Category: umami hypothesis

Probiotics Help Preterm Infants

Seth Roberts1 Comment

It has just come to my attention that a systematic review published two years ago found that probiotics help preterm infants ward off necrotizing enterocolitis. Here is a summary of the review:

Necrotizing Enterocolitis (NEC) is a serious disease that affects the bowel of premature infants in the first few weeks of life. Although the cause of NEC is not entirely known, milk feeding and bacterial growth play a role. Probiotics (dietary supplements containing potentially beneficial bacteria or yeast) have been used to prevent NEC. Our review of studies found that the use of probiotics reduces the occurrence of NEC and death in premature infants born less than 1500 grams.

The reductions in the likelihood of this disease and of death (presumably from this disease) were both greater than 50%.

The Oneness of Fermentation

Seth Roberts4 Comments

A New York article about the suicide of a Dalton student contains this interesting observation. The dead boy

left filthy socks (which smelled, a cousin said, like kimchi) on his pillow

From which I conclude not only that kimchi is a good source of bacteria (“fermented foods” is a vague category — fermented for how long? — that might contain poor sources of bacteria) but also that our olfactory systems are good at detecting bacteria or more precisely bacterial byproducts. (Kimchi and used socks involve vastly different bacteria but are lumped together.) We don’t use smell to avoid predators or find food. We use vision and hearing for that. Maybe we use smell mainly to decide what to eat — to decide what contains calories (by learning smell-calorie associations, the basis of the Shangri-La Diet) and, as this observation suggests, what contains bacteria.

Mark Frauenfelder says that fermenting foods (yogurt, sauerkraut, kombucha) makes him happy.

Ernst Wynder on the Nurses’ Health Study

Seth Roberts22 Comments

It says a lot about the Nobel Prize in Medicine that Ernst Wynder, co-discoverer that smoking causes cancer, never got one. Wynder was also one of the founders of modern epidemiology. Here’s what he believed about the Nurses’ Health Study:

He had a strong skepticism about methods of dietary assessment, and always felt that the failure of analytic studies such as the Nurses’ Health Study to report associations between cancer and diet were due to a combination of random misclassification related to the imprecision of food frequency questionnaires and the narrow range of nutrient intake within a given population. I feel certain that he would have criticized the recent negative findings from the Women’s Health Study on dietary fat and breast and colon cancer on similar grounds. This was one area where he felt that international comparisons at the ecological [country-by-country] level provided better etiologic support than [more] analytic studies, and he published many studies over a period of decades to make just that point.

For example,

He developed a friendship with Kunio Aoki at the Aichi Cancer Research Institute in Nagoya, Japan, which resulted in our study which found that Japanese men with smoking habits similar to American men had considerably lower lung cancer risks.

I didn’t know that. It suggests that either Americans eat something that promotes cancer or the Japanese eat something that protects against it. I suspect it’s the latter — specifically, the big consumption of fermented food in Japan and not in America. I’m sure the food-frequency questionnaires Wynder criticizes, written by Americans, are tone-deaf to fermented food. I doubt they ask about kimchi or kefir or miso consumption, or distinguish between pickles aged for a day and pickles aged for a year. In Japan, people eat fermented food in many forms: vinegar drinks, yogurt, other fermented milk drinks, and alcoholic beverages. Above all, they eat miso and long-fermented pickles daily. They also have the longest life expectancy in the world.

Assorted Links

Seth Roberts1 Comment

Thanks to Mark Griffiths.

Gouda Cheese Did Not Stimulate Immune System

Seth Roberts2 Comments

A recent study in Finland found that cheese with added lactic acid bacteria (sold commercially) stimulated the immune systems of elderly subjects. Earlier studies had found similar effects when the bacteria were put in milk or yogurt. To me, the most interesting result was that the cheese alone (Gouda, a fermented cheese) had no detectable effect. I take that to mean that some fermented foods contain too little bacteria to make a difference. I’m going to have to stop using my umami hypothesis as an excuse to eat cheese — although cheese may also be good for the fat it contains.

Thanks to Anne Weiss.

Where to Find Umami

Seth Roberts5 Comments

Here is a list of umami-rich foods. As regular readers of this blog know, I believe we like umami flavor so that we will eat more bacteria-rich foods. In this list, notice that fresh foods tend to have much less umami than older foods. Cured ham (337 units) is much higher than pork (2.5). Cheese (182-1680) is much higher than milk (1-4). Soy sauce (412-1264) is aged; so is fish sauce (621-1383). Seaweed (kombu) is high (241-3190) but since seaweed is sold dried, I suspect the drying process is at least partly responsible for the high umami content. Marmite (1960) is not aged — but its main ingredient is yeast.

As far as I know, all meat sold commercially in America is aged: it doesn’t taste right until it’s aged. Umami is sometimes described as a “meaty” taste.

Animals Like Fermented Food?

Seth Roberts2 Comments

I’ve blogged a zillion times about the value of fermented food. Animals seem to agree with me:

At least twice in the past ten years [1998-2008], [elephant] herds in India have stumbled upon barrels of rice beer, drained them with their trunks, and gone on drunken rampages. (The first time, they trampled four villagers; the second time they uprooted a pylon and electrocuted themselves.) Howler monkeys, too, have a taste for things fermented. In Panama, they’ve been seen consuming overripe palm fruit at the rate of ten stiff drinks in twenty minutes. Even flies have a nose for alcohol. They home in on its scent to lay their eggs in ripening fruit, insuring their larvae a pleasant buzz.

It’s possible that the elephants were thirsty, of course, but these stories support the idea that our liking for fermented foods goes back a long way and has a genetic basis. I heard a story about horses preferring rotting apples to fresh ones, which shows how to improve the evidence: give animals a choice between fresh and older food.

Your Gut Bacteria Are What You Eat

Seth Roberts3 Comments

A new study found that Japanese people, but not Americans, have gut bacteria that help them digest seaweed. The Japanese eat a lot more seaweed than Americans, of course. Presumably they acquired the gut bacteria from eating seaweed that wasn’t hyper-sterile. It’s more evidence that we are not designed to eat hyper-sterile food.

Thanks to Aaron Blaisdell and Deborah Estrin.

Health Benefits of Miso, According to the Marukome Company

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The Marukome company calls itself “the leading miso manufacturing company in Japan.” As a corporate brochure says, “world-renowned Japanese longevity is deeply related to the traditional food of Japan.” Miso is probably the most traditional food of Japan, in the sense that the Japanese eat a lot of it per capita, far more per capita than people in any other country. They eat lots of fish, too, but that’s not unusual.

A corporate brochure for the Marukome company that I got at the recent Fancy Food Show makes many health claims for miso. Some involve the whole product. Two are interesting. 1. “Miso soup also helps prevent heart disease and diabetes.” This is vague, unfortunately. 2. “In 1981, researchers at Japan Cancer Center announced that miso soup lowers the risk of stomach cancer when consumed every day. Miso soup also lowers the risk of other cancers including liver cancer.” This sounds like a survey result: daily consumption of miso was associated with lower risk of various cancers. At least it is specific enough to check.

The brochure also makes health claims based on components: Vitamin B2, Vitamin B12, Vitamin E, “Enzyme”, Sabonin, etc. Each somehow improves health — for example, Vitamin B12 “reduces mental fatigue.” What interests me is that “improves immune function” isn’t on the list, nor does the list mention the microorganisms that grow in miso. Improves immune function I believe to be the main benefit of miso and the reason it reduces cancer. Judging by this brochure, you’d think this is a new idea in Japan, where lots of fermented foods are eaten. In Japan I met someone (a nurse) who said that perhaps a third of Japanese think that to be healthy you should eat fermented foods regularly. Perhaps the usual belief is that they improve digestion and better digestion somehow wards off cancer.

The Chinese Military and the Umami Hypothesis

Seth Roberts6 Comments

In an article about China’s military, James Fallows says American forces are much stronger, partly because:

In modern times, American forces are continually in combat somewhere in the world. This has its drawbacks, but it means that U.S. leaders, tactics, and doctrine are constantly refined by the realities of warfare. In contrast, vanishingly few members of the People’s Liberation Army have any combat experience whatsoever.

He could have used the word readiness. One reason I believe my Umami Hypothesis — that we require a steady stream of bacteria in our diet to be healthy — is the underlying logic: That a steady stream of bacteria continuously activate the immune system, keeping it in working order. Without low-level activation, the immune system will (a) react too slowly, causing noticeable colds, and (b) overreact, which causes allergies and other immune system disorders, such as arthritis.

I wonder if the same logic applies in other situations — if a constant low-level threat improves performance. Is Chinese governance better because Chinese leadership feels threatened?