I’m in Vancouver for the Joint Statistical Meetings. The local Whole Foods sells a small bottle of kombucha for $22. It’s in a refrigerator in the health section, next to flaxseed oil. I asked an employee how this kombucha was different than the kombucha sold in the drinks section. More potent, she said. The next time I give someone homemade kombucha I’ll say that it sells for $22 in Canada.
Kombucha, let me repeat, is extremely easy to make. Tea + sugar + store-bought kombucha + three weeks.
I’m sure we need to ingest plenty of bacteria for our digestion and immune systems to work properly. What about the brain? When I started eating lots of fermented foods, I didn’t notice any brain-related changes, such as changes in mood or sleep. Suggesting that fermented foods have little effect on the brain. But a new study in the American Journal of Psychiatry suggests I reexamine the question. The researchers followed 160,000 high-school students in Taiwan for eleven years.
The incidence rate of suicide mortality in participants with current asthma at [the start of the study] was more than twice that of those without asthma (11.0 compared with 4.3 per 100,000 person-years), but there was no significant difference in the incidence of natural deaths.
Linking immune-system dysfunction (asthma) with brain dysfunction (suicide). I believe fermented foods will substantially reduce asthma. This finding makes it more plausible they’d also improve brain function.
In a comment on an old post — in which I described how a friend’s acid reflux was greatly alleviated by kombucha — Dave Schulz says he had a similar experience:
My heartburn occurs daily unless a) I stick to a strict diet with no carbs, dairy, or greasy/fatty food, like the Paleo Diet or b) I drink kombucha daily. It’s not always possible to do a), so kombucha has literally been a life saver for me.
Daily kombucha eliminates his heartburn for long periods of time, not just for a few hours after drinking it. Due to the current ban he can no longer get it and his heartburn came back. He got the idea from a friend. Before kombucha, he’d tried many remedies that didn’t work. The three doctors he saw were no help.
On the Mayo Clinic website a doctor says that “until definitive studies quantify the risks and benefits of Kombucha tea, it’s prudent to avoid it.” This is what the Protestant Reformation was about: Speaking directly to God rather than waiting for “definitive studies” by experts that “quantify the risks and benefits”.
Mark Frauenfelder describes how he makes yogurt with a yogurt machine. Made by Hand, his new book, has a chapter about fermented foods.
Let me add my two cents. After several years of making yogurt, I finally figured out there are two crucial steps: 1. Denaturing (expanding) the milk proteins. 2. Growing the bacteria. They require different temperatures. The milk proteins, as far as I can tell, denature at temperatures starting around 130 degrees F. You want the milk to be in that range for an hour or so. Below that temperature, the milk proteins curl up again unless bacteria get in the way. The best temperature for growing the bacteria is said to be around 110 degrees F., although I’ve found that incubation at 92 degrees F. also works.
So the ideal process for making yogurt is something like this: 1. Keep the milk at 140 degrees for a few hours. 2. Add the starter bacteria. 3. Keep the milk at 110 degrees for a long time, say 12 hours. I have a yogurt maker that approximates the initial higher-temperature phase by having you add boiling water around the container. The first time I tried it I was surprised how well it worked (how creamy the yogurt was) because it was much simpler than the usual recipes where you boil the milk, let it cool, and so on — and which after all that produced mediocre results. It took me a long time to realize I’d get even better results with my yogurt maker if the milk was warmer when I started.
If you know anything about heart disease epidemiology, you know that Japan has the lowest rate of heart disease in the world. The usual explanation is high fish consumption. But other countries, such as Norway, also eat a lot of fish but don’t have low heart disease rates.
My visits to Japan suggest to me that Japanese eat far more fermented foods than people in other countries, including Norwegians. If heart disease is due to infection, then it’s clear that the immune stimulation provided by fermented foods helps fight infection. My umami hypothesis — that we like umami, sour, and complex flavors to encourage bacteria consumption, which we need to be healthy — began with a trip to Japan in 2008, when I noticed, in a food court, many types of miso for sale. Back in Berkeley, I started making miso soup. I was stunned how well it worked. All you needed was miso. No other flavorings. It was so easy and good I ate it every day. It was my first bit of evidence that fermented foods are different and better than other foods.
Here are some fermented foods that are easy to get in Japan:
1. Miso soup. Most Japanese eat this daily. In a few countries, such as France, many people eat yogurt daily. Koreans eat kimchi daily. In most countries, as far as I know, it’s hard to find a fermented food (apart from cheese and alcoholic drinks) that’s eaten daily by most people. Miso is also used to flavor fish.
2. Japanese pickles. The best pickles in the world. Some are pickled as long as as two years, developing noticeable alcohol. Other countries have pickles, of course, but as far as I know the only pickle restaurants are in Japan. Moreover there are pickle shops in big Japanese cities. The only other pickle shops I’ve seen are in New York City.
3. Pickled apricots (umeboshi). At a food court you have a choice of acidity, anywhere from 5% (slightly sour) to 25% (extremely sour).
4. Vinegar drinks. Tokyo 7-Elevens sell a black vinegar drink. Vinegar and water. In food courts you can buy special vinegars for this purpose. I’ve never seen vinegar drinks for sale anywhere else.
5. Natto.
6. Yogurt. The Japanese yogurts I’ve tried were sweetened but weren’t as sweet as the yogurts sold in Beijing.
7. Yakult. The fermented milk drink. It’s sold in such small packages it’s pretty clear it must appeal to people who think it improves their health. It doesn’t boost energy, quench thirst, or taste especially good. The manufacturer says it is good for health and that one bottle per day is all you need.
8. Beer and wine.
Because soy sauce is used in small amounts, it doesn’t count. At a Tokyo restaurant I met a nurse who said she thought you should eat fermented foods every day to be healthy. She said perhaps a third of Japanese believe this.
I’ve never seen high Japanese consumption of fermented foods noticed by epidemiologists. Individual fermented foods (such as miso), yes; the whole category, no. You can see how hard it would be to combine across foods: how much miso equals how much Yakult? Yet I’m sure fermented food consumption is extremely healthy.
Doenjang is a fermented soybean paste often served in Korean restaurants — as a vegetable dip, for example. This study found that the longer it’s fermented, the more powerful its anti-cancer action:
Doenjang fermented for 24 mo exhibited a two- to three-fold increase in antitumor effects on sarcoma-180-injected mice and antimetastatic effects in colon 26-M 3.1 cells in mice compared with the 3- or 6-mo fermented doenjang. The 24-mo fermentation was the most effective in preventing cancer by decreasing tumor formation and increasing natural killer cell activity in spleens and glutathione S-transferase activity in livers of mice.
Many things about doenjang stay roughly the same during fermentation. This study shows that what’s increasing (bacteria, etc.) is responsible for the anti-cancer effect, which supports my umami hypothesis (that we need fermented foods or something similar to be healthy).
I make yogurt rather than buy it so that I can ferment it a long time (e.g., 24 hours in a yogurt machine). The yogurt I make is much sourer than commercial yogurt.
Thanks to Michael Bowerman.
Thanks to Steve Hansen and Gary Wolf.
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%.