Alzheimer’s disease may get most of the news headlines, but it’s far from the only frightening brain disease out there. There’s also Huntington’s disease, which in the end robs you of the ability to speak, walk, or control your movements. There’s multiple sclerosis, in which your own immune system attacks your nerves and your brain. There’s ALS, which eventually paralyses you and takes away the ability even to breathe on your own—usually within about five years. There are various types of dementia aside from Alzheimer’s.
And then there’s Parkinson’s disease, which robs you of the ability to control your movements and eventually leaves you trapped in your own body even though your mind is intact. As many as 60,000 new cases of Parkinson’s are diagnosed each year, and victims may live with the disease for decades.
There is no cure for any of these diseases. In fact, though we’re well-versed in the symptoms and medicine has some theories, we really don’t know what causes any of them. The sad fact is that when it comes to brain diseases we’re still stumbling around in the dark.
That may be about to change.
A new study published this month in the journal Cell suggests that when it comes to the cause of Parkinson’s, we might have been looking in the wrong place. It could be that Parkinson’s—and possibly other neurodegenerative diseases—starts not in the brain but…in the gut.
Gut bacteria control your life
We’ve learned a lot of things about the human body in recent years. Some have been on the microscopic level. Some have been more obvious but were still overlooked for centuries. Some sound like science fiction—such as the fact that your brain isn’t the only part of your body that contains brain cells. Or that your gut also has its own “brain”—one extensive enough that scientists think it may control more than just digestion. But by far what we’ve learned the most about is the bacteria that call your gut home and the profound effect they appear to have on nearly every system in your body.
We now know, for instance, that the wrong gut bacteria can make you obese—and the right ones can make you lose weight. We know that gut bacteria influence your immune system. We’ve shown they can have a hand in heart disease. There are even hints that they might play a role in the development of Alzheimer’s. That makes the new theory about Parkinson’s—a disease which, like Alzheimer’s, features protein buildup and death of brain cells—somewhat less surprising but no less earthshaking. If it proves to be true, it could mean a real cure for Parkinson’s in the future…and that cure might be as simple as probiotics.
The new finding would also explain some things that have puzzled researchers for years. For instance, people with Parkinson’s usually suffer from constipation. It’s one of the most common early symptoms; the problem may start as long as ten years before the first muscle tremors begin. And scientists have known for a decade that the protein fibers in Parkinson’s brains also appear in patients’ guts. They just didn’t know why. This study shows that they don’t just occur in the same place at the same time. Instead, they appear to form in the gut and migrate to the brain.
Toxic gut = toxic brain?
In Parkinson’s, molecules of a protein called alpha-synuclein stick together and form protein fibers. These fibers build up in clumps in the brain much like beta-amyloid plaques and tau protein tangles in Alzheimer’s. Scientists believe these fibers cause damage to the nerve cells, resulting in Parkinson’s symptoms. And when researchers began seeing these same protein fibers in the gut, it made them wonder. Was it just coincidence? Was something going on that affected gut and brain both? Or were the fibers being made in the gut, then traveling to the brain somehow? That’s what this study wanted to know.
To find out, they used—you guessed it—two groups of mice. Both groups, not surprisingly, had been genetically modified. In this instance, they were bred to make too much alpha-synuclein and are prone to develop Parkinson’s symptoms. Now as always, what’s true in mice doesn’t necessarily translate to humans, especially when the mice are genetically engineered. However, the results are still compelling. And if the experiment is replicated with non-engineered mice it could completely change the way we think about Parkinson’s.
The study had two parts. In the first, researchers raised groups of mice in either sterile, germ-free environments or in normal cages. The mice raised in normal cages soon began to develop Parkinson’s symptoms. Those raised in a sterile environment didn’t (they also had fewer alpha-synuclein fibers in their brains). That alone suggests that there is some sort of microorganism at work. The theory is backed up by the fact that antibiotics—yes, antibiotics—reduced symptoms in the mice from the non-sterile environment.
In the second part of the study, researchers injected the germ-free mice with gut bacteria from either healthy people or people who had Parkinson’s disease.
The mice who got Parkinson’s patient bacteria quickly developed symptoms. The other group didn’t.
Of course one study isn’t absolute proof. The study needs to be replicated. Science needs to take a look at just what strains of bacteria Parkinson’s patients have that healthy people don’t. And of course that will take years. But in the meantime, here’s what you can do to ensure that you have a healthy mix of gut bacteria:
First and foremost, eat fermented food. Fermented foods are the #1 source of probiotics—good gut bacteria. Eat kimchi and sauerkraut, yogurt and kefir and buttermilk. Provided they’re organic (and so non-GMO), fermented soy products like miso and tempeh are also good choices.
Eat prebiotic foods. These are foods that don’t actually contain good bacteria but feed the good bacteria you already have. Some of the most powerful probiotics include:
- Leafy greens
- Jerusalem artichokes
- and onions
And of course, one of the most important things you can do is avoid processed junk that’s full of sugar, artificial colors and flavors, and other additives. Eat real food. Your gut—and your brain—will thank you.