Monday, March 19, 2012
Ways of knowing
For years women told one another that you could cure a UTI by drinking cranberry juice, no one new why it worked, but it worked so often for so many women that word got around. Science decided to test the cranberry juice theory, who knows, maybe all these women were on to something. The theory was that cranberry juice must acidify the urine so much it killed bacteria, so the scientists gave different test subjects different amounts of cranberry juice and tested the PH of the urine, and it turned out no matter how much cranberry juice you gave the women it didn't really change the PH. Cranberry juice for UTIs was declared an old wives tale, and Doctors everywhere rolled their eyes at patients who insisted that the juice worked.
Meanwhile, many people for whom it did in fact work stopped believing in science a little bit.
We know now that cranberry juice does indeed reduce the duration and frequency of UTIs, but by a totally different mechanism than was expected. Turns out there is a sugar in cranberry juice that humans don't digest, that is cleared in urine, that sugar blocks the part of E. Coli bacteria that normally latches on to the urinary tract, allowing the bacteria to be washed away.
There is no question that well designed scientific research is a very good way of proving and disproving things, perhaps the best way we have right now. But there are a number of limitations to science. One major limitation is the tendency of humans to pay more attention to evidence that supports their bias, and disregard the limits of that evidence. The doctors and scientists didn't want to believe that cranberry juice helped UTIs, though they were willing to test it just in case. When their test was negative they were completely comfortable rejecting any possible mechanism for cranberry juice to work. In fact their test just showed that cranberry juice didn't work by acidifying urine.
Another great example is food and acne. Many people have noticed that their diet impacts their acne. Various food culprits have been blamed. If you ask a doctor they will tell you in total certainty that food has no impact on acne. All the people who see their diet impacting their acne stop believing their doctors a little when that happens. Apparently the research the doctors are quoting was one brief study comparing a group that ate a chocolate bar with a group that ate a candy bar with no chocolate. I hope you can see the gross limitations of that research.
So back to the beans. Harold McGee, a very interesting food writer, wrote a book called "On Food and Cooking." He wanted to test whether soaking beans increased their digestibility. Indigestible polysaccharides are blamed for the gas promoting effect of beans, we can't digest certain sugars, but the microbes in our gut can, and they over grow and produce gas. So McGee soaked some beans, measured the sugar content of the soaking water, and determined that soaking didn't increase the sugar in the water, and if you think about it, how could soaking leach out more than a tiny fraction of the polysaccharides from the beans any way? Soaking was declared unnecessary. Most people who write about food have read McGee, or at least heard of him, so the don't bother soaking message is really wide spread. The food expert on the radio was almost certainly referencing McGee today. By the way, I think McGee is a smart guy, and I have learned a lot from his books.
But it turns out that much of the problem with beans and grains is in phytates and other anti-nutrients which the plant uses to defend itself. Mice and other animals produce a lot of phytase, an enzyme that digests the phytates. Healthy cows have micro-organisms in their rumen that produce phytase, and some lucky humans have robust intestinal flora that can help them digest beans with no problem. Soaking and thus partially sprouting beans activates all sorts of enzymes as the living bean begins the process of growing into a plant. If beans aren't a huge part of your diet, if you are getting ample vitamins and minerals from other sources, than traditional soaking is probably enough.
People all over the world have figured out that soaking beans makes them more digestible, and eating them with certain herbs also helps. I have noticed that when I soak beans for a good long time (changing the water regularly) that they have a better texture, a better flavor, and they don't bother my tummy as much. They are more pleasurable to me, and they help me feel connected to a long tradition of cooking and eating. Beans taste best if you eat them with spices in the cumin/fennel/caraway family and herbs like rosemary, oregano, cilantro, and epazote. Cultures that have eaten beans for a long time flavor them with those spices and herbs, they soak and ferment the beans.
I don't eat beans very often any more, they move my blood sugar too far too fast. But I do feed them to my vegetarian children, what are the alternatives? Soy dogs and wheat gluten burgers? When I do feed beans to my kids, I prepare them carefully, and I trust to thousands of years of human experimentation to figure out how to make them as safe as I can. This doesn't mean that I reject scientific research, I understand it as a very important way of knowing. But that research is dependent on figuring out a good hypothesis, figuring out a correct test, and don't forget actually getting the research funded. In the mean time, I can use other ways of knowing to make choices, and conveniently they tend to be more aesthetically pleasing.
Here is an article at Weston Price about preparing beans and grains.
Here is a lovely post by one of my favorite bloggers about her experiences with food intolerances and figuring out what she needs to eat to feel well.