Written by Jessica Patella, ND. Of the 163 obese Moroccan women, those who supplemented with 200 micrograms of iodine for 6 months decreased their TSH levels by 33% and their total cholesterol by 11% compared to those who took no iodine.
The human body is intricately connected and the body can adapt for certain deficiencies. One such deficiency is iodine deficiency. When the body is deficient in iodine, there is an increase in thyroid hormone (TSH) which stimulates the thyroid to absorb more iodine. This can result in subclinical hypothyroidism, meaning the person has symptoms of hypothyroidism, such as slowed metabolism, weight gain, feeling cold, and/or dry skin, yet the lab results are still within normal range (1-3). Both hypothyroidism and subclinical hypothyroidism can then increase the risk of high cholesterol in the body (dyslipidemia) and even result in insulin resistance and inflammation (4,5).
To determine if iodine supplementation could alter thyroid hormone levels and cholesterol levels, 163 overweight or obese, iodine-deficient Moroccan women were randomly assigned to either a placebo group or a treatment group. The treatment group received 200 micro-grams of iodine each day for 6 months.
After 6 months, the thyroid hormone (TSH) was 33% lower in the treatment group than in the placebo group (P=0.024). Thyroid hormone ratios also improved (T3:T4 decreased -15%) in the iodine group (P=0.002).
The most drastic results were observed with reduction in cholesterol levels in the body. Total cholesterol in participants with elevated cholesterol at baseline was reduced by 11% after supplementation with iodine (P=0.034). The following results were also observed in cholesterol reduction:
Percent of Women with High Cholesterol (total cholesterol >5mmol/L)
| Placebo Group | Iodine Treatment Group | |
|---|---|---|
| Baseline | 36.8% | 44.2% |
| After 6 Months | 34.8% | 21.5% |
Percent of Women with Elevated LDL or “Bad” Cholesterol (LDL cholesterol >3mmol/L)
| Placebo Group | Iodine Treatment Group | |
|---|---|---|
| Baseline | 47.4% | 50.6% |
| After 6 Months | 44.9% | 35.4% |
(P-interaction =0.23) – Not statistically significant
There were no significant changes observed in HDL cholesterol, insulin or glucose levels (1).
Overall, iodine supplementation modestly improved thyroid function and had a significant improvement in cholesterol levels (1). Researchers concluded that iodine supplementation in those who are deficient may decrease thyroid disorders and help reduce cardiovascular disease (1).
*Approximately 40% of the world is deficient in iodine. In the United States, salt is iodized, making iodine deficiency rare. Although with more and more recommendations to reduce salt intake and to choose sea salt, the intake of iodine has dropped an estimated 50% in the US today (6). Various health professionals feel there is a silent epidemic of iodine deficiency occurring today (7, 8).
Source: Herter-Aeberli, Isabelle, et al. “Iodine supplementation decreases hypercholesterolemia in iodine-deficient, overweight women: A randomized controlled trial.” The Journal of nutrition 145.9 (2015): 2067-2075.
© 2015 American Society for Nutrition.
Posted October 5, 2015.
Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health. She earned her ND from Southwest College of Naturopathic Medicine in Tempe, AZ, and is a member of the North Carolina Association of Naturopathic Physicians. Visit her website at www.awarenesswellness.com.
References:
- Isabelle H-A, et al. Iodine Supplementation Decreases Hypercholesterolemia in Iodine-Deficient, Overweight Women: A Randomized Controlled Trial. 2015. The Journal of Nutrition. DOI:10.3945/jn.115.213439.
- Zimmermann MB. Iodine deficiency and endemic cretinism. In: Braverman L, Cooper SC, editors. The thyroid. Philadelphia: Lippincott, Williams & Wilkins; 2013.
- Andersson M, Karumbunathan V, Zimmermann MB. Global iodine status in 2011 and trends over the past decade. J Nutr 2012;142:744–50
- Pearce EN. Update in lipid alterations in subclinical hypothyroidism. J Clin Endocrinol Metab 2012;97:326–33.
- Biondi B, Cooper DS. The clinical significance of subclinical thyroid dysfunction. Endocr Rev 2008;29:76–131.
- American Thyroid Association. Iodine Statistics.
- Life Extension. The Silent Epidemic of Iodine Deficiency.
- Dr. Mercola. How Iodine Deficiency May Affect Your Child’s Brain Function.
