SOURCES:

Lauri Wright, PhD, RDN, national spokesperson, Academy of Nutrition and Dietetics and chair, department of nutrition and dietetics, University of North Florida.

M. Elizabeth Swenor, DO, in charge of Lifestyle, Integrative, and Functional Medicine, Henry Ford Health System, Detroit.

Mount Sinai: “Vitamin B12 (Cobalamin).”

Merck Manual: “Vitamin B12 Deficiency.”

National Institutes of Health Office of Dietary Supplements: “Vitamin B12.”

Cleveland Clinic: “The Best Sources of Vitamin B12.”

Harvard Medical School: “Vitamin B12 deficiency can be sneaky, harmful.”

National Heart, Lung, and Blood Institute: “Pernicious Anemia.”

International Journal of Cancer: “Biomarkers of folate and vitamin B12 and breast cancer risk: report from the EPIC cohort.”

Memorial Sloan Kettering Cancer Center: “Vitamin B12.”

National Health Service UK: “Complications – Vitamin B12 or folate deficiency anaemia.”

Archives of Internal Medicine: “Folic Acid, Vitamin B6, and Vitamin B12 in Combination and Age-related Macular Degeneration in a Randomized Trial of Women.”

American Academy of Dermatology: “Can oils, probiotics, or vitamins heal eczema?”

Dermatology: “Association of Serum Vitamins with Eczema in US Adults (NHANES 2005–2006).”

Mayo Clinic: “Vitamin B-12.”