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Is there a such thing as a true omnivore? How do you classify animals as herbivores, carnivores, granivores, fructivores or omnivores? Are humans really omnivores?
Human beings are brought up on the notion that they are omnivores but are they really? In fact is there really a such thing in nature as a true omnivore? The way biologists distinguish between these is by an animal’s digestive system. Carnivores, herbivores, granivores and fructivores all have distinct biological characteristics. Carnivores have sharp, pointed teeth and a short digestive tract. A carnivore’s system is biologically suited to quickly eliminate meat before it putrefies and to eliminate dietary cholesterol. Carnivores also secrete the enzyme uricase which breaks down uric acid in meat. By comparison herbivores have long digestive tracts and digestion begins in the mouth. Herbivores secrete an enzyme in the saliva that breaks down the plant cells whereas this not true of carnivores. Granivores also have a differently designed digestive system. They have a beak and a crop. They have two stomachs, one glandular and one muscular. Their pancreas has three outlet ducts and they have lengthy intestines with tiny follicles or cavities. This kind of digestive system is designed around ingesting grains and seeds. Fructivores digestive systems are meant to derive large amount of energy from fruits and nuts. Most primates are fructivores. The simple fact with humans is that they taught themselves to eat everything. Humans have a digestive system consistent with herbivores. Human beings are not natural meat eaters. This can be easily pointed out by their teeth. Human teeth are not meant for tearing into flesh and bone. The teeth are too close together to comfortably eat meat since meat is easily stuck in between. Humans cannot digest grass and have great difficulty digesting raw vegetables. Wheat cannot be eaten in its raw form and beans are potentially toxic if eaten raw. In fact, after 10,000 years of eating grain many people still have difficulty digesting it. Food residues can form during digestion that can cause problems. If these residues originate from starchy foods they can form lactic acids and short-chain fatty acids that can irritate the intestinal wall and cause an upset stomach and diarrhea. Protein residues can release peptides and amino acids that can form into nitrogen compounds known as amines. Amines are pungent and toxic and unlike odorous intestinal gas from fermentation in the gut can be dangerous. The proteins from amines damage the intestinal wall and causes it to secrete protein and fluid to nourish the flora in the gut thus allowing them to leak through the intestinal wall, get into the blood and travel all the way up to the brain. As can be seen there are many clear cut signs that human beings are not in any way true omnivores. What some call an omnivore others might call a biological garbage disposal and garbage disposals eventually get clogged up, overused and quit working.
The copyright of the article Are Humans Omnivores? in Microbiology is owned by Marc Anthony Rios. Permission to republish Are Humans Omnivores? in print or online must be granted by the author in writing.
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