Ask The Dr.: Brain Drain

Five things you need to know about leaky brain—and how to prevent it.
For optimal brain health, prioritize foods that are beneficial to the gut. Photo courtesy of Google DeepMind

Here’s a new one for you: leaky brain, and it’s a syndrome that everyone who has a brain needs to be aware of—but chances are, you’ve probably not heard the term before. Though, for the sake of introducing the idea, think of it as a close cousin of leaky gut, a condition you probably have heard of. 

As you may know, the condition called leaky gut syndrome shows the profound connection between the health of the gut and the health of the body as a whole. If the single-cell-thick lining of the gut wall begins to spring “leaks,” then bacteria and tiny food particles can cause the gut’s own immune system to go into overdrive, dumping inflammatory chemicals into the bloodstream and potentially wreaking havoc throughout the entire system: skin eruptions, joint pain, fatigue, you name it. 

None of this should be news to my regular readers. But here’s a big piece of the health puzzle that you probably haven’t heard about. Integrative doctors call it “leaky brain” and it’s remarkably similar to leaky gut but, just like the name says, at the level of the brain. The two conditions often feed off each other. Taken together, leaky brain and gut give us a much fuller picture of how a bad diet and too much stress conspire to make us feel and look less than our best, pushing us away from optimal health and toward chronic disease. 

Here’s what you need to know about leaky brain and how to avoid it, or fight back against it if you’re already experiencing the first symptoms. 

So what is leaky brain?

Ever notice that a number of leaky gut symptoms affect the brain? Fatigue yes, but also brain fog and emotional problems like anxiety and depression. That’s not an accident. The body’s longest cranial nerve, the vagus nerve, connects gut and brain, creating the so-called gut-brain axis. It’s a two-way highway. Not only is the brain vulnerable to inflammation that may have its origin in the gut, but the bacteria inside the gut, the microbiome, helps produce neurochemicals like dopamine and serotonin, which likely influence how we feel at a conscious/brain level. Likewise, stress signals coming from the brain affect what goes on in the gut (including the production of those neurochemicals). “Butterflies in the stomach” isn’t just a metaphor! 

But it goes deeper than that. In almost exactly the same way that the lining of the gut wall is supposed to keep the “bad guys” from leaking into the bloodstream, the brain has its own one-cell-thick lining inside the tiny blood vessels that bring oxygen and nourishment to the cells of the brain. It, too, acts as a protective barrier—in fact, it’s called the blood-brain barrier. It is semipermeable. Like a drawbridge in a medieval castle, it opens up to let the “good guys” in and raises up to block the bad guys’ entry. That’s especially important because bacteria and inflammatory cytokine molecules that may be able to circulate in the below-the-neck bloodstream without doing too much damage can become positively toxic when let loose inside the brain’s delicate cellular machinery. That’s why the blood-brain barrier evolved in the first place. 

But, unfortunately, the same stresses that contribute to the gut becoming leaky likely do a similar number on the brain. The best evidence we have that leaky brain is a real thing, and a dangerous one? Solid research that links it with neurological diseases like autism, Alzheimer’s, Parkinson’s and depression. When it comes to other symptoms that we’ve always attributed to leaky gut, like fatigue and brain fog, it’s hard to know whether any given problem began in the gut or whether the brain, specifically the blood-brain barrier, is being attacked from different or additional directions. The research is still in its early days. 

What we do know for sure: When we live in a way that nurtures the gut, especially the gut microbiome, we also take care of the brain. 

Eating with a leak-free brain in mind. 

A handy rule of thumb: Food that is good for the gut is good for the brain. That means the nonstarchy veggies like leafy greens, broccoli and onions, which contain loads of prebiotic fiber that feeds the gut bacteria which, in turn, help build up that all-important gut wall. Fermented foods like sauerkraut and kimchi introduce new strains of bacteria, which help the resident gut bacteria do their jobs. (A probiotic supplement is another way to get a bacterial boost.) 

Remember, the more secure the gut wall, the fewer rogue bacteria and inflammatory molecules will be released into the bloodstream, and potentially head for the brain—so the more we can do to plug up the gut wall holes, the better. We also have preliminary evidence showing that certain foods can improve brain health directly, not just via the gut. Healthy fats fall into that category. Omega-3 fatty acids, found in food (small, oily fish provide the most concentrated source) or in supplement form, look to protect the blood-brain barrier. In one small study, people with mild cognitive impairment who consumed a daily dose of extra-virgin olive oil—which is rich in monounsaturated fat—for six months showed improvement in cognitive function and improved blood-brain barrier function. It’s a revealing glimpse into the future of “food as medicine,” and possibly a bit of inspiration to add a bit more EVOO into your daily mix.

Foods to avoid: a no-brainer for brain health

The poster child for foods that cause brain problems is gluten, a protein found in wheat and other grains—and the millions of tons of processed foods that Americans eat every year is shot through with the stuff. Gluten causes all sorts of cognitive problems in people with celiac disease, an autoimmune disease, and a larger group who have a sensitivity to it. 

The research shows that gluten elevates levels of a protein called zonulin, which, in susceptible people, not only makes the gut wall more prone to leakage, but, upstairs in the brain, it interferes with the protective blood-brain barrier. In my experience, many of my patients just feel better if they cut way back on or eliminate gluten. There are, of course, other must-to-avoids. Eating a lot of sugar, going deep on processed foods and consuming a lot of alcohol are surefire ways to increase gut leakiness and, by increasing oxidative stress, may have a directly negative effect on the brain as well. When you truly embrace the idea that eating poorly can actually have the power to damage your brain, it makes consciously eating well a lot more appealing. 

Stress helps inflame the brain.

As I tell my patients, it’s not just what you eat but how you live that affects the health of your brain. A growing body of research, both animal and human, tells us that high levels of stress, manifested in high levels of our primary stress hormone cortisol, not only can injure our cardiovascular health, but also chip away at the blood-brain barrier that protects our brains.  

The result can be what the researchers call neuroinflammation. I call it the inflamed brain. Bad or inadequate sleep, a major stress driver, rounds out the picture. The studies show that sleep problems, especially sleep habits that run roughshod over our natural light/dark circadian rhythms, contribute to the assault on the blood-brain barrier and make us more vulnerable to toxins that are waiting to slip inside our brains. 

Taming stress and locking in good sleep habits is a story (or two) in itself, but focusing on the fundamentals will never steer you wrong: Take time out every day for relaxing or meditative activities; make sure you’re moving enough; power down at least an hour or two before bedtime (no screens!) and be sure to expose yourself to as much early morning light as you can, preferably outside. 

Leaky brain and “toxic load.”

The threats to brain health are all around us. There’s good evidence that mycotoxins, mold spores in plain English, can be particularly damaging if they break through the brain’s defenses. The same goes for other environmental toxins, such as  pesticides or heavy metals. My advice is to play both aggressive defense and offense. Defensively, try to limit your toxic exposure—I like to call it your “toxic load”—as much as you can. 

Start with the basics, like for example, checking for mold, which has become so common after the water damage that so many homes have been subjected to recently. Take steps to get rid of the mold ASAP. Next, work on clearing the air in your home, by investing in a high-end HEPA air purifier system (if that’s financially feasible). You can also assemble your own inexpensive DIY box-fan-and-filter system known as a Corsi-Rosenthal box, which does a surprisingly good job of sucking up the stuff you don’t want to be breathing in. Trade in toxic household cleaners for more Earth- and human-friendly ones. 

But, just as important, maybe even more important, go on the offense. By eating and moving and living in the healthy ways I’ve sketched out here, you can help your brain (and your gut) protect itself against whatever it may run up against now, and for years to come.