Fountain of Youth

Hello and welcome to Nutrition Facts – the podcast that brings you the latest in evidence-based nutrition research.  I’m your host Dr. Michael Greger.

I’m often asked what my opinion is about one food or another.  I know what people are asking but, you know, I’m not interested in opinions. I’m not interested in beliefs.  I’m interested in the science.  What does the best available balance of evidence published in the peer-reviewed medical literature show right now?  That’s why I wrote my book, “How Not to Die” and why I created my nonprofit site NutritionFacts.org and, now, this podcast.

Today, we’re going to talk about something we all do and that’s age.  If we live long enough, we get old.  But, what’s the best way to age in good health?  That’s what we’re going to find out.

Our first story is about a bacteria discovered on Easter Island.  It may hold the key to the proverbial Fountain of Youth, producing a compound that inhibits the engine-of-aging enzyme TOR.  Here’s the story.

It sounds like science fiction; a bacteria in a vial of dirt taken from a mysterious island creating a compound that prolongs life and not in the traditional medical sense. Thanks to advances in modern medicine, we are living longer, but we’re doing it by lengthening the morbidity phase.  In other words, we live longer, but sicker lives.

Traditional medicine increases the number of old people in bad health.  Ideally, though, we’d extend lifespan by slowing aging to delay the onset of deterioration and that’s what this appears to do. They called it rapamycin, named after Easter Island, known locally as Rapa Nui.  It inhibits an enzyme they called TOR, which stands for “target of rapamycin”, which may be a master determinant of lifespan and aging.  The action of TOR has been described as the engine of a speeding car without brakes.

Rather than thinking of aging as slowly rusting, a better analogy may be a speeding car that enters the low-speed zone of adulthood and damages itself because it does not and cannot slow down.  Why don’t living organisms have brakes?  Because they’ve never needed them. In the wild, animals don’t live long enough to experience aging, most die before they even reach adulthood.  Just a few centuries ago, life expectancy in London was less than 16 years old.

Therefore, living beings need to grow as fast as possible to start reproduction before they die from external causes. The best evolutionary strategy may be to run at full speed, but once we pass the finish line, once we win the race to pass on our genes, we’re still careening forward at an unsustainable pace, thanks to this enzyme TOR, which in our childhood is an engine of growth, but in adulthood can be thought of as an engine of aging.  Nature simply selects for the brightest flame, which in turn casts the darkest shadow.

Sometimes, though, in our youth–even in our youth–our bodies need to turn down the heat.  When we were evolving, there were no grocery stores, periodic famine was the norm and, so, sometimes even young people had to slow or they might never even make it to reproductive age.  So, we did evolve one braking mechanism.  The way caloric restriction extends lifespan appears to be mainly through the inhibition of TOR.

When food is abundant, TOR activity goes up, prompting the cells in our body to divide.  When TOR detects that food is scarce, it shifts the body into conservation mode, slowing down cell division and kicks in a process called autophagy, from the Greek auto meaning self, phagy meaning to eat, autophagy: meaning eating one’s self.  Our body realizes there isn’t much food around and starts rummaging through our cells looking for anything we don’t need–defective proteins, malfunctioning mitochondria, stuff that isn’t working anymore and our body cleans house, clears out all the junk and recycles it into fuel or new building materials, renewing our cells.

So, caloric restriction has been heralded as a fountain of youth.  The potential health and longevity benefits of such a dietary regimen may be numerous, but symptoms may include dropping our blood pressure too low, loss of libido, menstrual irregularities, infertility, loss of bone, cold sensitivity, loss of strength, slower wound healing, and psychological conditions such as depression, emotional deadening, and irritability and you walk around starving all the time.  There’s got to be a better way.

Now, it’s the power of berries.  The consumption of blueberries and strawberries is associated with delayed cognitive aging by as much as 2 1/2 years. 

A plant-based diet is thought to have played a significant role in human evolution and the consumption of whole plant foods and even just extracts have repeatedly been associated with decreased risk of aging-related diseases and, by healthy aging, I’m not talking preventing wrinkles.  What about protecting our brain?

Two of the most dreaded consequences of dementia with aging are problems moving around and difficulty remembering things.  Dementia robs older adults of their independence, control, identity.  What can we do about it?

Well, fruits and vegetables help reduce the risk of other chronic diseases, might they work for brain diseases as well?  There has been a proliferation of recent interest in plant polyphenols as agents in the treatment of dementia.  There are 4,000 different kinds found ubiquitously in foods of plant origin, but berries are packed with them, possessing powerful antioxidant, anti-inflammatory properties and there’s a subset of a subset called anthocyanidins, natural blue-purple pigments uniquely and specifically capable of both crossing the blood–brain barrier and localizing inside brain regions involved in learning and memory and that’s where we need it.  The brain takes up less than like 2% of the body weight but may burn up to 50% of the body’s fuel, creating a potential firestorm of free radicals.  So, maybe these brain-seeking phytonutrients in berries could fight oxidation, inflammation, and increase blood flow.  So, this raised a thought-provoking idea.  Maybe a nutritional intervention with blueberries may be beneficial in forestalling or even reversing the neurological changes associated with aging.  So, did researchers give blueberries to people and see what happened?  No.  As I noted in earlier video, they gave blueberries to rats.  It would be a decade before the first human trial, but it worked!  Blueberry supplementation improves memory in older adults, suggesting that consistent supplementation with blueberries may offer an approach to forestall or mitigate brain degeneration with age.

What other blue-purple foods can we try?  Concord grape juice had a similar benefit, improving verbal learning, suggesting that supplementation with purple grape juice may enhance cognitive function in older adults with early memory decline.  Why use juice and not whole Concord grapes?  Because then you couldn’t design a placebo that looked and tasted exactly the same to rule out the very real and powerful placebo effect and, also, because it was funded by the Welch’s grape juice company.

This effect was confirmed though in a follow-up study, showing for the first time an increase in neural activation in parts of our brain associated with memory using functional MRI scans.  But, this brain scan study was tiny, just 4 people in each group; and same problem in the blueberry study, it just had 9 people in it.

Why haven’t large population-based studies been done?  Because we haven’t had good databases on where these phytonutrients are found.  We know how much vitamin C is in a blueberry, but not how much cyanidin–until now.  The Harvard Nurses’ Health Study followed the cognitive function of more than 16,000 women for years and found that higher long-term consumption of berries was associated with significantly slower rates of cognitive decline in this cohort of older women, even after careful consideration of confounding by socioeconomic status, meaning even after taking into account the fact that, you know, rich people eat more berries.  The first population-based evidence that greater intakes of blueberries and strawberries were highly associated with slower rates of cognitive decline and not just by a little bit.  The magnitude of associations were equivalent to the cognitive difference that one might observe in women up to 2 1/2 years apart in age.  In other words, women with higher intake of berries appeared to have delayed cognitive aging by as much as 2 1/2 years.

Why not just take some kind of anthocyanidin supplement?  Because there hasn’t been a single study that found any kind of cognitive benefit just giving these single phytonutrients.  In fact, the opposite. Whole blueberries appear to be more effective than individual components, showing that the whole is greater than the sum of its parts.  These findings potentially have substantial public health implications, as increasing berry intake represents a fairly simple dietary modification to test in older adults for maintaining brain function.

What can we eat to combat “inflammaging,” the chronic low-grade inflammation that accompanies the aging process?  Here’s the story.

One of the most recognized consequences of aging is a decline in immune function, illustrated by vulnerability to dying from the flu, a poor response to vaccinations.  But, about 20 years ago, a paper was published showing that the immune cells of 80-year-olds produced significantly more proinflammatory signals, suggesting the worst of both worlds, a decline in the part of the immune system that fights specific infections but an aggravation of nonspecific overreactions that can lead to inflammation.  This has since been formalized in a concept referred to as “inflammaging,” a chronic low-grade inflammation we now know is typical of aging, which may be responsible for the decline and the onset of disease in the elderly.

So, what can we do about it?  Inflammaging appears to be a major consequence of growing old.  Can it be prevented or cured?  The key to successful aging and longevity may be to decrease chronic inflammation without compromising an acute response when exposed to pathogens.  How are we going to do that?  Nutrition.  What we eat is probably the most powerful and pliable tool that we have to attain a chronic and systemic modulation of the aging process.

In the first systematic review of the associations between dietary patterns and biomarkers of inflammation ever published, the dietary patterns associated with inflammation were almost all meat-based or so-called “Western” diet patterns, while vegetable and fruit-based or “healthy” patterns tended to be inversely associated, meaning more plant-based, less inflammation.

The reason why meat is associated with inflammation may be because of both the animal protein and the animal fat.  In the first interventional study that separately evaluated the effects of vegetable and animal protein on inflammatory status as it relates to obesity and metabolic syndrome when you’re trying to lose weight, what they found was that a higher intake of animal origin protein—specifically meat—is associated with higher plasma levels of inflammatory markers in obese adults.

The reason obesity is associated with increased risk of many cancers may be because of obesity-associated inflammation.  Obesity-driven inflammation may stimulate prostaglandin-mediated estrogen biosynthesis in breast tissues.  That means the inflammation may activate the enzyme that allows breast tumors to make their own estrogen via this inflammatory compound called prostaglandin.  If you measure the level of prostaglandins in women’s urine, it correlates with breast cancer risk and how do you get high levels of this inflammatory compound?  Smoking, a high-saturated-fat diet, and obesity.  Why does eating saturated fat lead to prostaglandin production?  Because prostaglandins are made from arachidonic acid and arachidonic acid is a major ingredient in animal fats and so animal fats contain arachidonic acid.  Arachidonic acid is what our body produces inflammatory compounds, like prostaglandins, with and they can then go on to stimulate breast cancer growth, and may also play a role in colon cancer, lung cancer, or head and neck cancer as well.  Whereas whole plant foods have anti-inflammatory effects, though some plants are better than others.  The folks made to eat five-a-day of high antioxidant fruits and vegetables, like berries and greens, had a significantly better impact on reducing systemic inflammation and liver dysfunction compared to five-a-day of the more common low antioxidant fruits and veggies, like bananas and lettuce.

Dr. Dean Ornish showed that a plant-based diet, exercise, and stress management intervention could in effect reverse the aging of our DNA.  So, I wanted to know, what effect might the stress management component have had?

In my Research into Reversing Aging video, I highlighted Dean Ornish’s landmark study showing that a low-fat, whole foods, plant-based diet high in vegetables, fruits, whole grains, beans, along with walking, stress management, and support, could not only reverse heart disease, open up arteries without drugs and surgery, and potentially reverse the progression of early-stage prostate cancer, but was the first intervention ever shown to increase telomerase activity, the enzyme that builds and maintains these caps at the tips of our chromosomes called telomeres, which appear to slow the aging of our cells.  Yes, this new finding was exciting and should encourage people to adopt a healthy lifestyle in order to avoid or combat cancer and age-related diseases, but was it the diet, the exercise, or the stress management?  That’s what researchers have been trying to tease out in the six years since this study was published.

Let’s look at stress first.  In the film, The Holiday, Cameron Diaz, exclaimed, “Severe stress caused the DNA in our cells to shrink until they can no longer replicate”.  Did Hollywood get the science right?  Do people who are stressed have shorter telomeres?  To answer that question, researchers measured the telomere lengths in mothers of chronically ill children.  What could be more stressful than that?  The longer a woman had spent being the main carer of her ill child, the shorter were her telomeres.  The extra telomere shortening in these most stressed mothers was equivalent to that caused by at least a decade of aging.

We see the same thing in caregivers of Alzheimer’s patients and those suffering severe work-related exhaustion.  Even those abused as children may grow up with shorter telomeres.  Not much we can do about our past but, if we manage our stress, can we grow some of telomeres back?

Well, if you go off to a meditation retreat and meditate for 500 hours, you can, indeed, boost your telomerase activity; 600 hours of meditation may be beneficial as well but, come on, there’s got to be a quicker fix and this exciting new study delivered.

Caregivers of family members with dementia randomized to just 12 minutes of daily meditation for 8 weeks, so just about 10 hours in total, experienced significant benefit, better mental and psychological function accompanied by an increase in telomerase activity suggesting improvement in stress-induced cellular aging.  

Thanks for listening to this episode of Nutrition Facts.  To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts podcast landing page.  There, you’ll find all the videos I highlighted with links to all the sources cited.

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Thanks for listening to Nutrition Facts.  I’m Dr. Michael Greger.