In several of my articles on fermented foods, I’ve stated that our preagricultural ancestors consumed primarily fresh foods, as opposed to fermented ones, and that I think we would be wise to follow in their footsteps. I strongly believe that people who harbor a dysbiotic gut microbiota can benefit from consuming small-moderate quantities of certain types of fermented foods, in particular fermented vegetables; however, I think it’s a bad idea to take in substantial quantities of fermented foods on a daily and indefinite basis. Part of the reason is that I think we’re inadequately adapted for such a practise.
In the comment section of one of my most recent articles on fermented vegetables, a reader challenged my statement regarding the evolutionary novelty of fermented foods. In this post, I thought I’d reply to his comment, which is shown below:
Hi Eirik,
I would have to dispute that fermented products are evolutionarily novel.
While our hunter-gatherer ancestors may not have eaten sauerkraut or kimchi, a substantial part of their diet would have been raw insects and their gut contents: eat a raw locust, termite or mopani worm (a Southern African delicacy which now sells at three times the price of prime beef), and a goodly proportion of what goes into the eater’s gut is microbial ferment in the insect’s gut. Really interesting bacteria too – a large part of the insect’s diet is cellulose, which can only be utilised if broken down by bacterial action.
Bigger animals too: When a paleolithic hunter butchers an antelope, expect rumen contents (a bacterial ferment) to get over everything, especially the hunter’s unwashed hands and the raw or undercooked flesh that is eaten.
Cheers
Richard
My answer:
Hi Richard,
Thanks for the input.
Our hunter-gatherer ancestors would obviously have been exposed to a variety of microorganisms through the consumption of food.
What you have to keep in mind though is that the microbial ecosystem that’s found in the guts of animals differs markedly from the one that’s found in fermented foods like for example sauerkraut. Sauerkraut typically contains a narrower range of bacteria and is massively dominated by lactic acid bacteria, in particular Lactobacillus plantarum. The primary reason is that the number of nutritional substrates that are available for fermentation is very limited. Animals, on the other hand, typically consume a diversity of different foods; and hence, there will be a lot of different substrates available for microbes to “digest”. The microbial end products are obviously also going to differ.
In the human colon, for example, Lactobacilli only constitute a small portion of the total microbial ecosystem. Moreover, the primary microbial end products are short-chain fatty acids, not lactic acid, as in fermented foods like sauerkraut.
In nature, there is great inter-individual and inter-species variation in microbiota composition. That’s important to point out, as it means that someone who’s exposed to microorganisms associated with a diversity of plants and animals will be exposed to a great diversity of different organisms. The same cannot be said for someone who only consumes one or a few types of lacto-fermented fermented foods (e.g., kefir. sauerkraut, kimchi). Such foods vary with respects to their microbiota composition; however, they are all dominated by lactobacilli.
The consumption of raw animal intestines is in many ways more analogous to a fecal microbiota transplantation than it is to the consumption of fermented foods such as sauerkraut.
Furthermore, I question the statement that our ancestors took in a substantial amount of insects and foreign gut contents. Many of our ancient forebears undoubtedly ate insects (In general, hunter-gatherers eat what’s available to them in their local environment); however, I’ve never seen any evidence supporting the notion that insects made up a large part of Paleolithic human diets. Contemporary African hunter-gatherers such as the Hadza eat primarily larger animals, and I see no reason to think that the situation was substantially different in the past. Optimal foraging theory dictates that hunter-gatherers who go out into their local environment in the search for food want to get the most bang for the buck, in the sense that they want to maximize their caloric gain. Hence, it’s not surprising that they often go for larger animals over smaller ones.
Finally, as pointed out in the beginning, hunter-gatherers are exposed to a diversity of microorganisms through their consumption of food. However, I’ve never seen any evidence supporting the notion that it’s common for hunter-gatherers to ingest substantial quantities of fermented gut contents on a regular basis. Also, it’s important to remember that hunter-gatherers often (but certainly not always) cook meat prior to eating it, and in the process eliminate bacteria, as well as break down various heat-sensitive substances.
The bottom line is that hunter-gatherers are exposed to a very different mix of microbes and microbial metabolites than people who eat a diet heavy in fermented foods such as youghurt, kimchi, kefir, sauerkraut, and kombucha. Perhaps most importantly, they typically don’t ingest substantial quantities of just one or a couple of microbial strains; rather, they are exposed to a diversity of different types of microbes.
Please let me know if you have any further objections or concerns!
– Eirik
Richard Doehring says
November 4, 2018 at 11:55 pmHi Eirik,
Contemporary hunter-gatherer lifestyles are likely a very distorted a representation of those of our ancestors of fifty thousand years ago.
Large game may be a preferred food source, but before the invention of the bow and arrow, and the discovery of arrow poisons, it will have been a rare treat. Even with bow and arrow, many hunts will have yielded nothing.
Cooking, too, is from an evolutionary viewpont relatively recent, and it is doubtful whether the cooking pot is any older than agriculture. Before then, any cooking done would have been over an open fire, and been uneven.
The rumen, is not the colon. I expect, admittedly without any evidence, that our ancestors would be less likely to try to remove rumen contents from meat that to remove faecal matter. Butchering an animal would not have been an hygienic process. I have also come across an image of a Hadza hunter using rumen contents to clean the blood off his hands – no soap and water! I will grant that the amount of bacterial fermnt from rumen contents on the hands and food would have been much less than a serving of sauerkraut, but I don’t think it would have been inconsequential.
Eating of insects is another matter: Of all the peoples of the world, it is only Western Europeans, and their colonial descendants, who do not eat insects as a matter of course. Grasshoppers and locusts are permitted foods in Leviticus. Insects are a lot easier to catch than antelope, and would have been the first food items which children would have caught for themselves. They are tasty and nutricious,
If one eats a raw locust, one is eating the whole of its gut content as well, a substantial fraction of the insect’s mass. Eat several dozen, and you are looking at a consumption of a fairly substantial mass of microbial ferment of grass.
OK, these gut ferments are different, and have more microbial diversity than contemporary fermented foods, but at least the fermented foods go part of the way to replace a food intake of bacteria which would have been substantial for our ancestors.
While talking about fermented foods, not all are equal: Those made from raw ingredients, without defined starter cultures, have a much more diverse microbial (fungi and protozoa as well as bacteria) content than commercial products made from pasteurised ingredients inoculated with defined cultures. This is particularly true of milk products: African sour milk (Inkomazi, to the amaZulu, amasi to the amaXhosa) made the traditional way from raw milk, is very different in microbiology from commercial yoghurt,
One final evolutionary perspective (I promise it is the last) -150 million or so years ago all the mammals that there were on Earth were insect eaters. We are all descended from a shrew-like creature that lived on insects
Best regards,
Richard
Richard Doehring says
November 5, 2018 at 12:59 amHi Eirik,
Just another comment to insect eating. I think one rather persuasive bit of evidence that our ancestors (or at any rate, those of our ancestors who did not live on the edge of the sea) had insects as a substantial part of their diet is the requirement for good health in primates for dietary long-chain omega-3 fatty acids.
Unlike other animals, primates cannot synthesize omega-3 fatty acids. Plants, particularly their seeds, are a source of short-chain omega-3 fatty acids, but the long chain ones are most reliably found in fish, shellfish and, you got it, insects! On the African highveld fish and shellfish are not easily come by, but insects are.
You can get long-chain omega-3 fatty acids from the meat of antelope and other mammals, but it is in a lower and less desirable ratio to omega-6 fatty acids than in insects (or shellfish).
Regards
Richard
Pascal Baudar says
November 6, 2018 at 5:36 amHere is a example of traditional fermentation in Alaska (Inuit) but a similar thing could have been done a very long time ago. Winter could have been a time to settle down a bit for hunters/gatherers due to cold temperature and weather, such fermentation would preserve the food and provide probiotics in the same time. It’s hard to know because you won’t find traces of such process from prehistory.
https://gizmodo.com/5885202/this-inuit-delicacy-is-the-turducken-from-hell
Here is another example of fermented food – stomach content from caribou
“Additionally, the stomach contents of the caribou, which consists of fermented lichens, and grasses which are not otherwise digestible by humans, provide important vitamins and minerals that are difficult to obtain in the arctic”
Source: http://www.aihd.ku.edu/foods/caribou.html
So I think it’s possible and with a bit more research, one could find examples that would apply to a hunter-gatherer lifestyle.
Just my 2 cents….
Pascal Baudar says
November 6, 2018 at 5:46 amAnother example is the Cassava fermentation by tribes in Brazil and they’re hunter gatherers. It’s partly lacto fermentation but also involves yeast. So yes, I think it could have been part of the diet, we just don’t know… locally I ferment wild mustard roots as a preservation method.