Caffeine can not cause hypothyroidism. Hypothyroidism is rarely caused by diet -- the only dietary factor that influences thyroid function is iodine. And since salt was iodized in the U.S. and most developed nations -- specifically to prevent low thyroid function -- iodine deficiency is rare in first-world countries. The University of Maryland Medical Center does note that caffeine could impact your condition or medication -- but that's only after you are already diagnosed with hypothyroidism.
Low Thyroid Function
Your thyroid is a small butterfly-shaped gland that sits at the base of your throat, in front of your vocal cords. Part of your endocrine system, your thyroid produces two hormones -- T3 and T4 -- which control the rate your body uses oxygen and energy. These control your metabolism, which is the amount of calories you burn daily. If your thyroid function slows and you don't produce enough hormones, called hypothyroidism, you could gain weight, be more sensitive to the cold, have a slower or erratic heart beat and notice that your hair and nails are weak or brittle.
Causes
The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto's thyroiditis. The immune system attacks the thyroid gland. This is not diet-related, and there is no way to prevent Hashimoto's, according to the National Institutes of Health. Other causes of low thyroid function include birth defects, pregnancy, radiation treatments, certain medications and surgery that removes the thyroid. An iodine deficiency can also cause low thyroid function. In that case, increasing iodine intake usually resolves the problem. Except for an iodine deficiency, nothing in your diet, including caffeine, can cause hypothyroidism.
Treatment
Hypothyroidism is treated with a synthetic hormone replacement, called levothyroxine; sold commercially as Synthroid, Unithroid, Levoxyl or Tirosint. Levothyroxine replaces T4 hormone and your body can use it to synthesize T3 as needed -- even with hypothyroidism. It can take several weeks to find your correct dose of replacement hormone, and you will have to continue taking levothyroxine daily for the rest of your life. It's important to avoid anything that can interfere with the way your body absorbs the hormone -- and this is where diet can influence hypothyroidism.
Diet
Your thyroid supplement should be taken on an empty stomach at least 30 to 60 minutes before eating. Iron and calcium can interfere with the absorption of levothyroxine -- do not take your medication with other vitamins and supplements. Antacids containing magnesium or aluminum, certain cholesterol drugs and ulcer medications can also block your hormone replacement. High-fiber foods, walnuts, cottonseed meal and soybean flour should be consumed several hours after taking your thyroid medication, notes the Mayo Clinic.
References
- Medline Plus; Hypothyroidism; Ari S. Eckman, M.D.; April 2010
- National Institute of Diabetes and Digestive and Kidney Diseases; Hypothyroidism; May 2008
- MayoClinic.com; Hypothyroidism Diet -- Can Certain Foods Increase Thyroid Function?; Todd B. Nippoldt, M.D.; November 2010
- University of Maryland Medical Center: Hypothyroidism
