CHAPTER TEN
Food and Telomeres: Eating for Optimal Cell Health
Some foods and supplements are healthy for your telomeres, and some just aren’t. We are happy to report that you do not need to give up carbs or milk products to be healthy! A whole-foods diet that features fresh vegetables, fruits, whole grains, nuts, legumes, and omega-3 fatty acids is not only good for your telomeres, it also helps reduce oxidative stress, inflammation, and insulin resistance—factors that, as we’ll explain here, can shorten your healthspan.
It happens every single day: Morning arrives. I (Liz) am not a morning person, but I get out of bed and stagger to the kitchen, slowly waking up as I go. My husband, John, who is an early bird by nature, has kindly brewed me a cup of coffee.
“Milk?” he asks.
Well, that’s a tough question for the predawn hours, made tougher by nutrition advice that often feels confusing. Yes, I like milk in my coffee. But should I pour it in? Milk is healthy, right? After all, it contains calcium and protein and is fortified with vitamin D. But should I reach for whole milk or skim? Or should I take a pass altogether?
Each additional breakfast item poses its own set of nutrition dilemmas:
Toast. Too many carbs, even if it’s whole wheat? What about a potential reaction to gluten?
Butter. Will a little fat increase feelings of fullness, which is good, or will it clog the arteries, which is bad?
Fruit. Better to just ditch the toast idea and make a smoothie instead? Or… is fruit dangerously loaded with sugars?
These are a lot of questions to answer when you’re still barely awake and the coffee hasn’t kicked in yet. We are both scientists, trained in sifting through complicated evidence, but sometimes we still struggle to figure out what is healthiest to eat.
On mornings like this, telomeres offer a fundamental guide to the foods that are best for us. We trust telomere evidence because it looks at how the body responds to foods at the microlevel. And we take the evidence seriously, because it aligns well with the emerging knowledge in nutrition science. These findings tell us that diets don’t work, and that the most empowering choice we can make is to eat fresh, whole foods instead of processed ones. As it turns out, eating for healthy telomeres is very pleasant, satisfying, and nonrestrictive.
THREE CELLULAR ENEMIES AND HOW TO STOP FEEDING THEM
You’ve heard us issue warnings about inflammation, insulin resistance, and oxidative stress, which create an environment that is toxic for telomeres and cells. Think of these conditions as three enemies that lurk inside each of us. You can eat foods that feed these three villains—or you can eat foods that fight them, shifting the cell environment to one that is healthier for telomere upkeep.
The First Cellular Enemy: Inflammation
Inflammation and telomere damage share a mutually destructive relationship. One makes the other worse. As we’ve explained, aging cells, with their short or damaged telomeres (plus any other breaks in the DNA that do not get repaired), send out proinflammatory signals that cause the body’s immune system to turn on itself, damaging tissues all over the body. Inflammation can also cause immune cells to divide and replicate, which shortens telomeres even more. Thus a vicious cycle is set up.
Here’s what can happen to an inflamed mouse: Researchers took a group of mice and knocked out part of a gene that protects against inflammation; without that part of the genetic code, the mice quickly developed a serious case of chronic inflammation. Their tissues accumulated short telomeres and senescent cells. The more senescent cells in their liver and intestines, the faster the mice died.1
One of the best ways for you to protect yourself against inflammation is to stop feeding it. The glucose absorbed from French fries or from refined carbohydrates (white bread, white rice, pasta), and from sugary candies, sodas, juices, and most baked goods, hits your bloodstream fast and hard. That uptick of blood glucose also causes an increase in cytokines, which are inflammatory messengers.
Alcohol acts as a kind of carb as well, and too much alcohol consumption appears to increase C-reactive protein (CRP), a substance that is produced in the liver and rises when there is more inflammation in the body.2 Alcohol is also converted to a chemical (acetaldehyde, which is a carcinogen) that can damage DNA and in high doses could also harm telomeres. At least, it harms telomeres in cells in the laboratory—we have no idea if such high doses are ever achieved in humans. So far, it appears that chronic heavy alcohol use may be associated with shorter telomeres and other signs of an aged immune system, but there are no consistent relationships between light alcohol intake and telomeres.3 It is okay to enjoy your occasional drink!
There is more good news, too, especially if you are concerned about those mice who were genetically engineered for chronic inflammation. When the mice were given an anti-inflammatory or an antioxidant drug, the telomere dysfunction was reversed. The mice’s telomeres rebounded, and senescent cells stopped accumulating, so that cells could continue their dividing and renewing. This suggests that all of us can protect our telomeres from inflammation, but it’s safest and smartest to do it without drugs. For a start, we can simply eat the foods that help prevent an inflammatory response from happening in the first place. And what a marvelous selection of sweet and savory plant foods we have to choose from: think of red, purple, and blue berries; red and purple grapes; apples; kale; broccoli; yellow onions; juicy red tomatoes; and green scallions. All these foods contain flavonoids and/or carotenoids, a broad class of chemicals that gives plants pigment. They are also especially high in anthocyanins and flavonols, subclasses of flavonoids that are related to lower levels of inflammation and oxidative stress.4
Other anti-inflammatory foods include oily fish, nuts, flaxseed, flax oil, and leafy vegetables—because all these items are rich in omega-3 fatty acids. Your body requires omega-3s to reduce inflammation and keep telomeres healthy. Omega-3s help form cell membranes throughout the body, keeping the cell structure fluid and stable. In addition, the cell can convert omega-3s into hormones that regulate inflammation and blood clotting; they help determine whether artery walls are rigid or relaxed.
It’s been known for a while that people with higher blood levels of omega-3s have lower cardiovascular risk. Newer research suggests an exciting additional possibility: omega-3s may be helping to do that by keeping your telomeres from declining too quickly. Remember, telomeres shorten with age; the goal is for this shortening process to happen as slowly as possible. One study looked at the blood cells of 608 people, all of whom were middle-aged and had stable heart disease. The more omega-3s in their blood cells, the less their telomeres declined over the next five years.5 And the less the telomeres declined, the more likely it was that these subjects, who were not so healthy to begin with, would survive the next four years.6 Of those who had telomere shortening, 39 percent died—whereas of those who had apparent lengthening, only 12 percent died. The less your telomere length declines, the less likely you are to fall into the diseasespan and early death.
Figure 23: Omega-3 Fatty Acids and Telomere Length over Time. The higher the levels of omega-3s in the blood (EPA and DHA), the less telomere shortening over the next five years. Each one standard deviation above the average omega-3 levels predicted 32 percent lower chances of shortening. This effect was even stronger in those who started off with longer telomeres (since longer telomeres shorten more quickly).7
So enjoy fresh oily fish (including sushi), salmon and tuna, leafy vegetables, and flax oil and flaxseeds. (For state-by-state U.S. recommendations for fish that are caught or farmed in ways that cause less harm to the environment, consult the Monterey Bay Aquarium Seafood Watch website at http://www.seafoodwatch.org/seafood-recommendations/consumer-guides.) But should you take omega-3 supplements, otherwise known as fish-oil capsules? There has been only one randomized trial on omega-3 supplementation and telomeres, a study by psychologist Janice Kiecolt Glaser at Ohio State, and the results were suggestive. She found that people who took fish-oil supplements for four months did not have longer telomeres than people who took a placebo. However, across all the groups, the greater the increases in omega-3s in the blood relative to their levels of omega-6 fatty acids, the greater the telomere lengthening over that period.8 The omega supplementation also reduced inflammation, and the greater decreases in inflammation were associated with increases in telomere length. (Omega-6s are polyunsaturated fats that come from sources like corn oil, soybean oil, sunflower oil, seeds, and certain nuts.) We must note, though, that those taking the supplements had other significant telomere-friendly changes: reduced levels of oxidative stress and inflammation. The results appear to depend on how well each person absorbed the levels of omega-3 polyunsaturated fats from the supplements.
Your blood levels of omega-3s, or any nutrient, are not always directly related to whether you’re consuming dietary or supplement sources. All kinds of complicated and mostly unknowable factors affect this number: how well you absorb the nutrient, how well your cells use it, how fast you metabolize and lose it. (This is a good piece of information to keep in mind whenever you read recommendations for diet and supplementation.) In general, we suggest that everyone try to get their nutrients from their diet, but when that’s just not possible, supplementation can be a reasonable alternative (make sure you check with your physician first). Even the most innocent-seeming supplements can have side effects or interact with medications you’re already taking. They could also be contraindicated for people with certain health conditions. A general consensus seem to be a daily dosage of at least 1,000 milligrams of a mixture of EPA and DHA, which is similar to the low dose tested in the Ohio State study. For sustainability reasons, we strongly suggest the vegetarian alternative, which is made from algae. Fish have omega-3s because they eat algae. We can eat algae, too, sustainably farmed algae that contains DHA. The oceans cannot support enough fish oil to maintain the world’s healthy telomeres. So far, it appears the DHA from algae promotes similar benefits to cardiovascular health as the DHA from fish.
Telomere research suggests that you should make consumption of omega-3s a priority. But you also have to keep an eye on the balance between your omega-3s and omega-6s, because the typical Western diet tilts us more toward omega-6s than omega-3s. To keep your omegas in balance, we suggest that you keep eating healthy, unprocessed foods like nuts and seeds—but dramatically reduce your consumption of fried foods, packaged crackers, cookies, chips, and snacks, which often contain oils made with high amounts of omega-6s, as well as saturated fats, which are a risk factor for cardiovascular disease.
There’s another chemical in our body worth getting to know: homocysteine, which is chemically related to cysteine, one of the amino acid building blocks of proteins. Homocysteine levels go up with aging, and correlate with inflammation, wreaking havoc on the lining of our cardiovascular system to promote heart disease. In many studies, having high homocysteine is associated with having short telomeres. But telomeres reflect the input of many factors. So it is no surprise that in one study, the relationship between telomeres and mortality appears to be due in part to both high inflammation and high homocysteine—we don’t know which came first.9 The good news here is that if you have especially high homocysteine, this is one of the cases where a vitamin pill might help—B vitamins (folate or B12) appear to reduce homocysteine.10 (Check with your doctor to see if you should be taking this supplement.)
The Second Enemy: Oxidative Stress
Human telomeres have a DNA sequence that looks like this: TTAGGG, repeated in tandem over and over, commonly over a thousand times at each chromosome end. Oxidative stress—that dangerous condition that occurs when there are too many free radicals and not enough antioxidants in your cells—damages this precious sequence, especially its GGG segments. Free radicals take aim at that big juicy row of GGG pieces, a particularly sensitive target. After free radicals have their way, the DNA strand is broken; the telomere gets shorter faster.11 It’s as if the rich meal of GGGs has been fed to the cellular enemy, oxidative stress. In cells grown in the lab, oxidative stress damages telomeres, and it also reduces the telomerase activity that can replenish shorter telomeres. It’s a double whammy.12
But if you pump up the cells’ medium (the liquid soup that supports a cell’s life when it’s sitting in a lab flask) with vitamin C, the telomere is protected from the free radicals.13 Vitamin C and other antioxidants (like vitamin E) are scavengers that gobble up free radicals, preventing them from harming your telomeres and cells. People with higher blood levels of vitamins C and E have longer telomeres, but only when they also have lower levels of a molecule known as F2-isoprostane, which is an indicator of oxidative stress. The higher this ratio between blood antioxidants and F2-isoprostane, the less oxidative stress there is in the body. This is just one of the many reasons you should eat fruits and vegetables every day; they offer some of the best sources of antioxidant protection. To get sufficient antioxidants in your diet, eat plenty of produce, especially citrus, berries, apples, plums, carrots, green leafy vegetables, tomatoes, and, in smaller portions, potatoes (red or white, with the skin on). Other plant-based sources of antioxidants are beans, nuts, seeds, whole grains, and green tea.
At this point, we don’t suggest getting your antioxidants from a supplement if your goal is telomere health. That’s because the evidence for a connection between antioxidant supplements and healthy telomeres is still inconclusive. Some studies have found that the higher the level of certain vitamins in the blood, the longer the telomeres, and we have listed these in the table here. However, while some studies find multivitamin use accompanies longer telomeres,14 at least one study found that taking a multivitamin was related to shorter telomeres.15 Also, high antioxidant levels even provoked laboratory-grown human cells to take on certain cancerous properties, a finding that, again, may warn us that too much of a good thing may be, simply, too much. In general, antioxidants from food are typically better absorbed by the body and may have more powerful effects than supplements.
The Third Enemy: Insulin Resistance
Nikki, a physician and administrator at her hometown hospital, has a vice: massive consumption of the sugared soda Mountain Dew. She developed the habit in residency, when she learned to rely on its sugar and caffeine to stay awake. The habit has remained with her. Early each morning, Nikki pulls a one-liter bottle of Mountain Dew from a small refrigerator in her garage, which is dedicated to warehousing her stash. She sets the bottle in the passenger seat of her car on the way to work. At each stoplight, she unscrews the bottle and takes a swig. When she arrives at work, the bottle goes into the fridge. After grand rounds: a swig. After a meeting: swig. After finishing some paperwork: swig. By the end of her long, grueling day, the bottle is empty. “I couldn’t get through without it,” Nikki says, with a fatalistic shrug of her shoulders.
As a doctor, Nikki knows that a daily one-liter dose of Mountain Dew is not a healthy habit. But like nearly half of all Americans, she drinks soda anyway. These folks might as well give the third enemy—insulin resistance—a straw and say, “Drink up; this stuff will help you get as big and as terrifying as you want to be.”
Here’s a frame-by-frame shot of what happens when you swallow sugary soda, or “liquid candy”: Almost instantaneously, the pancreas releases more insulin, to help the glucose (sugar) enter cells. Within twenty minutes, glucose has built up in the bloodstream and you have high blood sugar. The liver starts to turn sugar into fat. In about sixty minutes, your blood sugar falls, and you start thinking about having more sugar to pick you back up after the “crash.” When this happens often enough, you can end up with insulin resistance.
Is soda the new smoking? Maybe. Cindy Leung, a nutritional epidemiologist at UCSF and one of our collaborators, found that people who drink twenty ounces of sugary soda daily have the equivalent of 4.6 extra years of biological aging, as measured by telomere shortness.17 That, astonishingly, is about the same level of telomere shortness caused by smoking. When people drink eight ounces of soda, their telomeres are the equivalent of two years older. You may be wondering if people who drink soda have other unhealthy habits that may affect the results—and that’s a great question. In this study, which looked at around five thousand people, we did what we could to address confounding factors. We corrected for some available factors, including diet and smoking; and then we corrected for all available factors, including diet, smoking, BMI, waist circumference (to gauge belly fat), income, and age, that might have otherwise explained away this association. The association did not go away. This association between soda and telomeres exists in young children, too. Janet Wojcicki found that at three years old, children who were drinking four or more sodas a week had a greater rate of telomere shortening.18
Sports drinks and sweetened coffee drinks are liquid candy, too. They contain as much sugar as a typical soda (42 grams in a 12-ounce-tall Peppermint Mocha from Starbucks) so it is wise to stay away from them, or to drink them only rarely, as a special treat.19 Sodas and sweetened beverages are a dramatic example of sugar’s harm to telomeres, because of the delivery method. It’s a fast rush of sugar with no fiber to slow it down. Almost anything that’s considered a dessert or a treat is a source of high sugar: cookies, candy, cakes, ice cream. Once again, refined products like white bread, white rice, pasta, and French fries are high in simple or rapidly absorbed carbohydrates and can wreak havoc on your blood sugar levels, too.
To prevent insulin spikes that can eventually lead to insulin resistance, focus on foods that are higher in fiber: Whole-wheat bread, whole-wheat pasta, brown rice, barley, seeds, vegetables, and fruits are all excellent sources. (Fruits, although they contain simple carbohydrates, are healthy because of their fiber content and overall nutritional value; fruit juices, from which the fiber has been extracted, are generally not.) These foods are also filling, which helps you avoid eating excess calories. They are the same foods that help reduce the belly fat that is so closely associated with insulin resistance and metabolic disorder.
Figure 24: Finding a Balance—as Guided by Telomeres. Choose more foods high in fiber, antioxidants, and flavenoids, like fruits and vegetables. Include foods high in omega-3 oils, like seaweed and fish. Choose less refined sugars and red meat. A healthy dietary balance, like the one pictured above, will lead to healthy shifts in your blood to high nutrients and less oxidative stress, inflammation, and insulin resistance.
A HEALTHY EATING PATTERN
Platters of freshly caught fish, bowls heaped with fruits and vegetables in deep, rich hues, dishes of hearty beans, whole grains, nuts and seeds… it’s a menu for a feast. It’s also a recipe for supporting a healthy cellular environment. These foods reduce inflammation, oxidative stress, and insulin resistance. These foods fit into a healthy eating pattern that is great for telomeres and overall health.
Around the world—from Europe to Asia to the Americas—eating habits can be very roughly divided into two categories. There are people whose diets feature lots of refined carbohydrates, sweetened sodas, processed meat, and red meat. And then there are people who have a high intake of vegetables, fruits, whole grains, legumes, and low-fat, high-quality sources of protein, including seafood. This healthier diet is sometimes called the Mediterranean diet, but most cultures around the globe have some version of this eating pattern. Some of the details vary—some cultures eat more dairy or seaweed—but the general idea is to eat a variety of fresh, whole foods, and for most of these foods to come from a low spot on the food chain. Some researchers call this the “prudent dietary pattern.” That’s an accurate label, though it doesn’t capture just how delicious and healthy these foods are.
People who follow this prudent pattern have longer telomeres, no matter where they live. In Southern Italy, for example, elderly people who followed the Mediterranean diet had longer telomeres. The more closely the adhered to this type of a diet, the better their overall health and the more they could fully participate in the activities of daily living.22 And in a population study of middle-aged and older people in Korea, people who followed the local version of a prudent dietary pattern (i.e., more seaweed and fish) had longer telomeres ten years later than people who ate a diet high in red meat and refined, processed foods.23
We’ve been speaking of broad dietary patterns, but what are the best particular foods for healthy telomeres? The Korean study gives us a clue. The more that people ate legumes, nuts, seaweed, fruits, and dairy products, and the less they consumed red meat or processed meat and sweetened sodas, the longer their telomeres in their white blood cells.24
The benefits of eating wholesome, unprocessed foods—and not too much red meat or processed meats—hold strong across the world, through adulthood, and all the way into old age. In 2015, the World Health Organization identified red meat as a probable cause of cancer and processed meat as a cause.25 When types of meat are examined in telomere studies, processed meat appears worse for telomeres than unprocessed red meat.26 Processed meat refers to meat that has been altered (smoked, salted, cured), such as hot dogs, ham, sausage, or corned beef.
Of course, it is best to eat well throughout your entire life, but it is never too late to begin. The chart that follows can help guide your daily food choices. In general, though, we suggest that you worry less about any particular food item (an attitude that makes mornings easier for Liz) and focus instead on eating a variety of fresh, wholesome foods. You’ll find yourself enjoying foods that fight inflammation, oxidative stress, and insulin resistance, without needing to plan carefully in advance. And you will find that you naturally follow the kind of eating plan that is healthy for your telomeres. Plus, you won’t shorten your telomeres by worrying too much about all of the food choices you make every day!
We have discussed vitamin D and omega-3 supplements, which are often found to be deficient. However, outside of these, we do not make specific recommendations on supplements, because each person’s needs are different, and nutrition studies’ conclusions about supplements are notoriously changed by new studies. It’s hard to be confident about the effects and safety of high doses of anything.
NUTRITION AND TELOMERE LENGTH**
Food, Drinks, and Telomere Length
Associated with Shorter Telomeres:
Red meat, processed meat29
White bread30
Sweetened drinks31
Sweetened soda32
Saturated fat33
Omega-6 polyunsaturated fats (linoleic acid)34
High alcohol consumption (more than 4 drinks per day)35
Associated with Longer Telomeres:
Fiber (whole grains)36
Vegetables37
Nuts, legumes38
Seaweed39
Fruits40
Omega-3s (e.g., salmon, arctic char, mackerel, tuna, or sardines)41
Dietary antioxidants, including fruits, vegetables, but also beans, nuts, seeds, whole grains, and green tea42
Coffee43
Vitamins
Associated with Shorter Telomeres:
Iron-only supplements44 (probably because they tend to be high doses)
Associated with Longer Telomeres:
Vitamin D45 (mixed evidence)
Vitamin B (folate), C, and E
Multivitamin supplements (mixed evidence)46 47
TELOMERE TIPS
Inflammation, insulin resistance, and oxidative stress are your enemies. To fight them, follow what’s been called a “prudent” pattern of eating: Eat plenty of fruits, vegetables, whole grains, beans, legumes, nuts, and seeds, along with low-fat, high-quality sources of protein. This pattern is also known as the Mediterranean diet.
Consume sources of omega-3s: salmon and tuna, leafy vegetables, and flax oil and flaxseeds. Consider supplementation with an algae-based omega-3 supplement.
Minimize red meat (especially processed meat). You might try to go vegetarian for at least a few days each week. Eliminating meat can benefit your cells as well as the environment.
Avoid sugary foods and drinks, and processed foods.