Chapter 47
Supplements
Fiber intake may just be a marker for the consumption of plant foods, since only they contain fiber. So the apparent link between fiber intake and telomere length may have nothing to do with fiber at all; perhaps it is due to one or more other protective components of plant foods. This is like the studies of people with longer telomeres who take in more carotenoids through their diet or have more of them in their blood. Carotenoids are plant pigments, such as beta-carotene. There, too, we may be dealing with some other effect of eating plants. Coffee drinking is also associated with longer telomeres, and coffee contains neither fiber nor carotenoids. Interestingly, coffee is associated with longer telomeres, but caffeine with shorter ones, presumably because these days such a large portion of caffeine intake comes from sodas and sugar-sweetened energy drinks.
Green tea was linked to longer telomeres in older men, and in rats it has been proven to protect telomeres, but clinically it wasn’t tested until 2016 in an intervention study. Since it’s hard to make a convincing placebo tea, there were capsules with green tea extract. In my video see.nf/nutsandtea I show that the participants randomized to drink the equivalent of about four cups of green tea a day for five months experienced a substantial increase in telomere length compared to the placebo group. (Whether nuts are useful for our telomeres is unclear.)
In principle, green tea is green leafy vegetables in hot water. What about eating green leafy vegetables? In the video I show a dietary intervention in which the equivalent of one and a quarter cups of kale daily—cooked, not raw—increased telomerase activity after just five days. For the first time, the study provided evidence that telomerase activity can respond to a dietary intervention within days. However, not with just any food, but with the healthiest food in the world—dark green leafy vegetables in the crucifer family. 16 days after the end of kale consumption, however, telomerase activity dropped back to the old levels. So try, as I recommend in my Daily Dozen, to incorporate cruciferous vegetables into your diet every day.
Supplements
One of the reasons I don’t recommend supplements with green tea extracts is the risk of liver toxicity. In the past, such reactions were thought to be rare, on the order of 1 in 100 000. But now that we have large studies like the Minnesota Green Tea Trial, it has become clear that they are probably closer to 1 in 20. (In contrast, none of the studies in which green tea was simply consumed as a normal beverage turned up a liver problem.) Are there other, less risky dietary supplements that protect our telomeres?
Vitamin D
So far, almost no supplement study has found a benefit for our telomeres. Neither fish oil trials, nor cold-pressed olive oil, B vitamins, or zinc supplements successfully stopped telomere shortening. Of the ten studies on vitamin D and telomeres, only two were double-blind, randomized, and placebo-controlled, and both showed a benefit (with 60 000 IU once a month and 800 IU once daily). For details see see.nf/dtelomeres.
Astragalus
Astragalus root is one of the most widely used herbal remedies in traditional Chinese medicine and has been promoted for millennia as a “life-extending” tonic. A component of the root called cycloastragenol (product name: TA-65) appeared to slightly increase telomerase activation in vitro, but the only study suggesting a clinical benefit was funded by the company that sold TA-65 online for 600 dollars per bottle. Before the company was targeted by the Federal Trade Commission for false and misleading claims, the product grossed more than 50 million dollars. For anyone who wants to learn more, I explain the pros and cons at see.nf/astragalus.
Gotu Kola
In 2019, the strongest telomerase activator discovered to date was identified with Centella asiatica, also known as gotu kola. It nearly increased telomerase activity ninefold, making it four times more potent than TA-65. Gotu kola is widely used in both Ayurvedic and traditional Chinese medicine and is a green leafy vegetable that in Malaysia and Indonesia is typically eaten fresh in salads or cooked in soups, and in India and Thailand is consumed either juiced or as tea. In India it is seen primarily as “brain food,” and in mice it improved cognitive function, but a meta-analysis of the handful of studies conducted in humans to date found no significant effect on mental performance. Should a clinical benefit yet emerge, you can buy gotu kola tea online for only about five cents per cup.
Food for Thought
Telomeres are one of the pathways of aging that has recently entered the public consciousness. The idea of lengthening telomeres to slow or prevent aging is popular, but the research on it is, as I said, controversial. Telomere lengthening is possible by activating the enzyme telomerase, yet a constant battle rages between the forces that gnaw at our telomeres, such as aging, oxidative stress, and inflammation, and lifestyle changes that can help rebuild them.
There are concerns that boosting telomerase activity could theoretically increase cancer risk, since tumors have already hijacked the telomerase enzymes and used them to secure their own immortality, but the lifestyle changes Dr. Ornish used to protect telomeres slowed tumor development, halted it, and even reversed it in a randomized controlled dietary study in early-stage prostate cancer.
In response to Ornish’s work showing that plant-based diets can increase telomerase and lengthen telomeres, one article expressed the view that such studies might uncover mechanisms that the pharmaceutical industry would then exploit, since “in today’s world it is not always possible to live healthfully …”. If you are reading this book, you are hopefully motivated to take at least one or two steps toward a healthier life, which in the case of telomere protection includes no longer smoking and consuming less refined grain, soda, processed meat, and dairy products, while reaching for more fruits, vegetables, and other foods rich in antioxidants.
To slow this pathway of aging, you should daily:
Bottom Line
Our knowledge about these pathways of aging has made the greatest advances over the last 20 years, after I finished medical school, so much of the research I reviewed while working on this book was illuminating even for me. The more we learn about the pathways of aging, the clearer it becomes how intertwined they are. They do not exist in isolation, but interlock in complex cycles: A boost in AMPK throttles mTOR while ramping up autophagy and NAD+ levels, which in turn increases sirtuin activity, which in turn lowers IGF-1 and increases AMPK. That is why it is not surprising that they have so many common triggers.
Here is a table of interventions that can intervene in the pathways of aging and thereby slow it:
Interventions to regulate the eleven pathways of aging
Cellular senescence
Notably, since the turn of the century, research has discovered a half dozen components that can substantially extend the life span of mammals. Although the pathways of aging exchange complex signals with one another, the drugs or supplements that extend life primarily each target one of these pathways. Metformin, for example, can extend the life expectancy of mice by boosting AMPK, and rapamycin by suppressing mTOR. When taken together, they appear to work together—not only better than either one alone, but also better than the sum of their individual effects. This could be a major advantage for changes in diet and lifestyle, because they address numerous pathways of aging at the same time.