A strict vegan diet -- defined as avoiding the consumption of all animal products -- may lead to deficiency of important vitamins that are critical to eyesight. The warning comes from the case of a French patient who lost most of his eyesight as the result of following a strict vegan diet, without taking vitamins, leading to B12 deficiency. B12 is important in maintaining the health of nerves, including the optic nerve that transmits signals from the eye to the brain.
The case report involves a 33-year-old patient who had been a vegan since the age of 20. His diet contained no eggs, dairy products, fish or animal protein. He had no history of alcohol abuse and did not smoke cigarettes, and he was not taking any vitamin supplements. At the time of examination, the patient was diagnosed with severe optic neuropathy in both eyes, with poor vision of 20/400 each eye. With no evidence of an infectious cause for this severe loss of vision, the researchers took blood samples to check for vitamin deficiencies. They found that his levels of B1, B12, A, C, D, E, zinc, and selenium were all measurably below normal.
The researchers treated the patient by giving him intramuscular and oral multivitamins until his blood levels normalized, but his eyesight did not recover. They concluded that the nutritional deficiencies in the patient's vegan diet -- particularly the insufficient amount of vitamin B12 he had been absorbing -- may be the cause for the deterioration in the optic nerves and the resulting blindness. They note that such damage to the optic nerves may prove to be irreversible.
References 1. Ashkenazi S, Weitz R, Varsano I, Mimouni M. Vitamin B12 deficiency due to a strictly vegetarian diet in adolescence. Clin Pediatr (Phila) 1987;26:662-3. Return to Text 2. Renault F, Verstichel P, Ploussard JP, Costil J. Neuropathy in two cobalamin-deficient breast-fed infants of vegetarian mothers. Muscle Nerve 1999;22:252-4. Return to Text 3. Miller NR, Newman NJ. Walsh and Hoyt's clinical neuro-ophthalmology. 5th ed. Vol. 1. Baltimore: Williams & Wilkins, 1998:663-79. Return to Text 4. The Cuba Neuropathy Field Investigation Team. Epidemic optic neuropathy in Cuba -- clinical characterization and risk factors. N Engl J Med 1995;333:1176-82.
The New England Journal Of Medicine March 23, 2000;342:897-898. http://www.nejm.org/content/2000/0342/0012/0897.asp
So, what can we learn from this? It is my belief that we were designed to eat animal products. When one avoids them, serious harm and damage can occur. Because animals eat plants, any pesticides are bioaccumulated in the fat tissue thus making it much riskier to eat non-organically. Most of us do not eat organic meat due to the inconvenience and cost. However, it is important for optimized health. One can purchase a deep freeze and find a person who will raise the animals organically and then buy them at a greatly reduced rate. This has been my solution for some of my meats and my plan to incorporate it to all of my meats. Many of my patients also employ this strategy.
If one does require B12 therapy it is important to recognize that B12 is the largest vitamin. What does this mean? Well, it means it absorbed orally very poorly. One requires intrinsic factor secreted by the stomach to bind to it so it can be absorbed in the small intestine. One can use sublingual (under the tongue) therapy, but IM (intramuscular) injections seem to be far superior and relatively inexpensive. It is the form I recommend for all my patients. There is a prescription nasal spray but that costs nearly $100 while the injections cost closer to $10.
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