B12 is critical in the human body and lymies especially are deficient due to poor digestion (lacking the intrinsic factor in the stomach). Here is some helpful info:
Get a plentiful amount in your food. Liver or shellfish eaten at least once a week is the the best way to ensure that you are taking in adequate amounts.
Avoid overconsumption of foods that block vitamin B12 intake or increase the body’s need for the vitamin, such as soy foods and spirulina.
Avoid antacids and drugs that lower stomach acid levels: acid-suppressing drugs such as Tagamet, Zantac and Losec can lead to serious B12 deficiency (Koop H. Aliment Pharmacol Ther 1992;6:399-406 [review]; Marcaurd SP and others. Ann Intern Med 1994;120:211-215).
Avoid diabetes drugs such as Glucophage which also interfere with B12 absorption (Archives Int Med 2002 Feb 25;162:484-85.
Consume plenty of calcium. Calcium is involved in the absorption of B12 from the lower small intestine. Best sources are raw dairy products and bone broths. (Bone broths also help heal intestinal inflammation that could cause absorption problems.) Dolomite powder can also be used as a calcium source.
Take coconut oil and consume lacto-fermented foods: these help fight against pathogens such as helicobacter pylori, which is associated with B12 deficiency. Eradication of the organism often clears up B12 deficiency. (Archives of Internal Medicine, May 8, 2000 160:1349-53)
Avoid foods fortified with folic acid. Taking folic acid without B12 can mask signs of B12 deficiency in red blood cells but will not protect against deficiencies in the nervous system. Folic acid and B12 work together and any supplementation program should include both of these nutrients (Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes: Thiamin, riboflavin, niacin, vitamin B6, folate, vitamin B12, pantothenic acid, biotin, and choline. National Academy Press. Washington, DC 1998).
Avoid taking excess vitamin C, especially for long periods. The ability of vitamin C to destroy B12 has been observed by several researchers--although this is disputed by others. Small amounts of natural vitamin C are a better choice than large amounts of synthetic vitamin C. (Herbert V and Das KC. Folic acid and vitamin B12. In: Shils ME, Olson JA, Shike M, eds. Modern Nutrition in Health and Disease. 8th ed. PhiladelphiaL Lea & Febiger, 1994:404.)
Don’t smoke. Cigarette and cigar-smoking deplete vitamin B12 (New Eng J Med 1995 Nov 2;333(18):1176-82).
Take extra B12 before and after surgery. Nitrous oxide anesthesia during surgery can deplete B12, a fact that may explain many cases of post-operative depression (Marie RM and others. Arch Neurol 2000 Mar;57(3):380-2).
Avoid vaccinations containing thimerosol and other mercury-containing compounds. Vitamin B12 is depleted by mercury (J Molecular Psychiatry Apr 2004).
Avoid molds in the environment and your food. Mycotoxins produced by molds disrupt or interfere with the normal functions of vitamin B12 (Anyanwi EC and others. Scientific World Journal 2004 Aug;4:736-45).
Do not take oral contraceptives (the pill), which can deplete vitamin B12. (Henley S. Body Forum 1977 Jan 30;2(7):20; Sutterlin MW and others.