In his other book, Grain Brain: The Power of Gut Microbes to Heal and Protect Your Brain–for Life, Perlmutter discussed in detail how chronic inflammation and the action of free radicals cause brain degeneration. In Brain Maker, he discusses how human gut bacteria and overall gut health influence and even “drive” these harmful mechanisms. Perlmutter argues that a dietary prescription can heal the gut bacteria, preventing chronic inflammation and the action of free radicals. He proposes a practical regimen that comprises six important keys: prebiotics, probiotics, gluten-free foods, low-carb foods, fermented foods and healthful fat.

Perlmutter also advocates such treatments for restoring and supporting gut health as probiotic enemas and fecal transplantation. For example, he describes the case of a young man with multiple sclerosis who was unable to walk without canes until he underwent several fecal transplantations in Europe. When he returned home from Europe, he was able to walk without any assistance.

Perlmutter proposes basic steps to safeguard gut and brain health. These include the consumption of probiotic-rich and prebiotic-rich foods; eating a low-carb and high-fat die; drinking wine, tea, coffee and filtered water; consuming chocolate in small amounts (the chocolate should be at least 70 percent cocoa). Filtered water is preferable because tap water contains high levels of chlorine capable of killing the good bacteria in the gut.

Perlmutter recommends fasting a few times per year. He argues that the occasional 24-hour fast, which allows plenty of water, no food, and no caffeine, can help to clear your body of toxins.

In order to protect your microbiome, you have to limit consumption of antibiotics and consume whole, uncooked, organic, non-genetically modified (non-GM) foods, as well as traditionally fermented and cultured foods. You should avoid consuming meats that come from the animals raised on antibiotics and avoid eating foods treated with pesticides as they can alter gut bacteria.

It seems that Brain Maker offers a revolutionary plan for maintaining a healthy lifestyle and keeping your gut and brain healthy. However, I think that it should be taken with a grain of salt. Let me explain why I think so.

It is well known that medical research is almost exclusively empirical. Without thorough understanding of how the human body and more specifically the brain functions, medical scientists often draw conclusions from direct and indirect evidence that come from studies where too many factors and uncertainties are involved. You will notice this reliance on stretching or cherry-picking data to fit conclusions by counting how many times Perlmutter talks in his book about “connecting the dots.”

Perlmutter tells readers that numerous diseases can be treated by changing the gut bacteria and supplying good bacteria. “It’s like discovering the new world!” However, this new world is full of its own dangers and predators that are not easy to deal with. Unfortunately, Perlmutter does not discuss them in his book, which reminds us that medical scientists may selectively pick the data “to connect the dots.”

 For example, Perlmutter refers in his book to Canadian researchers who stated that “overall, dietary changes could explain 57% of the total structural variation in gut microbiota whereas changes in genetics accounted for no more than 12%. This indicates that diet has a dominating role in shaping gut microbiota and changing key populations may transform healthy gut microbiota into a disease-inducing entity.” How about the other 31 percent of the total structural variation in the gut microbiota? What causes these variations? Isn’t it important to address the causes for these variation before prescribing special diets, probiotic treatments and fecal transplants?

Let us take a look at some “missed-out dots.” The human digestive tract is home to a huge number of bacteria and viruses. The viruses in the gut are collectively called the virome. Most of these viruses are known to prey on the gut bacteria. They are also called bacteriophages (“bacteria-eaters”). Instead of directly attacking humans, bacteriophages infect bacteria in the human gut. They can kill bad bacteria, curing many diseases caused by bad bacteria. Bacteriophages can also attack harmless and good bacteria, killing them or transforming them into bad bacteria and making the human host sick. Yet, bacteriophages and viromes are never mentioned in Perlmutter’s Brain Maker.

Suttle, a scientist at the University of British Columbia, writes in his article “Marine viruses–major players in the global ecosystem,”

Viruses are by far the most abundant ”lifeforms” in the oceans and are the reservoir of most of the genetic diversity in the sea. The estimated 10³⁰ viruses in the ocean, if stretched end to end, would span farther than the nearest 60 galaxies. Every second, approximately 10²³ viral infections occur in the ocean. These infections are a major source of mortality, and cause disease in a range of organisms, from shrimp to whales. As a result, viruses influence the composition of marine communities and are a major force behind biogeochemical cycles. Each infection has the potential to introduce new genetic information into an organism or progeny virus, thereby driving the evolution of both host and viral assemblages.

There are about ten bacteriophages for every microbial cell, making these “bacteria-eaters” the most abundant entities on the Earth. Studies of the bacterial genome propose that they are one of the main forces responsible for shaping the composition and diversity of the gut bacteria.

Golomidova and her colleagues, for example, report that the diversity and abundance of E. coli strains in the horse gut are directly linked to the relative abundance of specific gut viruses. According to F. Rodriguez-Valera and his colleagues, the gut viruses attack certain bacteria that are present at high numbers in the gut (“kill-the winner” strategy).

As discussed in Brain Maker, people are recommended to take probiotic supplements in order to change the gut bacteria populations. However, studies show that such treatments may not have any long-lasting effect because the gut viruses (bacteriophages) can attack the ingested probiotics. Genome-based investigations have revealed that gut viruses attack almost all of the good bifidobacteria that are delivered to the human gut with probiotic supplements. Consequently, the gut bacteria population returns to the balance that existed before the probiotic treatment.

With this information in mind, let us take a look at the treatments that involve fecal transplants. In spite of what Perlmutter says in his book, fecal transplants may not be the magic solution to various health problems. A few years ago, Max Nieuwdorp, a gastroenterologist at the Academic Medical Center in Amsterdam, transplanted microbes from slim donors to patients diagnosed with metabolic syndrome, which frequently predicts type 2 diabetes.

The recipients of the fecal transplants demonstrated improved sensitivity to insulin. Additionally, their microbiota had become enriched. However, six months later, the patients had relapsed. Their metabolic improvements had receded and their gut microbes had returned to their original state. This study indicates that replacing “sick” microbiota with new ones may not consistently treat the “sick” microbiota.

Moreover, in their article “Rapid evolution of the human gut virome,” S. Minot and his colleagues report that the virome of one person can be very different from the virome of another person, and the virome of any person can evolve and change very rapidly. The evolution and diversity of the virome can influence a person’s predisposition and resistance to certain diseases, as well as the effectiveness of medication. Considering that the gut viruses can change quickly and attack the gut bacteria, treating the sick gut bacteria can be very challenging.

A good diet, exercise and avoidance of unnecessary stress and antibiotics will not eradicate the problems created by bacteriophages that attack the good and bad bacteria populating your gut. Whereas Perlmutter mentions very briefly in his book that viruses are present in the human gut, he does not discuss how the gut viruses affect the gut bacteria. Consequently, he does not recommend any diagnostics or treatments that would specifically deal with the virome.

Furthermore, some changes in dietary habits can be harmful to the gut bacteria. For example, Peter Turnbaugh, a microbiologist at the University of California, San Francisco, conducted experiments that demonstrated that a high-fat and high-protein diet prompted an expansion of bacteria called Bilophila wadsworthia, which has been associated with inflammatory bowel disease.

Even though Perlmutter calls for limiting the intake of protein, a question arises: is it wise to encourage thousands of readers to drastically and rapidly change their dietary habits and preferences? For example, a study conducted by Kristen E. D’Anci and other researchers from the Department of Physiology at Tufts University examined how a low-carb diet affects cognitive performance. The study involved women participating in one of two weight-loss diet regimens: a low-carb or a reduced-calorie balanced diet, which is similar to the diet recommended by the American Dietetic Association (ADA diet).

Three days before beginning their diets and then 2 days, 1, 2, and 3 weeks after beginning their diets, participants completed a series of tasks that allowed the researchers to assess their cognitive abilities (memory, ability to concentrate, etc.). Results showed that low-carb dieters performed worse on memory-based tasks than ADA dieters. These deficiencies were ameliorated after carbohydrates were added back  into their diets.

The Mayo Clinic website actually cautions readers about the risks associated with rapid changes in dietary habits and a transition to a low-carb diet:

If you suddenly and drastically cut carbs, you may experience a variety of temporary health effects, including headache, bad breath, weakness, fatigue; constipation or diarrhea.

In addition, some diets restrict carbohydrate intake so much that in the long term they can result in vitamin or mineral deficiencies, bone loss, and gastrointestinal disturbances and may increase risks for various chronic diseases.

Severely restricting carbohydrates to less than 20 grams a day can result in a process called ketosis… Side effects from ketosis can include nausea, headache, mental and physical fatigue, and bad breath.

Most importantly, scientists from the Mayo Clinic disclose that possible long-term health risks of a low-carb diet are not known because most research studies of such diets have lasted less than a year.

Speaking of dietary habits, please remember that your rich-in-vegetables diet has to exclude fried meat and vegetables. Medical studies have revealed that garlic, onions and such vegetables as green peppers and zucchinis can produce the toxic contaminant acrylamide when processed at high temperatures (for example, in a wok). Acrylamide is capable of damaging the nervous system. It has also been identified as a probable cause of cancer.

Department of Health of China, for example, strongly advises people to avoid stir-fried vegetables; and the US National Cancer Institute states,

Heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are chemicals formed when muscle meat, including beef, pork, fish, or poultry, is cooked using high-temperature methods, such as pan frying or grilling directly over an open flame. In laboratory experiments, HCAs and PAHs have been found to be mutagenic—that is, they cause changes in DNA that may increase the risk of cancer.

Yet, the 7-day meal plan proposed by Perlmutter in Brain Maker includes such meals as grilled chicken, roasted chicken, grilled steak, vegetables sautéed in butter and garlic, “unlimited stir-fried veggies,” stir-fried onions, mushrooms and spinach and roasted vegetables.

In order to be really healthy, the 7-day meal plan has to have all the “grilled, stir-fried and roasted” foods replaced with raw, boiled and steamed foods. And even after that, the poorly-understood long-term risks of a low-carb diet continue to apply to this plan.

***

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