A sluggish thyroid, or hypothyroidism, can do far more than just muck with your metabolism. While these conditions alone can send your energy levels south, it turns out they could also be robbing you of vitamin B12 taking those tired-all-the-time feelings to a whole new low.1
Your thyroid is responsible for energy and metabolism
The thyroid gland is a small, butterfly-shaped gland in the front of your neck. It’s the brain of the endocrine system and responsible for synthesizing thyroid hormones T3 and T4 which control metabolism and heartbeat.2 The gland secretes more thyroid hormone when you need a boost in energy, such as when you’re cold.
That hormone boost cues your body to speed up your metabolism, or the rate at which chemical reactions occur, and this generates more heat raising your body’s temperature. Consequently, thyroid hormones affect your basal metabolic rate (BMR) and that determines how many calories you burn while you’re at rest.3
B-12 deficiency interferes with crucial functions
Although daily B-12 requirements are fairly low (just 2.4 micrograms for teens and adults4) the vitamin plays a crucial role in metabolic and cellular processes. B-12 is the driving force behind red blood cell production, DNA synthesis, protein conversion, neurological function,5 fatty acid synthesis,6 and nerve health.4
The process of metabolizing vitamin B-12 is a complicated one and there are several ways to develop a deficiency. The vitamin B-12 found naturally in food is bound to proteins. Once in the stomach pepsin and gastric acid cause it to separate from these proteins. From here, it immediately binds to R protein from saliva which protects it from damage in the acidic environment.
In the duodenum, the first section of the small intestine, the B-12-R protein complex splits apart. Intrinsic factor (IF), a protein secreted in the stomach, joins B-12 and safely transports it past the protein-digesting enzymes that would otherwise destroy the vitamin. Once it reaches the last part of the small intestine, the ileum, it’s absorbed from the GI tract where B-12 detaches from IF and joins transcobalamin to become B-12–TC-II. This last complex is taken up by your bone marrow, liver, and other cells; the liver stores 90 percent of your B-12.1
A B-12 deficiency may result when you either don’t consume enough B-12, or your body doesn’t absorb enough B-12.
Absorption problems can result from…
- inadequate intrinsic factor,
- digestive enzyme problems,
- or organ damage.
Low B-12 can effect everything from fatigue to memory problems
Symptoms of deficiency vary depending on severity. The most common include fatigue (that no energy tired-all-the-time problem mentioned earlier), constipation, decreased appetite, tingling in the hands and feet, impaired memory, depression, and soreness of the tongue.4
Some people have a higher risk of B-12 deficiency:
- Older adults, due to decreased hydrochloric acid in the stomach.4
- People whose bodies don’t produce enough intrinsic factor.4
- Vegetarians and vegans who don’t get B-12 from food.4
- People with conditions that irritate mucosal lining in the stomach and intestines, such as Crohn’s or celiac disease,7 chronic alcoholism, or inflammatory bowel disease.8
How hypothyroid effects B-12 absorption
Hypothyroidism can compromise your ability to absorb vitamin B-12. An infection of Helicobacter pylori bacteria may also interfere with gastric secretions and hinder B-12 absorption.9
Experts believe that 4.6 percent of the U.S. population age 12 and up suffers from hypothyroidism.6 One study found that approximately 40 percent of hyperthyroid patients also suffer from a B-12 deficiency. Adding supplementary B-12 to these patients’ routines improved weakness, memory, mood, and other symptoms.10
The USDA recommends B-12 supplementation for people at risk of deficiency because it’s more easily absorbed than B-12 from food sources.11
Getting vitamin B-12 through diet
The most common sources of B-12 are meat, seafood,12 eggs, and dairy.13 Since vitamin B-12 is produced by a soil based bacteria,14 animals pick it up while foraging for food. Some vegetarian sources such as fortified cereals and nutritional yeast do exist if you’re trying to avoid animal products. A B-12 supplement is a great way to fill the gaps in your nutritional intake.
A B-12 supplement is invaluable for fighting fatigue and other troubling symptoms, especially for older adults. B-12 supplements are easily absorbed and provides the B-12 the human body requires. All people at risk of B-12 deficiency should consider a supplement.4 While B-12 is an essential vitamin for supporting thyroid health, the importance of getting enough iodine and selenium shouldn’t be overlooked also.
Have you added a B-12 supplement to your day? What effects have you noticed? Leave a comment below and share your experience with us.
References:
1. Kibirige, Davis, and Raymond Mwebaze. “Vitamin B-12 Deficiency Among Patients with Diabetes Mellitus: Is Routine Screening and Supplementation Justified?” 12. (2013): n.pag. Web. 23 Aug. 2016.
2. “Thyroid diseases.” NIH. U.S. National Library of Medicine, 18 Aug. 2016. Web. 23 Aug. 2016.
3. “How does the thyroid work? – PubMed health – national library of medicine – PubMed health.” (2015): n.pag. Web. 23 Aug. 2016.
4. “Office of dietary supplements – vitamin B-12.” 24 June 2011. Web. 23 Aug. 2016.
5. “Office of dietary supplements – dietary supplement fact sheet: Vitamin B-12.” NIH. 11 Feb. 2016. Web. 23 Aug. 2016.
6. “B-12.” Australian Government National Health and Medical Research Council. 1 Jan. 2005. Web. 23 Aug. 2016.
7. “Hypothyroidism (Underactive Thyroid).” National Institute of Diabetes, Digestive and Kidney Disorders. 18 Aug. 2016. Web. 23 Aug. 2016.
8. America, Colitis Foundation of. “CCFA: Nutrition and IBD.” Crohn’s & Colitis Foundation of America. 2016. Web. 23 Aug. 2016.
9. Lahner, Edith, and Bruno Annibale. “Pernicious Anemia: New Insights from a Gastroenterological Point of View.” 15.41 (2009): n.pag. Web. 23 Aug. 2016.
10. Jabbar, A, et al. “Vitamin B-12 Deficiency Common in Primary Hypothyroidism.” JPMA. The Journal of the Pakistan Medical Association. 58.5 (2008): 258–61. Web. 23 Aug. 2016.
11 “Questions to ask before taking vitamin and mineral supplements.” 22 Aug. 2016. Web. 23 Aug. 2016.
12. “Foods highest in vitamin B-12.” SELF Nutrition Data. 2014. Web. 23 Aug. 2016.
13. Wax, Emily, et al. “Vegetarian diet: MedlinePlus medical encyclopedia.” MedlinePlus. 12 Jan. 2014. Web. 23 Aug. 2016.
14. Campbell, Thomas, Alan Goldhamer, and Jill Edwards. “12 questions answered regarding vitamin B-12 – nutrition.” Articles. Center for Nutrition Studies, 6 Feb. 2015. Web. 23 Aug. 2016.

Dr. Edward F. Group III has his Naturopathic Doctorate, Clinical Herbalist, Holistic Health Practitioner, Clinical Nutritionist certifications, and is a Diplomate of the American Clinical Board of Nutrition and the American Board of Functional Medicine. He founded Global Healing Center Inc. in 1998 which has earned recognition as one of the largest alternative, natural and organic health resources on the Internet.
A dynamic author and speaker, Dr. Group focuses solely on spreading the message of health and wellness to the global community with the philosophy of full body cleansing, most importantly colon cleansing, consuming pure clean organic food, water, air, exercise and nutritional supplementation. Visit GlobalHealingCenter.com to learn more about living green and healthy!

Latest posts by Dr. Edward Group (see all)
- Top 6 reasons to try kombucha tea - October 4, 2016
- Always tired? Your thyroid could be to blame - September 24, 2016
- 9 surprising uses for the chili pepper extract capsaicin - September 1, 2016