There are seven things that differentiate living organisms from non living ones, summed up by the memnomic MRS GREN. Move, Respire, Sensitive, Grow, Reproduce, Excrete and Nutrition. Living things whether they are animals or plants all eat, move, breathe, poop, respond to stimuli, grow and have younger versions of themselves.
If the organism cannot reproduce before it dies, then its genetic material dies with it and if the entire species cannot reproduce before its members die, the species becomes extinct.
It is easy to see how animals survive long enough to have babies. The parents raise the young, looking after them until they can survive on their own. Some animals have young that are mobile very soon after birth and can live independently very quickly. Some are armed with teeth and claws, others fast and some invisible. If all else fails, baby animals are cute – after all who could kill these lovelies?
When it comes to plants though it is harder to see how they prevent themselves being eaten before they have a chance to set seed and ensure the survival of the species. Plants can’t run away, they don’t have claws and they can’t call for help so how do they survive?
Some plants make it difficult to eat their babies by giving them a tough coat (think nuts) or protection with thorns. Some plants make sure that the seeds are indigestible but package them up in a nice tasty fruit in the hope that the fruit will be eaten and the seed dropped in a pile of poop to give it a head start growing.
Plants that rely on other means of dispersal such as wind or being attached to an animals coat, protect themselves with chemicals to deter animals from eating them more than once. In the case of grains there are antinutrients which can be reduced if the grains are prepared properly but still cause us problems.
Gliadin is the prolamin in wheat which causes serious health problems in people with coeliac disease and has been implicated in a large number of other health complaints noteably autoimmune disorders. Gliadin causes the production of zonulin a protein which opens up gaps in the intestine wall causing leaky gut allowing undigested food particles into the bloodstream causing inflammation and illness.
While wheat, barley and rye contain Prolamins which cause the most problem to humans, all grains contain Prolamins to some extent – see this post for more details.
Lectins are antinutrients present in grains, beans, dairy and plants from the nightshade family such as potatoes, tomatoes and sweet peppers. Lectins cause inflammation and irritation to the digestive system. It is the modern form of wheat though which contains the most problematic lectin – Wheat Germ Agglutinin (WGA) – which has been implicated in a wide range of human disorders.
If gliadin and lectins are not enough to save seeds from being eaten there is also phytic acid to consider. This compound, also called phytate preferentially binds with minerals in our bodies making them inaccessible to us as we cannot absorb them once they are bound to phytic acid.
Phytic acid binds to calcium, zinc, copper, iron and niacin. Even though these nutrients are present in grains, grains are not a good source of minerals because of phytic acid. Vegetarians suffer a double whammy in this respect as animal foods are better sources of these minerals and vegetarians eat more grain products containing phytic acid meaning they are more likely to be deficient in one or more minerals.