Vitamin B-12 and your thyroid gland are both essential to your metabolism. Vitamin B-12 works in conjunction with other B vitamins, and are considered to be part of the vitamin B complex. These vitamins have a role in the metabolism within every single cell. A deficiency of vitamin B-12 can alter this process. Hypothyroidism, a condition associated with inadequate thyroid hormones can also disrupt the metabolic process.
The thyroid's most important role is its involvement in the regulation of your metabolism and calcium balance. The thyroid tissues secrete two iodine-containing hormones called thyroxine (T4) and triiodothyronine (T3). Hypothyroidism occurs when these hormones are not produced in adequate amounts. Symptoms of hypothyroidism include constipation, depression, weakness and unintentional weight gain.
Vitamin B-12 is a water soluble vitamin found naturally in some foods such as fish, meat and poultry. According to the Office of Dietary Supplements, Vitamin B-12 is required for proper red blood cell formation, neurological function, and DNA synthesis. Deficiencies of vitamin B-12 can lead to anemia, fatigue, loss of appetite and weight loss.
Research was conducted on 116 hypothyroid patients who were evaluated to determine if they showed signs or symptoms of Vitamin B12 deficiency. The Journal of the Pakistan Medical Association published the findings in 2009, which showed that there is a prevalence of B12 deficiency in approximately 40 percent of hypothyroid patients.
Hypothyroidism is commonly treated with prescription medication. Your doctor may recommend other types of treatment in addition to your medication. According to National Center for Biotechnology Information, you should not take a multi-vitamin while taking your thyroid medication, including those that contain vitamin B-12. Your diet is an important factor in the absorption of your medication. Vegetarians are more likely to experience B-12 deficiency because their diet already lacks in foods commonly containing vitamin B-12. Vegetarians may also consume a greater amount of soy. National Center for Biotechnology Information recommends speaking with your doctor if you have hypothyroidism and consume larger amounts of soy or high fiber foods.
- Journal of the Pakistan Medical Association; Vitamin B12 Deficiency Common in Primary Hypothyroidism; Jabbar A, Yawar A, et al.; February 2009
- Office of Dietary Supplements: Vitamin B-12
- University of Maryland Medical Center; Endocrinology Health Guide; August 2010
- National Center for Biotechnology Information; Hypothyroidism; Ari S. Eckman, MD; April 2010