Make Sure Iodine is in Your Prenatal

Although severe iodine deficiency was eliminated in the United States nearly a century ago after the introduction of iodized salt, iodine intake has declined in recent decades. “Public health efforts to limit salt intake to decrease cardiovascular risk, in conjunction with increasing use of kosher salt and sea salt (neither of which contain iodine),” may in part be to blame. Not adding salt to foods is a good thing, as sodium is considered the second leading dietary killer in the world (second only to not eating enough fruit), but if you do add table salt, make sure it’s iodized. “It is a myth (often also false advertising) that ‘natural’ sea salt contains significant amounts of iodine.”

Fruits and vegetables provide iodine, but the amounts can vary depending on where it’s grown and how much iodine is in the soil. Because iodine is particularly important for fetal brain development, there’s a recommendation that “all US women who are pregnant, lactating, or even planning a pregnancy should ingest dietary supplements containing 150 mcg of potassium iodide per day,” which I discuss in my video Iodine Supplements Before, During, and After Pregnancy.

Is there evidence they’re not getting enough? We’d like to see urine levels over 150 mcg/L in pregnant women, but in the United States, pregnant women only average about 125 mcg/L. For example, a recent survey in New York City showed only about half of pregnant women were making the cut.

Don’t most pregnant women take prenatal vitamins, though? Only about half of prenatal multivitamins contain any iodine at all, and so only about one in five pregnant women in the United States are following the recommendations of the American Thyroid Association to take a daily iodine supplement, specifically in the form of potassium iodide rather than seaweed, as the levels in seaweed are subject to natural variability. Though the iodine content was as much as 90 percent off in some of the potassium iodide prenatal supplements, the kelp supplements varied even wider, off by as much as 170 percent.

Now, the American Thyroid Association admits it doesn’t have evidence that the current borderline insufficiency levels are leading to undesirable outcomes and so its rationale that all pregnant women take iodine supplements is a bit tenuous. Until such data are available, though, it figures better safe than sorry.

A randomized, placebo-controlled, interventional trial would answer the question once and for all, but the existing evidence for iodine supplementation during pregnancy is so convincing that it would be considered unethical to randomize pregnant women to a placebo.

When it comes to sufficient iodine intake during pregnancy, I’d recommend: Just do it.


Women eating plant-based diets may find this video of special importance: Pregnant Vegans at Risk for Iodine Deficiency.

This isn’t to say sea vegetables aren’t good for you in their own right. See Which Seaweed Is Most Protective Against Breast Cancer?.

For more videos on having a healthy pregnancy, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

From Adequate Nutrition to Optimum Nutrition

Research in human nutrition over the past four decades has led to many discoveries as well as a comprehensive understanding of the exact mechanisms behind how food nutrients affect our bodies. As I discuss in my video Reductionism and the Deficiency Mentality, however, the “prevalence of epidemics of diet-related chronic diseases, especially obesity, type 2 diabetes, osteoporosis, cardiovascular diseases, and cancers, dramatically increases worldwide each year.” Why hasn’t all this intricate knowledge translated into improvements in public health? Perhaps it has to do with our entire philosophy of nutrition called reductionism, where everything is broken down into its constituent parts; food is reduced to a collection of single compounds with supposed single effects. “The reductionist approach has traditionally been and continues today as the dominant approach in nutrition research.” For example, did you know that mechanistically, there’s a chemical in ginger root that down-regulates phorbol myristate acetate-induced phosphorylation of ERK1/2 and JNK MAP kinases? That’s actually pretty cool, but not while millions of people continue to die of diet-related disease.

We already know that three quarters of chronic disease risk––diabetes, heart attacks, stroke, and cancer—can be eliminated if everyone followed four simple practices: not smoking, not being obese, getting a half hour of exercise a day, and eating a healthier diet, defined as more fruits, veggies, and whole grains, and less meat. Think what that could mean in terms of the human costs. We already know enough to save millions of lives. So, shouldn’t our efforts be spent implementing these changes before another dollar is spent on research such as figuring out whether there is some grape skin extract that can lower cholesterol in zebra fish or even trying to find out whether there are whole foods that can do the same? Why spend taxpayer dollars clogging the arteries of striped minnows by feeding them a high cholesterol diet to see whether hawthorn leaves and flowers have the potential to help? Even if they did and even if it worked in people, too, wouldn’t it be better to simply not clog our arteries in the first place? This dramatic drop in risk and increase in healthy life years through preventive nutrition need not involve superfoods or herbal extracts or fancy nutritional supplements—just healthier eating. When Hippocrates supposedly said, “Let food be your medicine and medicine be your food,” he “did not mean that foods are drugs, but rather, that the best way to remain in good health is to maintain a healthy diet.” (Note: Hippocrates probably never actually said that—but it’s a great sentiment anyways!)

The historical attitude of the field of nutrition, however, may be best summed up by the phrase, “Eat what you want after you eat what you should.” In other words, eat whatever you want as long as you get your vitamins and minerals. This mindset is epitomized by breakfast cereals, which often provide double-digit vitamins and minerals. But the road to health is not paved with Coke plus vitamins and minerals. This reductionistic attitude “is good for the food industry but not actually good for human health.” Why not? Well, if food is good only for a few nutrients, then you can get away with selling vitamin-fortified Twinkies.

We need to shift from the concept of merely getting adequate nutrition to getting optimal nutrition. That is, we shouldn’t just aim to avoid scurvy, but we should promote health and minimize our risk of developing degenerative diseases.

Bringing things down to their molecular components works for drug development, for example, discovering all the vitamins and curing deficiency diseases. In the field of nutrition, “[h]owever, the reductionist approach is beginning to reach its limits.” We discovered all the vitamins more than a half-century ago. When is the last time you heard of someone coming down with scurvy, pellagra, or kwashiorkor, the classic deficiency syndromes? What about the diseases of dietary excess: heart disease, diabetes, obesity, and hypertension? Ever heard of anyone with any of those? Of course we have. Yet we continue to have this deficiency mindset when it comes to nutrition.

When someone tries to reduce their consumption of meat, why is “where are you going to get your protein?” the first question they get asked, rather than “if you start eating like that, where are you going to get your heart disease?” The same deficiency mindset led to the emergence of a multibillion-dollar supplement industry. What about a daily multivitamin just “as ‘insurance’ against nutrient deficiency?” Better insurance would be just to eat healthy food.


Professor Emeritus T. Colin Campbell wrote a Whole book about this issue, and I’m looking forward to doing many more videos on the topic.

So, where do plant-eaters get protein? Check out Do Vegetarians Get Enough Protein? to learn more.

The concept of optimal, rather than merely adequate, nutrition is illustrated well in this video about fiber: Lose Two Pounds in One Sitting: Taking the Mioscenic Route.

Other videos on reductionism include

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Alzheimer’s Disease and Dietary Copper

Though the underlying cause of Alzheimer’s disease has yet to be found, there is increasing concern about the role of metals in the development of the disease, as I discuss in my video Alzheimer’s Disease, Copper, and Saturated Fat. “Iron and copper,” for example, “are strongly concentrated within the neuritic plaques and neurofibrillary tangles that represent the hallmarks of the [Alzheimer’s] brain.”

Alzheimer’s disease victims have higher levels of copper in their blood and in the fluid that surrounds their brain, as well as inside their brain. Researchers found that in a slice of Alzheimer’s-diseased brain tissue, the amyloid plaques correspond to copper hotspots. Copper may then make these amyloid plaques more toxic, “leading to increased oxidative stress.” “Free Cu [copper] is extremely efficient in the generation of free radicals,” and when copper is removed with a chelating (metal-binding) drug, the free radical oxidation drops.

Unfortunately, when researchers gave that drug to nine Alzheimer’s patients in a pilot study, it did not seem to have any effect on slowing the clinical progression of the disease. Perhaps we need to prevent the copper buildup in the first place?

“Organ meats and shellfish are the richest food sources of copper,” but should we also consider cutting down on plant sources, such as nuts, seeds, legumes, and whole grains? Copper intake only seems to be a problem when consumed with saturated fat or trans fat. In the Chicago Health and Aging Project, thousands of elderly Chicagoans were followed for six years. Those who were getting the highest copper doses, largely from multivitamin supplements, combined with a diet high in saturated fats, lost cognition as if they had aged 19 years in a period of 6 years, tripling their rate of cognitive decline. However, copper intake “was not associated with cognitive change when the diet was not high in saturated fats.”

Diet-induced high cholesterol “has been shown to increase the formation and progression of [amyloid] plaques in the brain.” As well, “dietary copper may interfere with clearance of [amyloid] from the brain and may further promote [the plaque] accumulation that results from elevated cholesterol levels.” Copper has been shown to interact badly with amyloid, causing its clumping and the production of hydrogen peroxide, a potent pro-oxidant neurotoxin.

This may explain why the higher the levels of copper, the quicker Alzheimer’s disease may progress, particularly among people with high cholesterol levels. What do we think may be happening? As cholesterol and copper levels rise, cholesterol is incorporated into the nerve cell membrane, causing it to stiffen. The amyloid protein in the membrane detaches to form plaques, at which point iron and copper generate neurotoxic free radicals. Inside the cell, similar havoc is created. Finally, cholesterol-enriched diets can lead to nerve cell death, DNA damage, and blood-brain barrier disruption.

“In conclusion, the present systematic review suggests that a diet rich in [copper and iron] might aggravate the detrimental effects of a high intake of cholesterol and [saturated fat] on the risk of developing [Alzheimer’s disease].” So, diets rich in saturated fat and deficient in antioxidants appear to promote the onset of the disease, while more plant-based diets would likely suppress its onset. There are compounds in plant foods that not only scavenge free radicals and prevent oxidative damage, but are also known to chelate, or bind up, metals, potentially making them additionally protective against the onset of Alzheimer’s. Therefore, the practical implications could be to eat lots of fruits and vegetables, avoid copper-containing supplements, and avoid high intakes of saturated fat and excessive iron intake.


Isn’t Alzheimer’s genetic? What about the “Alzheimer’s gene”? Just because we’ve been dealt some bad genetic cards doesn’t mean we can’t reshuffle the deck with diet. See The Alzheimer’s Gene: Controlling ApoE.

If the relationship between cholesterol and dementia is new to you, see Alzheimer’s and Atherosclerosis of the Brain and Cholesterol and Alzheimer’s Disease for more.

What else can we do to protect our brain? Check out:

It’s never too early to start eating healthier, because Alzheimer’s May Start Decades Before Diagnosis.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: