Most Americans Are Deficient In These Two Nutrients, Are You?

A groundbreaking study led by Harvard scientists has uncovered an alarming truth: billions of people, even in high-income nations like the U.S., fail to get enough essential vitamins and minerals from their diets.

Nearly everyone—regardless of wealth or location—silently suffers from hidden nutrient deficiencies. And, researchers say, if you’re falling short, it’s likely in these two nutrients…

Key Takeaways

• Micronutrient Deficiency is a Global Crisis – Over 5 billion people worldwide don’t get enough iodine, vitamin E, and calcium, and more than 4 billion are deficient in iron, folate, and vitamin C.
• The U.S. is Not Immune – Despite being a wealthy nation, the U.S. has widespread nutrient deficiencies, particularly in iodine and vitamin E.
• Dietary Habits & Food Quality Matter – With ultra-processed foods making up about 60% of the U.S. diet, many Americans are not getting enough essential nutrients, even with supplements.

Think You’re Getting Enough Nutrients? The Data Says Otherwise

Harvard-led scientists conducted the first-ever study to estimate the global dietary intake of 15 micronutrients critical to human health. Their findings were described as “alarming,” with 5 billion people deficient in three nutrients and over 4 billion deficient in four.

Micronutrient intake estimates worldwide are not new, but rely on food supply and availability data for each country. However, supply-based estimates are inaccurate because they don’t account for household and restaurant food waste. In high-income countries, this underestimates nutritional shortfalls.

The best indication of deficiencies comes from nutritional biomarkers, which require individual testing. Even then, results can be skewed because of disease states, absorption issues, inflammation problems, and the quality of the gut microbiome. Therefore, the best way to identify populations at risk of deficiency is to focus on what people eat.

Out of the 29 micronutrients known to be essential, the new analysis included 15 derived from food, excluding fortification and supplementation in 185 countries. The key findings are a significant cause of concern.

Iodine - The World’s Most Deficient Nutrient

The researchers found that most of the global population has an inadequate intake of at least one micronutrient.

• Iodine (68% of the global population)
• Vitamin E (67%)
• Calcium (66%)

More than 4 billion people do not consume enough:

• Iron (65%)
• Vitamin B2 (55%)
• Folate (54%)
• Vitamin C (53%)

Women were in worse shape than men when it comes to intakes for:

• Iodine
• Vitamin B12
• Iron
• Selenium

Men especially need to pay attention to this next part. Inadequate intakes were higher for men than for women for:

• Vitamin A
• Vitamin B1
• Vitamin B3
• Vitamin B6
• Vitamin C
• Magnesium
• Zinc

The Silent Deficiency Epidemic Affecting 2 Out of 3 People Worldwide

In The Lancet Global Health in October, the researchers pointed to “the vast scale of micronutrient intake inadequacy across the world [which] contribute to a large burden of morbidity and mortality.”

Dr. Ty Beal, a research team member, said: “These results are alarming. Most people—even more than previously thought, across all regions and countries of all incomes—are not consuming enough of multiple essential micronutrients. These gaps compromise health outcomes and limit human potential on a global scale.”

Of course, many countries worldwide don’t have the level of income found in Western nations, so deficiencies would be expected. If you think a wealthy country like the U.S. would be free of such deficiencies, then think again because they’re widespread here, too, with two nutrients standing out.

Two Severe Deficiencies In The USA

The two nutrients deficient in the vast majority of the U.S. population are iodine and vitamin E.

Iodine is needed for the thyroid gland and for cognitive development in infants. It also plays a role in the immune system, keeps the skin healthy, and can help protect against some cancers.

Iodine specialist Professor Elizabeth Pearce from Boston University wrote almost a decade ago that iodine deficiency, even in a wealthy country like the U.S., is "not entirely surprising" because intake has halved since the 1970s. Interestingly, the new study found Canadians ingest sufficient amounts of iodine.

Good sources include saltwater fish and shellfish, kelp, seaweed (kelp, nori, kombu, wakame), sea salt, iodized salt, and dairy products. Vitamin E findings align with a previous study that found nine out of ten Americans are deficient.

Vitamin E is a potent antioxidant in cell membranes and helps maintain healthy skin, circulation, nerves, and muscles. Muscle weakness and impaired coordination are common symptoms of deficiency.

Good sources include leafy green vegetables, nuts, seeds, and the germ from whole wheat.

The situation in the US may not be as bad as the study shows because it doesn’t consider supplements. A survey published last year found 74 percent of adults take supplements, with over half of them qualifying as “regular users.”

How Much Do You Need?

It’s important to note that many nutrition experts regard the recommended daily amounts (RDAs) for most nutrients as too low, which means the overall picture could be even worse than The Lancet study suggests. Yet, even with the current RDAs, a review published in May 2024 found from 2003 through 2018, “United States adults under consumed vitamins A, C, D, E, and K; calcium; potassium; magnesium; and choline, even when DSs (dietary supplements) intake was included.”

With ultra-processed foods comprising about 60% of the U.S. diet, perhaps we shouldn’t be surprised. That’s why we recommend supplementing with a daily multi-vitamin and other nutritional supplements targeted to your health concerns and your physical needs. Studies show that those who supplement are better able to fight off illness in the long run.

Summary

A new Harvard-led study published in The Lancet Global Health has revealed that over 5 billion people worldwide are deficient in at least three essential micronutrients, with iodine, vitamin E, and calcium being the most commonly lacking. More than 4 billion people fall short on iron, folate, and vitamin C, with women particularly at risk for deficiencies in iodine, vitamin B12, and iron. Surprisingly, even in high-income countries like the U.S., these deficiencies are widespread, with iodine and vitamin E being the most common. The study underscores the critical need for improved dietary habits, better food quality, and possibly revised nutritional guidelines to address this global health crisis.

Frequently Asked Questions

• What are the most common micronutrient deficiencies worldwide?
  The most common deficiencies are iodine, vitamin E, calcium, iron, folate, and vitamin C, affecting billions globally.
• Why are even wealthy countries like the U.S. struggling with nutrient deficiencies?
  Factors like poor dietary habits, processed food consumption, and declining nutrient levels in soil contribute to widespread deficiencies.
• How does iodine deficiency impact health?
  Iodine is essential for thyroid function, cognitive development in infants, immune health, and even cancer protection.
• What are the best food sources to combat these deficiencies?
  Iodine: Seaweed, seafood, dairy. Vitamin E: Nuts, seeds, leafy greens. Calcium: Dairy, leafy greens, fortified foods.
• Can supplements alone fix these deficiencies?
  While supplements can help, whole foods provide additional beneficial compounds that enhance absorption and overall health.