The Essential Book of Fermentation (11 page)

While mouse experiments can’t necessarily be extrapolated to humans, these studies do open up potentially important areas for human study. “Mouse experiments hint that gut bacteria could play a role in a wide variety of brain and psychiatric disorders such as depression, autism, and schizophrenia,” the
Science News
report said. In its conclusion, the scientists reported that the effect on the brain and subsequent behavioral effects were not found in mice whose vagus nerve was cut or removed, thus identifying the vagus as a major communication pathway between the bacteria in the gut and the brain. The study concludes that gut bacteria play an important role in communication between the gut and the brain axis. It may be that certain intestinal organisms can be useful in developing therapies for stress-related disorders such as anxiety and depression.

As you can probably attest, delivery of a delicious, satisfying meal to the stomach and the alimentary tract beyond can induce feelings of well-being and satisfaction. That very well could be your intestinal flora sending a thank-you note to your brain.

Bacteria inside the intestine also communicate with the mucus-producing cells that line the organ and with the body’s immune system that is working at the intestinal site, and all of this is to protect the host (that’s you and me). “The intestine is the primary immune organ of the body,” according to a report published in the
American Journal of Clinical Nutrition,
a peer-reviewed scientific journal.

It stands to reason when you think about it. Into the mouth goes food that’s covered with mold spores, bacteria of various types, fungal spores, and other microbes in numbers that reach the trillions. And this is good fresh food. Among the food’s payload of microbes are some pathogens that can cause sickness and disease. But if we’re careful, very few times will our food’s bad guys cause illness. And that’s because the passage of food through the digestive system is a gauntlet of peril for pathogens. The gut is lined with elaborate systems for the prevention of illness because from the time our distant ancestors started eating, mixtures of microbes have been passing through evolving guts that have been refining and improving their ability to ward off illness.

The colon’s permanent immune system components—colonies of beneficial bacteria, the mucosal barrier, and the local immune system—literally communicate with one another, and with the temporary, in-transit bacteria provided by certain probiotic foods such as yogurt and sauerkraut.

The Gut and Psychology Syndrome

The link between intestinal flora and the brain has another champion in Dr. Natasha Campbell-McBride, a Russian neurologist and neurosurgeon who has a postgraduate degree in human nutrition and has been practicing for two decades in Cambridge, England. She attributes a dysfunctional intestinal ecosystem as a root cause for illnesses as disparate as ADHD, ADD, dyslexia, depression, schizophrenia, and, most intriguingly, autism. This is a controversial area, and conventional medical practitioners and scientists have cast doubt on the role of a compromised gut in these conditions. I don’t know if Dr. Campbell-McBride’s idea is correct, partially correct, or off base, but there is enough evidence to suspect that she’s on to something fundamentally important in medicine, and that is the role of a healthy intestinal flora in human well-being.

Dr. Campbell-McBride has some firsthand knowledge of a possible link between a dysfunctional gut and autism. Her firstborn son was diagnosed with autism at age three and she soon realized that her specialty of neurology had little advice for how to treat him. She also noted a rapid rise in autism, from one child in 10,000 in 1984 to one child in 150 by 2005, and today the number is one in 66 in the UK and one in 88 in the United States, with similar numbers in Australia and New Zealand. Her studies in human nutrition led her to discoveries about intestinal flora, which she applied to her son, changing his diet to strengthen his gut ecology. Today he is no longer autistic.

Dr. Campbell-McBride believes that autistic children have perfectly normal brains and sensory organs when in the sterile environment of the womb. The trouble starts when their mothers reach term and they enter the birth canal. “What happens in these children [is that] they do not develop normal gut flora from birth,” she says. Instead of a healthy intestinal flora picked up from a mother with a healthy gut ecosystem, the child’s intestines are colonized by pathogens. She believes that as a result, the child’s digestive system becomes a major source of toxicity, with pathogenic microbes damaging the gut wall, allowing toxins and microbes to flood into the bloodstream and reach the child’s brain. These toxins, she posits, interfere with the ability of the child to process sensory information. They turn the sensory information into noise, from which the child can’t learn how to communicate, how to understand and use language, or how to develop all the natural behaviors and coping behaviors that normal children develop. She calls this abnormal condition Gut and Psychology Syndrome, and it is the cause of autism in her opinion.

It should be recognized that Dr. Campbell-McBride’s opinion is very controversial, and often debunked by the scientific community. However, current research into autism shows that one of its root causes may be chronic inflammatory disease, which scientists call immune dysregulation, that can occur in a pregnant woman. This includes allergies and autoimmune diseases like rheumatoid arthritis. A large Danish study that tracked 700,000 births over a decade found that a mother’s rheumatoid arthritis raised a child’s risk of autism by 80 percent and that if the mom had celiac disease, an inflammatory disease caused by proteins in wheat, while pregnant, the child’s risk of developing autism was 350 times greater than children of mothers who had no inflammatory disease during pregnancy. This study suggests that the mother’s immune system is constantly flooding her body—and the fetus’s—with pro-inflammatory molecules. Cells in the baby’s developing brain that help build and maintain neurons are enlarged by chronic activation. The brain’s wiring gets scrambled. That’s the supposition.

So, if many cases of autism are related to immune dysfunction, what has happened to our modern immune systems that has caused such a precipitous rise in its prevalence? Writing in the
New York Times
, Moises Velasquez-Manoff, author of
An Epidemic of Absence: A New Way of Understanding Allergies and Autoimmune Diseases,
says that “scientists have repeatedly observed that people living in environments that resemble our evolutionary past, full of microbes and parasites, don’t suffer from inflammatory diseases as frequently as we do.”

The bottom line of this train of thought is that if inflammatory disease can be reduced during pregnancy, there’s a chance that autism rates could be reduced, too. There hasn’t been enough science done on this topic to know whether this hypothesis will hold water when it’s tested. But there are so many good reasons to eat fermented foods that it’s certainly wise for pregnant women and women planning a pregnancy to keep their intestinal ecosystems strong and healthy.

Dr. Campbell-McBride says that the baby acquires its intestinal flora from the mother’s vagina at birth, so whatever microbes live in the vagina become the baby’s flora. The vaginal flora comes from the bowel, so if the mother has abnormal gut flora, there will be abnormal flora in the birth canal. She thinks that the epidemic of abnormalities in gut flora began during World War II, when antibiotics were discovered. Antibiotics tend to wipe out the beneficial bacteria, and that offers a window of opportunity for the pathogens to proliferate. Given the routine use of antibiotics in the production of meat and milk in the countries with high autism rates, one can theorize that these antibiotic residues are constantly harming the diversity and extent of the intestinal flora.

“What I see in the families of autistic children is that 100 percent of the moms of autistic children have abnormal gut flora and health problems related to that,” Campbell-McBride says. Again, this is merely anecdotal evidence and not hard science, but it suggests a possibly fruitful area for science to investigate and it makes sense for moms-to-be to ingest probiotic foods that promote a normal and healthy intestinal flora.

Once more, there’s the parallel with what we see in agriculture and horticulture. If we wipe out the so-called pest insects, we are really destroying the whole insect ecosystem, because the beneficial insects are more susceptible to pesticides than the pests, and the so-called pests are food for the beneficials. So the farm or garden is effectively sterilized of insects. The first insects back in won’t be the beneficial insect-eating bugs because there will be no food for them. It’s the pests that return first, because now the field lays open to them, with no predation from the good guys. And once again, the same kind of ecological pressures affect the world of microbes, with the same results: a proliferation of pathogens after a sterilization.

It’s vitally important for women of childbearing age to establish a healthy, strong intestinal flora. The easiest way to do that is to first eat organic foods that by law do not contain pesticides, antibiotics, or genetic modifications; second, seed their intestines with a diverse mix of microbes by regular ingestion of probiotic foods such as kefir, yogurt, kombucha, sauerkraut, and the rest of the healthy fermented food family; and third, breast-feed the baby, which bathes the child’s intestinal tract with food for healthy gut bacteria that nature will provide in abundance.

If for no other reason, minding the health of your intestinal flora makes you a healthy mom—and dad, too, for dad’s flora colonizes the groin and is shared with mom during intercourse. And a healthy mom and dad can only be beneficial for baby.

There’s a further thought that this information brings up. It seems that our intestinal flora—nine out of every ten cells and 99 percent of the DNA in our bodies—really does communicate with our brains, affecting our moods as well as our physical and mental health. An intestinal tract damaged by chemicals and rife with shattered ecosystems and pathogenic organisms talks to the brain in a broken and misinformed voice, so to speak.

But a healthy, diverse ecosystem of beneficial microbes sequesters pathogens, prevents them from getting a toehold in the gut, destroys them with bacteriocins, and in other ways keeps them from harming us. It eliminates the static that shreds meaning. It speaks clearly and plainly.

It’s possible that the healthy communication between gut and brain has much more to do with who we are than we allow. We think of ourselves as autonomous beings with free choice and the ability to screen out unwanted information from our environment. But we can’t screen out the communication that our flora and brain share out of our conscious sight, deep within the silence of autonomous nervous systems within us. And this communication doesn’t stop when we sleep, because bacteria and other microbes don’t sleep. That communication with the brain continues. Scientists know that the brain continues to function during sleep—and we know that, too, because we dream, and because our unconscious eyes jitter as they search the emptiness during REM sleep. Could mood-improving intestinal microbes keep nightmares away? If they can improve our mood during the day, why not at night? After all, we all remember Ebenezer Scrooge’s reaction when confronted by Marley’s ghost in
A Christmas Carol.
Scrooge at first doesn’t believe in the ghost, and the ghost says to him, “Why do you doubt your senses?”

FERMENTED FOODS FOR A SEXIER YOU

Male mice fed bacteria-rich yogurt developed a certain swagger to their gait, according to an unpublished study by cancer biologist Dr. Susan Erdman and evolutionary geneticist Eric Alm, both at the Massachusetts Institute of Technology. This was caused by the males projecting their testicles outward. And this happened because the testicles were 5 percent heavier than those of mice fed a typical diet and 15 percent heavier than mice fed junk food.

As a result, the males fed yogurt inseminated females faster and had more offspring. Females fed yogurt had larger litters and were more successful in raising their pups to maturity. “The probiotic microbes in the yogurt help to make the animals leaner and healthier, which indirectly improves sexual machismo,” the researchers reported. Now scientists at Harvard are investigating the effect of yogurt consumption on semen quality in human males. So far, they say, their results are consistent with those on mice.

“Because,” says Scrooge, “a little thing affects them. A slight disorder of the stomach makes them cheats. You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato. There’s more of gravy than of grave about you, whatever you are!” Ever prescient, Dickens knew that bad food could lead to bad dreams. So did the great cartoonist Winsor McCay, who created
Dreams of the Rarebit Fiend
in the early twentieth century (he also did
Little Nemo in Slumberland
). In these fantastically well-drawn strips, the protagonist each time finishes a rarebit and sinks into a haunted nightmare. Perhaps a few forkfuls of sauerkraut or a long draft of kefir would have prevented that.

The gut flora looks out for us, for we are its hosts and carriers. Without us, the flora is lost. And so a healthy flora whispers its healthy signals to the brain. Conversely, without our healthy gut flora, we are lost. It’s time for humanity to realize what’s really going on within us and to cherish our symbiotic flora by giving it what it needs to grow strong and healthy.

It’s literally true that our body and our flora are functionally one being.

A bacterium called
Mycobacterium vaccae
acts as an antidepressant when it gets into your bloodstream. It causes people to produce more serotonin and norepinephrine, two compounds that make people feel happier. The bacteria also boost the immune system, vitality, and general cognitive function, according to a paper published in the journal
Neuroscience.