Iodine Plus measures levels of iodine, selenium, bromine and cadmium in a first morning or 24-hour urine collection. Iodine and selenium are key elements in thyroid function, and bromine and cadmium can interfere with the actions of iodine and selenium respectively.
Iodine deficiency is on the rise for two reasons: decreased intake of iodine, and increased intake of bromine. The Iodine Plus urine test can help determine whether you have sufficient iodine and whether excess bromine could be negatively impacting your iodine status. Iodine Plus also includes selenium and cadmium. Selenium is an essential element for thyroid function, and cadmium is known to interfere with the actions of selenium.
Iodine is a key component of the thyroid hormones T3 (tri-iodothyronine) and T4 (tetra-iodothyronine). Selenium is needed to convert T4 to the more active T3 form, a process which frees up iodine that can be reused. Since thyroid hormones regulate metabolism (the process of converting stored energy into usable energy), a lack of iodine and/or selenium may affect energy, metabolism, mood, and development. Selenium is also necessary for glutathione enzymes which are potent antioxidants. The following are examples of conditions related to low iodine and/or selenium :
Weight gain: a lack of iodine and/or selenium may slow metabolism and result in weight gain or inability to lose weight.
Fatigue: slowed metabolism results in decreased energy and fatigue.
Depression, mental impairment: slowed metabolism affects brain function and may lead to impaired mental abilities and/or depression.
Fibrocystic breast disease: iodine supplementation has been shown to reduce the signs and symptoms of fibrocystic breast disease.
Cancer: adequate iodine intake may provide protection against breast, thyroid and prostate cancer. Selenium provides support for immune health and is also important for protection against certain cancers.
The 2012 Iodine Status of Canadians paper found nearly three out of every ten Canadians have a mild to moderate iodine deficiency. Iodine is clearly essential for health and well-being and yet many Canadians don’t get enough and don't know it . Selenium is also essential, and may be deficient in foods.
Iodine was added to table salt in the 1920’s in an effort to address the growing problem of iodine deficiency. Use of iodized salt has reduced the incidence of goitre (swollen thyroid) in areas with low iodine intake. Unfortunately, decreased intake of iodine is still relatively common in North America. Some of the factors associated with declining iodine intake are:
- increased consumption of commercially-produced foods prepared primarily with non-iodized salt.
- decreased use of iodized salt at the dining room table in compliance with health messages to reduce salt intake.
- declining use of iodine-containing disinfectants by the dairy industry. Iodine disinfectants were absorbed into cow's milk and increased the iodine content of dairy foods.
- bromine hidden in disinfectants, flame retardants and medications interfering with transport of iodine into thyroid cells.
- Selenium deficiency is rare in those eating a healthy, balanced diet. However, people with gut problems, those who've had gastric bypass surgery and the elderly are more at risk for low levels. Symptoms of selenium deficiency are
similar to those of low thyroid hormone levlels. The recommended daily intake is between 60 and 75 micrograms, and more than 200 micrograms/day may be toxic for some.
The importance of testing iodine:
- Too little iodine may contribute to the symptoms listed above, and an excess of iodine can shut down thyroid hormone production and cause hypothyroidism. Urine iodine reflects recent iodine intake, and having consistently low iodine levels in urine suggests iodine intake is insufficient.
The importance of testing selenium:
Selenium helps the body use iodine more efficiently thus potentially improving thyroid function. Urine selenium levels reflect recent intake and can be used to track selenium supplementation, as high doses of selenium can be toxic. Other selenoproteins are essential for health parameters like fertility and fetal development, mitochondrial function, calcium homeostasis, liver and kidney health, plus general antioxidant status. Selenium deficiency has been implicated in cardiovascular disease, various cancers, myopathies, and is currently under investigation for its role in insulin resistance and diabetes.
The importance of testing bromine and cadmium
- Bromine competes with iodine for transport into the thyroid, so it interferes with the beneficial effects of iodine. Animal studies show that having adequate iodine decreases the amount of bromine that is taken up by thyroid cells.
- Cadmium can interfere with the beneficial effects of selenium. Elevated PBDE in breast milk correlates with lower birth weight and length, decreased BMI and reduced head and chest circumference.
- PBDE levels in breast milk correlate with increased incidence of undescended testicles in newborns.
- PBDEs affect neuron activity on several levels including: presynaptic neurotransmitter homeostasis, intracellular signalling, and neurotransmitter release. The toxic effect of PBDEs on nervous system development involves changes in the cholinergic system and may also be related to altered thyroid homeostasis.
- PBDEs may compete with thyroxine (T4) for the serum transport protein, transthyretin.
- PBDEs can disrupt calcium homeostasis by causing mitochondria and endoplasmic reticulum stores to release calcium. This in turn alters both calcium channel activity in cell membranes and neurotransmitter release.
- Hydroxylated PBDEs have been shown to inhibit the aromatase enzyme.
- PBDEs cause oxidative stress.
Cadmium is considered an endocrine/neuroendocrine disrupter, and tends to concentrate in the kidney and thyroid. The biological half-life of cadmium is more than 5 years, and exposure typically occurs through inhalation.14 There are several means by which cadmium can interfere with biological functions:
- Cadmium induces reactive oxygen species (ROS).
- Cadmium acts on the pituitary glands, resulting in secretory changes in prolactin, growth hormone, ACTH and TSH that can negatively impact sperm production, follicular development and other gonadal functions.
- Cadmium toxicity impairs deiodination, leading to lower plasma T3 and T4 while the effects of cadmium on the pituitary may prevent compensatory increases in TSH in response to low T3 and T4.
- Cadmium may interfere with steroid hormone synthesis. Cholesterol is transported into cell membranes for steroidogenesis via a T3 dependent transport protein. Because cadmium impairs deodination and T3 levels, the availability of transport proteins for steroid synthesis may be affected.
- Cadmium is also known to displace other elements (i.e. zinc, iron, magnesium, calcium, and copper) from biological systems and tissues.
- Rocky Mountain Analytical participates in both EQUIP (Ensuring the Quality of Urine Iodine Procedures), an international iodine testing program adminstered by the Center for Disease Control and QMEQAS (Quality MultiElement Quality Assurance Program), to ensure quality results.