Saturday, December 26, 2009

Dr. Cordain Comments on New Evidence of Early Human Grain Consumption

Dear Readers,

Dr. Cordain was recently asked by a reporter from the journal Nature to comment on an article entitled "Mozambican Grass Seed Consumption During the Middle Stone Age" by Julio Mercader in the journal Science, citing evidence that humans consumed grain much earlier than was previously thought. In addition, one of our readers asked Dr. Cordain to comment on an article in Scientific American entitled "Humans feasting on grains for at least 100,000 years," by Katherine Harmon.

Dear Dr. Cordain,

I am a huge fan of your books and have been eating a paleo diet for years. I've had your graph of the land/water meat/fish, and fruit, nut, seed % breakdown taped to my fridge for years, although I'm so familiar with it that i no longer need to look at it for reference.

The Paleo Diet is predicated upon the fact that humans did not have grain cultivation and consumption until 5,000-8,000 years ago, which coincides with the advent of 'modern' civilization diseases. Up until now, this hypothesis have not been challenged as the archival evidence of grain agriculture matches it.

However, the current issue of Scientific American has an article stating archaeological evidence that humans were eating lots of grains 100,000 years ago.

I am most curious about your opinion about this and how it effects the paleo dietary theory.


Dr. Cordain's response:

This is an interesting paper ( Mercader J. Mozambican grass seed consumption during the middle stone age. Science 2009;326:1680-83) as it may push probable (but clearly not definite) cereal grain consumption by hominins back to at least 105,000 years ago. Prior to this evidence, the earliest exploitation of wild cereal grains was reported by Piperno and colleagues at Ohalo II in Israel and dating to ~23,500 years ago (Nature 2004;430:670-73). As opposed to the Ohalo II data in which a large saddle stone was discovered with obvious repetitive grinding marks and embedded starch granules attributed to a variety of grains and seeds that were concurrently present with the artifact , the data from Ngalue is less convincing for the use of cereal grains as seasonal food. No associated intact grass seeds have been discovered in the cave at Ngalue, nor were anvil stones with repetitive grinding marks found. Hence, at best, the data suggests sporadic use (and not necessarily consumption) of grains at this early date. Clearly, large scale processing of sorghum for consumption for extended periods seems unlikely.

Further, It should be pointed out that consumption of wild grass seeds of any kind requires extensive technology and processing to yield a digestible and edible food that likely did not exist 105,000 years ago. Harvesting of wild grass seeds without some kind of technology (e.g. sickles and scythes [not present at this time]) is tedious and difficult at best. Additionally, containers of some sort (baskets [not present at this time], pottery [not present] or animal skin containers are needed to collect the tiny grains. Many grain species require flailing to separate the seed from the chaff and then further winnowing ([baskets not present]), or animal skins] to separate the seeds from the chaff. Intact grains are not digestible by humans unless they are first ground into a flour (which breaks down the cell walls), and then cooked (typically in water – e.g. boiling [technology not present]) or parched in a fire which gelatinizes the starch granules, and thereby makes them available for digestion and absorption. Because each and every one of these processing steps requires additional energy on the part of the gatherer, most contemporary hunter gatherers did not exploit grains except as starvation foods because they yielded such little energy relative to the energy obtained (optimal foraging theory).

If indeed the grinder/core axes with telltale starch granules were used to make flour from sorghum seeds, then the flour still had to be cooked to gelatinize the starch granules to make it digestible. In Neolithic peoples, grass seed flour most typically is mixed with water to make a paste (dough) that is then cooked into flat breads. It is highly unlikely that the technology or the behavioral sophistication existed 105,000 years ago to make flat breads. Whole grains can be parched intact in fires, but this process is less effective than making flour into a paste and cooking it to gelatinize the starch granules. Hence, it is difficult to reconcile the chain of events proposed by the authors (appearance of sorghum starch granules on cobbles or grinders = pounding or grinding of sorghum grains = consumption of sorghum). I wouldn’t hang my hat on this evidence indicating grains were necessarily consumed by hominins at this early date. To my mind, the Ohalo II data still represents the best earliest evidence for grain consumption by hominins.

Loren Cordain, Ph.D., Professor


  1. I read an interesting comment on Twitter from Keith Norris. He thought the more likely scenario was that these grains were used for pigments or paint.

  2. @Beth, I worked in a paper plant for a while where starch is used for glue. Many better uses for starchy plants that food :)

    Nice followup Professor Cordain.

  3. Dear Readers,

    Dr. Cordain's comments on the articles in Science and Scientific American were emailed to our newsletter subscribers following publication on this blog. We've received many responses from our readership, which I will post here for your information.

    Thank you to the Paleo Diet community for your responses and readership.

    Patrick Baker
    Blog Admin

  4. Hi there Loren,

    I saw the article just a few days ago and was a bit suprised by the data. I have to congratulate you again on addressing something like this so quickly, and helping us along with the questions this kind of information brings up with those that follow the Paleo Diet.

    Just a quick note of thanks for being present and topical in helping us out with keeping the wheat from the chaff and from our plate! Haha a little gluten free joke :)

    All the best to you through the holiday season and thank you again for the fine work you continue to do and the wonderful help you bring the world in the realm of healthy eating and lifestyle.

    Kind Regards,

    Holistic Nutritionist

  5. Darn it, I was hoping for a slice of bread over the holidays, like my 105,000 year old hominid ancestors!


  6. Hi,

    Thanks for this article.

    I worked in medical laboratory, including microbiology, for thirty years, and I am aware that soaking and fermenting grains is a very simple procedure that can alter them, so that they are more digestible ... and this procedure is/has been practiced for many centuries.

    I have a proposition for you. soak washed whole grain brown rice for 24 hours and then wash them in chlorine free water in a strainer, and then easily make a mash of them and then ferment them for 24 more hours ... Test them for digestibility and i would be interested to see what you find out. of course, it may be my Norwegian "longitudinal nutritional genetics" that allow me to handle this.

    This procedure can also be used for beans.

    Additionally, after soaking and fermenting, cooking makes digestibility even better.


  7. Dr. Cordain gave a well presented balanced answer.


  8. Hi Loren,

    Thank you for your email on the "Mozambican Grass Seed Consumption During the Middle Stone Age." It came precisely at a time when I was in a tug of war, so to speak, with a friend on this very topic.

    I recently presented a one and one half hour talk on "Diseases of Civilization and the Paleo Diet" to second year Red River College nursing students and their teacher here in Winnipeg, and it was very enthusiastically received. I used quite a bit of the info from your book, "The Paleo Diet for Athletes."

    Since grain and dairy are a very big part of Western Canada's economy, I am not surprised that someone from Calgary would come up with this Mozambican story. This story even appeared in the "Winnipeg Free Press" as a credible article on December 18, 2009.

    Have you written anything more in your newsletter "The Whole Wheat Heart Attack"? I am ever so grateful for the work that you and your world wide team of research scientists have done over the past ten years. Thank you for that.

    Best Regards,
    George in Winnipeg

  9. It seems almost beyond controversy that hominids would not have eaten grass seeds as early as 100,000 years ago. Those creatures ate anything that was not poison - I mean everything. Bugs, worms, carrion, and all edible plats. The issue is not whether or not they ate grains, but was it a staple. While hunting I, and many I have known, pull the seeds form wild grain while walking through the fields and eat them - grinding it with our teeth. Certainly early humans would also have done the same and if the grain was plentiful enough it would have been gathered. Birds and rats do it - why not early people?


  10. Sorghum is not like most grains. The seed is big compared to the seed of wheat or oats, closer to the size of corn kernels. In fact, sorghum can be popped to make popcorn. Or fermented to make alcohol. So milling would not have been needed to process sorghum as a food.

    Besides, all we need to assume for the period when grass seeds were eaten in Madagascar or anyplace else is that the Earth's climate was in a cold phase when droughts were common and other foods were not available.

    Grain eating in the archeological record is a sign of food shortage relative to population pressure, something which may be expected to occur whenever climate cools after a prolonged warmer phase. Over the past million years, climate has frequently shifted from warm to cold and back again, thus there must have been many periods when humans were forced to eat grains instead of more healthful foods.


  11. Readers might be interested in this addition to the discussion. Australian aborigines, who had a stone age culture by any measure, used to collect seeds from the nardoo plant and grind them up on flat stones, which are found near intermittent inland waterways. I have such a stone myself. Nardoo was a low fern-like plant which grew in outback areas flooded after rare heavy rain, river overflow events etc. It was ground up, made into paste and cooked into a type of bread. The doomed explorers Bourke and Wills famously tried to copy the aborigines but continued to starve because they missed out the critical step of cooking the seeds before grinding - this destroys an enzyme which if eaten prevents the body from taking up thiamin. Although this demonstrates some level of "seed eating technology" it also shows that the seed eating was very occasional and not without risk.

  12. Dear Paleo Diet Team,

    I have a very important question for you in regards to the digestion of meat. I have read opinions of numerous nutritionists (e.g. Linda Allen, Nancy Appleton, Jon Barron) who are all uneasy about eating quantities of meat due to humans' apparent difficulty with digesting meat, especially if the meat is cooked. They claim that it burdens the organism to eat cooked meat, as the lack of necessary enzymes for meat digestion impairs the function of the digestive tract. It has been said that cooked meat denatures and becomes a "foreign substance" to the body, producing free radicals and in general having a toxic effect.

    I have found a very interesting video on youtube of colonoscopies performed on patients with various health problems (including cancer). The patients were all put on a special, fully vegetarian diet, drinking alkalized water. The "before and after" videos are truly amazing -- the colons are squeaky clean!
    Please watch this fascinating (although quite graphic) video: or simply search for Hiromi Shinya on youtube.

    Given all this seeming conflicting information, I am a bit torn between going the Paleo way, or going the raw, vegan way. I would much appreciate any clarification of this subject. It will have a direct effect on what I put in my mouth every day!

    I can understand that perhaps raw meat would be easier on the digestive tract for us... but realistically, who in our society will eat raw meat or fish, save for a bit of sashimi here and there?

    Thank you,
    Barbara H.

  13. Would love to see an answer to Barbara's question. I am a big fan of meat but are the suggestions of difficulty in digesting true?

    Newcastle, UK


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