Autism and Digestive Problems

A new study in Pediatrics has a brief but useful summary of the evidence linking autism and digestive problems. Here’s one study. Here’s a review, with this abstract:

Recent publications describing upper gastrointestinal abnormalities and ileocolitis have focused attention on gastrointestinal function and morphology in [autistic] children. High prevalence of histologic abnormalities in the esophagus, stomach, small intestine and colon, and dysfunction of liver conjugation capacity and intestinal permeability were reported. Three surveys conducted in the United States described high prevalence of gastrointestinal symptoms in children with autistic disorder.

There is also evidence that immune dysfunction is associated with autism.

I believe that few people in America eat enough bacteria — in practice, this means not enough fermented food — and that this causes digestive and immune problems. A vast number of people will say, “of course, good food is really important, bad food causes X, Y, and Z” — where X, Y, and Z can be practically anything. The difference between my views and theirs is the prescription: They inevitably think that people should eat more fresh unprocessed food. (Usually fruits and vegetables, for some curious reason.) Fermented food, of course, is not fresh and not unprocessed.

Bacteria and Learning?

Do bacteria-laden foods improve learning? A recent study:

The ability of dietary manipulation to influence learning and behavior is well recognized and almost exclusively interpreted as direct effects of dietary constituents on the central nervous system. The role of dietary modification on gut bacterial populations and the possibility of such microbial population shifts related to learning and behavior is poorly understood. The purpose of this study was to examine whether shifts in bacterial diversity due to dietary manipulation could be correlated with changes in memory and learning. Five week old male CF1 mice were randomly assigned to receive standard rodent chow (PP diet) or chow containing 50% [raw] lean ground beef (BD diet) for 3 months. As a measure of memory and learning, both groups were trained and tested on a hole-board open field apparatus. Following behavioral testing, all mice were sacrificed and colonic
stool samples collected and analyzed by automated rRNA intergenic spacer analysis (ARISA) and bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) approach for microbial diversity. Results demonstrated significantly higher bacterial diversity in the beef supplemented diet group according to ARISA and bTEFAP. Compared to the PP diet, the BD diet fed mice displayed improved working (P = 0.0008) and reference memory (P < 0.0001). The BD diet fed animals also displayed slower speed (P < 0.0001) in seeking food as well as reduced anxiety level in the first day of testing (P = 0.0004). In conclusion, we observed a correlation between dietary induced shifts in bacteria diversity and animal behavior that may indicate a role for gut bacterial diversity in memory and learning.

Previous studies had found that changes in diet changed behavior. This article says that changes in diet can produce changes in bacterial diversity and these bacterial changes might have caused the behavior changes.

Eventually I will stop eating lots of fermented food and see what happens. Perhaps my arithmetic scores will get worse.

Where Does Umami Come From?

As previously blogged, the evolutionary reason we like umami taste may be so that we’ll eat more bacteria-laden food. This makes sense only if bacteria-laden food would have been the main source of umami. Nowadays, you can get umami from MSG. What about before MSG?

The Umami Information Center sent me a free booklet called Umami The World — a better title than Umami: An Introduction. Umami taste is mainly supplied by glutamic acid, a protein building block. My assumption was that glutamic acid is usually a protein breakdown product. Bacteria feed on protein, leaving a pile of bricks — glutamic acid among them. Was this correct? Or could you get umami taste without bacteria?

You can, but in most cases you don’t. In Japanese cooking, a potent source of umami is konbu, a type of seaweed. Perhaps because konbu produces so much umami and so little else that umami was discovered by a Japanese scientist. Umami flavorings are used in many other cuisines but the source is usually fermented food. In many Asian countries, umami comes from fermented fish sauce and fermented bean products (e.g., miso, soy sauce). In Chinese cooking, umami comes from a condiment called jiang, which is made from fermented grain, meat, or fish. In Western cuisines, cured pork is often used as a flavoring agent. “The curing process liberates more of the glutamic acid content of the meat.” Curing takes place at room temperature, which means bacteria grow. “Much of the food of ancient Rome was routinely seasoned with a sauce [that] was made from salted fish, fermented and strained. . . The polar Eskimo people traditionally fermented a small portion of their harvest of fish.” Tomatoes and shitake mushrooms are non-fermented sources of umami.

A telling comment in the book is that umami usually comes from sauces (e.g., fish sauce) or liquids (e.g., dashi, bouillion). Cooks use sauces and liquids to add what is missing. The presence of umami in so many sauces — as if sauces have been devised or selected to be high in umami — suggests that ordinary foods don’t have much umami. A table of glutamate concentration says that parmesan cheese has 1700 mg/100 g whereas several vegetables — tomatoes (246 mg/100 g), green pea (106), onion (51), spinach (48), potato (10) — and meats — beef (10), chicken (22), pork (9) — have much less.

The breakdown process I imagined is spelled out: “During the ripening of cheese, proteins are broken down progressively into smaller polypeptides and individual amino acids. Large increases in free amino acid content also occur during the curing of ham.” Surely the same will be true during room temperature aging of any protein source. Beef is routinely aged at room temperature for about a week to give it a “meaty” flavor (not from the umami book but from here).

Umami Burger

A new restaurant with the excellent name Umami Burger has just opened in Los Angeles. According to The Foodinista, the food is as good as the name:

An attractive space with an attractive clientele. The tightly edited menu consists of 10 burgers, and a few sides including fries and a market salad. But, we’re told at 12:45 pm on a Tuesday afternoon, they’ve run out of buns. . . . amazing homemade ketchup . . . The beef patties on all of the above, really flavorful and just plain GOOD. I don’t know how they can make such a great burger and charge so little. . . . I’m telling you, the burgers are great.

Review by Jonathan Gold.
Thanks to Tucker Max.

Shades of Homeopathy! Peanut Allergy Cured . . . With Peanuts

Doctors at Addenbrooke’s hospital in Cambridge gave four children tiny doses of peanut flour every day, gradually increasing the dose until now they can eat ten or more nuts a day.

Previously the children would have risked anaphylactic shock or even death if they accidentally ate even a trace amount of peanut.

The team say this is the first time that so-called desensitization treatment has been successful.

From the Telegraph. Notes: 1. No blinding. 2. No control group. 3. Started small (with 4 patients), now doing a larger study (18 patients). 4. Jewish kids in Israel have a 10-fold lower rate of peanut allergies than Jewish kids in the UK, according to a 2008 study. In Israel, peanuts are eaten at an earlier age.

Thanks to Oskar Pearson.

Pagophagia and the Umami Hypothesis

Pagophagia is an eating disorder where you chew a lot of ice. A friend of mine had it. After she discovered she loved crunching ice cubes, she started going through several trays of ice cubes per day. A trip to Russia, where ice cubes were unavailable, was highly unpleasant. Eventually my friend learned that pagophagia is caused by iron deficiency. When she started eating more iron, her ice craving went away.

Why do we work this way? The evolutionary reason, I think, is that in the ancient world where this tendency evolved, a desire to crunch something was usually satisfied by crunching bones. After you discovered how pleasant it was to crunch bones, you sought them out. Bone marrow is high in iron. Crunching those sought-out bones increased your iron intake.

The umami hypothesis says that we like umami tastes, sour tastes and complex flavors so that we will consume more harmless-bacteria-laden food (which keeps our immune system on its toes). In the ancient environment where these tendencies evolved, in other words, a desire to eat food with these characteristics led us to eat bacteria-laden food. At the Fancy Food Show, I met a maker of sparkling tea who was unable to get enough complexity without using bacteria.

Just as a person with pagophagia chews ice, most of us do one or more of these:

  • add monosodium glutamate (e.g., Accent) for umami taste
  • add vinegar for sourness (I put a few drops of vinegar in coffee-like drinks)
  • add many spices for complexity

The result, I suspect, is that most of us have immune systems with plenty of room for improvement. I stopped getting easy-to-notice colds when I started sleeping better so the high frequency of reported colds (the average American adult gets about three per year) may be a sign that this is true.

More Natto, Please

Natto. This is on the list because, for one, it’s one of the few foods I’ve eaten that I truly don’t like. But mainly, it’s here because we’ve really messed up the way we eat soy. Natto is fermented soybeans and very popular in Japan, which is where I had it. It’s becoming more popular here and this is most likely due to its health benefits. Nearly all the soy options we’re offered in the U.S. are non-fermented. The list of health benefits of fermented soy is a mile long. It’s associated with reducing the risk of cancer, minimizing the likelihood of blood clotting, aiding digestion, increasing blood circulation, an improved immune system, improving bone density, lessening the likelihood of heart attacks, more vibrant skin, and reducing the chance of balding. And it also has strong antibiotic properties, among other things. So you might want to ditch the soy crisps, soy ice cream, and your iced soy mochas and add some natto to your diet.

From 10 Foods You Should Eat. It’s a very reasonable list.