Tens of millions of people around the world are risking their health every day, and it’s all because of a math mistake too few people know about. 

In the United States, 41 percent of people are deficient in vitamin D*. That is staggering. Our body uses vitamin D for everything from building bones, to fighting sickness. This means two-fifths of the population does not have enough of a vitamin that is essential for their body to maintain minimum health standards. 

Vitamin D protects against leading causes of death

The risk factors of some of the leading causes of death in the United States, like heart disease, cancer, and respiratory diseases, are linked to vitamin D deficiency*. This should be alarming because vitamin D supplements are widely available. If we take the proper amount of vitamin D, we reduce those risk factors, reduce the prevalence of these fatal diseases, and live healthier lives, right? 

The problem is, we think we are getting the proper amount of this essential vitamin, but a recently discovered mathematical error proves we’ve been wrong about vitamin D for years*.

Vitamin D doses have been wrong for decades

There is a consistent amount of vitamin D that has to be present in our blood to offer disease prevention benefits and to nourish the daily needs of our body. This amount can be measured by tracking the level of “serum 25 (OH)D” in our blood*. When we take vitamin D, our body processes it, the vitamin D appears in our blood as serum 25 (OH)D, and our body uses that for bone health, fighting disease, and our day-to-day immunity against viruses like aggressive strains of the cold or flu*. 

Several scientific studies were conducted to determine how much vitamin D we need to get through our diet or sunlight to maintain the amount of serum 25 (OH)D to benefit our body, and from this, the Recommended Dietary Allowance (RDA) was determined. 

However, a statistical error in this calculation has led to an RDA that is far lower than what is needed to stay healthy.

The daily dose is not enough to prevent disease

In the United states and Canada, the Institute of Medicine determines the RDA for essential nutrients. The RDA is based on how much of these vitamins and minerals are needed to keep the vast majority (97.5 percent) of the population healthy. Through scientific study, the RDA for vitamin D was determined to be 600 International Units (IU) per day. But as new health benefits associated with vitamin D have been studied, this has led scientists to re-evaluate the previous research on vitamin D and how much is a proper daily dose*.

The math problem that caused a crisis

During this re-examination, a detrimental mathematical error was discovered*. Upon recalculation, one study determined that in order to maintain the amount of serum 25 (OH)D in our blood that is associated with disease prevention and bone health, you would need to take 8,895 IU of vitamin D per day, or nearly 15 times the current daily dose recommended by the IOM*. 

This dose is way beyond what has been studied long-term. However, a study by the IOM, the group that sets the recommended daily dose, has determined that 4,000 IU per day of vitamin D is safe for most people*. Regardless, modern research is showing that the current RDA of 600 IU is extremely low. 

How much do YOU need?

While the difference between the RDA of vitamin D and the amount we actually need for health benefits may be shocking, it is understandable. As more benefits for vitamin D are discovered, the dosage size is re-evaluated. Before 1997, the RDA was based on the amount of vitamin D that was needed to prevent rickets in infants. Then, as modern research showed the expanded role of vitamin D for our health, the RDA was increased.

The discovery of the mathematical error in determining the RDA of vitamin D and new research into its benefits show us that this is an evolving area of study. Just over 40 percent of the population of the United states is deficient in vitamin D, and new research shows that only about 10 percent of the population has the amount of vitamin D in their blood associated with disease prevention. For these reasons, it’s worth a conversation with your health professional to figure out how much vitamin D you personally need to stay healthy.