Natural food-Grains Beans and Seeds

The human animal evolved in the forests, woodlands, and plains of Africa. The human animal spread into virtually all environments, from tropical rain forest to arid desert because that animal, which is you and me today, had evolved the kind of guts that could digest most kinds of food - plant (except woody twiglets and cellulosy grass blades) or animal. Our natural diet is everything edible. But in any given area of the world, we relied on starchy plants, nut and seed oils, or animal fat for fuel to burn for energy. Animals that know how dangerous humans are tend to run - fast, and in the opposite direction - and are fat only at certain times of year. Plants have the virtue of standing still, so underground storage tubers and carbohydrate rich seeds are a reliable energy, and in some cases, fat and protein source.
No reasonable energy source was ignored, and wild seeds were no exception. Indeed, grindstones with adherent plant starch from before 160,000 years ago - when the first recognisably modern humans appear in the fossil record - may have been used to grind grass seeds [[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]]. We, of course, ate every non-toxic seed (including [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]) present in the environment we had moved into. There are many plants with edible seeds in the various climatic zones of Africa, but relatively few have big enough seeds, or are productive enough, to be worth expending the energy which are nicer to eat, easier to store, and require no preparation.
Of those wild African species that are worth collecting, probably the most important are the numerous species of wild 'millets' native to West and East Africa. The term 'millet' is a slightly confusing generic name to mean both 'millet' (Panicum, Setaria, Echinochloa, Eleusine, and Pennisetum spp.) and 'sorghum' (Sorghum spp.).
Early humans exploiting the riches of marsh, delta and riverine environments had access to the seeds of a reed-like grass, Phragmites autralis (communis) 'ditch reed' or 'water grass', which, although the yeild was probably relatively poor (there is little literature on this subject to form a view), had the virtue of being both widespread and in thick stands. When we migrated out of Africa, we would find this seasonal food source in damp and marshy places from the tropics to the temperate lands. These grass seeds were indeed our 'evolutionary fellow travellers'.
Numerous legume seeds were available to our African ancestors, for example the 'morama bean', Tylosema esculentum, which grows in sandy arid to semi-arid areas of the more Southern parts of Africa and tastes like cashews when roasted. In addition to having a large edible tuber, this legume has pods containing one to two oil and protein rich seeds with a nutritional value similar to soya beans or peanuts (the protein content ranges between 30% to 39% - the oil content is in the 36% to 43 % range). The widespread Acacia spp. mostly have edible and sustaining gums, but one, A. albida has seeds eaten in times of food shortage. The shrubby Bauhinia petersiana of Southern Africa is an extremely important food for several months of the year for the Kade Bushmen of the Kalahari, who gather and roast their nutritious beans. Another important legume seed for the Bushmen is 'Chivi', Guibourtia coleosperma, of the arid sandy areas of the more northern parts of Southern Africa. The pod encloses a fleshy aril from which an edible oil is extracted, and the single seed is a staple food of Bushmen, especially as they are edible for a long time after having fallen from the tree. This seed is valued by the Bushmen as second only to the [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] (manketti) nut. Some tribes regard them only a famine food, others boil them for long periods or soak them before eating, and others merely roast them. According to an unpublished manuscript (Maguire, B 1954) quoted in 'Food from the Veldt' by F.Fox and M. Norwood-Young, the bushman eat about 25kg each per week. This quantity seems a little unlikely, and it may perhaps be 2.5kg per person per week. Anyway, these seeds are available to the tribespeople for the better part of the year. According to the authors of the previously mentioned book, the seeds of another leguminous shrub, the 'Hottentot's bean', Schotia afra, of the Cape Province of South Africa, "...were eaten by Stone Age Man." Seeds of three species in this genus have been recorded as food used by African people, both savannah and scrubby woodlands having representatives. The only African legumes to be eventually domesticated seems to be the lablab bean, the cowpea, and the guar bean.
As humans radiated out of Africa into all the regions of the world, they exploited all food sources they came across, grasses included. In parts of Australia, the aboriginal people regularly harvested wild grass seeds (chiefly a wild 'millet', Panicum spp.), and it is likely that given time, they would have domesticated them. Indigenous tribespeople of the grasslands of Southern South America gathered grass seeds for food, and even brought one species of brome grass into cultivation. In Mexico, one of the local 'panic grasses' (Panicum spp., a kind of 'millet') was collected, and ultimately, domesticated. Palaeanthropologists have found 19,000 year old stone mortars for grinding grain show that wild grains were not just parched, but processed, from at least since that time.[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط] There is a lovely cave art picture of women gathering wild grasses in the once productive Sahara region of Africa at the Paleologos site ([ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]
Our ancestors probably parched the whole grains on ember-heated stones (this would have burnt off the adherent husks around the seed), and made a dough from the cooked flour (Tibetan people today eat a dough from roasted barley flour mixed with tea and yak butter and formed into a ball - tsampa). Such doughs laid on hot stones or embers would have made the first unleavened 'bread' . Or the roasted flour could perhaps have been mixed with water to make a thin 'porridge'.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]. J Very brief notes on the variability of protein and oil content of the wild African Morama bean. Ironically, it is being considered as a 'new food'. In fact, it may be about the 'oldest' food in the human diet.

While grubs, meat, tubers, fish and plant foliage can be eaten raw, all these things are physically easier to eat cooked, or cause intestinal disturbance if they are not cooked. Seeds are no different.
While you 'could' eat whole rice grass seeds (for example) without parching them first, only about 25% of the proteins are able to be digested. Cook the whole seed, and about 65% of the protein is available. Grinding raw rice seeds would probably make more than 25% available, but equally, grinding and cooking would likely improve protein availablity beyond 65%. The cultural evolution of both grinding and cooking seeds brought evolutionary advantage in the form of greater access to protein - at least, for those tribal groups who had the technology.
Grass seeds, in particular, had to be heat 'parched' anyway, to get rid of the adherent woody 'chaff' covering the seed (later, with domestication, this chaff became easy to remove by beating). So a degree of 'cooking' was more necessary than a choice.
A few seeds have somewhat less protein digestability after cooking, but they are the exception. You would have to cook grass seeds at 200-280°C (392-536°F) to reduce rather than improve, their protein digestibility. Meat protein digestibility, in comparison, decreases when cooking is above only 100°C (212°F).
Seeds contain 'antinutrients' - substances such as saponins, tannins, 'protein splitting enzymes' inhibitors, and phytates. These compounds reduce the body's ability to access the nutrients in seeds. The type, and amount of anti-nutrient varies both with the species of plant, and with the local variety of the species (common beans, Phaseolus vulgaris, for example, have a wide range of phytic acid and tannin concentrations - with white seeded beans having least tannins-depending on the variety). Some have several different anti-nutrients, some have few, some have relatively a 'lot' of any one anti-nutrient, some have very little.
Most, but not all, antinutrients are destroyed or reduced by cooking. Soaking and leaching are necessary to reduce some antinutrients, particulalry in some varieties of bean and other legumes. Soaking and sprouting seeds also reduces phytates. Soybeans, for example, contain a contain a 'tryptophane inhibiter' that interferes with the absorbtion of the amino acid 'tryptophane'. The inhibitor can be neutralized both by cooking and by sprouting (the sprouted root must be 3 to 4 inches long for this to be largely complete).
A very low percentage of the starches in some seeds 'resist' being digested ( up to 7% for wheat, and oats and 20% for baked beans) These undigested starches are fermented by the microflora of the colon, producing variable quantities of gas.
Guided by the practices of recent African gatherer-hunters, it seems likely our African ancestors mainly dealt with anti-nutritional factors by roasting the seeds. Sometimes they were soaked as well, either before or after roasting (and grinding). These are classic techniques that we use even today when preparing legumes; although westerners rarely roast any other than peanut seeds, and occasionally soya seeds.
Sprouting and soaking
Sprouting seeds is a form of 'delayed gratification' far beyond the wait for the seeds to parch by the fire. It probably didn't figure in our biochemical evolution. Certainly, in very recent but pre-industrial times, legumes (particularly) were sprouted. It conserves fuel in de-forested areas, and it makes seeds reasonably palatable and much more usefully digestible. Sprouting seeds converts some of the starches to simple sugars. In grains, a simple sugar, maltose, is formed.
In the middle ages of Europe, there is some suggestion that wheat soaked in hot water, and left overnight by the fire to soften and 'gell' ('frumenty') was as common as leavened bread.

Carbohyrate source
Whole grains are made of a rich starch store (the endosperm) comprising from 60- 80% of the seed (depending on the species and variety), the embryo plant (the germ) rich in protein and fats and vitamins and comprising only about 3% of the seed, and the seed coat, the bran, which is where most of the B vitamins (and many of the minerals) are. At 80% carbohydrate, seeds are, like tubers, an excellent fuel for daily activity. And whole seeds contain the B1 vitamin necessary for carbohydrate metabolism. Grains are relatively 'slow burners', so they don't push up your blood sugar levels and then suddenly drop them - they tend to keep blood sugars relatively stable.
Protein source
Protein builds growing bodies, and protein is made up in turn of 'building blocks' called amino acids. Grains are low in the amino acid 'lysine', which makes their protein content less useful than it would otherwise have been. Wheat has about 8-15% protein, depending on the variety (ancient wheats had a higher protein content), rice has a low content, at 7%. So grains in general are perhaps best regarded primarily as an energy and vitamin and mineral source.
Legumes, on the other hand, are very good sources of protein. Peanuts, for example, are protein rich, with about 25% or more protein content (and with a favorable amino acid profile). Lentils have about 25%, cowpeas have from 23-35%, common beans (Phaseolus) have about 22%, and so on. Legumes tend to be low in the amino acids methionine and cystine, but are high in the amino acid lysine. Lysine is low in grains, so eating the two together leverages the protein content of both. Co-incidentally, legumes such as lentils and peas tended to grow as weeds among wheat and other grains at the time they were being domesticated; in South America maize, a grain, was (and is) grown with beans, a legume. In Asia rice and Soya beans complement each other.
In conjunction with tree seeds, and to a lesser extent meat/marrow, the protein and oils of wild African legumes may have been the deciding factor in allowing humans to develop a big brain, and consequently evolve to the point where you can read this on the Internet!
Other seeds are also rich in protein. Sesame seeds are about 20% protein, altho, like grains, they are low in lysine. Mixing them with a legume such as the chickpea, Cicer arietum, (e.g. in the middle Eastern dish 'houmous') balances it out. Both sunflower seeds and pumpkin seeds are also high in protein.
Mineral and vitamin source
Grains are a very good source of magnesium, calcium, and potassium. Grains are a good source of chromium- necessary for maintaining normal glucose tolerance (low chromium intakes are very common in the industrialized diet, and over the long term this chromium deficiency may contribute to onset of type 2 diabetes mellitus, or middle-age diabetes). Legumes are a useful source of these minerals. Seeds in general are excellent sources of B-complex vitamins and vitamin E.
Two of the most critical nutrients for humans are folic acid, essential for normal cell division, immune response and correct developement of the fetus in the womb; and thiamine, vitamin B1, essential for metabolising the carbohydrates in seeds, nuts, and tubers. Legumes, interestingly, are particularly rich sources of both these fundamentally important elements.
Legumes are high in iron and B vitamins, particularly B6. The iron in beans is reasonably bioavailable, ranging from 53% to 76%, depending on the variety. The iron levels also vary between cultivated varieties - the range is from about 50 to 150 micrograms/gram (dry weight). USDA Agriculture Research Station experiments have also shown that once cooked, there is no relationship between phytate or tannin concentrations and the amount of iron that is bioavailable. Researchers in Japan are currently working to genetically engineer legume iron carrying protein (ferritin) into rice, which, it is estimated, would enable a typical rice meal to supply from 30-50% of daily dietary iron needs. Sesame seeds are rich in calcium and in vitamin E, altho' when hulled the calcium analysis drops off.
Fibre source
Whole grains have a lot of 'woody' (for want of a better description) fibre in their seed coat which help regulates bowel activity. What is less well known is that many also contain soluble fibre, which also has positive health benefits. The soluble and insoluble fiber in seeds is known to be helpful in preventing constipation and diseases of the digestive tract such as diverticulitis. It is also suspected that fiber may have a protective effect against colon cancer. Oats contain quite high amounts of soluble fiber, as does barley, and to a lesser extent, wheat. Legumes high in soluble fiber are lentils, pinto beans, and black beans. Legumes are also an excellent source of insoluble fiber. The fiber content of legumes slows the digestion of their carbohydrates content, regulating blood sugar levels.
Source of fats, including essential fatty acids
The oils in oily seeds are an excellent energy source, and when eaten as part of the whole seed are slowly parcelled out into the blood stream over a period of hours. While oily seeds are a concentrated source of calories, like any calory containing (or convertable) food, their calories are only stored as fat when we eat more calories than we need for energy. Otherwise, the oils and carbohydrate are burnt in the furnace of active life.
Legumes from which oil is extracted, such as peanuts (40-59% oil content) and soya beans, obviously have a high oil content (some non leguminous seeds, such as sesame seeds also have a high oil content - sesame has between 45% and 60%) . When whole seeds are eaten, it is suspected that the oil portion is very slowly released and metabolised, preserving and enhancing both stable energy levels and favorable blood fat chemistry (the effect on blood fat profile of consuming the expressed oils can be quite different). Whole peanuts have been found to be particularly helpful in maintaining energy levels in times of sustained exertion, such as playing soccer.
Two kinds of fats, 'omega-3' and 'omega-6' are essential for various body functions, and have to be obtained from the food we eat, as the human body can't synthesise them from other dietary fats. While omega-6 fatty acids are quite pervasive in the Western diet, Omega-3 is not. Linolenic acid, an omega-3 fat, is found in flax seeds, soya beans, and pumpkin seeds. Flaxseeds (linseed) is a very rich source of omega-3 fatty acids, with about 18.1% omega-3 content.
The very oily seeds of the Perilla plant ('Korean sesame'), Perilla frutescens are also a rich source of linolenic acid.
Hormone regulatory effect in women
Naturally occurring plant substances, particularly in legumes, have been shown to have a weak hormonal effect. Given our long evolutionary association with legumes, one must wonder if this effect hasn't become integrated into our genetic biochemical background.
Flax oil, in particular, is said to be 'estrogenic', that is it can attach itself to cellular estrogen receptors. This plant derived source of 'plant estrogen' may be helpful for postmenopausal women showing signs of hormone deficiency, such as atrophy and thinning of the vaginal walls. The natural lignans in as little as 10 grams of ground whole flaxseed (daily intake) have been shown to reduce two forms of estrogen associated with breast cancer risk - estrone sulfate and estradiol - in the blood of postmenopausal women. Soybeans also have a weak estrogenic effect, and are also believed to be protective against breast cancer risk.
Whole grains in general are suspected to help regulate estrogen levels in the body, through their natural plant estrogens (phytoestrogens) content, and through an effect of their fiber content. The fibre 'lignan' in grains has been found to be weakly estrogenic.
Hormonally potent forms of estrogen (estradiol and estrone) are naturally metabolised in the liver to a less active form (estriol). This metabolite is eliminated into the bile, which empties into the digestive tract. The fibre in seeds binds to this estrogen, and it is removed from the body. There is some suggestion that without sufficient fibre, this estriol is altered by gut bacteria to the more potent forms and re-absorbed, altering the ratios of the forms of estrogen in the blood. There is some suggestion that such inbalances of the 'estrogen profile' may tend to predipose such a woman to pre-menstrual syndrome, fibroids, heavier menstrual bleeding, and maybe even breast cancer.
Soybeans are filled with natural plant estrogens (or phytoestrogens) called bioflavonoids. Certain bioflavonoids are weak estrogens, having 1/50,000 the potency of a dose of synthetic estrogen. As weak estrogens, these compounds bind to estrogen receptors and act as a substitute form of estrogen in the body. They compete with the more potent estrogens made by a woman's body for these cell receptor sites. As a result, bioflavonoids can help to regulate estrogen levels.
After menopause, estrogen levels drop, and dietary sources of estrogen may have an important role in the female body. In Japan, where phytoestrogen rich soybeans are a common part of the diet (altho' only around 4-5 grams of soyabeans per day are eaten, on the average), only 10-15% of women experience menopause symptoms, where 80- 85% of European and North American women (and who eat a standard western diet) do experience symptoms at menopause. A recent study found postmenopausal US women had only around 5% of the phytoestrogen intake of their Asian counterparts - and almost all that small intake was from lignans in fruit.
Some people assert that the early onset of puberty in girls in the West is 'caused by' the soya component of food. However, Asian girls, who eat similar or higher amounts of soy do not have early puberty. The much simpler and more obvious explaination is that the calorie rich Western diet both brings the body mass up to the critical 45kg that allows the onset of menstruation much earlier, and that the intricate glucose metabolism/sex hormone synthesis mechanism has been made potentially partly dysfunctional by evolutionary inappropriate dieatary composition and it's concommitant unusual metabolic pathways (unusual compared to the biochemical compostion of the food that was presented to our metabolic pathways over the last million years or so) .
In a recent study menopausal women were asked to supplement their diet with a phytoestrogen containing food - soy flour, flax seed oil, or red clover sprouts. The soy flour and flax oil (only) significantly prevented the vaginal mucosa from thinning and drying; but the effect of eliminating these foods caused the mucosa to return to the previous menopausal thinning and drying.
In yet another study, post-menopausal women with bad blood fat profiles were split into two groups, with one group given bread and muffins made with flax seeds, the other group foods made with sunflower seeds. After six weeks, they switched seeds for another 6 weeks. The flaxseed lowered the 'bad' LDL cholesterol by 25 mg/dL (a 14.7% reduction) and levels of a protein called 'lipoprotein (a)', by 0.07 mm/L. Artificial estrogen supplements lower levels of this particular protein, 'lipoprotein (a)', but this is the first study to demonstrate that diet can also reduce the levels, possibly due to the weakly estrogenic lignans (according to the researchers).
The importance of this is that when estrogen levels drop off after menopause, the increase in lipoprotein (a) (in woman eating a western, industrial diet) oxidizes LDL cholesterol, making it more dangerous, and increases both clotting and cholesterol deposition on artery walls.
Other studies have found a relationship between the levels of phytoestrogen in the blood and both 'cardiac favorable' blood fat biochemistry and artery 'reboundability'; an indicator of arterial health. (This relationship of better cardiac health indicators and phytoestrogen levels in the blood was found to be independant of both the bodies own naturally produced estrogen levels and additional estrogen from hormone replacement therapy)
Perhaps older women were good legume gatherers in our evolutionary past. Perhaps menopausal and older woman are biologically dependant on external sources of estrogen - from legumes - in the same way as males and females are dependant on vitamin C from [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط]...?
General Protective effects
Eating substantial amounts of soybeans and soybean products has been linked to a lower incidence of breast cancer in Japanese women, and in Japanese men, lower mortality from prostate cancer.
A recent study in USA of diet and heart disease in older women showed that one daily serving of whole grains - as cereal or wholegrain bread - cut the risk of death from ischemic heart disease death by nearly a third. Eating refined grains (for example white bread) didn't have a protective effect. When the protective effect of fiber, phytic acid and vitamin E were factored out, there was still a protective effect. The researchers speculate that it may be due to an as yet undiscovered phytochemical in grains, perhaps working together synergistically with the other protective plant compounds and forms of vitamin E in the seed.
The most important anti-oxidant we normally think of is vitamin E. Yet there may be other anti-oxidants in some grains that are just as powerful. Oat flour, for example, has long been known for it's anti-oxidant properties - to the extent it used to be used as a component of such things as 'ready-mix' cakes, in order to slow oxidative deterioration of the mix.
In a study where men and women ate a controlled diet, with one group getting 1,000 calories of their daily maintainence requirements from oats, and the other getting 1,000 calories from wheat, the people who used oats for energy dropped their blood levels of low-density lipoprotein cholesterol (LDL or "bad" cholesterol) by 23 mg/per deciliter, and the wheat eaters dropped LDL by 13 mg/dL. In addition, at the end of the six week study period, the oat eaters lowered their systolic blood pressure by 7 millimeters of mercury, and the wheat eaters showed a lowering of 2 mm/Hg. The reseachers speculate that the bood chemistry improvement and lower blood pressure are due to the soluble fibre. Oats contain more soluble fibre than wheat. They speculate that the soluble fiber slows down the rate of both digestion and absorbtion, slowing the release of insulin, high rates of release of which is implicated in blood pressure rise in some people. There may also be 'unidentified factors' in oats which have a beneficial effect on blood vessels.
Women eating a diet that included 1.3 'servings' of 'whole grains' had about a 30 to 40% lower risk rate of ischemic stroke, relative to the women whose 'normal' intake was a half a serving of whole grains per day. So boosting intake of natural grains to even one serving per day has a powerful stroke protective effect. What particular attribute of grains in gneral, or their effect on metabolism, that is so helpful isn't known. But some useful chemical constituents have been identified.
Plants contain a class of common natural chemicals called 'Isoprenoids'. They help regulate such things as seed germination, and plant growth. Grain seeds contain an isoprenoid called 'gamma-tocotrienol', chemically somewhat similar to vitamin E. Laboratory experiments on the growth of human leukemia and breast cancer cell lines showed that the cancer lines growth was three times slower compared to a normal human cell culture which received the same dose of isoprenoid. The important point is that the experiment used a dose of isoprenoids that anyone might be able to be obtain from eating a standard natural diet.
Recent (1998) research has shown that nitric oxide in the body has a protective effect on the integrity of the blood vessels. An amino acid, arginine, is the main source of nitric oxide in the body. Peanuts, sesame seeds and sunflower seeds are the richest sources of arginine, along with meat and nuts. The arginine content of wild legumes and nuts in the African and Asian ancestral environment has not been reported (except for the Southern African [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط], which has the highest concentration of all, with 3.5 mg/100 mg - peanuts are the next highest with 2.8mg/100 grams). Arginine is said to also be useful in treating some cases of 'penile hypotumescence'. Ahem.
The natural 'phytochemicals' known as 'phenols' and 'polyphenols' are hypothesized to be responsible for reducing the risk of cancers in people who eat sufficient fruit and vegetables. The various kinds of polyphenols have a variety of protective modes of action - carcinogen compound blocking, antioxidant and free radical scavenging, and tumour proliferation repression. While the phenols in fruit, black tea, red wine, and vegetables are well known, few know that in fact barley, at 1,200 to 1,500mg/100gms, and some forms of sorghum, (at up to 10,260mg/100 grams) have by far the highest amounts of any foods -other than dried figs (around 1,000mg per 100grams of product).

People are quick to seize new technologies - that is a major reason we are so successful. So the initial wild grasses and legumes that had already been domesticated acted as a sort of 'pre-emptive strike' against the domestication of other perfectly edible wild species. Once the advantages of growing these 'new technology' seeds was apparent, wild harvesting (and thus the possibility of domestication) of other equally promising species effectively ended. That is why we eat dried peas, Pisum sativum, and not the equally good, closely related species Pisum fulvum. The same effect prevented any of the other numerous edible relatives of flax, barley, lentils, or chickpeas being domesticated. It's not that they weren't good enough. They just weren't first.
Domestication of seeds meant that on average, vastly more people could live per square kilometre than if the same space was used for gathering and hunting. Increased births resulted in pressure for more land, more forest was cleared for seeds, and continues to be cleared today. The destruction of wild places to catch meat, gather nuts and fruits, meant a much narrower dietary base, more possiblity that key nutrients would be missed.
Much depended - and still depends - on cultural beliefs and practices. Maize is deficient in the B group vitamins. In Central and South America, the Indians ate it with B vitamin rich fish, avocadoes, tomatoes, peppers, and green leafy plants such as 'Malva' (depending on the region). In North America, prior to the arrival of the colonizers, it was steamed with clams, cooked with beans and meat, and generally used as a staple of a mixed diet. In some parts of Africa, maize, once introduced, overtook some of the original grains, and became heavily relied on. With increasing population pressure, it became almost a sole food, and pellagra, vitamin B deficiency, showed up.
A diet based exclusively on seeds and vegetables is not optimal; a diet based predominantly on a wide variety of seeds, roots, vegetables and nuts, with a small amount of animal or sea food is certainly one of the optimal ways of meeting human evolutionary nutritional needs.

The human animal survived and spread because we are generalist. We are not tied to any one food. We don't have to eat any one food; we just have to eat. Animals eat grass, we eat animals: "all flesh is grass", as the ancient saying goes. But grasses also create 'survival capsules' to carry themselves over the dry periods and to spread. These are of course, seeds. And seeds need a food supply for energy while the newly emerging plantlet 'finds it's roots', as it were, and also protein to build the tiny plant body until it is independently making its own. We need carbohydrates and protein as well, so what could be better than to steal and eat the grasses pre-packed survival pods?
Well, a lot of things actually. Most grasses just don't pack a large enough lunch for humans to consider them worth collecting. But in sheer production per given area, there is a lot of food going begging. We ('we' being women, no doubt) likely only collected wild grass seeds when tree seeds, meat, or starchy roots weren't available. Parts of the human population may have had to turn more and more to grass seeds as a resource as richer lands were already occupied. And there is evidence that we harvested quantities of wild grass seeds at least 12,000 years ago. We have almost certainly always eaten wild grass seeds in our evolutionary history, but probably as a short seasonal harvest, rather than a daily fare. A site ('Ohalo II') on the shores of the Sea of Galilee, in the Jordan Valley shows that we were harvesting and eating wild wheat and wild barley over 19,000 years ago, as part of a seasonally mixed diet that included fish, animals, tree seeds (acorn), fruit, and other plant parts.
Certainly, when we radiated out of Africa into the Eastern Mediterranean and South West Asia there was an annual abundance of waving grasses in the foothills - and the animals that grazed them, no doubt. Experiments with harvesting wild 'einkorn' wheat (higher in protein than domestic wheat) in Turkey showed that one hour of work yielded nearly 1 kilogram of grain. Every 1 kcal of energy expended yielded about 45 kcal of energy food. (see also [ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذا الرابط])
One thing is certain - we would have preferred the larger seeds and the more palatable seeds.Of the 23 or so edible grass seeds of the grasslands of the eastern Mediterranean, two had big seeds - relative to the rest, anyway. One was emmer, a form of wild wheat, the other was barley. Emmer had the additional advantage of the seeds not sticking to the outer husk, unlike barley (even today, barley has to be 'pearled', that is, the adherant hull abraded off mechanically). The temperate zone grasses did not spread south beyond the climatically similar Nile valley. Dryland grasses are not suited to Equatorial and Sub Equatorial Africa's humid climate and pattern of summertime rainy season.
In the hot and humid parts of Africa and Asia, the aquatic grass we call 'rice' met the prescription for larger and more palatable seeds.
Domestication of grass seeds
'Millets'
This is a slightly dismissive term used by European colonialists to describe predominantly African and Asian grains that Europeans themselves didn't ordinarily eat. It includes 'common' or 'broom-corn' millet Panicum miliaceum, theshiny seed usually fed to budgies in the west; 'foxtail millet' Setaria viridis var. italica, an Asian species domesticated in China for at least 2,500 years and used in the west primarily as 'millet sprays' for your budgie cage (a native middle Americas species, S. parviflora, was almost domesticated by 3,500 years ago, but was abandoned as maize emerged) ; 'Japanese millet' Echinochloa frumentacea a very fast maturing grass seed widespread in many climatic zones of South East Asia; but not much now used; 'pearl' or 'bulrush millet' Pennisetum typhoides a white seeded millet on a bulrush-like head, which, unlike bulrushes, is adapted to semi arid areas and probably originated in the Sudan or immediate sub Saharan Africa ; 'finger millet' Eleusine coracana, a species native to tropical east Africa, is a short stemmed, dry land adapted, millet with excellent storage characteristics and an outstanding mineral content, and is still a staple in parts of central and eastern Africa; and 'sorghum' Sorghum bicolor, from Ethiopia a relatively large seeded drought resistant millet that doesn't keep well. It was probably domesticated in Ethiopia or Central Africa, initially maybe around 5,000 years ago, and carried to West Africa, perhaps 3,000 years ago, where it was further developed by the Mande people, especially the high quality white seeded forms (red grained types are bitter).