by Dave Asprey
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11
HUMANS ARE WALKING PETRI DISHES
There is no doubt that antibiotic use was a major contributor to my accelerated aging process. As a child and well into my teens, I was on a course of antibiotics almost every month due to chronic strep throat and sinusitis. These drugs dramatically altered my microbiome, the community of trillions of microorganisms living in the gut that include bacteria, fungi, viruses, and other microbes. We are learning more every day about how the microbiome impacts our health—including the aging process—and many cutting-edge doctors and researchers now believe that the microbes in your digestive tract are in fact calling the shots regarding how quickly you age.
A brand-new study shows that as animals (and likely humans) age, the gut bacteria change, and this change in bacterial composition harms your vascular system, making it stiffer. The study revealed that the gut biomes of older mice have more pathogenic inflammatory species. When these pathogenic bacteria ferment protein, they produce three times the amount of a damaging compound called TMAO than other, more beneficial bacteria. Excess TMAO leads to a stiffening of the vascular system and an increased risk of heart disease. When researchers used antibiotics to knock out the gut bacteria in the old mice, their vascular systems magically became less stiff. The researchers concluded that “the fountain of youth may actually lie in the gut.”1
But bacteria don’t just control us—they are us. In 2016, scientists from the Weizmann Institute in Israel found there are approximately 39 trillion bacterial cells in the human body.2 To date, we know of over a thousand unique species of bacteria in the human gut, and they are not just idle passengers. These bacteria digest your food, keep your immune system humming along, protect your intestines from infections, remove environmental toxins, and produce essential vitamins and chemicals to communicate with the rest of your body. As you read earlier, the mitochondria that power your cells evolved from bacteria, too.
DIVERSITY IN THE GUT
Though all human microbiomes contain roughly the same thousand species of bacteria, the exact makeup of each person’s individual microbiome is unique. Your microbiome will look very different from mine. You will have a higher percentage of some species and less of others. However, there are specific hallmarks of a young, healthy, and well-functioning gut. For instance, they contain specific combinations of microbes and, most important, a diverse mix.3 As you get older, this composition shifts in predictable and unfortunate ways unless you do something to stop it. In fact, researchers at Insilico Medicine, a biotechnology company, can now predict a person’s age within four years based solely on their gut bacteria composition.
You can think of the gut as an ecosystem similar to living soil, which is a complex mix of many different bacteria and fungi that work together to make the soil fertile. Since humans don’t have roots like plants do, we carry our soil around inside of us. Without the right mix of germs making fertile soil, a plant will die. And we are no different. If our balance of microorganisms is off, we age rapidly, develop disease, and die.
This mix of germs must contain plenty of good bacteria and some bad ones, too. Not every species of bacteria in a healthy gut is beneficial. Even the most Super Human among us has some bad bacteria and even parasites in his or her gut. But if you are young and healthy, your diverse species of good bacteria will overpower the bad ones. The idea isn’t to get rid of harmful bacteria completely, but rather to strike a balance between the good bacteria that help you become Super Human and the inevitable bad bacteria that can cause disease and aging when they overgrow.
There is evidence that having some, but not too many, of these “bad” bacteria and parasites in the mix actually helps keep the gut in balance. We evolved along with these parasites, so our immune system functions better when they are present. In 2005 I read the first study showing that taking certain parasites that cannot reproduce in the human body can alter your immune response and actually reduce inflammation. Supplementing with these parasites (which is called helminth therapy) enhances the function of regulatory T cells (Tregs), the immune cells that modulate the immune system and prevent autoimmune disease.4
As soon as I read that 2005 study, I ordered pig whipworm eggs from Thailand. They were shockingly expensive, and my friends thought I was nuts, but I was desperate to heal my gut. In all honesty, I didn’t feel much of a difference after swallowing those eggs. It’s possible that it would have taken more than one dose for those little guys to have an impact, but I couldn’t afford to take them regularly at $600 a dose.
Ten years later, after I had grown metabolically younger, I tried helminth therapy again, this time with rat tapeworm larvae. I felt a reduction in inflammation and an improvement in my GI function right away. I’ve been hacking my inflammation for so long that I can immediately tell how inflamed I am when I wake up in the morning. I can see it in my love handles (or lack thereof) and feel it in my brain. And those little tapeworm larvae definitely dialed down my systemic inflammation. I took them every two to four weeks until it got too difficult to coordinate with my travel, and I plan to take a course of them every six months for good measure. I would certainly continue more frequently if I were suffering from one of the conditions that helminth therapy is proved to treat, such as multiple sclerosis or inflammatory bowel disease.5
Thankfully, most of us don’t need helminth therapy, since having the right mix of gut bacteria will help prevent inflammation. But over the past several decades, our beneficial gut microbes have taken a hit—we’ve collectively damaged our microbiomes through an overreliance on antibiotics, antibacterial soaps, hand sanitizers, and the insecticides that we spray on our food.6 Since gut bacteria have a direct impact on inflammation levels and the immune system, damage to our gut biomes makes us more susceptible to autoimmune disease, which you read earlier is when the immune system attacks healthy tissues in the body.
It’s no coincidence, then, that autoimmunity and inflammation have been on the rise in older people for the past several years. In fact, many of the diseases we associate with normal aging are actually underpinned by autoimmune disorders. Approximately 50 million Americans—that’s 20 percent of the population—are suffering from an autoimmune disease right now. The standard of care is for autoimmune patients to take drugs that suppress the immune system and leave them unable to fight off everyday viruses and infections. But it is possible to turn autoimmunity around by reducing inflammation and healing the gut instead. This one is especially personal for me. As a young man, I suffered from arthritis and Hashimoto’s thyroiditis, both of which are autoimmune diseases. Today I have no symptoms of either condition, and that’s without taking any immune-suppressing drugs.
What would you think if you heard that there was a species of probiotic that doubled life-span in mice? There is good science behind the idea of supplementing with specific bacteria to enhance longevity. The specific species with those magic powers works because the bacteria produce spermidine. (Yes, researchers originally isolated spermidine from semen—hence the name. Bear with me on this one.) In one study, when mice were supplemented with the bacteria that produce spermidine, it was shown to double their life-span.7
You can supplement with spermidine directly, but fair warning—it smells and tastes exactly as you’d expect given from whence it was discovered. As research for this book, I ordered some, held my nose, and swallowed it. But it’s easier to get spermidine from the same source as the mice in that study, and that’s the species of bacteria that produces it. The more of these bacteria you have in your gut, the more spermidine you produce. I imported this probiotic, which is called LKM512, from Japan, and now I have friendly bacteria in my gut producing plenty of spermidine for me. No more bad-tasting spermidine to swallow, and there’s a good chance I’ll live longer as a result!
If there’s one thing I hope you take from this book, it’s the importance of nurturing a healthy and diverse gut biome. But the best way to do that is probably not what y
ou think …
GERMS ARE YOUR FIRST GIFTS FROM MOM
Your gut bacteria have been with you for a long time. When you were born, you got your first dose of microbes as you passed through your mother’s birth canal. And the way you were born affects the makeup of your microbiome. Studies have shown that children delivered vaginally have a gut biome that is similar to the mother’s gut biome. Children who are delivered via C-section have a gut biome that is more similar to the mother’s skin biome.8 While the skin is its own diverse ecosystem, the species of bacteria that dominate the skin are typically different from the ones that are most prevalent in the gut.
We are only beginning to understand how the way a baby enters the world might affect its long-term health. Obviously, not every woman is able to deliver vaginally, but one way to counter the potential changes to the microbiome caused by a C-section delivery is to swab the newborn baby with microbes from the mother’s vagina. There is some debate about how effective this practice is, but it’s a relatively risk-free way of exposing a baby to the bacteria he or she would have otherwise encountered in the birth canal. If you’re reading this, you can’t change what bacteria you got … but if you are planning a family, you can use this knowledge to give your kids a Super Human start.
The baby’s first source of nutrition also plays a significant role in shaping his or her early gut biome. Breast milk contains up to six hundred different species of bacteria that help promote bacterial diversity in a child’s gut.9 Unfortunately, formula does not contain these bacteria. And studies show that formula-fed infants tend to have less diverse gut biomes than their breastfed peers, along with an overrepresentation of Clostridium difficile, potentially harmful bacteria.10
The baby’s microbiome continues to evolve during the first few years of its life to support the transition from drinking formula or breast milk to eating solid foods. Studies that have examined stool samples of infants reveal that their microbiomes initially comprise the exact species of bacteria that can best utilize the lactate in the mother’s milk. A few months later, the gut shifts to have a higher percentage of bacteria that can metabolize energy from solid foods. In other words, the baby’s gut primes itself in preparation to begin digesting solids. Then as the baby eats more and more foods, the bacteria associated with digestion of carbohydrates and vitamins from solid foods proliferate even more.11 When children are around the age of three, the microbiome stabilizes and becomes similar to an adult microbiome.
The exact makeup of this early microbiome has a huge impact on how the child’s immune system develops, and therefore can affect his or her health and longevity much later in life. Specifically, certain species of gut bacteria produce short-chain fatty acids that play an important role in the proliferation and differentiation of immune cells, including T cells and B cells, which produce essential antibodies.12 As such, the period between birth and the age of three is a critical window in which to establish a healthy microbiome and build a strong immune system. A surplus of bad bacteria and/or a lack of diversity may lead to issues such as autoimmunity, allergies, and asthma.13
Finally, exposure to antibiotics in infancy also impacts the health of the microbiome. Antibiotics wipe out both dangerous and beneficial strains of bacteria, causing a reduction in microbial diversity. Studies have shown that early antibiotic use can increase a child’s lifetime risk of developing asthma, eczema, and type 1 diabetes, which are all diseases of the immune system.14 If you’re over thirty-five, you lived through the time when doctors handed out antibiotics like candy, and it’s likely impacting how you age.
There is no doubt that the makeup of your microbiome during infancy impacts your likelihood of developing specific diseases later in life. In fact, researchers have been able to pinpoint some of the bacterial strains that are crucial for optimal health. For example, infants who develop asthma often have a low abundance of the beneficial bacteria Bifidobacterium, Akkermansia, and Faecalibacterium and a high relative abundance of fungi like Candida and harmful bacteria that release inflammatory metabolites. As you know, those inflammatory compounds are at the root of all Seven Pillars of Aging. So what would happen if you had harmful bacteria in your gut releasing them from the time you were an infant? You would age prematurely, that’s what.
Of course, there are plenty of things you can do to wreck (or heal—we’ll get to that in a minute) your gut biome long after the age of three. All hope is not lost, even if you had a less-than-ideal start, like I did! It’s never too late to take control of your gut bacteria. But it’s fascinating to know that what happens during the first minutes and years of your life actually plants the seeds for how you’ll age decades later.
PROBIOTICS CAN MAKE YOUR GUT WORSE
Given all the bad things that were going on in my gut years ago, I was desperate to fix my microbiome. So desperate, in fact, that in 1998 I ordered a special electrical stimulating pill from Russia. It contained a battery connected to electrodes that was small enough to swallow. As it went through my gut, it used electricity to stimulate the muscles in my intestines. As you’d expect, it felt weird, but it got worse when the pill lodged near a nerve on my left leg. For an entire afternoon, my leg twitched uncontrollably every five seconds when the unit fired.
Needless to say, that wasn’t something I wanted to repeat. So I gave up on swallowing weird medical devices from Russia and went back to the gut intervention that most people try first—probiotics. After all, we are bombarded with marketing messages about the health benefits of probiotics, so they must be just the things to fix our gut problems, right? Not so fast.
Unfortunately, many of the probiotics on the market contain an abundance of histamines. When you hear the word histamine, you probably think of allergies—we pop an antihistamine pill to block the chemicals our bodies create during an allergic response. But certain bacteria also create histamines through a fermentation process. In addition to playing a role in immune system response (hence the itchiness and sneezing of an allergy attack), histamines act as neurotransmitters, communicating messages to the brain. We need some histamine in our bodies, but an excess of histamine can lead to a condition called histamine intolerance, which causes migraines, sinus issues, and the type of widespread inflammation that is so incredibly aging.
There are two main causes of histamine intolerance: an overpopulation of the bacteria that produce histamines and too little of an enzyme that breaks them down, which is called diamine oxidase (DAO). If you are histamine intolerant, the worst thing you can eat is a food containing histamines. Yet when we are concerned about our guts, many of us turn to the very foods that contain the greatest amounts of histamines, such as fermented foods like yogurt, sauerkraut, or kombucha. Since bacteria create histamines as a part of the fermentation process, fermented foods often (but not always) contain plenty of histamines.
When you’re looking to heal your gut, it’s important to be aware of which bacteria produce histamines, which degrade them, and which don’t affect them at all. Too many people hear about the importance of gut bacteria and start blindly swallowing probiotics, but this is a really bad idea. Remember, everyone’s microbiome is unique, and the exact makeup of bacteria in your gut will greatly affect how you age. So you want to make sure you are supplementing with the right species of bacteria for you.
The other problem with taking generic probiotics to heal the gut is that if you have an overgrowth of fungus such as Candida, probiotics alone aren’t enough to fix it. Probiotics are species of bacteria, not fungus. If you have a fungus issue and take probiotics, the fungus will just fight with the probiotics. I was eventually able to get rid of my own candida issue by taking antifungal medication for sixty days straight. Incidentally, you can’t “starve” Candida fungus by going into ketosis because Candida can live just fine on sugar or ketones. If you know you have an issue with Candida, it’s vital that you work with a functional medicine doctor to fix it in order for your anti-aging program to succeed. If you don’t wipe out the f
ungus, your beneficial microbes will never have a chance to do their good work.
I know all of this now as the result of trial and error and lots of research. But back when I was first attempting to heal my gut, I made the common mistake of popping probiotics, thinking they would help. I decided to add a prebiotic, or food for probiotics, called fructooligosaccharide to my Bulletproof Coffee in the morning and take a probiotic at the same time. Unbeknownst to me, the probiotic I took contained Lactobacillus casei, a histamine-producing species of bacteria. I gained ten pounds in seven days, with noticeable inflammation in my gut. After I stopped the probiotics, it took only seven days for me to lose that weight. It wasn’t fat; it was inflammation from the wrong probiotic.
So how do you know which probiotics to take, if you choose to take them at all? If you don’t think you have a histamine issue, I recommend probiotics that are neutral, such as Streptococcus thermophilus and Lactobacillus rhamnosus. To repair an unhealthy gut and decrease histamine intolerance, work on minimizing histamine-producing bacteria and maximizing histamine-degrading bacteria (more on this below). Histamine-producing bacteria include Lactobacillus casei, Lactobacillus reuteri, and Lactobacillus delbrueckii subsp. bulgaricus. These are found in most yogurts and fermented foods including sauerkraut, some kombucha, pickles, fermented soy products, soy sauce, fish sauce, buttermilk, kefir, mature cheese, red wine, breads made with yeast, and processed, smoked, and fermented meat. If these foods agree with you, that’s great, but pay attention to how you feel after eating them. If you think you might have a histamine issue, avoid these high-histamine products as well as some of the probiotics they contain.
It’s possible to take supplements that contain histamine-degrading bacteria such as Bifidobacterium infantis, Bifidobacterium longum, and Lactobacillus plantarum. But if you don’t have the right food for those bacteria present in your gut, you’re wasting money on probiotics because they’ll die before they can help you. Even if you never take probiotics, beneficial bacteria will often naturally grow in your gut when the right fuel is present. Invest in those before probiotics that may not even make it through your stomach. The trick is to focus on eating the foods that help good bacteria grow and reproduce: prebiotic fiber and resistant starch.
