Wednesday, October 15, 2008

Pregnant, But is Your Baby Getting Enough Iodine from Your Prenatals ?

The American Thyroid Association recommends prenatal vitamins with 150 mcg elemental iodine during pregnancy. The Institute of Medicine recommends 220 mcg iodine in pregnancy, and 290 mcg when breast feeding. There is no mandate for U.S. prenatal vitamins to have 150 mcgs of iodine. What does a pregnant women do to insure her baby is getting enough iodine?
The internet listed 127 nonprescription, and 96 prescription brands on the market in the U.S. Only 69% of non-RX brands had iodine listed. Even lower percentage of prescription brands listed iodine. 90% of them with iodine, listed > 150 mcg of iodine. 150 mcg of KI is only 114 of elemental iodine. Kelp based prenatal vitamins had >150 mcg iodine. This labeling is misleading. Researchers at Boston University measured 60 brands of prenatal vitamins for iodine content. The prenatal with KI had 119 mcgs as expected.
However, the kelp based prenatal had 33-610 mcgs of iodine. Over half had content that was different than listed on the label, including 10/25 with low iodine content. Kelp iodine content is variable, and one should stick to potassium iodide KI as the source of their prenatal iodine, not kelp.

1. 69% of non RX prenatal, and 28% of prescription prenatal vitamins have iodine.
2. Kelp is a poor source of iodine due to variable amounts of iodine.
3. KI based prenatal is more consistent but only have 76% iodine content of the labeled 150 mcg, or 120 mcgs.
4. KI prenatals should be the drug of choice.
5. However future Prenatal vitamins should have 197 mcg KI to get to the recommended 150 mcgs elemental iodine supplement needed during pregnancy, and lactation.

What should the woman do now?

Get KI based Prenatal vitamins, and add a 100 mcg KI pill, to get the extra 80 mcgs you need.

Good Luck with the pregnancy,


Iodine Content of U.S. Prenatal Multivitamins
Leung, et al
American Thyroid Association national meeting abstract #106
Thyroid supplement page S-45
October 3 2008.

Thursday, October 02, 2008

Thyroid Nodule Therapy in Patients with Insulin Resistance

Recent studies have shown that patients with high levels of insulin seen in obesity, diabetes, and in thin patients with insulin resistance have a larger thyroid gland by volume studies by ultrasound, and have a significant increased number of nodules.Thyroid vol.18(4),461-164 2008. Obese and non-obese patients with insulin resistance had increased thyroid volumes, compared to obese, and normal patients without elevated insulin levels. Also the number of nodules was increased over controls without excess insulin. Well if increased insulin is a thyroid growth factor as seen in animals studies, and suggested by these data, maybe we need to consider another medical approach to nodule therapy. Well the thyroid group from Argentina has treated patients with the drug metformin to reduce the insulin levels in patients with thyroid nodules. Metformin alone, with T4, T4 alone, and control with no therapy for 6 months. TSH was kept at 0.1-0.9 range,in the treated groups. The metformin dose was 1 gram. The patients were all from an iodine deficient country. The dramatic results were a marked reduction in the nodules with metformin alone, 73%, but this was even better with the addition on T4, 95%. The control without therapy was 26% reduction, and the T4 only was 35%. T4 only just prevented increased growth, but did not decrease nodule volume compared to controls. Insulin and TSH are growth factors for thyroid nodules. The dramatic results in Argentina is partially due to iodine deficiency, and the effects should be less in the USA. However,combination therapy may be worth a try in diabetic, obese patients, or thin patients with proven high insulin levels seen during a 75 gram glucose load test, who have benign thyroid nodules by Ultrasound Guided FNA.

6 th World Congress on Insulin Resistance Syndrome
September 25-27 2008
Los Angeles Ca
Abstract #20
Metformin Treatment of Benign Thyroid nodules in Euthyroid Patients with Insulin Resistance
H. Niepomniszcze et al.