The Raw and the Cooked By Mrs Vera West
The title is from a book which I have never read, but was popular with structuralists and other trendies in the 1960s, The Raw and the Cooked (1964), by French anthropologist Claude Levi Strauss. The idea was that social understanding could proceed in terms of binary opposites. Yes, I an asleep already. However, there is a more important sense of the raw and the cooked which relates to gut bacteria and gut health, which is far more important that intellectual nonsense:
“Because cooking involves exposing food to heat, it tends to change the various foods' physical and chemical properties. But do these alterations change the delicate microbial environment of the gut? That is the question that researchers from the University of California, San Francisco, Harvard University, in Cambridge, MA, and other institutions recently set out to answer. "Our lab and others have studied how different kinds of diet, such as vegetarian versus meat-based diets, impact the microbiome," says the senior author of the new study, Peter Turnbaugh, Ph.D., an associate professor at the University of California, San Francisco. In the new study — the findings of which appear in Nature Microbiology — the researchers started by looking at how different types of cooked and raw food might affect the gut microbiota of mice. To do so, they fed mice a diet of either raw or cooked beef or raw or cooked sweet potato. The team used these foods, in particular, because previous studies had shown that cooking alters their nutritional components and because both commonly feature in human diets. First, the researchers found, surprisingly, that raw meat and cooked meat did not affect the mice's gut microbiota in obviously different ways. However, there were clear differences between how raw and cooked sweet potatoes affected the gut environment in rodents. Mice on a raw potato diet had poorer bacterial diversity in the gut, as well as slightly fewer bacteria, compared with baseline measurements. They also had a higher proportion of Bacteroidetes bacteria, which play a key role in the degradation of glycans, a form of sugar. To confirm these findings, the researchers performed another series of experiments, in which they fed mice not just raw and cooked sweet potatoes, but also white potatoes, beets, carrots, corn, and peas — foods with various degrees of starchiness and digestibility. As before, the researchers found that cooked versus raw potatoes — of both varieties — affected microbial diversity in the gut differently. The same was not true of the other foods.
This, the authors explain in their study paper, is likely because potatoes — unlike the other foods in this experiment — have "a high quantity of low digestibility starch," a carbohydrate with properties that are transformed by exposure to heat. "We were surprised to see that the differences were not only due to changing carbohydrate metabolism, but also may be driven by the chemicals found in plants," notes Turnbaugh. "To me, this really highlights the importance of considering the other components of our diet and how they impact gut bacteria," he adds. The team also noticed that mice on the raw food diets lost weight, which seemed to suggest that the changes in the gut microbiome may be responsible. However, when the researchers transplanted gut bacteria from mice fed raw diets to mice eating regular chow, the latter actually gained fat. This conundrum left the researchers at a loss, and they are still trying to find out what may have caused this surprising outcome.”
So, what are the take home and eat lessons for human health? There is too little research done on humans to make any recommendations, but it is likely that there are going to be observed effects on gut bacteria. Until there is definitive research it is always best to hedge one’s bets and eat a wide variety of both cooked and raw foods, primarily raw fruits and suitable vegetables raw. Raw meats are never a good idea. Common sense, as always, is the best guide.