- “Save eating raw leaves and grass until there’s famine. In the mean time, there are more nutritious foods available to nourish yourself with.” Rob Turner
- “Don’t make digestion and assimilation hard on yourself. Leave raw leaves to those animals designed to digest them (and then eat that animal and/or its milk).” Rob Turner
- “Maybe we will evolve to benefit from salad, but until then it’s best to leaf it alone.” Rob Turner
- “Poor people, especially in the spring when other foods were scarce, have sometimes subsisted on foliage such as collard and poke greens, usually made more palatable by cooking them with flavorings, such as a little bacon grease and lots of salt. Eventually, “famine foods” can be accepted as dietary staples. The fact that cows, sheep, goats and deer can thrive on a diet of foliage shows that leaves contain essential nutrients. Their minerals, vitamins, and amino acids are suitable for sustaining most animal life, if a sufficient quantity is eaten. But when people try to live primarily on foliage, as in famines, they soon suffer from a great variety of diseases. Various leaves contain antimetabolic substances that prevent the assimilation of the nutrients, and only very specifically adapted digestive systems (or technologies) can overcome those toxic effects.
Some plants have specific “pests,” such as insects, that have adapted to be resistant to that plant’s toxins, but if the plant and its predator are to survive, there has to be a balance between the plant tissue’s digestibility and its toxicity. Injury of a plant stimulates it to make increased amounts of its defensive chemicals. Plant toxins are known to be specific for animal tissues; for example, a toxin will inhibit the action of an enzyme from an animal, but a plant enzyme that catalyzes the same reaction won’t be affected.
A particular plant will have a variety of defensive chemicals, with specific functions. Underground, the plant’s roots and tubers are susceptible to attack by fungi and nematodes. The leaves, stems, and seeds are susceptible to attack by insects, birds, and grazing animals. Since the plant’s seeds are of unique importance to the plant, and contain a high concentration of nutrients, they must have special protection. Sometimes this consists of a hard shell, and sometimes of chemicals that inhibit the animal’s digestive enzymes. Many plants have evolved fruits that provide concentrated food for animals, and that serve to distribute the seeds widely, as when a bird eats a berry, and excretes the undigested seed at a great distance. If the fruit were poisonous, it wouldn’t serve the plant’s purpose so well. In general, the plant’s most intense toxins are in its seeds, and the fruits, when mature, generally contain practically no toxins. Roots contain chemicals that inhibit microorganisms, but because they aren’t easily accessible by grazing animals and insects, they don’t contain the digestive inhibitors that are more concentrated in the above-ground organs of the plant.
The toxins of plants include phenols, tannins, lectins/agglutinins, and trypsin-inhibitors, besides innumerable more specific metabolic inhibitors, including “anti-vitamins.” Unsaturated fats themselves are important defenses, since they inhibit trypsin and other proteolytic enzymes, preventing the assimilation of the proteins that are present in seeds and leaves, and disrupting all biological processes that depend on protein breakdown, such as the formation of thyroid hormone and the removal of blood clots.
Generally, fruits, roots, and tubers provide a high concentration of nutrients along with low concentrations of toxic antimetabolic substances.” Raymond Peat, PhD., Vegetables, etc.—Who Defines Food?
- “The widespread occurrence of toxic substances in plants must have greatly restricted their usefulness as food for primitive man.” Toxic substances in plants and the food habits of early man. Leopold & Ardrey (1972)
- ‘”Everyone knows that plants react to light, and scientists also know that plants use volatile chemicals to communicate with each other: for instance, when danger – such as a herbivore – approaches,” UWA researcher Monica Gagliano said.’ Secret life of plants: Scientists discover plants can talk
- “A scene from the “Wild South America” episode, Amazon Jungle. This shows how leaves and seeds in the rain forest have become very poisonous to protect themselves from being eaten. The animals, however, have gone one better and found a way to protect themselves from the toxins, they eat clay. This is truly a remarkable behavior rarely seen in the wild like this.” Wild South America – Amazon Jungle – Clay Lick