Hypothyroidism, also known as underactive thyroid disease, is a condition where the thyroid gland does not produce enough thyroid hormones. This can lead to a variety of symptoms like fatigue, weight gain, hair loss, and feeling cold. Taking vitamin B12 supplements can help manage some hypothyroidism symptoms.
What is the connection between B12 and hypothyroidism?
There are several connections between vitamin B12 levels and hypothyroidism:
- Low thyroid hormone levels can reduce absorption of B12 from foods.
- Thyroid hormones help convert B12 into its active form which is usable by the body.
- B12 deficiency can cause symptoms like fatigue and weakness which are also common in hypothyroidism.
- Treating B12 deficiency can help improve energy levels and reduce fatigue in those with hypothyroidism.
In summary, an underactive thyroid can contribute to vitamin B12 deficiency, and improving B12 status may help relieve some hypothyroidism symptoms.
What are the benefits of taking B12 for hypothyroidism?
Some key benefits of taking B12 supplements if you have hypothyroidism include:
- Increased energy and reduced fatigue: B12 plays a role in energy metabolism. Supplementing can help improve fatigue caused by hypothyroidism.
- Better thyroid hormone function: B12 is needed to activate thyroid hormones. Ensuring adequate B12 can support proper thyroid hormone synthesis and action.
- Improved cognition and mood: B12 deficiency can contribute to cognitive decline, depression, and mood changes which may already be affected by hypothyroidism.
- Decreased numbness and tingling: B12 deficiency can cause peripheral neuropathy. Supplementing may help reduce associated numbness and tingling.
While B12 may not treat the root cause of hypothyroidism, optimizing your B12 status can help manage common symptoms associated with an underactive thyroid.
How much B12 should you take each day?
The recommended daily amount of B12 for adults is 2.4 mcg. However, higher doses may be appropriate in certain cases. Some general dosage guidelines include:
- For B12 maintenance – 10-25 mcg per day
- For mildly deficient B12 levels – 50-100 mcg per day
- For severe deficiency – Up to 1000 mcg per day until levels normalize
- For those with absorption issues – Sublingual supplements or high oral doses like 1000 mcg daily
Those with hypothyroidism are more prone to B12 deficiency, so a daily supplement around 50-100 mcg is often recommended. Always discuss optimal dosing with your healthcare provider.
What causes B12 deficiency with hypothyroidism?
There are several factors that can contribute to B12 deficiency in those with hypothyroidism including:
- Impaired absorption – Low stomach acid can reduce B12 absorption from foods.
- Thyroid hormones effects – Thyroid hormones help convert B12 into its active forms.
- Medications – Drugs that reduce stomach acid like PPIs can lower B12 absorption.
- Autoimmunity – The autoimmune cause behind hypothyroidism can also damage cells that help absorb B12.
- Diet – Being deficient in B12 rich foods like meat, eggs, and dairy may contribute.
Testing B12 levels is recommended for those with hypothyroidism so any deficiency can be detected and supplemented as needed.
What foods contain B12?
The best dietary sources of B12 include:
- Beef liver – 70 mcg per 3 ounces
- Sardines – 14 mcg per 3 ounces
- Salmon – 4.8 mcg per 3 ounces
- Tuna – 2.5 mcg per 3 ounces
- Eggs – 0.6 mcg per large egg
- Milk – 1.2 mcg per cup
- Yogurt – 1.5 mcg per 6 ounces
- Nutritional yeast – 1.3 mcg per tablespoon
For those following plant-based diets, fortified foods or supplements are important since B12 is not found naturally in plant foods. Common fortified options include non-dairy milks, breakfast cereals, and nutritional yeast.
Can you get too much B12?
Unlike some water-soluble vitamins, B12 is not thought to cause harm at high supplemental intakes. No Tolerable Upper Intake Level has been established for B12 because excess amounts are believed to be well-tolerated.
However, extremely high single doses above 1000 mcg may trigger temporary side effects like nausea, headache, anxiety, itchiness, or dizziness. Sticking to daily doses below 1000 mcg is unlikely to cause any issues.
Those with conditions like leukemia, polycythemia, kidney disease, or calcium deficiency should be cautious with B12 supplements and follow dosing guidelines from their doctor.
What type of B12 supplement should you take?
There are a few different forms of B12 used in supplements including:
- Cyanocobalamin: Synthetic B12 that is readily converted into active forms by the body.
- Methylcobalamin: Active form of B12 used primarily in the nervous system.
- Hydroxocobalamin: Active form that helps convert cyanocobalamin into usable B12.
- Adenosylcobalamin: Active form used in energy metabolism.
For those with hypothyroidism, cyanocobalamin and methylcobalamin tend to be the preferred supplemental forms of B12. Either can be taken daily in doses of 50-100 mcg.
Can you get B12 injections for hypothyroidism?
B12 injections or shots may be an option for those with very low B12 levels or absorption issues. Injections deliver B12 directly into the bloodstream, bypassing any absorption problems.
Typical regimens involve getting 1000-2000 mcg B12 injections every 1-3 months. This allows you to get a therapeutic dosage while only taking occasional shots. Talk to your doctor to see if B12 injections could be beneficial.
How long does it take to notice a difference with B12 supplements?
Most people can expect to see benefits within 1-2 weeks of starting B12 supplementation if deficient. However, it can sometimes take up to 6 weeks to experience the full effects like improved energy, reduced numbness/tingling, and better cognitive function.
It’s important to take supplements consistently each day during this period rather than sporadically. Let your doctor know if symptoms have not started improving within 2 months of beginning supplementation.
Are there drug interactions with B12 supplements?
There are no known negative interactions between B12 supplements and other medications. However, a couple things to be aware of include:
- Blood thinners – Large doses of B12 could theoretically affect coagulation, so coagulation testing may be needed if also on blood thinners.
- Acid reducers – Medications like PPIs and H2 blockers can reduce absorption of oral B12 supplements.
- Thyroid hormones – B12 is needed to activate thyroid hormones, so optimal B12 status ensures your thyroid meds work effectively.
Discuss any interactions with your healthcare provider, especially if taking blood thinners or acid reducing drugs.
When should you seek medical advice about B12 levels?
You should see your doctor if you have symptoms of B12 deficiency including:
- Persistent fatigue or weakness
- Tingling or numbness in hands and feet
- Dizziness or lightheadedness
- Pale skin or jaundice
- Cognitive changes like memory loss or confusion
- Vision problems
- Mood changes like depression or anxiety
- Sore tongue or mouth ulcers
Testing B12 levels can help detect if supplementation is needed. Those over age 50 should also have periodic assessment of B12 status.
Conclusion
Vitamin B12 supplements can provide significant benefits for those with hypothyroidism including improved energy levels, mood, cognitive function, and thyroid hormone activity. Adults should aim for around 50-100 mcg of supplemental B12 per day, in the form of cyanocobalamin or methylcobalamin.
B12 injections may also be an option under medical supervision, especially for those with absorption issues. Ensuring adequate B12 intake from foods and/or supplements can help manage common hypothyroidism symptoms.