8/19/2026

This is the sixth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

After discussing ultra-processed foods, sweeteners, salt, carbohydrates, protein, fat, caffeine, alcohol, and red meat, Topol turns to the other side of the equation: What should we actually eat?

Good Food

1. A healthy diet is strongly associated with a longer healthspan and lower disease risk.

Large, long-term studies consistently associate healthy eating with a 15–20% lower risk of cardiovascular disease, as well as lower all-cause mortality, cancer and neurodegenerative diseases.

There also appears to be a dose-response relationship: the more consistently people eat healthy foods, the lower their risk of several major chronic diseases.

Topol's healthy eating list:

• Fruits and vegetables

• Legumes such as beans and lentils

• Whole grains

• Nuts and seeds

• Olive oil and avocados

• Fatty fish such as salmon and tuna

These are mostly whole or minimally processed foods, with plenty of fiber and healthy fats.

Olive oil, for example, has been associated with about a 20% lower risk of all-cause mortality, and consuming at least 7 grams a day was associated with a 28% lower risk of dementia in one large observational study.

Nuts and seeds are another interesting example. Despite being calorie-dense, eating a handful regularly has been associated with about a 20% lower risk of cardiovascular disease. Interestingly, nut consumption has also been associated with less obesity and weight gain rather than more.

So calories alone don't tell us whether a food is healthy. Food quality matters.

2. Fiber is one of the stars of the story.

Topol recommends roughly 30 grams of fiber a day, adjusted for age, sex, and body size.

A large body of research has associated high-fiber diets with lower risks of:

• heart disease

• type 2 diabetes

• colon cancer

• overall mortality

Fiber slows digestion, reduces blood-glucose spikes, helps regulate cholesterol, and supports a healthier gut microbiome.

One fascinating finding he mentions is that a high-fiber diet can actually reduce the number of calories absorbed by the body. In one randomized trial, participants eating a high-fiber diet absorbed more than 100 fewer calories per day, with some people absorbing more than 400 fewer.

In a memorable phrase, Topol describes it as “pooping calories instead of absorbing them.”

This is almost the opposite of the ultra-processed-food diet.

Ultra-processed foods tend to be easy to digest, highly palatable, and calorie-dense, while fiber slows digestion and helps regulate the metabolic response to food.

3. The Mediterranean diet: the best-supported dietary pattern.

Of all the dietary patterns Topol discusses, the Mediterranean diet has perhaps the strongest overall evidence behind it.

It emphasizes:

• olive oil

• vegetables

• fruits

• legumes

• whole grains

• nuts

• fish and seafood

while reducing red and processed meat, sweets, and highly processed foods.

Evidence from large observational studies and several randomized trials—including the PREDIMED trial and the Lyon Heart Study—has associated the Mediterranean diet with lower risks of cardiovascular disease, diabetes, cancer, neurodegenerative disease, and overall mortality.

In older adults, a Mediterranean diet has also been shown to favorably affect the gut microbiome, reduce inflammation and frailty, and potentially support cognitive function.

Topol even discusses a “green Mediterranean” diet, which adds more plant-based foods while further reducing meat. A small randomized trial found improvements in LDL cholesterol, inflammation, blood pressure, and weight, although it was too small to establish long-term health outcomes.

So far, however, Topol doesn't claim that we have found a diet that is definitively better than the Mediterranean diet.

4. Taurine: promising, but not proven.

Taurine is an interesting example of how longevity research can move beyond established dietary advice.

Taurine levels appear to decline with age, and lower levels have been associated with diabetes, hypertension, abdominal obesity, and inflammation.

Animal studies are particularly intriguing. Taurine supplementation has been associated with improvements in mitochondrial function, DNA damage, inflammation, cellular senescence, and other markers of aging.

In aged rhesus monkeys, six months of taurine supplementation produced several promising improvements in health markers, including fasting glucose, bone density, and markers of mitochondrial, liver, and immune function.

Taurine-rich foods include shellfish, dark poultry meat, milk, yogurt, cheese, and peanuts. It is found in very few plant foods.

But an important caveat:

Promising animal research ≠ proven anti-aging treatment in humans.

We don't yet have randomized human trials demonstrating that taurine supplements extend healthspan.

5. Choline: important for the brain.

Choline is an essential nutrient involved in several important brain functions.

Good food sources include:

• egg yolks

• fish

• meat

• milk

• soybeans

• mushrooms

• broccoli and other cruciferous vegetables

The recommended daily intake is about 550 mg for men and 425 mg for women.

For most people eating a varied, whole-food diet, getting enough choline shouldn't be particularly difficult.

There are some intriguing findings suggesting that higher choline intake or supplementation may benefit cognitive function in older adults. But once again, Topol emphasizes that randomized trials are needed before we can draw firm conclusions.

The bigger picture

Healthy aging is about establishing a dietary pattern that consistently gives the body the right inputs.

Eat more:

vegetables, fruits, legumes, whole grains, nuts, seeds, olive oil, and fish. Get plenty of fiber.

Eat less:

ultra-processed food, added sugar, sugary drinks, processed meat, and excessive alcohol.

And don't become obsessed with any single nutrient while ignoring the quality of the overall diet.

Don't ask only, “How many calories, grams of protein, or grams of fat am I eating?” Ask, “What kind of food am I putting into my body?”

For healthy aging, food quality and overall dietary pattern may matter more than chasing nutritional extremes.

8/18/2026

This is the fifth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

Let's see what he has to say about caffeine, alcohol, red meat, and plant-based diets.

Caffeine

There are five main points Topol makes about caffeine and coffee.

1. Coffee consumption is associated with lower mortality

This is the headline finding. Large observational studies have found that coffee drinkers tend to have lower all-cause mortality, with some studies reporting reductions of around 30%.

The apparent benefit seems to peak at around four cups a day, rather than continuing to increase indefinitely.

2. Coffee is associated with a lower risk of several diseases

Across hundreds of studies, coffee and caffeine consumption have been associated with lower risks of:

• cardiovascular disease

• heart failure

• type 2 diabetes

• Parkinson's disease

• breast cancer

• colon cancer

• endometrial cancer

• prostate cancer

That's an impressive list.

But Topol is careful about the word “associated.” Most of these are observational studies. Coffee drinkers may differ from non-coffee drinkers in other ways, including exercise, diet, smoking, socioeconomic status, and other lifestyle factors. So, as always:

Correlation does not establish causation.

3. The old fear that coffee causes dangerous heart rhythms appears overstated

For decades, people with heart problems were often warned to avoid coffee because caffeine was thought to increase the risk of arrhythmias. But newer evidence does not support such a broad warning.

Large studies have found no higher overall risk of arrhythmias among coffee drinkers, and some studies have actually found a lower risk.

Topol's practical conclusion is that, for most people, coffee does not appear to pose the cardiovascular danger that was once widely assumed.

4. Decaf coffee may also have benefits

Some of the favorable associations have also been observed with decaffeinated coffee.

That suggests caffeine may not be the only—or even necessarily the main—reason coffee might be beneficial.

Coffee contains hundreds of compounds, including polyphenols such as chlorogenic acid.

Topol mentions several possible mechanisms, including:

• antioxidant effects

• improved insulin sensitivity

• reduced inflammation

• favorable changes in the gut microbiome

• effects on brown adipose tissue

• possible effects on DNA repair

But he emphasizes that none of these explanations has been established as the definitive mechanism.

5. The big caveat: we still don't know whether coffee itself causes the benefit

Topol is enthusiastic about the evidence, but he doesn't overstate it.

The overall evidence is reassuring and potentially quite encouraging, but we still don't have unequivocal proof that coffee itself causes people to live longer or become healthier.

Alcohol

The evidence surrounding alcohol is much less favorable than the evidence surrounding coffee.

1. The supposed health benefits of moderate alcohol consumption are highly questionable

The long-standing belief that moderate drinking—particularly red wine—is good for the heart has been seriously challenged.

The famous “French paradox” does not establish that wine itself protects against cardiovascular disease.

2. Alcohol is a known carcinogen

Alcoholic beverages are classified as carcinogenic to humans.

There is particularly strong evidence linking alcohol consumption to cancers of the oral cavity and esophagus, along with several other cancers.

Several countries are therefore moving toward stronger health warnings on alcohol products.

3. Very light drinking appears to carry relatively little risk, but risk rises with consumption

Some studies produce a J-shaped curve, in which very light alcohol consumption is associated with slightly lower observed risk, followed by rapidly increasing risk at higher levels of consumption.

But Topol does not interpret this as proof that alcohol is beneficial.

4. Alcohol increases blood pressure and cardiovascular risk

There is a dose-response relationship between alcohol consumption and hypertension.

Topol also cites Mendelian-randomization research supporting a causal relationship between alcohol consumption and certain cardiovascular diseases.

As consumption increases, the risks become substantially greater.

5. Overall conclusion

The message is much clearer and more negative than his discussion of coffee:

Alcohol is not a health-promoting substance. If someone enjoys an occasional drink, very light consumption may carry relatively little risk, but there is no good reason to drink for health benefits, and the risks rise quickly as consumption increases.

Red Meat and Plant-Based Diets

Topol places red meat and plant-based foods at almost opposite ends of the spectrum—not only in terms of potential health effects, but also in terms of environmental impact.

1. Processed meat is the biggest concern

Processed meats such as bacon, hot dogs, and sausages are classified by the World Health Organization's cancer agency as carcinogenic and are associated with increased cancer and mortality risks.

Their production also has a substantial environmental impact.

Unprocessed red meat, particularly beef and pork, is classified as “probably carcinogenic” and has also been associated with higher mortality risk.

2. But the evidence deserves some caution

This is an important qualification.

Systematic reviews involving nearly 120 studies found an increased cancer risk associated with processed and unprocessed red meat, but concluded that the absolute increase was small and the certainty of the evidence was low.

The evidence concerning cardiometabolic outcomes is similarly unsettled.

A large U.S. cohort followed for 19 years found small increases in all-cause mortality associated with both processed and unprocessed meat, but not with fish or poultry. Another analysis found that consuming two or more servings of meat or poultry was associated with a modest 4–7% increase in cardiovascular-disease risk.

So Topol's argument is that the long-term evidence consistently points in an unfavorable direction as red-meat consumption increases, particularly for processed meat.

3. Whole-food plant-based diets show a much more favorable pattern

Multiple large studies have found associations between plant-centered diets and better health outcomes:

• A pooled analysis of nine studies involving more than 300,000 participants found a 23% lower risk of type 2 diabetes among people following plant-based diets.

• A meta-analysis of 32 studies found that replacing processed meat with plant foods was associated with lower all-cause mortality, cardiovascular mortality, and type 2 diabetes.

• Among more than 72,000 people in Japan, greater plant-protein intake was associated with an 11% lower risk of total and cardiovascular mortality.

• Replacing just 3% of calories from animal protein with plant protein was associated with a substantially lower risk of cancer mortality.

• A randomized trial involving identical twins found that a plant-based diet slowed the pace of biological aging based on DNA-methylation markers compared with an omnivorous diet.

The important distinction here is whole plant foods: vegetables, fruits, beans, lentils, nuts, seeds, and whole grains.

4. “Plant-based” does not automatically mean healthy

This is another important caveat.

Commercial plant-based meat substitutes are not necessarily equivalent to whole plant foods.

Some can be:

• high in sodium

• relatively high in saturated fat

• highly processed

• nutritionally quite different from beans, lentils, and other whole plant protein sources

Topol also raises questions about heme iron in some products and notes that long-term human evidence on these newer meat alternatives remains limited.

So:

A lentil-and-vegetable meal and a highly processed plant-based burger may both be called “plant-based,” but they are not nutritionally equivalent.

The Bottom Line

Topol's overall message is fairly straightforward:

The more red meat you eat, especially processed red meat, the less favorable your health profile is likely to be.

At the same time, the evidence for whole plant foods and plant-centered diets is considerably more encouraging.

Perhaps the simplest way to put it is:

Eat more of what comes from the ground, less of what comes from a factory, and don't expect any single food or nutrient to be a magic bullet for longevity.

8/17/2026

This is the fourth piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

There is so much to talk about in this book. In this chapter, Topol takes a close look at some of the most basic components of our diet: sweeteners, salt, carbohydrates, protein, and fat.

What I find particularly interesting is that he doesn't simply label one nutrient “good” and another “bad.” Again and again, he emphasizes that the amount matters, but so does the type and quality of what we consume.

Sweeteners

The evidence linking sugar-sweetened beverages to poor health outcomes is particularly consistent. Topol cites studies associating high consumption with higher all-cause mortality, cardiovascular mortality, cancer mortality, increased atrial fibrillation, and dental disease.

One reason is obvious: sugary drinks can deliver a large amount of rapidly absorbed sugar without making us feel particularly full.

Topol is much more cautious about artificial and non-nutritive sweeteners. The evidence is mixed. Some studies have found little compelling evidence of harm, while others suggest that certain sweeteners may affect glucose regulation or alter the gut microbiome.

His overall conclusion is that artificial sweeteners appear less concerning than large amounts of sugar, but they should not automatically be regarded as completely harmless.

For ordinary people, the practical advice is simple:

Best choices: water, unsweetened tea, unsweetened coffee, and whole fruit.

Occasionally having a sweetened drink is one thing, but don't make it a regular part of your life.

Perhaps the deeper lesson is to gradually train ourselves to need less sweetness altogether.

Salt

Topol's discussion of salt is more nuanced than simply saying, “The less, the better.”

1. Too much sodium is a problem.

The relationship between high sodium intake and hypertension is well established, although the size of the effect varies considerably from person to person.

2. Don't blindly pursue “the lower, the better.”

Different health organizations recommend somewhat different sodium limits, and the evidence doesn't support the idea that reducing sodium indefinitely will produce proportionally greater benefits.

Topol notes that moderate sodium intake is not necessarily a problem, while very high intake is much more clearly associated with cardiovascular risk.

3. Sodium may affect more than blood pressure.

Topol also discusses evidence that excessive sodium may impair blood flow to the brain through dysfunction of the blood-vessel lining, potentially affecting cognitive health.

4. Moderation is more realistic than a miserable diet.

His practical suggestions include:

• Don't routinely add salt to food.

• Pay attention to sodium on food labels.

• If you have hypertension, be particularly careful about sodium.

• If you don't have kidney disease, consider a potassium-chloride salt substitute.

• Don't turn healthy eating into an intolerable, flavorless diet.

In other words, the goal is sensible reduction, not eliminating salt from your life.

Carbohydrates

Topol introduces the term “carbotoxicity” to describe the potential harms associated with excessive carbohydrate consumption.

His message is both very low carbohydrate intake—less than about 40% of total calories—and very high intake—more than about 70%—have been associated with increased all-cause mortality.

The more important question is:

What kind of carbohydrates are you eating?

Good carbohydrates

Topol gives priority to:

• non-starchy vegetables

• legumes

• fruits

• whole grains

• resistant starch

• other high-fiber, minimally processed foods

He cites a large body of research involving 185 prospective studies and 58 randomized trials showing that consuming roughly 25–30 grams of dietary fiber per day was associated with substantially lower risks of cardiovascular disease, type 2 diabetes, colorectal cancer, and all-cause mortality.

Poor-quality carbohydrates

These include:

• added sugars

• refined grains

• rapidly digested starches

• highly processed potato products

• foods with a high glycemic load

These foods can cause rapid rises in blood glucose and insulin and are associated with weight gain and poorer cardiovascular outcomes.

So once again, the message:

“Eat better carbs.”

Protein

The standard protein RDA of 0.8 grams per kilogram of body weight per day may not adequately reflect the needs of seniors. Much of the evidence behind that recommendation came from relatively short-term studies involving younger adults.

Because sarcopenia—the age-related loss of muscle mass and strength—is one of the major threats to healthspan.

Topol argues that older adults probably need more protein than the basic RDA, although the optimal amount remains uncertain. He considers increasing intake to around 1.2 g/kg/day reasonable.

But he also warns against assuming that more protein is always better.

Very high protein intake—particularly above about 1.5 g/kg/day—has been associated in some research with potentially unfavorable effects, including changes in the gut microbiome and production of pro-inflammatory metabolites. He also discusses concerns about leucine-rich animal proteins and pathways related to atherosclerosis and cellular waste disposal.

However, this is an area where Topol acknowledges significant uncertainty.

We don't yet have the kind of long-term, large-scale randomized trials that could definitively tell us exactly how much protein older adults should consume to maximize healthspan and prevent sarcopenia.

There's another interesting limitation: food labels don't tell us how much of each essential amino acid a food contains. So consumers can't easily compare foods based on amino acids such as leucine, lysine, or methionine.

The practical message I take from this section is:

Older adults should pay attention to getting enough protein to preserve muscle, but don't assume that an extremely high-protein diet is automatically healthier.

Fat

Fat is another example of why nutrition isn't as simple as “avoid fat.”

Topol explains that fat activates a gut-brain reward pathway involving the vagus nerve. This pathway can work together with the brain's sugar-reward pathway to increase dopamine signaling and encourage overeating.

That helps explain why combinations of fat + sugar can be so difficult to resist.

These foods combine multiple powerful reward signals while packing a lot of calories into a relatively small amount of food:

• ice cream

• pastries

• donuts

• cookies

• chocolate

• many packaged desserts

Fat quality matters

Topol also emphasizes that the type of fat matters.

Replacing saturated fats with mono- and polyunsaturated fats, particularly plant-based unsaturated fats, has been associated with more favorable cardiovascular and metabolic outcomes.

This is another reason not to think simply in terms of “high-fat” versus “low-fat.”

A handful of nuts, olive oil, or avocado is very different from a highly processed food loaded with saturated fat.

What about the ketogenic diet?

Topol is skeptical of the popular ketogenic diet, which is extremely high in fat and very low in carbohydrates.

He cites research associating ketogenic diets with potential problems including:

• higher cholesterol

• cardiovascular risk

• “keto flu”

• brain fog

• fatty liver

He also discusses a randomized NIH study comparing a ketogenic diet with a plant-based, low-fat diet. Interestingly, participants on the ketogenic diet consumed about 700 more calories per day during the two-week study, and the low-fat group lost more weight.

That finding challenges the idea that simply lowering carbohydrates and insulin will necessarily reduce hunger and food intake.

So what is the big picture?

I think Topol's message can be summarized in one sentence:

On carbohydrates, protein, or fat; pay attention to their quality, their source, and the amount you consume.

All three macronutrients are necessary. They can also contribute to health problems when consumed in inappropriate forms or excessive amounts.

In summary:

Carbohydrates: choose fiber-rich, minimally processed sources.

Protein: get enough to preserve muscle as you age, but don't assume extremely high intake is better.

Fat: favor unsaturated fats and pay attention to the powerful combination of fat and sugar in highly palatable foods.

Sugar: particularly avoid making sugary beverages a regular habit.

Salt: reduce excessive intake without turning healthy eating into an unsustainable low-sodium diet.

8/16/2026

This is the third piece in my series about Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

Ultra-Processed Foods (UPFs)

One topic in the book that caught my attention is ultra-processed foods, or UPFs.

In simple terms, these are industrially formulated food products made from processed ingredients and additives rather than primarily from whole foods. They often contain combinations of added sugars, refined fats, sodium, artificial flavors and colors, emulsifiers, and other additives. Many are designed to be inexpensive, convenient, shelf-stable, and extremely palatable.

Common examples include:

• sodas and energy drinks

• packaged chips, cookies, and candy

• mass-produced packaged breads and buns

• frozen ready-to-heat meals, such as pizza and TV dinners

• reconstituted meat products, such as hot dogs, fish sticks, and chicken nuggets

• sweetened breakfast cereals

In Chinese, people might loosely put some of these foods under terms such as 零食、预制食品 or 垃圾食品, although these terms are not exact equivalents of “ultra-processed foods.”

What does the research show?

Topol cites a randomized controlled trial in which participants who followed an ultra-processed-food diet gained weight, while those who ate an unprocessed diet lost weight, despite the diets being matched in the amount of calories, sugar, fat, fiber, and other nutrients that were offered.

He also cites research associating higher UPF consumption with a range of health problems, including fatty liver disease, some cancers, sleep disorders, inflammatory bowel disease, depression, and dementia.

One statistic particularly caught my attention:

A 62% increase in all-cause mortality was associated with consuming more than four servings of UPF per day.

Topol says this finding was supported by a comprehensive review of 45 studies involving approximately 75,000 women and 40,000 men followed for up to 30 years.

But perhaps the most fascinating part of the chapter is a personal experiment conducted by Topol's friend, Chris van Tulleken, a British physician-scientist and author of Ultra-Processed People.

One month on an 80% UPF diet

Van Tulleken conducted an experiment on himself. He increased the proportion of ultra-processed foods in his diet from about 20% to 80% for one month, while undergoing extensive assessments before and after the experiment, including blood tests and brain imaging.

The result was shocking: 

He gained 15 pounds in one month.

He also reported major changes in brain connectivity involving regions associated with habitual behavior, reward, and appetite.

His hunger-related hormonal responses changed dramatically as well. According to Topol, one of his appetite-related measures showed a fivefold increase, while his C-reactive protein, a marker associated with systemic inflammation, doubled.

But there was another fascinating twist.

Chris and his identical twin brother, Xand, had both undergone whole-genome sequencing, and their genetic profiles included many variants associated with a predisposition to obesity.

So one might expect the two brothers to respond similarly to the same diet. They didn't.

When Xand conducted the same ultra-processed-food experiment, he gained 44 pounds—nearly three times as much as Chris.

According to Topol, this was the largest weight difference observed in the extensive twin study in the United Kingdom.

Once again, it's not all in the genes

This brings me back to one of the most interesting themes in Super Agers.

Genes matter. But they don't determine everything.

The two brothers had essentially the same genetic background, yet their responses to the same diet were dramatically different.

And this is also consistent with what Topol found in the Wellderly research we discussed in my first piece: exceptional healthy aging cannot be explained simply by having the right genes.

There are clearly complex interactions among genes, diet, environment, behavior, metabolism, and many other factors.

So what should we do?

Topol's practical advice is straightforward:

Read the labels.

When choosing packaged foods, look at the ingredient list. When there is a choice, favor products with fewer ingredients and fewer unnecessary additives, and be particularly cautious about products loaded with added sugars and highly refined ingredients.

He suggests using the Open Food Facts app when you're uncertain about a product. It provides nutritional and ingredient information for millions of food products, Open Food Facts

I find this particularly useful because the most practical lesson isn't necessarily:

“Never eat processed food.”

It's: Know what you're eating.

Will UPFs eventually be treated like cigarettes?

Topol makes a provocative prediction:

Ultra-processed foods may eventually come to be regarded much like cigarettes.

The evidence concerning UPFs is compelling enough to take seriously, but it is not identical to the decades of evidence establishing the enormous harms of tobacco.

My takeaways

1. Eat more food that looks like food. Eat less food that looks like a chemistry experiment.

2. "Fiber is the polar opposite of ultra-processed foods—it slows digestion, lessens glucose spikes, and helps reduce cholesterol."

Finally, eat less of the foods that were designed NOT with your health as their primary purpose.

8/15/2026

I'm going to continue yesterday's sharing from Eric Topol's book, Super Agers: An Evidence-Based Approach to Longevity.

Topol coins two interesting terms in the book. He calls the small group of exceptionally healthy older people the “Wellderly”—healthy-aging outliers—and contrasts them with the much larger group he calls the “Illderly,” people whose later years are increasingly affected by chronic disease.

Here are some numbers that put the situation into perspective:

1. In the United States, 60% of adults aged 18 and older have at least one chronic disease.

2. 40% have two or more chronic diseases.

3. Among people aged 65 and older, 80% have two or more chronic diseases, 23% have three or more, and about 7% have five or more.

As Topol puts it:

“If you or someone you know has a chronic condition, it is probably one of the big four: diabetes, heart disease, cancer, or some kind of neurodegeneration. Beyond these, chronic lung and kidney disease are high on the list.”

This, he says, is what his book is ultimately about: how we can maximize our healthspan and stay on the Wellderly path rather than moving toward the Illderly path.

Why the immune system?

When Topol turns to age-related diseases, I was somewhat surprised that he began with the immune system.

But his explanation is fascinating.

He writes:

“The recognition of the immune system as a common mechanistic underpinning for chronic diseases, whether it be related to why they occur or to the untoward sequelae that they induce, is a historic turning point.”

In other words, the immune system plays a central role in many of the diseases associated with aging.

Heart disease, cancer, and neurodegenerative diseases often take decades to develop. That means there may be a very long window during which we can potentially intervene before they become clinically apparent.

Take atherosclerosis, which can eventually lead to heart attacks and strokes. It remains the world's leading cause of death and disability. A major component of the process is inflammation in the walls of blood vessels—and inflammation is generated by the immune system.

Cancer provides another example. Cancer doesn't usually become deadly simply because a tumor exists; the danger often comes when cancer cells spread to other parts of the body. Our immune system plays an important role in recognizing and controlling abnormal cells.

The Brain is another example. Increasing evidence points to the role of chronic inflammation and immune-system activity in neurodegenerative diseases such as Alzheimer's and Parkinson's disease.

And when the immune system mistakenly attacks our own tissues, we get autoimmune diseases—for example, attacking the nervous system in multiple sclerosis or the joints in rheumatoid arthritis.

Topol therefore makes a much broader argument:

Dysfunction of the immune response is one of the principal drivers of accelerated aging.

This is where things get particularly interesting.

The answer isn't simply to “boost” the immune system. An immune system that is too weak can leave us vulnerable to infection and disease, but an immune system that is excessively or chronically activated can also damage our own tissues.

Topol compares it to a Goldilocks problem:

Too little isn't good. Too much is bad. We need to get it just right.

And perhaps the most important part is that the right balance may be different for different people and different tissues.

Only relatively recently have scientists begun developing tools to precisely modulate immune and inflammatory responses. According to Topol, this is an area where the science is advancing rapidly.

Which brings me to the question I'm most interested in:

If healthy aging depends partly on keeping our immune response “just right,” how do we actually do that?

That may be where the story gets really interesting.