Using data from the government-sponsored research program National Health and Nutrition Examination Survey (NHANES), a group of researchers compiled data on seven vitamins from over 15,000 people in the US. They determined that 31% of the American population is at risk for at least one vitamin deficiency; 23% of Americans are at risk for deficiency in at least two vitamins, and 6% are at risk for three or more vitamin deficiencies.
The data came from a variety of sources: dietary recall, reported supplement use, and lab results – some information less quantifiable than others. Researchers concluded that the most common vitamin deficiency in the United States is vitamin B6, of which a staggering 20% of Americans are deficient. However, scientists concede that biomarkers of nutrient status are affected by inflammation, suggesting that deficiency rates may be even higher. In addition, nutrient status did not correlate with dietary intake (according to their data), which is not surprising given that determining specific deficiencies via dietary intake is notoriously difficult to quantify. Dietary recall is rarely accurate; even if intake is measured with precision (this is difficult to do and therefore unlikely), absorption of said nutrients is an entirely different problem (itself nearly impossible to assess). A review of the available literature supports the view that a one-size-fits-all approach to micronutrient requirements is both outdated and inaccurate.
The investigators stated that “sub-clinical deficiency symptoms for many vitamins and minerals are non-specific, and may include fatigue, irritability, aches and pains, decreased immune function, and heart palpitations,” all of which further complicate the quantification of micronutrient deficiency. Functional measurement of intracellular micronutrient status may gain attention as studies like this are published.