I wish more women would take iodine. Not for thyroid—but to prevent breast cancer.
We have long known that iodine relieves breast symptoms like pain and cysts, and that deficiency is a risk for breast cancer. It was logical to think that it’s thyroid hormone that breasts need. But it’s not. It’s iodine.
Benefits beyond thyroid
Yes, iodine is important for the thyroid gland, but 80 percent of the body’s iodine is not in the thyroid gland. It’s in the immune system. It’s in eyes, stomach, salivary glands, brain, and ovaries–and breast tissue. It’s there because it’s an important electron donor and antioxidant. It protects cell membranes from oxidative damage by attaching to the double bonds of polyunsaturated fatty acids. It’s also involved in immune function and fighting infection, which is why there’s a greater concentration of thyroid hormone in infected tissue. Neutrophils harvest iodine from thyroid hormone in order to fight infection.
Iodine is particularly important for breast tissue. It alters gene expression in the breast by down-regulating estrogen-responsive genes and up-regulating genes involved in estrogen detoxification. That’s why iodine-deficiency causes breast ductal tissue to be hyper-sensitive to estrogen.
Interestingly, progesterone enhances iodine uptake, which may be why progesterone protects against breast cancer.
Researcher Carmen Aceves is so convinced of the mineral’s benefits that she wants to trial it as a viable treatment for breast cancer.
Safe use of iodine
The conventional view is that supplementation causes thyroid disease, and that view is not without merit. Overdose can trigger autoimmune thyroid disease and hypothyroidism. Fortunately, that is less likely to occur when there is adequate selenium to stabilize thyroid tissue.
What dose of iodine?
How can you get enough for breasts without injuring the thyroid?
A daily dose of 400 mcg to 1000 mcg is safe for most people, even those with autoimmune thyroid disease (and especially if they co-supplement with selenium). The RDI is 150 mcg, which is simply inadequate because we are all exposed to environmental toxins that interfere with iodine uptake. 150 mcg will prevent goitre, but it will not supply your breasts with what they need. On the other hand, high dose tablets with 30,000 – 50,000 mcg (30-50 mg) are not safe. (Safety tip: Read your supplement label. There is a 1000x difference between mcg and mg). If you felt well on a big dose, that is probably because of its antimicrobial effect.
High dose iodine is a real danger to your thyroid.
What type of iodine?
In her paper “Is Iodine A Gatekeeper of the Integrity of the Mammary Gland?”, researcher Carmen Aceves explains why molecular iodine (I2) is better for breasts than potassium iodide, and why it’s safer for thyroid. I2 is available in some solutions (together with potassium iodide) and from kelp. I’m not a fan of kelp. Clinically, it seems less effective than potassium iodide. It also contains the bromine (which blocks iodine uptake) and possibly toxic metals such as mercury.
Please also read:
- Why I Prescribe Iodine for Breast Pain, Ovarian Cysts, and PMS
- The Extrathyronine Actions of Iodine as Antioxidant, Apoptotic, and Differentiation Factor in Various Tissues [full text]