Are you following the advice of medical authorities by working up a sweat, avoiding dairy foods, and keeping the salt shaker at arms-length?
Exercising is generally good advice, avoiding salt is generally not such good advice, and avoiding milk products we could debate all night – but what we do know is all three of these common health tips come with a downside.
They can promote iodine deficiency — a factor that could increase the risk of several forms of cancer. In fact, lack of iodine is one of the most common causes of cancer. . .
Intake down half since the 1970s
The thyroid gland regulates many body processes including protein synthesis and metabolic activity, and it directly affects many facets of the immune system. It does so by secreting hormones that depend on iodine.
Most people know that an iodine deficiency causes goiter, an enlargement of the thyroid gland. If you are a senior like me, you probably know this. When we were children, the health authorities made a point of seeing to it that people got enough iodine.
Most table salt was iodized, starting around 1924. And the mineral was even baked into bread.
There was a reason for this. When I was a toddler I remember seeing a woman on the street who suffered from goiter. She had a bulge the size of a baseball hanging from her neck, where the thyroid gland is located (at least it seemed that big to me at the time.)
Lesser iodine deficiencies can give rise to fatigue, nervousness, irritability, weight gain, slow physical and mental reactions, cold hands and feet, headache, dry and thickened skin, hair loss, learning and memory problems, low resistance to disease, irregular and excessive menstruation and diminished interest in sex.
Why we no longer get enough iodine
Thanks to the introduction of iodized foods, I’m probably among the last people who can remember ever seeing a goiter. But these days, a lot of people don’t use iodized salt anymore, and iodine is no longer baked into bread.
I’d venture to say most people depend on whatever iodine occurs naturally in their food, and that’s a mistake.
Levels of iodine in the diet depend on the amount in the soil. The Great Lakes, Appalachians, and Northwestern regions of the U.S are called the “goiter belt” because the soil has a hundred times less iodine compared to soil-rich areas. Iodine-rich soil is almost always located near the ocean, which contains high iodine levels.
Seafood is another source of iodine, but Americans are not great fans of seafood. Shrimp is maybe the only seafood the average American eats with any kind of frequency. A three-ounce serving is said to contain around one-fourth of the recommended daily amount (RDA) – and the RDA is not nearly enough, in the opinion of many alternative cancer doctors.
Renowned clinical investigator, endocrinologist, and epidemiologist Professor Elizabeth Pearce from Boston University has made significant contributions to the science of iodine nutrition.
In 2015 she wrote that iodine deficiency, even in a wealthy country like the US, is “not entirely surprising” because intake has halved since the 1970s.
This has occurred, she contends, because concerns about high blood pressure have reduced salt consumption, consumers prefer to buy non-iodized salt, and the vast majority of salt that Americans do ingest comes from typically non-iodized processed foods.
Certain groups most at risk
The current major source of iodine is dairy food. Iodine is supplemented to cattle to prevent deficiencies in the animals and it’s also used to sanitize dairy equipment and udders.
Vegans and others who avoid milk and dairy products are most at risk of deficiency, as are pregnant and lactating women, for whom the adult RDA of 150 mcg rises to 220 mcg and 290 mcg respectively.
Wheat used to provide a quarter of our iodine intake because the trace mineral was used in the processing of flour. But now, as the American physician and author Jacob Teitelbaum, MD, explains:
“…a lot of flour in the US is processed with a chemical cousin of iodine, bromide (potassium bromate), which helps makes flour doughier, rise higher, and gives the loaf a better appearance. But bromide…not only has replaced iodine, it may block the activity of iodine.”
While exercise is essential to good health, endocrinologists from University College Dublin, Ireland, informed us that “those participating in vigorous exercise can lose a considerable amount of iodine in sweat, depending on environmental factors such as temperature and humidity.”
These are not the only factors that can reduce your iodine levels. There are others. I’ll tell you more in a moment, but right now the point is that iodine deficiency should be high on your list of health concerns because a healthy iodine level has been shown to reduce the risk of cancer.
It does so through antioxidant, anti-inflammatory, proapoptotic (induces cancer cell death) and pro-differentiating (promotes normal cellular function) actions and more.
Suppresses breast tumor growth
As far back as the 1960s iodine was shown to be vitally important to the health of the breast, the only organ apart from the thyroid that stores iodine.
A number of studies since then have demonstrated that patients with fibrocystic breast disease respond well to iodine in reducing both pain and fibrosis.
Deficiency is also believed to play a causative role in the development of breast cancer.
FDA epidemiologist B.V. Stadel, writing in the Lancet in 1976, found that geographical regions with low intake of iodine had higher rates of breast cancer.
Seaweed – a popular dish in Japan — is a rich source of iodine and may help account for the low rate of breast cancer in that country. It seems something in the Japanese diet prevents breast cancer, because the risk of this disease increases in Japanese women who emigrate and adopt a Western diet.
In animal models of breast cancer, researchers from Mexico concluded that iodine “has a potent anti-neoplastic [tumor-growth-suppressing] effect on the progression of mammary cancer.” They proposed that iodine supplements should be used together with conventional treatments in breast cancer therapy.
The supplements come in various forms. I get mine from a kelp supplement manufactured by Nature’s Way. Kelp is a seaweed, as I assume most readers know. It’s best to get minerals from food and I’m wary of so-called “free” minerals that aren’t bonded to a large food molecule.
But I have to note that for breast tissue protection or treatment, molecular iodine (I2) has proved best in the studies we have. This form combines potassium iodide (KI) with either free/elemental iodine or potassium iodate (KIO3).
In 2017, scientists at BioPharmX, a specialty pharmaceutical company, presented findings at the American Association for Cancer Research annual meeting.
They showed that molecular iodine was potent in its ability to prevent tumor growth and promote tumor cell death on two types of breast cancer cell lines without harming normal breast cells.
Lee Shulman, Professor of Obstetrics and Gynecology at the Feinberg School of Medicine at Northwestern University in Chicago, who was not involved with the research, said, “The possibility that a known, non-toxic, and non-chemotherapeutic molecule may have a differential regulating effect on breast cancer cells versus normal breast cells is very exciting.”
I have to take exception to the “non-toxic” adjective in this, because iodine is toxic in very large amounts, and that makes supplementing with it tricky. I don’t want to be alarming – people can tolerate MUCH larger amounts of iodine than the RDA. Very few people indeed have to worry about overdoing it. But there is a limit.
In the BioPharmX study, iodine upregulated proteins called PPARs and RXR, thereby inhibiting cancer cell proliferation. Iodine also increased BCL-2 and Caspase 3, proteins that induce apoptosis.
Other studies suggest iodine impedes growth of blood supply to mammary tumors and inhibits and modulates estrogen pathways that induce cancer growth.
Protects against stomach cancer
Like the thyroid gland and breast tissue, parts of the digestive tract, particularly the stomach, have high levels of iodine. The mineral’s antioxidant, anti-inflammatory and pro-differentiating activities help protect against stomach cancer.
For almost a century gastric cancer has been linked to goiter. Oncologists in Turkey compared 61 patients with gastric cancer to 55 healthy control subjects. Almost half the cancer patients had goiter compared to one in five of the controls.
Virtually identical results were obtained by Iranian researchers who found 49% of 100 stomach cancer patients had severe iodine deficiency compared to 19.1% of 84 healthy adults.
In other words, it sure looks like iodine deficiency causes stomach cancer.
The Turkish biochemists, of course, didn’t have enough evidence to make such a big leap. They found gastric cancer tissue had lower amounts of iodine than surrounding healthy tissue. They concluded from this that “iodine plays an important role in gastric cancer development.”
After the iodization of salt in Poland in 1996 due to high goiter prevalence, the incidence of stomach cancer, which had been sizable, started to fall. Polish endocrinologists believe improved uptakes of iodine and lower rates of this form of cancer are very likely linked.
The prostate also needs iodine
There is good evidence that the prostate readily takes up iodine and needs it for the overall health of the gland.
In a study of men with benign prostatic hypertrophy (BPH), supplementing with iodine increased urine flow and reduced PSA levels over a period of eight months.
Population studies also suggest a link between high iodine intake and low risk of prostate cancer, with one study of the American population showing a 29% lower risk in men consuming the highest versus the lowest amounts.
Prostate cancer is four times lower in Japan than in the US. We don’t have enough evidence to say for sure, but the higher iodine intake may be an important factor.
Environmental toxins reduce uptake
Women of child-bearing age and their children are especially at risk of iodine deficiency. A review of iodine intake published earlier this year by researchers at the College of Health Sciences, Texas Woman’s University, concluded that lack of iodine was “a public health concern needing immediate attention.”
In their view, “The current iodine intake guidelines are the minimum for disease prevention [mainly goiter], but not necessarily whole-body health. It is still unknown how much iodine is necessary for iodine sufficiency beyond prevention of goiter.”
They described many factors that act as goitrogens – i.e., that interfere with iodine uptake by the thyroid.
These include chlorine and fluorine in the water supply [once again showing that fluoridated water is a terrible idea], cruciferous vegetables and lima beans, oral contraceptives, amiodarone (a drug that treats irregular heartbeats) and the environmental toxins BPA and perchlorate, common in plastic bottles, which find their way into the food and water supply.
Deficiencies of nutrients such as vitamin A, selenium, iron, and zinc also adversely affect iodine metabolism. [NOTE: Few people need to supplement with iron. It’s always best to get a blood test to see what nutrients you need, rather than guessing.]
While the value of iodine has been largely forgotten today, in 1957 Nobel laureate Albert Szent-Gyorgi, the physician who discovered vitamin C, wrote, “When I was a medical student, iodine in the form of KI was the universal medicine. Nobody knew what it did, but it did something, and did something good.”
The usual dose given was one gram containing 770 mg of iodine. By today’s standards that dose is off the charts.
Ditto for a research project involving 4000 patients taking 12.5 to 50 mg a day (83 to 333 times the RDA) over seven years. Positive results were seen, with well under one person in a hundred experiencing adverse reactions. But these doses are extraordinarily high. We’ve interviewed dozens of alternative cancer doctors over the last 15 years and not one was employing iodine at these levels.
For healthy people (not cancer patients, who were the subjects in the study above), you should know that the Japanese consume an estimated 1000 to 3000 mcg a day and have a much lower cancer rate and longer life expectancy than Americans who consume 190 to 300 mcg. There are a million micrograms in a gram, just to give you an idea of how high the doses are in the previous paragraph.
On current evidence, adults should be looking to go well beyond the RDA to reach the Food and Nutrition Board’s Tolerable Upper Limit of 1,100 mcg per day.
This will require adding seaweed (kelp, nori, kombu, wakame) to the diet or taking iodine in supplement form.