The question of whether it might be helpful for us to avoid some grains, or all of them, comes up so often that I thought it might be worthwhile to review some of the basic facts involved. Since IMO, there is no better source of information on this topic than Dr. Cordain, here is how he starts a detailed article that discusses cereal grains, (written over 10 years ago). (Note that "Maize" is the name used in most of the world, for the grain that we here in the U. S. refer to as "Corn"). Also, the red emphasis is mine, of course:
Introduction
The number of plant species which nourish humanity is remarkably lim-
ited. Most of the 195,000 species of flowering plants produce edible parts
which could be utilized by man; however less than 0.1% or fewer than 300
species are used for food. Approximately 17 plant species provide 90% of
mankind’s food supply, of which cereal grains supply far and away the greatest
percentage (tables 1, 2). From table 1, it can be shown that the world’s four
major cereal grains (wheat, maize, rice and barley) contribute more tonnage
Table 1. The world’s top 30 food crops
Million metric tons
(estimated edible dry matter)
1 Wheat 468
2 Maize 429
3 Rice 330
4 Barley 160
5 Soybean 88
6 Cane sugar 67
7 Sorghum 60
8 Potato 54
9 Oats 43
10 Cassava 41
11 Sweet potato 35
12 Beet sugar 34
13 Rye 29
14 Millets 26
15 Rapeseed 19
16 Bean 14
17 Peanut 13
18 Pea 12
19 Musa 11
20 Grape 11
21 Sunflower 9.7
22 Yams 6.3
23 Apple 5.5
24 Coconut 5.3
25 Cottonseed (oil) 4.8
26 Orange 4.4
27 Tomato 3.3
28 Cabbage 3.0
29 Onion 2.6
30 Mango 1.8
Adapted from Harlan [3].
to humanity’s food supply than the next 26 crops combined. Eight cereal
grains: wheat, maize, rice, barley, sorghum, oats, rye, and millet provide 56%
of the food energy and 50% of the protein consumed on earth [1]. Three
cereals: wheat, maize and rice together comprise at least 75% of the world’s
grain production (table 1). It is clear that humanity has become dependent
upon cereal grains for the majority of its food supply. As Mangelsdorf [2] has
pointed out, ‘cereal grains literally stand between mankind and starvation’;
therefore, it is essential that we fully understand the nutritional implications
of cereal grain consumption upon human health and well being.
Modern man has become so dependent upon eating cereal grains (grass
seeds) that it has prompted at least one author [3] to say that we have become
‘canaries’. However, this has not always been the case. For the vast majority
of mankind’s presence on this planet, he rarely if ever consumed cereal grains
[4]. With the exception of the last 10,000 years following the agricultural
‘revolution’, humans have existed as non-cereal-eating hunter-gatherers since
the emergence of Homo erectus 1.7 million years ago. Although the first
anatomically modern humans (Homo sapiens) appeared in Africa 90,000
years ago, humans prior to the mesolithic period (~15,000 years ago) like
other primates rarely if ever utilized cereal grains [4]. Post-pleistocene (~10,000
years ago) hunter-gatherers occasionally consumed cereal grains; however
these foods were apparently not major dietary components for most of the
year [5]. It is apparent that there is little or no evolutionary precedent in our
species for grass seed consumption [6–8]. Consequently, we have had little
time ( 500 generations) since the inception of the agricultural revolution
10,000 years ago to adapt to a food type which now represents humanity’s
major source of both calories and protein.
The sum of evidence indicates that the human genetic constitution has
changed little in the past 40,000 years [7]. The foods which were commonly
Table 2. Food group totals (estimated edible dry matter)
Million metric tons
1 Cereals 1,545
2 Tubers 136
3 Pulses 127
4 All meats, milk and eggs 119
5 Sugar 101
6 Fruits 34
Adapted from Harlan [3].
Table 3. Key events in the development of agriculture and domestication of cereal grains
Event Time from present Location
years
Development of agriculture 10,000 Near East
8,000 Greece, West Africa
7–8,000 Central and S. America
7,000 China, India and SE Asia
6,500 Paris basin
6,000 Central Africa
5,500 Scandinavia, England
Domestication of wheat and barley 10,000 Near East
Domestication of rice 7,000 China, India and SE Asia
Domestication of maize 7,000 Central and S. America
Domestication of millets 5–6,000 Africa
Domestication of sorghum 5–6,000 East Africa
Domestication of rye 5,000 SW Asia
Domestication of oats 3,000 Europe
available to preagricultural man were the foods which shaped modern man’s
genetic nutritional requirements. Although our genetically determined nutri-
tional needs have changed little in the past 40,000 years, our diet has changed
dramatically since the advent of agriculture 10,000 years ago [7]. Cereal grains
as a staple food are a relatively recent addition to the human diet (table 3) and
represent a dramatic departure from those foods to which we are genetically
adapted. Discordance between humanity’s genetically determined dietary
needs and his present day diet is responsible for many of the degenerative
diseases which plague industrial man [9]. Although cereal grains are associated
with virtually every highly developed civilization in mankind’s history and
now occupy the base of the present day food selection pyramid in the United
States [10], there is a significant body of evidence which suggests that cereal
grains are less than optimal foods for humans and that the human genetic
makeup and physiology may not be fully adapted to high levels of cereal grain
consumption.
37 pages later, he offers these conclusions:
And here is a PDF of the complete article, for anyone who wants to read all the details. Note that there are no less than 342 references.Conclusions
From an evolutionary perspective, humanity’s adoption of agriculture,
and hence cereal grain consumption, is a relatively recent phenomenon. Table
3 shows that this event occurred in most parts of the world between 5,500
and 10,000 years ago. Cereal grains represent a biologically novel food for
mankind [341, 342], consequently there is considerable genetic discordance
between this staple food, and the foods to which our species is genetically
adapted.
Cereal grains lack a number of nutrients which are essential for human
health and well-being; additionally they contain numerous vitamins and min-
erals with low biological availability. Furthermore, the inability of humans to
physiologically overcome cereal grain antinutrients (phytates, alkylresorcinols,
protease inhibitors, lectins, etc.) is indicative of the evolutionary novelty of
this food for our species. This genetic maladaptation between human nutrient
requirements and those nutrients found in cereal grains manifests itself as
vitamin and mineral deficiencies and other nutritionally related disorders,
particularly when cereal grains are consumed in excessive quantity. More
disturbing is the ability of cereal grain proteins (protease inhibitors, lectins,
opioids and storage peptides) to interact with and alter human physiology.
These interactions likely occur because of physiological similarities (resultant
from phylogenetic commonalities) shared between humans and many herbi-
vores which have traditionally preyed upon the gramineae family. The second-
ary compounds (antinutrients) occurring in cereal grains (gramineae family),
were shaped by eons of selective pressure and were designed to prevent pre-
dation from traditional predators (insects, birds and ungulates) of this family
of plants. Because primates and hominids evolved in the tropical forest, wherein
dicotyledonous plants prevailed, the human physiology has virtually no evolu-
tionary experience with monocotyledonous cereal grains, and hence very little
adaptive response to a food group which now represents the staple food for
many of the world’s peoples.
Cereal grains obviously can be included in moderate amounts in the diets
of most people without any noticeable, deleterious health eects, and herein
lies their strength. When combined with a variety of both animal- and plant-
based foods, they provide a cheap and plentiful caloric source, capable of
sustaining and promoting human life. The ecologic, energetic eciency
wrought by the widespread cultivation and domestication of cereal grains
allowed for the dramatic expansion of worldwide human populations, which
in turn, ultimately led to humanity’s enormous cultural and technological
accomplishments. The downside of cereal grain consumption is their ability
to disrupt health and well being in virtually all people when consumed in
excessive quantity. This information has only been empirically known since
the discovery of vitamins, minerals and certain antinutrients in the early part
of this century.
The realization that cereal grain peptides interact with and induce change
in human physiology and therefore elicit disease and dysfunction is even newer
and dates to the early 1950s with the discovery of wheat gluten as the causative
agent in celiac disease. In the past 10 years has come the evidence (admittedly
incomplete) that certain cereal peptides may interact with the immune system
to elicit a variety of autoimmune-related diseases. These two seemingly distinct
entities (autoimmune disease and consumption of a staple food) are connected
primarily through an evolutionary collision of dissimilar genes which bear
identical products (molecular mimicry). Although, cereal grain consumption
may appear to be historically remote, it is biologically recent; consequently
the human immune, digestive and endocrine systems have not yet fully adapted
to a food group which provides 56% of humanity’s food energy and 50% of
its protein.
Cereal grains are truly humanity’s double-edged sword. For without them,
our species would likely have never evolved the complex cultural and techno-
logical innovations which allowed our departure from the hunter-gatherer
niche. However, because of the dissonance between human evolutionary nutri-
tional requirements and the nutrient content of these domesticated grasses,
many of the world’s people suffer disease and dysfunction directly attributable
to the consumption of these foods.
http://www.thepaleodiet.com/articles/Ce ... rticle.pdf
Loren Cordain knows his stuff.
Tex
