A regular, reliable source of vitamin B12 is critical for anyone eating a plant-based diet. Though deficiency for those starting out with adequate stores may take years to develop, the results of B12 deficiency can be devastating, with cases reported of paralysis, psychosis, blindness, and even death. Newborn infants of mothers who eat a plant-based diet and who fail to supplement may develop deficiency much more rapidly with disastrous results. Getting enough vitamin B12 is absolutely nonnegotiable for those centering their diets around plant-based foods.
Since the above post was made, I think Dr. Greger has recommended higher doses of supplemental B-12 for adults over age 50 and age 65 – in newer remarks he made in 2024.
Reminder – if you intend to pursue “plant-based eating”, you must let your doctor know, you must consult with a dietician or nutritionist, and you should plan to have blood tests run at least annually. Follow the advice of your doctor and nutritionist. A Vitamin B-12 deficiency is a serious health problem and can lead to death.
Additional information from another post (now merged into this one):
This is a good article:
A lack of vitamin B12 can result in “consequences like megaloblastic anemia (abnormally large red blood cells) or irreversible neurological damage.” To avoid these outcomes, it’s important to note that the recommended daily intake of vitamin B12 “varies by age, gender, and other individual factors,” says Aguirre.
Vitamin B12: what it’s for, benefits, and potential side effects
This, below, is technically true but omits important context:
For “most adults,” the recommended daily intake is at least 2.4 micrograms (mcg), although this may increase slightly during pregnancy and breastfeeding, to 2.6 and 2.8 mcg, respectively.
We need to absorb 2.4 mcg/day. My doctor has me taking 1,000 mcg per day because we may absorb as little as 10-13 mcg per day from that dosage.
Also, the U.S. 2.4 mcg per day level was, per Dr. Michael Greger, set in 1958. Looking online finds some other countries recommend 7-10 mcg per day – suggesting the exact amount might not be well understood.
