Assorted Links

Thanks to Paul Sas and Gary Wolf.

Assorted Links

Thanks to Peter Spero and VeganKitten.

Asthma and Farm Life

For a long time it’s been clear that living on a farm protects children against asthma (compared to city life). A new study, done in Germany, tried to go a little further than that: to ask if it was microbial exposure that made the difference. Non-American scientists have been far more interested in the environmental causes of disease than American scientists.

They measured microbial exposure by studying mattress dust. One branch of the study used DNA techniques to measure microbial diversity of the dust; the other branch measured microbial diversity by seeing how many microbes could be cultured from the dust.

They found the usual farm/city difference in asthma: The city kids had roughly twice as much. They found the expected farm/city difference in microbial diversity of mattress dust: For a given species of bacteria or fungi, there was roughly twice as much chance of finding it in the farm dust.

Did the microbial difference explain the asthma difference? To find out they corrected for the farm difference. I think this means they looked within the farm kids to see if in this restricted group there was a microbial diversity/asthma risk correlation. In one branch of the study, there was a significant correlation. In the other branch, the correlation was nearly significant.

In all, the results support the idea that differences in microbial exposure explain the farm/city asthma difference. The biggest strength of this study is that they gathered useful evidence related to a major problem (asthma). The biggest weakness is how difficult it was. It involved about 15,000 kids and probably cost more than a million dollars.

Thanks to Aaron Blaisdell.

The Baltimore Shipyard Study

In a comment on my last post, Sean Estey described a study of Baltimore shipyard workers, some of whom handled radioactive materials. The ones exposed to more radiation were healthier than those exposed to less. The difference in death rate was huge: 25%. This is so large and consistent with other data I doubt it is due to a confounding.

You can read more about this study here and here. If one quarter of all deaths are due to suboptimal stimulation of repair systems, that’s extraordinary news. The study was finished around 1990. The plausibility of such a large benefit should have led to experiments. The observation that people in mountain states (such as Colorado) have less cancer than those in gulf states (such as Alabama) as well as greater radiation exposure suggested to John Cameron, a professor of toxicology, an experiment in which some gulf state residents are exposed to enough radiation to bring their total exposure up to what mountain state residents receive. This has yet to be done.

In a paper about the effects of low-dose radiation, the authors say we should ignore the Baltimore study because of “the healthy worker” effect — the possibility that persons in one exposure group were healthier than those in another exposure group because workers are healthier than non-workers (and fitness for work may have differed between the exposure groups in the Baltimore study). They give three examples to illustrate the healthy worker effect. In these examples, a group in which everyone has a particular job were healthier than the general public, which includes many people without a job. In their examples, the median effect of being in the full-employment group (in which everyone has a job) is a 10% decrease in mortality compared to the general-public group (in which some people don’t have a job because of disability). That should give a good idea of the maximum size of the healthy worker effect — when something is explicitly varied, that’s what happens. The Baltimore study compares person with job to person with job, not person with job to person without job. This suggests that in the Baltimore study, the healthy worker effect was smaller than the effect in the examples, meaning smaller than a 10% reduction. Such an effect cannot explain a 25% reduction.

A comment by Alrenous on my earlier post linked to a 2007 study of people in Taiwan whose apartment building was accidentally contaminated with radioactive materials. By the time of data collection, they had gotten far less cancer (3% of what would have been expected) than the general Taiwan population. A healthy worker effect cannot explain this. Again, the reduction is so great it is unlikely to be due to confounding.

If I could buy something to put under my bed that would expose me to the level of radiation received by people in Colorado, I would.

Beijing Smog: Good or Bad?

I am in Beijing. The smog is bad. It is more humid than usual and the air is dirtier than usual. At his blog, James Fallows, who is also in Beijing, has posted  pictures and pollution measurements. (Incidentally, Eamonn Fingleton, an excellent writer, will be guest-blogging there. In Praise of Hard Industries is one of the best business/economics books I’ve read.)

The effect of smog on health isn’t obvious. Maybe you know about hormesis — the finding that a small dose of a poison, such as radioactivity, is beneficial. It has been observed in hundreds of experiments. It makes sense: the poisons activate repair systems. Even if you know about hormesis, you probably don’t know that one of the first studies of smoking and cancer found that inhaling cigarette smoke appeared beneficial: inhalers had less cancer than non-inhalers. R. A. Fisher, the great statistician, emphasized this (pp. 160-161):

There were fewer inhalers among the cancer patients than among the non-cancer patients. That, I think, is an exceedingly important finding.

This difference (a negative correlation) appeared in spite of two positive correlations: Heavy smokers get more cancer than light smokers; and heavy smokers are more likely to inhale than light smokers. It is far from the only fact suggesting the connection between smoking and health isn’t simple.

So I am not worried about Beijing smog. The real danger, I think, is not eating fermented foods. Which, thankfully, is infinitely more under my control.

Assorted Links

Probiotic Helps Children with IBS

Irritable bowel syndrome (IBS) — basically, recurrent pain during digestion — is common. A new study by Italian pediatricians asked if a probiotic would help. They randomized children into two groups: active and placebo. Children in the active group were given pills with a lot of lactobacillus bacteria, which they took twice per day. The placebo was made by the same manufacturer, so it looked identical. During the study, the researchers did not know who was in each group.

There was a big difference between the groups, which took about four weeks to emerge. The active group had painful episodes less than half as often as the placebo group, and the episodes they did have were less painful.

Overall this supports my broad point that we need to eat plenty of fermented foods to be healthy. That’s not what the authors of the study concluded. They concluded:

Demonstration of the efficacy of a given probiotic for a specific therapeutic target will help clinicians choose which probiotic to use when dealing with a specific disease. We are entering the era of targeted probiotic use.

Which reveals a bad case of gatekeeper syndrome. I wouldn’t expect them to say their results support the idea that everyone should eat fermented foods — that’s an “alternative” (and therefore “crazy”) idea. But they could have said their results imply that kids with IBS should eat yogurt.

Preposterous Health Claims of 2010

Katy Steinmetz, a writer for Time, made a list called “Nutty Health Claims of 2010” and “2010: The Year in Preposterous Health Claims.” The list of 12 includes:


Marion Nestle, the New York University nutrition expert, has often said she thinks the health claims made for yogurt are bogus — at least when big companies make them. She recently called Dannon’s claims “a case study of successful marketing”.

“Sour” in Chinese

The Chinese character for sour (pinyin suan) contains a bottle-like element that is sometimes translated wine, sometimes whiskey bottle, and sometimes “the tenth of the twelve earthly branches,” whatever that means. The bottle-like element appears in the character for alcoholic beverage, the character for vinegar, and several other characters with no obvious connection to fermentation. But the connection between sour and fermentation is clear.

My belief that we need to eat lots of fermented food to be healthy began when I realized that would explain why we like sour foods, foods high in umami, and foods with complex flavors — preferences I’d never heard explained. We like those foods, I theorized, so that we will eat foods high in bacteria. Bacteria tend to make sugar-containing foods sour, protein-containing foods high in umami, and all foods high in flavor complexity. I had not previously connected sourness and bacteria — but the Chinese had. I don’t yet know the Chinese characters for umami or flavor complexity.

Do Fermented Foods Shorten Colds?

Alex Chernavsky writes:

I had an interesting experience recently. On Thursday afternoon, I started feeling a little run-down. Then I began to sneeze a lot, and my nose really started to run. I thought I was coming down with a cold. I took an antihistamine and felt a little better. I woke up Friday morning with a mild sore throat (the sneezing/runny nose had stopped). Within a couple of hours, my throat wasn’t sore anymore — and I haven’t felt sick since then. In summary, I believe I had a cold that lasted less than 24 hours. This almost never happens to me. Typically, my colds last at least a week, and usually more (and I usually get two or three colds per year). There is only one other time in my adult life [he’s in his forties] when I can remember having a very short-duration cold.

Maybe it’s the fermented foods I’m eating. After I started reading your blog, I began to brew my own kombucha, and I drink it every day. I also sometimes eat kim chee, fermented dilly beans, fermented salsa, umeboshi plums, and coconut kefir.

This was the first cold he’s gotten since he started eating lots of fermented foods in June. I believe the correlation reflects causation — the fermented foods improve his immune function. The microbes in the food keep the immune system “awake”. I also believe that Alex’s colds would become even less noticeable if he improved his sleep.

Asthma and Probiotics

In a long comment on an earlier post, JohnG tells how he failed and succeeded to get rid of disabling exercise-induced asthma. Lots of things didn’t work:

I tried Vitamin D; it didn’t work, but it did help my nasal allergies somewhat. I tried low carb dieting, and just like Dr. Lutz of “Life Without Bread” said, it made asthma worse while it practically cured my nasal allergies. I also tried the Dr. Sears approach of taking as much as 7.5g of EPA/DHA a day; no change at all in the exercise induced asthma.

The idea that asthma is due to lack of microbes made sense to him and he started trying fermented foods and probiotics. At first, nothing:

I re-reviewed the probiotic slant and found the Helminth story and all the trials that were going on in PubMed for them. With that logic in hand, I set about to find a probiotic that worked. I tried yogurt, kefir, fermented cabbage, and buttermilk to no avail. I then tried store bought probiotics one by one. I tried The Maker’s Diet probiotic and it didn’t help; but I do think it helped make a 20 year long wart go away. I also tried all forms of probiotics on the market; even LGG. Nothing.

Finally, success:

I bought this super high dose probiotic and took it along with a L. Sporogenes/bacillus coagulans. Voila, three days later I could really feel the difference during exercise. I continued that for 10 days. By the 10th day, I didn’t have to hit my inhaler at all during exercise. Wow!

First, I had to decide which probiotic did the trick. I didn’t want to spend a ton on that high dose probiotic, so I stuck with the Bacillus Coagulans and it continued working normally. So, I found my probiotic. Now, I needed to verify it wasn’t placebo. A close cousin to exercise induced asthma is the phenomenon of waking up sneezing and then promptly getting an asthma attack/or closure after that.

I went off my bacillus coagulans that I had been on for 14 days. By the second day, I noticed a little difference. By the third day, I had to hit my inhaler during the workout. By the 10th day (bacillus coagulans supposedly lives in your intestines 7 days), I was full-blown back to having to use 4 inhaler puffs and it wasn’t doing the trick. This was test phase one.

I then went back on the bacillus coagulans for 10 days. The same process repeated itself. The nightly asthma attacks abated after about 4 days and the same no-puff needed during exercise continued as well.

I then went back off the bacillus coagulans for 10 days. I got the asthma back at day 3.

I’ve now been back on 5 billion CFU’s of bacillus coagulans (duraflora) for 18 days. I don’t have to use my inhaler for exercise. I can feel the asthma come on very slightly and then go away.

Very impressive. Shows what can happen if (a) you think for yourself, (b) persist, and (c) have access to a lot of helpful information. I think he needed all three.

Vitamin K2 and Fermented Foods

We evolved to like sour foods, foods with complex flavors, and umami foods, I believe, so that we would eat more bacteria-laden food. Why do we need to eat such food? Perhaps to get enough Vitamin K2. Vitamin K1 and Vitamin K2 are quite different. A brief introduction:

The term vitamin K refers to a group of compounds that have a 2-methyl-1,4-naphtoquinone ring in common but differ in the length and structure of their isoprenoid side chain at the 3-position. The 2 forms of vitamin K that occur naturally in foods are phylloquinone (vitamin K1) and the group of menaquinones (vitamin K2, MK-n), which vary in the number of prenyl units. Whereas phylloquinone is abundant in green leafy vegetables and some vegetable oils, menaquinones are synthesized by bacteria; therefore, they mainly occur in fermented products such as cheese.

A 2004 study found a huge protective effect of K2:

The scientists at Osaka City University gave 21 women with viral liver cirrhosis [which greatly increases your chances of liver cancer] a daily supplement of 45mg vitamin K2 (menaquinone) for a period of two years. A group of 19 women with the disease received a placebo for the same time. Liver cancer was detected in only two of the 21 women given vitamin K2 but nine of the 19 women in the control group, reports the team in today’s issue of JAMA (292:358-361). After adjustment for age, severity of disease and treatment, the researchers found the women receiving vitamin K supplementation were nearly 90 per cent less likely to develop liver cancer.

A huge effect, suggesting that K2 is necessary for a repair system to work properly. This recent article is more support for the idea that K2 protects against cancer. The effect is weaker, perhaps because there was less damage needing repair.