it up for awhile, feel great. Your brain and your body kinda know where they want to be in the long run, and when they get goosed, they start adapting, habituating, playing with the chemistry until they get back to where they want to be. Highs don’t last.
The body kind of knowing where it wants to be also applies to efforts to loose weight or to exercise. Your body reacts to your eating less by lowering its metabolic rate to try to maintain a weight set point it has decided on.
Anyway, my bottom line on supplements is that if you tell me you’ve found a product that is not dangerous and you think it makes you think better or feel more vital, it doesn’t matter whether the components are having a real biological effect or if it is a placebo effect, your belief in the product is causing the changes you feel. If it works for you, it works.
Let’s talk about exercise, both brain exercise and body exercise
Brain health is enhanced by novelty and new experiences, even things as trivial as shaving or brushing your teeth with the hand you don’t usually use. If you learn a new set of movements the part of brain managing that grows new connections and gets bigger. Habit - doing the same things on autopilot - causes areas of the brain to shrink. The use it or loose it rule applies to our brains.
Some of you may have heard of brain games you can play on your computer, to increase your attention, speed, acuity of processing. I’ve played with a number of these. They initially got a lot of hype, but by now there is a consensus that most claims about brain training making improving mental agility have no scientific basis. Most brain training only makes you better at the exercises themselves, and doesn't carry those gains over to your real-world concentration, productivity, or mental acuity.
One research study suggests that a single exception may be BrainHQ and Cognifit exercises that focus on improving visual processing speed. I've done the BrainHQ 'double decision' exercise, in which you see an image in the center of your vision – for example, either a car or a truck – and at the same time, you see another image way off in your peripheral vision. The images are only on the screen for a brief period of time–well under a second.
You then have to say whether you saw the car or the truck in the center of your vision, and then you have to show where you saw the image in your peripheral vision. This challenges the speed and the accuracy of your visual system. And as you get faster and more accurate, the speed increases and the peripheral vision task gets more demanding–pushing your brain further.
One followup study of 2800 older adults who did a 6 week regime of training with this game showed that 10 years later they had a 30% lowered rise of dementia compared with a control group.
The “Can we really change our aging?” question gets a resounding positive yes answer from massive scientific evidence on the importance of exercise.
Simply moving rather than sitting has a big effect on our general health and brain fitness. Especially anything to get just a little bit out of breath, whether your running, walking, using a walker, or in a wheelchair.
Sitting for long periods of time is bad for your health, there is universal scientific agreement on this. It causes an increase in the level of troponins that are produced by hurt of dying heart muscle cells and released into the blood stream. A heart attack causes a huge burst of troponin release. Just getting up occasionally and doing a bit of walking prevents this troponin increase.
Aerobic exercise increases blood flow to the brain, and helps to support formation of new neural and vascular connections. It improves attention, reasoning, and components of memory. It increases the number of stem cells that regenerate muscle, causes release of brain growth factor molecules that stimulate brain cell growth and connections.
People who exercise have more brain gray matter (nerve cells) and less alzheimers. The brains of super agers, people who in their 90s are still very athletic, on autopsy look like the brains of 50 or 60 year olds. Exercise is an antidote to depression, and generally makes people more relaxed and confident.
Finally, exercise changes the composition and activity of the trillions of microbes in our gut increasing the number of bugs that help the immune system fight infection and inflammation.
The exercise we are talking about here doesn’t have to be some big deal. Walking, housecleaning. Exercise beyond a certain point doesn’t confer lots of additional health benefits, people who are the least active to start with get the most health benefit from starting to exercise.
People in their 60’s who walk three times a week, building up to 40 minutes at a stretch, after a year have a 2% increase in the size of the memory part of the brain, the hippocampus, while in a control non-walking group the volume has gone down by 1.5%
Increasing amounts of aerobic exercise, from one up to 4 hours a week, go with corresponding increases cardiorespiratory fitness, but the maximum improvement in thinking skills, compared with people who don’t exercise, happens after only a hour of walking per week, and isn’t increased by more walking.
Short burst of fairly intense exercise are most effective in reversing the decline with aging of the energy metabolism carried out by mitochondria in our muscle cells. Bouts of brief higher intensity exercise cause a larger increase in the number of energy metabolism genes, compared with doing weight or resistance training, or moderate aerobic exercise like biking. It’s a good idea - during moderate walking, biking, or running - to intersperse 30 second intervals of much more intense effort. I’ve tried this when I’m swimming, can really feel the difference, that something is happening.
Life style - social support and connections.
I’ve talked about diet and exercise, but have not mentioned life style.
There is a famous 8-decade long longevity study started in 1921 at Stanford University by Lewis Terman, which has followed the histories of 1,500 gifted children from schools in the state and followed them from the age of 11 into adulthood.
The best predictor of a long and healthy life has turned out to be conscientiousness — the extent to which a child was prudent, dependable and persistent in the accomplishment of his or her goals. Working hard for long hours in a demanding job to achieve high status is better for your health and life expectancy than taking it easy and lacking ambition.
The authors also emphasize the benefits of an active social network — more common for women — as a buffer against life's harmful events.
Social connections are hugely important. Studies with feral children, raised by animals, show that we are not even human unless we grow up with rich maternal and other humans interactions that pattern us. We don’t grow a distinctive self unless we sense, absorb, and are patterned by the selves of others around us.
Studies on hunter gatherer tribes that still exist in small pockets that have remained isolated from the outside world for thousands of years (in Borneo and the Amazon basin), show that individuals that are exiled from their tribe are very likely to die not from starvation but from the psychological effects of social isolation.
In our society, social isolation is a growing epidemic — it has dire physical, mental and emotional consequences. Since the 1980s, the percentage of American adults who say they’re lonely has doubled from 20 percent to 40 percent.
Loneliness can disrupt sleep patterns, compromise the immune system, cause more inflammation, higher levels of stress hormones, all of which link to increased risk of heart disease, arthritis, type 2 diabetes, and dementia. Socially isolated individuals have a 30% higher chance of dying in the next seven years. In my blog I’ve done over 50 posts in the past few years pointing to research showing how physical and mental health is diminished by loneliness.
It is important to identify with a larger social group, have frequent and unplanned interactions with others, and have a few friends with whom we can share our painful conflicts.
Not all forms of social withdrawal are harmful. Individuals who actively seek out solitude may simply have thing that interest them, that they want to spend more time on relative to social interaction than the average. It turns out that people who seek solitude score higher on tests of intelligence and creativity, and are happier when they have fewer friends. Maybe they spend less time socializing because they are focused on some other longer term objectives.
A further point is that a structuring and supportive social environment lets us, during aging, begin to shift away from self initiated activities to social environmental support in choosing and performing tasks. It is a good thing that this support helps us function and perform, but there can be a downside if reliance on being structured by our surround results in loss of internal control and initiative. It is important for us also to continue actively initiating and crafting activities on own. Letting go of this too much can enhance the waning of one of our major brain systems, the attentional mode, as we start to spend more time using a system called the default mode, which is active during our mind wandering and passive receptivity.
So, I’ve talked long enough. Do I have a bottom line for this talk? Not really. Just the suggestion to keep the body moving a little bit and chill. Eat what you feel like, not too much. Do new things. Be social. And, be skeptical about anti-aging products that claim to be science based.