While plants have many of the same nutrients found in meat the human body doesn’t seem to absorb them efficiently. And vitamins like B12 aren’t found in plants at all and have to be supplemented if you’re on a vegan diet. To make matters even worse on a mainly vegetable diet is that you have to eat tons of plant based material in order to equal the same amount of nutrients in a small amount of meat. This is why people on a plant based diet have to eat so many times throughout the day. They find themselves famished after just a couple of hours.
The implications for cognitive health are huge. There is a clear, but underappreciated link between meat and the mind, says Charlotte Neumann, a pediatrician at the University of California, Los Angeles, who has studied meat eating in Africa and India for the past three decades. Deficiencies in the micronutrients found in meat have been linked with brain-related disorders, including low IQ, autism, depression and dementia. Iron is crucial for the growth and branching of neurons while in the womb; zinc is found in high concentrations in the hippocampus, a crucial region for learning and memory; vitamin B12 maintains the sheaths that protect nerves; and omega-3 fatty acids such as docosahexaenoic acid (DHA) help to keep neurons alive and to regulate inflammation.nature.com