How Not to Age: The Scientific Approach to Getting Healthier as You Get Older

by Michael Greger

But if we start early enough in life, it may be sufficient to lower LDL to only about 100 mg/dL, which is consistent with country-by-country data that suggested heart disease would bottom out at a population average of about one hundred.3598 That’s why healthy lifestyle choices may wipe out 90 percent or so of our risk for having a heart attack, whereas drugs may only reduce it by 20 to 30 percent.3599 But that 90 percent is only if you can keep it down your whole life.

Red yeast rice supplements, which contain a statin-producing mold, are not recommended,3624 as “dramatic” variations in the active components have been found (for example, hundredfold differences in lovastatin levels). Also, a third of retail red yeast rice supplements tested were contaminated by a potential kidney-damaging fungal toxin called citrinin.3625 An updated 2021 analysis found citrinin exceeding safety levels in 97 percent of sampled supplements, including supplements labeled “citrinin-free,” posing a “serious health concern.

The proscription against saturated fat extends to tropical oils, which are often used in junk foods, including coconut oil, palm oil, and palm kernel oil,

Lp(a) blood concentrations are mostly genetically determined,3685 but there are some dietary tweaks that can help.

You shouldn’t need to clean your ear canals at all because the wax should make its way out on its own. Ears are self-cleaning. The lining of your ear canal grows outward from your eardrum, so secreted earwax and any dirt that’s been trapped is eventually conveyor-belted out.

the researchers suggested that atherosclerosis clogging the small blood vessels feeding the inner ear may be the underlying cause of age-related hearing loss in most of the rest of the world.3978

Lower protein intake is associated with higher levels of DHEA,4034 and an interventional trial found that increasing fiber intake actively raised levels,

Furthermore, plant-based eating appeared particularly protective against the deadliest4131 types of tumors.4132 The California Teachers Study, with more than 90,000 women, found similar results, including significantly reduced breast cancer risk associated with a plant-based dietary pattern, particularly for the hardest-to-treat tumors.

Our body gets rid of excess estrogen the same way we evolved to get rid of excess cholesterol—by dumping it into the digestive tract, where it expects that there will be a lot of fiber to grab it, hold on to it, and flush it out.4140 Without fiber, excess hormones (and cholesterol) can just wind up getting reabsorbed into the bloodstream,4141 but our body just assumes our intestines are going to be packed with fiber all day long because that’s the context in which we evolved.

Pooling all the results, soy food intake after breast cancer diagnosis was associated with both reduced mortality and reduced recurrence—that is, a longer lifespan and less likelihood that the cancer comes back. This improved survival was for women with either estrogen receptor–negative tumors or estrogen receptor–positive tumors, and for both younger and older women.

Flaxseeds also have phytoestrogens (called lignans) that are associated with breast cancer prevention4192 and survival.4193 Interventional trials involving before and after biopsies have shown beneficial effects in breast cancer patients randomized to muffins containing flaxseeds versus flax-free placebo muffins.4194 Higher lignan exposure may reduce breast cancer mortality between 33 and 70 percent.

Also, like soy, flaxseeds have been shown to improve LDL cholesterol,4196 artery function,4197 and blood pressure.4198 Flaxseeds also lower other cardiovascular risk factors, including C-reactive protein4199 and Lp(a),4200 and can improve blood sugar and weight control.

beer may be more carcinogenic to the breast than some other forms of alcohol.4212

Another way to lower cortisol levels is by forest bathing, surrounding yourself with trees,4422 which may also elevate natural killer cell activity, as shown in a series of randomized controlled trials I document in see.nf/forestbathing. It turns out, as I explain in my follow-up video see.nf/treefragrance, trees produce aromatic volatile compounds called phytoncides,4423 like pinene, that you breathe into your lungs in the forest.4424 They enter your bloodstream4425 and boost natural killer cell activity.

these phytoncide compounds are part of the tree’s own immune system, which we may be able to commandeer.

we can confidently advise patients not to take elderberry.”4462 As I show in the video, similarly disappointing results have been reported for the herb echinacea.4463 Elderberry supplements may not even be safe.

blueberries can increase the numbers of natural killer cells,4468 the aromatic spice cardamom can increase their activity,4469 and black raspberries appear to do both,

Goji berries do actually appear to have relevant, real-world, beneficial effects on immune function.

Nitric oxide—not to be confused with nitrous oxide, aka laughing gas—is best known as the “open sesame” molecule our artery lining releases to enable our blood vessels to dilate, but it also has broad-spectrum antiviral, antibacterial, and antifungal properties.

Chlorella can also significantly improve natural killer cell activity.4517 This may play a role in reducing liver damage in chronic hepatitis C virus infection,4518 with benefits for cholesterol, blood pressure, and blood sugar control,4519 but as I note in my video see.nf/nkchlorella, there was a concerning case report of apparent chlorella-induced psychosis that makes me wary.

What happens if you cook it? If you compare raw chopped garlic to garlic that’s been cooked in various methods, you can see dramatic drops in one of the purported active ingredients. You can get a 66 percent drop when you boil it for six minutes, 94 percent less when you simmer it for fifteen minutes, and a full 100 percent wipeout from just one minute of stir-frying it.4525 What about roasted garlic? Surprisingly, even though roasting is done at temperatures hotter than boiling water, it preserves about twice as much. Raw garlic has the most, but it may be easier for some to eat two or three cloves of cooked garlic than the equivalent (half a clove) of raw.

Shiitake mushrooms have also been shown to improve human immune function.

Our body is always on the lookout for PAMPs, pathogen-associated molecular patterns. These are molecules foreign to our body that are associated with infection, such as components of bacterial cell walls. We have immune cells with pattern-recognition receptors that recognize these “nonself” signatures. Not all bacteria are pathogenic, though, so, in order to be more accurate, the name was changed to MAMPs, microbe-associated molecular patterns. The beta-glucans in yeast and mushrooms are major MAMPs.

The virgin olive oil rub worked significantly better than the drug in reducing pain. A similar conclusion was reached in a trial for rheumatoid arthritis, where topical extra-virgin olive oil seemed to beat out rubbing on an NSAID gel or nothing at all (a “dry massage” control).

Those with a total cholesterol of 225 mg/dL or higher have up to twenty-five times the odds of ending up with amyloid plaques in their brains ten to fifteen years later (compared to 224 mg/dL or less).5009 Too much cholesterol in our blood is now universally recognized to be a risk factor for the development of Alzheimer’s disease.

Total brain cholesterol levels of Alzheimer’s victims on autopsy are highly variable and not necessarily higher than in people who died from other causes.5017 But, oxidized cholesterol levels are a different story.5018 Levels have been shown to dramatically increase in the brains of people with Alzheimer’s,5019 as

Lowering blood pressures therefore appears to prevent cognitive decline.

Fourteen of fifteen cross-sectional studies correlated increased arterial stiffness with impaired cognitive performance, and six of the seven longitudinal studies found that arterial stiffness appeared predictive of cognitive decline.5034 How can we reduce artery stiffness? Reduce our sodium intake. High sodium intake causes excessive arterial fibrosis, the accumulation of scar tissue in the walls of our arteries, resulting in stiffening.

The artery stiffness caused by excessive sodium intake is in fact one of the mechanisms by which too much salt raises blood pressure.5038 However, excess salt intake is now recognized as a risk factor for dementia independent of blood pressure effects by impairing artery function as well.

What does this gene do to have such a powerful impact on our health and longevity? It codes for the primary cholesterol carrier in the brain5052 and plays a major role in packaging and transporting LDL (“bad”) cholesterol throughout the body.5053 The good news is that diet can trump genetics. In the video, I explain the so-called Nigerian paradox: how the population with the highest rate of the “Alzheimer’s gene” has one of the lowest rates of Alzheimer’s disease, thanks to their extremely low blood-cholesterol levels, due to a diet low in animal fat.5054 Humans appear to have evolved to sustain an LDL level of around 25 mg/dL.5055 The average in the Western world is approximately 120 mg/dL.

Alzheimer’s manifests as a disease of the elderly, but like heart disease and most cancers, it’s a disease that may take decades to develop. Most Alzheimer’s sufferers aren’t diagnosed until they’re in their seventies,5059 but we now know that their brains began deteriorating long before that. Based on thousands of autopsies, pathologists seemed to detect the first silent stages of Alzheimer’s disease—what appear to be tangles in the brain—in half of people by age fifty and even 10 percent of those in their twenties.5060 The good news is that the clinical manifestation of Alzheimer’s disease may be preventable.

Meta-analyses of all such studies have found that higher saturated fat consumption is associated with a 40 percent increased risk of cognitive impairment,5095 a 46 percent increased risk of Alzheimer’s disease, and more than twice the risk of developing dementia in general.5096 A recent review concluded that the link between saturated fat intake and Alzheimer’s appears to be “conclusive and detrimental.

The most abundant neurotrophin is called brain-derived neurotrophic factor, or BDNF,5193 the levels of which appear to correlate with integrity of the hippocampus, the memory center of the brain.

Thankfully, boosting BDNF is as easy as lacing up our walking shoes. Physical activity is the best studied factor for boosting BDNF.5203 Based on twenty-nine trials involving more than a thousand subjects, single sessions of exercise, regular exercise, and especially acute exercise in the context of regular exercise have been shown to increase BDNF levels.5204 Cycling at 70 percent maximal work rate for just ten minutes, for example, can significantly elevate levels.5205 The greater the workout intensity, the greater the rise in BDNF,5206 but even among elderly individuals with limited ambulation, a physical therapy intervention using progressive dynamic resistance training seemed able to boost BDNF blood levels.

One food is capable of boosting BDNF after just a single meal: rye groats. Healthy young adults were randomized to a late-evening meal of either a whole-grain bread containing intact rye kernels or regular white bread. Before breakfast the next morning, more than ten hours after eating their evening meals, their blood was drawn. Those who had eaten the whole intact rye the night before had 33 percent higher BDNF levels. Given the timing, this is suspected to be a microbiome effect, bolstered by a corresponding 30 percent increase in butyrate levels in the blood.

The administration of probiotics—the good bacteria themselves—did not seem to affect BDNF levels,5228 so it may be better to pamper the good bugs we already have.

BDNF is just one of the ways fiber-derived butyrate may contribute to brain health. Elderly individuals with higher levels of butyrate in their blood tend to have lower levels of amyloid in their brains on PET scan. In vitro, butyrate inhibits the neurotoxic clumping of amyloid beta.

Butyrate maintains and repairs the barrier function of the gut,

HOW TO LOWER HOMOCYSTEINE Most people get enough B12 and B6, but the reason the elderly individuals may be stuck at a homocysteine level of 11 µmol/L5335 is that they aren’t getting enough folate.

So, should all older adults take folic acid supplements? Everyone needs to get enough folate, which is one of many reasons I recommend people eat dark green leafy vegetables and legumes every day, but, as I noted here, folic acid is not folate and may carry safety concerns. So, the best way to get folate may be from food.

Even just one week on a plant-based diet can drop elevated homocysteine levels by 20 percent, from around 11 µmol/L to 9 µmol/L,5338 which is a normal level for those replete with B vitamins.5339 This may be directly due to the folate-rich vegetables and beans or indirectly due to the fiber in the plants. Every 1 g of daily fiber consumption may increase folate levels in our blood by nearly 2 percent, perhaps by boosting folate production in the colon by all our friendly gut bacteria.

eating a handful of berries every day, an easy and delicious dietary tweak, may slow your brain’s aging by years.

The rate of decline among those who consumed 1–2 servings per day was the equivalent of being 11 years younger compared with those who rarely or never consumed green leafy vegetables.

The retina, the back of our eyeball, is actually an extension of our central nervous system. It’s an outpouching of the brain during development, and, right in the middle, there’s a yellowish spot. This is what doctors see when we look into your eye with that bright light. That spot, called the macula, is our HD camera, where we get the highest-resolution vision, and it’s packed with lutein (from the Latin luteus for “yellow”).5417 Since levels in the retina can correspond to brain levels, our eyes can be a window into our brain, and indeed the amount of “macular pigment,” which consists of lutein and other carotenoids in greens, like zeaxanthin, correlates with cognitive test scores5418 and improvements of brain function5419 and structure.

Data on green tea, however, appear to have a linear dose-response, meaning that any green tea consumption is better than none when it comes to risk of cognitive deficits, and the more, the better.

The other anti-wrinkling beverage may surprise you: hot cocoa. After drinking a beverage with about two and a half teaspoons of natural cocoa powder, subjects had a significant increase in blood flow within the skin within two hours.6196 Drink it every day for six weeks, and the redness to the same UV dose is down by 15 percent and, after twelve weeks, by 25 percent. Skin thickness, density, and hydration also improved compared to the placebo, a cocoa from which most of the flavanols had been removed. No change was found in wrinkle severity after twelve weeks,6197 but a twenty-four-week study found a significant improvement in skin elasticity and a decrease in wrinkle depth6198—just from adding less than a tablespoon of cocoa powder to their daily diet.

Periodontitis is a chronic inflammatory bacterial disease that leads to the destruction of tooth-supporting structures, such as the gums and underlying ligaments and bone.6460 These bacterial pathogens can invade the bloodstream and trigger a systemic inflammatory burden.6461 This could explain the association between missing even just a few teeth and the elevated risk of heart attacks,

prospective studies following people over time have found that tooth loss appears to predict future cognitive decline, and the more missing teeth, the higher the associated risk.

I detail a fascinating series of experiments in see.nf/overdentures, where, for example, in a study subtitled “New Teeth for a Brighter Brain,” researchers found that replacing missing molars with crowns affects the size of your pupils, suggesting that a gap in the sensation of teeth pushing against each other adversely affects brain function.

If we were really interested in minimizing disease, the ideal goal would be to drop the intake of added sugars to zero.