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  • An interview with Gut Crisis co-author Robert

Stress and Immunity: The Microbiome Connection

Life has its ups and downs, and stress is a natural part of human existence. These days, though, American stress levels are at a record high, according to the American Psychological Association. We discussed the stress-microbiome connection with Robert Keith Wallace, Ph.D., who—along with his wife and co-author Samantha Wallace—wrote Gut Crisis: How Diet, Probiotics, and Friendly Bacteria Help You Lose Weight and Heal Your Body and Mind.

Dr. Wallace is a pioneering researcher on the physiology of consciousness and the mind/body connection as applied to behavioral medicine. His seminal research on higher states of consciousness has been published in Science, The American Journal of Physiology, and Scientific American. He’s currently Chair of the Department of Physiology and Health at Maharishi University of Management, of which he was a founding President.

Gut Feelings: Stress, the Gut & Immunity

vpk by Maharishi Ayurveda: You’ve made a lifelong pursuit of researching the mind/body connection. Can you tell us a bit about how mental and emotional stress can affect immunity?

KW: When I was starting off back in the ’70s, nobody really understood this connection. When you mentioned the word “stress,” people thought it was a good thing, not a bad thing. Now, we know that the mind works through the body like it’s walking into a pharmacy—if the mind doesn’t want to feel pain, it can produce endorphins and enkephalins, which essentially block pain. If you feel anxious, the mind sends a signal to one area of the brain, which produces a chemical to stimulate that part of the brain, and so on. So we know that the mind and body are incredibly closely connected, and they’re also connected to our immune system; when you experience stress, this can reduce the effectiveness of the immune system.

What’s new is the gut connection. Whoever thought the gut had anything to do with anything? Well, every ancient medicine did: Ayurveda, Traditional Chinese Medicine, even Hippocrates, who said, “All disease begins in the gut.” It was about 10 years ago that modern researchers first started looking at the bacteria in the gut.

New technology with DNA and gene sequencing has really opened the whole arena for understanding gut bacteria and the microbiome. The microbiome is all the organisms that live on every part of us, in and around us and on us; the largest percentage of that is bacteria in the gut.

The Leaky Gut Epidemic

vpk by Maharishi Ayurveda: What is a leaky gut and how does it affect a person’s health, emotions, and immune system?

KW: Researchers used to call this “increased intestinal permeability”—when things go from inside the gut out into the bloodstream without passing through the normal channels. A physician researcher named Alessio Fasano found that celiac patients have this problem where the barrier between the inside of the gut and the bloodstream is exposed; it’s a disaster because they get undigested food bacteria particles and all kinds of things going freely into their bodies. The gut lining is a 30-foot barrier, and nothing’s supposed to get in. When there’s a crack and things start to get through, the immune system doesn’t like it. The immune system is there to defend.

But it’s not just celiacs who can suffer from a leaky gut. There’s non-celiac gluten sensitivity and there’s even non-celiac, non-gluten sensitivity. Eighty percent of the immune system is in the gut lining—that’s 80 percent of your body’s defense system. That’s a huge number of cells, and they are ready to attack anything that gets in; with a leaky gut, the immune system gets over-activated and starts attacking the body and causing autoimmune diseases, though nobody understands why. In a sense, it’s a huge validation of Ayurveda and the ancient knowledge that the gut is really important.

The Gut-Brain Axis & Stress

vpk by Maharishi Ayurveda: In Gut Crisis, you talk about the “gut-brain axis.” What is that, and how does it relate to stress?

KW: Researchers have known that the nervous system, the endocrine system, and the immune system are connected, and new studies are now bringing in the gut and, particularly, the gut bacteria. So now we have something called “the gut-brain axis”—a bigger system that includes those three systems along with gut bacteria. It turns out that there’s a highway that goes between the gut and the brain, and it allows information to go back and forth. When we get stressed, we shut down our digestive systems, and if our digestive system gets upset it can send messengers to the brain.

Gut bacteria can communicate through nerves, they can communicate through chemical messengers, and they can change gene expression in the body. They produce all kinds of substances that get into the bloodstream and have a huge effect; they produce hormones, like ghrelin (the hunger hormone) and leptin (the satiety hormone); they also produce neurotransmitters.

The gut has a major impact on the brain. From Ayurveda we know that the seat of Vata is in the colon, the seat of Kapha is in the chest, and Pitta is in the stomach. Vata controls all transportation in the body and the nervous system, and once you understand the gut-brain axis and the microbiome, it all makes perfect sense. That’s one of the great things that’s happening right now in the world of research: ancient and modern medicine are meeting in the gut.

The Rest & Repair Diet

vpk by Maharishi Ayurveda: In your book you recommend a Rest and Repair Diet to help repair leaky gut syndrome and reset the microbiome for better mind-body health. Can you tell us about that?

KW: The concept is: let your agni, or digestive fire, settle down and give your gut a period of rest so it can repair itself. When we get a flu, we go to bed. The body is very intelligent; it knows how to repair itself.

Try a Rest and Repair diet for two or three weeks. Eliminate gluten, because gluten is harder to digest. Eliminate sugar as best you can—so that’s soda pop, high fructose corn syrup, and so on. Try to eliminate dairy. You can have as many vegetables as you want. Essentially, it’s a very basic vegetarian diet with stewed fruit in the morning and kitchari and cooked vegetables for lunch and dinner. Maybe a protein shake. Follow the general Ayurvedic principles, like eating your main meal at lunch.

After being on this elimination diet for two to three weeks, then gradually begin to reintroduce heavier foods. Have a donut, have some pancakes, and see how it affects you. Write it down in a food journal, check it out. It’s a process of self-discovery that teaches you how your food choices affect your mind and body.

The Power of Probiotics

vpk by Maharishi Ayurveda: You’ve written that probiotics are helpful not only for a person’s intestinal health, but also for their mental state. Which ones should people take?

KW: Probiotics are a miracle unto themselves. Both human and animal studies have shown that certain probiotics can change how our brain centers are activated under stress.

As for which ones to take, nobody has it down to an exact science yet. There’s no probiotic out right now that anyone can stand behind and say, “If you take this, you won’t feel stress.” But it will get to that someday.

The problem is it’s a very complex ecology. There are a thousand different types of bacteria. And when you take a probiotic you’re taking ten, twenty, or less sometimes. Probiotics are like gang workers. You already have a bunch of gangs down there in your gut, and they all have territory; if you’re introducing 5 billion probiotics, it’s nothing to the 30 trillion down there. You’re just introducing a small number of friendly bacteria who aren’t even the majority stakeholders. Lactobacillus acidophilus is just a minor character there, and bifidobacterium is just a small stakeholder.

There are some clear studies which show certain bacteria—the most common ones—do have really good results for things like Irritable Bowel Syndrome. But there aren’t any good studies indicating that refrigerated probiotics are any better than non-refrigerated, or that putting a coating on them will get them through the stomach acid or not. It’s a lot of good advertising, though the logic there is reasonable.

On my website at, I’ve gone through and rated 30-40 probiotics. I take into consideration five to six different factors and combine them for a rating of one to five stars. I rate probiotics on the simplest things—the larger the quantity of types and bacteria-count, the better, research shows.

vpk by Maharishi Ayurveda: In Ayurveda, lassi yogurt drinks are often recommended as a source of probiotics. How does lassi stack up against conventional probiotics?

KW: I think lassi’s great and ultimately you have to explore and see what works for you. Does kefir work better for you? Ayurveda’s not big on fermented foods, but some cultures like Japan and Germany love their prebiotic fermented products. You have to be open to trying different things.

Ayurveda is an ancient tradition, but there weren’t antibiotics back then, so all the microbiome damage wasn’t being done. We have so many new toxins in the world now that weren’t there before. There are new considerations, so you have to combine Ayurveda with Integrative Medicine a little bit to get up to date. You may be able to get by with just having lassi every day, and that’s what Ayurveda would recommend, but someone else might need something a little stronger.

These days, there are many things that could upset your gut bacteria. It’s a brave new world out there and you have to take control and be your own guide with probiotics, unless you can find a good doctor who will lead you through the process. Otherwise, you just have to take charge yourself and go

through your options systematically to find out what helps and what doesn’t. A lot of it is trial and error, but again, it’s a wonderful self-discovery process.

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