Super Human

by Dave Asprey

  PREBIOTIC FIBER

  Prebiotic fiber is what it sounds like—the thing that comes before probiotics. Simply put, it’s what the good bacteria in your gut like to eat. When they feed on prebiotics, these bacteria produce short-chain fatty acids like butyrate, which strengthens your brain15 and your gut.16 You can get prebiotics from vegetables that are rich in soluble fiber like sweet potatoes, Brussels sprouts, and asparagus. There is also a little prebiotic fiber in coffee and chocolate, but the best way to live a long time is to start eating a lot more vegetables … and maybe add some extra prebiotics, too.

  A 2019 review in The Lancet demonstrated that eating prebiotic fiber dramatically reduces your risk of developing the Four Killers.17 In the study, people who ate the most prebiotic fiber had a 15 to 30 percent decreased risk of cardiac-related death and death from any cause, a 16 to 24 percent reduced risk of stroke, and a 19 percent reduction in type 2 diabetes18 and colorectal and breast cancer.19 That’s a major reduction in three of the Four Killers!20 For the fourth killer, Alzheimer’s, we know that prebiotic fiber reduces intestinal and brain inflammation, with a corresponding reduction in inflammation of the immune cells of the brain called microglia.

  In another study,21 researchers gave type 2 diabetics either a 10- or 20-gram dose of prebiotic fiber daily for a month. They saw reductions in insulin resistance, waist/hip measurements, and LDL cholesterol, but the most important anti-aging lab change was in something called glycated albumin. This is a direct measure of the damage sugar is causing as it cross-links the protein in your cells. Another study showed prebiotic fiber works the same way on nondiabetics, too.22

  The importance of eating enough prebiotic fiber is one of the reasons you hear the bad advice to eat plenty of grains, legumes, and beans. These foods do contain prebiotic fiber, which does great things for your metabolism. Unfortunately, as I highlighted in The Bulletproof Diet, they also contain plant defense compounds called lectins, which damage your gut lining and cause inflammation and autoimmune conditions.23 Those legumes and whole grains are beneficial for balancing blood sugar, but they trash your long-term health by breaking your gut and, as a result, your immune system.24 Even if you think you can handle whole grains just fine, the evidence is in that a compound found in grains called agglutinins, or WGA, impairs the integrity of your intestinal lining, allowing small molecules to pass through into your blood. You simply won’t live as long as you want if you eat grains and legumes. However, you also won’t live as long as you want if you don’t eat enough digestive fiber. This has been a dilemma for thousands of years.

  Technology allows us to have the best of both worlds. Today the best way to feed your gut bacteria is to add at least 10 to 30 grams of prebiotic fiber powder to your diet and eat lots of vegetables. Over the last eighteen months, I’ve used 50 grams per day of the Inner Fuel prebiotic I formulated with my team at Bulletproof, often blended into my coffee in the morning. During that time, I went from 14 percent to 10.1 percent body fat. Thanks, prebiotics. Acacia fiber, one of the ingredients, also works well by itself, and is widely available.

  The science isn’t in yet about exactly how much prebiotic fiber you need to live as long as possible. The government recommends about 14 grams per 1,000 calories, which for most people is about 30 grams per day from all sources. But a study in the Netherlands that followed more than a thousand men for forty years found a 9 percent reduced risk of total death per 10 grams a day of prebiotic fiber.25 Another study in Israel found a 43 percent reduction in total death in people who ate more than 25 grams of fiber per day compared to those who ate less.26 In that study, an additional 10 grams per day reduced a man’s chance of dying by 12 percent and a woman’s chance by 15 percent. Yet another study found that increasing your fiber intake by only 7 grams per day produces a 9 percent reduction in cardiovascular disease.27

  The overarching point is that the right amount of prebiotic fiber is, to be specific, more. If you eat five to ten servings of vegetables a day, you may hit the government-recommended fiber levels. However, with this much evidence supporting the benefits, I eat as many vegetables as I can and add another 50 grams of fiber per day to my diet. This is a major upgrade in my recommendations, and the results are tangible. However, if you suffer from small intestinal bacterial overgrowth (SIBO), a condition in which bacteria that are normally in other parts of the gut overgrow in the small intestine, you may need to go on a short fiber-free diet to kill off those bacteria from where they don’t belong, so skip this recommendation for now.

  RESISTANT STARCH

  You read earlier that one benefit of prebiotic fiber is that it supports your bacteria in producing butyrate. You can also get your bacteria to produce more butyrate by eating resistant starch, a type of starch that acts more like a prebiotic than a typical starch, which the body converts quickly to sugar.28 Resistant starch gets its name from being “resistant” to digestion, meaning your body cannot break it down. Resistant starch moves through the stomach and small intestine undigested and arrives in the colon intact. There it acts as a prebiotic.

  There are four types of resistant starch:

  RS1 is embedded in the coating of seeds, nuts, grains, and legumes, which means it is packaged with lectins that harm your gut even though bacteria like to eat it.

  RS2 is the resistant granules in green bananas and raw potatoes.

  RS3 is a type of resistant starch formed when certain starchy foods, like white potatoes (which are a nightshade and thus harm your gut) and white rice, are cooked and cooled.

  RS4 is the man-made resistant starch. The nutrition label on a manufactured and processed food like a bread or cake might include polydextrin or modified starch. This is RS4. Man-made isn’t always a bad thing. One study found that resistant dextrin improved insulin resistance and reduced inflammation in women with type 2 diabetes.29 Just make sure it’s not from a GMO source, or you’ll be getting glyphosate with your RS4.

  Resistant starch does more than just help you produce butyrate. By feeding your good bacteria, it also helps protect you from the Four Killers. A 2013 study found that mice that fed on resistant starch had a decrease in the number and size of lesions associated with colon cancer. The resistant starch helped kill precancerous cells and reduced the systematic inflammation caused by cancer.30 It also helps to reduce insulin resistance. Since resistant starch isn’t digested, your blood sugar and insulin levels don’t rise after you eat it. A 2012 study found that obese men who consumed 15 to 30 grams of resistant starch every day for four weeks showed increased insulin sensitivity compared to a control group that ate no resistant starch.31 Insulin sensitivity, the opposite of insulin resistance, is incredibly important for your longevity.

  Eating resistant starch is also beneficial for weight control. One study found that women who ate pancakes made with resistant starch burned additional body fat after the meal compared to women who ate pancakes without the added resistant starch.32 This isn’t surprising since your good bacteria influence your metabolism and play a critical role in weight management. We’ve known for years that obese people and lean people have different types of microbes in their guts.33 Obese people tend to have more of a type of bacteria called Firmicutes and fewer of a type called Bacteroidetes34 than thin people. This is true even in cases of twins, when one twin is obese and the other isn’t.35

  You can’t buy Bacteroidetes as a supplement, but you can get more of them by eating spices and vegetables that contain polyphenols, which are the preferred food source of Bacteroidetes. When you eat a diet high in polyphenols, your Bacteroidetes thrive and reproduce. As a general rule, the more vibrant a vegetable’s color, the more polyphenols it contains. Vegetables that are dark green, deep red, purple, orange, and bright yellow all have high polyphenol content. Coffee, tea, dark chocolate, and fresh herbs and spices are exceptional polyphenol sources as well.

  Your gut bacteria also impact your weight by producing a hormone called fasting-induced adipose factor (FIAF), which tell
s the body to stop storing fat and to start burning it instead. The best way to ramp up FIAF production is to starve your bacteria of starch and sugar. When bacteria are “hungry,” they make more FIAF, and you burn additional fat. This is yet another reason it’s so important to fast occasionally if you want to keep getting better with age.

  BACTERIAL FUEL AND THE GUT LINING

  As you likely know, the vast majority of your gut bacteria live along your gut lining, which is made of mucus and acts as a barrier to protect your body from the contents of your digestive tract so that dangerous microbes don’t leak into your bloodstream. When things are working well, your gut lining allows nutrients in and keeps disease-causing pathogens out.

  Your gut microbes themselves help to maintain the integrity of this gut lining. The butyric acid they produce when they eat prebiotic fiber or resistant starch fuels the cells that line the intestinal wall. This keeps it strong and healthy and prevents you from developing leaky gut syndrome, a condition in which microscopic holes form in the gut wall, allowing intestinal contents to “leak” through the barrier and into the bloodstream.

  When you have leaky gut, proteins can get into the bloodstream and trigger allergies or even an autoimmune attack. So can bacteria and bacterial neurotoxins called lipopolysaccharides (gut researchers call them LPSs), which definitely don’t belong in your bloodstream. Once they leak out, they can impact other organs like the liver, kidneys, and heart, causing widespread inflammation and disease.36 Leaky gut has been linked to autoimmune disease, type 1 diabetes, inflammatory bowel disease, celiac disease, multiple sclerosis, and asthma, among other killers.37 Less serious but more common issues caused by leaky gut include acne, rosacea, stomachaches, headaches, and fatigue. In fact, I believe LPSs are a primary cause of inflammation and the aging it creates. You simply must reduce the quantity of lipopolysaccharides your gut makes and the quantity that can get into your bloodstream.

  To protect your gut wall, you need to give your good bacteria the food they need to thrive. A 2018 study published in Cell Host & Microbe38 reveals that good gut bacteria—specifically bifidobacteria—rely on fiber as a nutritional source to maintain a healthy gut lining. In the experiment, mice that were fed a low-fiber diet developed leaks in the mucus layer of their gut linings after only three days. The fiber-deprived mice then received a gut bacteria transplant from normally fed rodents, and they regained some of the protective coating necessary for a healthy mucus layer.

  When these mice later received a probiotic supplement of bifidobacteria, their mucus layer grew, but it did not repair the gut lining’s permeability. But adding a type of prebiotic fiber called inulin to their diets fixed this issue. The researchers concluded that bifidobacteria are crucial for proper functioning of the gut lining, and that—no surprise—bifidobacteria rely on prebiotic fiber to grow and multiply.

  This is a big deal. The movement of bacteria and toxins from the gut to the rest of the body is one of the most significant and preventable causes of aging in our modern society. It can prompt or worsen a chronic inflammatory response that causes rapid aging, and it can even lead to mental health issues. This is because gut health and brain health are closely connected—the gut and the brain communicate with each other constantly by sending chemical signals along what is called the gut-brain axis. A groundswell of research in recent years points to a strong link between what’s going on in your gut and various mood and behavioral disorders39 including depression,40 autism,41 and even neurodegenerative diseases.

  A 2018 study out of Japan found that transferring the fecal bacteria of depressed people to the intestines of rats led to depressed behavior in the rats.42 And another recent study showed that gut bacteria are in charge of activating certain parts of the brain during times of stress. Researchers analyzed the stool of forty healthy women and then divided the women into two groups based on their gut bacteria composition. They then showed the women negative images while monitoring their brains. It turned out that the dominant bacteria in the women’s microbiomes determined which parts of the brain were most active while viewing negative images.43

  There is clearly more to the gut-brain axis than we currently understand, and I’m excited to keep learning more. We do know that stress directly affects the gut. One study showed that exposing participants to a stressor actually changed the makeup of the microbiome, decreasing the relative abundance of one beneficial species of bacteria while increasing the relative abundance of pathogenic bacteria.44 These changes make people who experience significant stress more likely to develop major gastrointestinal disorders, including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS), and gastroesophageal reflux disease (GERD).45 Have you ever thought that stress was affecting your gut? You were right.

  So your gut has the power to change your brain, and your brain has the power to change your gut—and how you age along with it. For millennia we’ve thought of the inner workings of the gut as an unknowable mystery, but thanks to new technology and computing power, it doesn’t have to be that way.

  TRACK YOUR GUT LIKE YOU TRACK YOUR SLEEP

  By far the best way to figure out how and whether you need to heal your gut is to find out exactly what’s going on in there. Right now the most effective way to do this is through Viome, a company that uses technology that was developed by the U.S. defense department to detect biological warfare to analyze what’s going on in your gut. After you send a stool sample swab to Viome, they are able not only to identify every organism present but also to assess how active they each are by looking at what sort of beneficial or harmful compounds each type of bacteria is producing.

  While identifying the microorganisms in the gut is important, it’s even more helpful to understand their function. The microbes in the gut produce thousands of chemicals that affect how quickly you will age. By analyzing the genes that microbes express, Viome can identify which of these chemicals they produce and can determine their role in your body’s ecosystem.

  Every living organism produces RNA molecules from their DNA. Viome sequences all the RNA in the samples it receives; in this way your gut’s living microorganisms (including bacteria, viruses, bacteriophages, archaea, fungi, yeast, parasites, and more) can be identified and quantified at the species and strain level. The end result is a higher resolution view of your gut microbiome than has ever been available.

  Viome then feeds this information through its artificial intelligence technology and sends you a report that tells you which foods will feed the good gut bacteria you want to foster and which foods are causing an imbalance of gut bacteria. Viome’s report lets you fine-tune your gut microbiome function to minimize your production of harmful metabolites and maximize your production of beneficial ones. If this isn’t a powerful anti-aging strategy, I don’t know what is.

  Full disclosure: I joined the advisory board of Viome because it’s the first technology I’ve found in twenty years of searching that could actually tell me what was going on in my gut at every level. I think it’s a world-changing technology that’s using big data to allow us to look inside the black box of the gut.

  If it’s outside of your budget or you decide not to get customized dietary advice from Viome, the best way for anyone to starve bad bacteria and feed good ones is by cleaning up your diet. This means:

  Don’t eat grains, legumes, or nightshade vegetables, all of which lay the groundwork for leaky gut syndrome.

  Quit eating sugar. If you make one change to improve your gut health, make it this. Bad bacteria love sugar and feed off it. Excess sugar is the prime culprit behind small intestinal bacterial overgrowth (SIBO) and Candida.

  Never eat industrially-raised animals again, because the antibiotics they receive and the glyphosate in their food will end up in your gut and harm your gut bacteria.

  Feed your gut bacteria a whole lot more prebiotic fiber. Eat a variety of polyphenol-rich vegetables, drink coffee and tea, and add at least 10 grams of prebiotic fiber. I use 50 grams per day
of Bulletproof Inner Fuel, but you can also use plain acacia fiber.

  Add medium-chain triglyceride (MCT) oil to your diet. As you read earlier, the saturated fatty acids found in coconut oil have antifungal, antibacterial, and antiviral properties. I recommend Brain Octane Oil because it raises ketones more than generic MCT oil.

  Get more grass-fed collagen protein. Collagen helps your body maintain the gut lining so you can avoid leaky gut and more easily absorb nutrients.46 Eat collagen-rich foods such as bone broth, and add grass-fed collagen protein powder to your smoothie or Bulletproof Coffee.

  My Viome results provided both good news and bad news. On one hand, I am still recovering from antibiotic exposure even though I haven’t taken antibiotics in years. Because I’ve taken so many antibiotics, my bacterial genes show that I am resistant to five different strains. My first Viome test also found increased amounts of human DNA, which sounds like a good thing but actually means that my gut lining is turning over more than it should, causing inflammation. Finally, the test showed average metabolic fitness.

  It was these results that helped me discover that I wasn’t eating enough vegetables when I traveled, which led me to create a prebiotic blend I could take with me. After I used it for three months, my Viome test results shifted. My inflammation levels are now in the lower 27 percent of the population, and my metabolic fitness went from average to high, in the top 18 percent of the population. In addition, I went from the low end in terms of bacterial diversity (48 species) to the high-normal range (196 species). I’m certain that the changes to my gut are already helping me toward my goal of living to a hundred and eighty.