KANSAS CITY — The surprising conclusion from a sweeping scientific evaluation of vitamin D supplementation is a compelling case for mandatory fortification of enriched grains appears to be building. The study was published in June in The Journal of Clinical Endocrinology & Metabolism.
Josh Sosland, editor of Milling & Baking News. Source: Sosland Publishing Co.
This takeaway is surprising because it certainly was not the conclusion of the researchers, who pored over numerous studies to identify which population subsets should not take vitamin D supplements as well as which groups should. And indeed, they recommended against supplementation for the largest group they examined — adults between the ages 18 and 74. In 2020, 235 million Americans, or 71% of the US population total, fell within the age group.
The conclusion also is surprising because the literature review uncovered no evidence supplementation lowers the risk of a number of key diseases, including cancer, heart attacks, stroke, adult influenza and tuberculosis. For years, scientists have explored whether vitamin D deficiency elevates the risk of numerous diseases.
Looking at the study, “Vitamin D for the Prevention of Disease: An Endocrine Society Clinical Practice Guideline,” from a different vantage point generates a far more positive view for fortification. The number of adult Americans excluded from the supplementation recommendation turns out to be much smaller than 235 million because the researchers suggested two adult sub-groups, pregnant women and prediabetics, need supplementation. About 5 million women are pregnant each year, and approximately 90 million Americans are prediabetic. The researchers also recommended children as well as adults over 75, 73 million and 23 million, respectively, receive supplementation. In total, the study found about 190 million Americans, more than 58% of the population, would benefit from supplementation. Meanwhile, the researchers described the risks of vitamin D supplementation as “trivial.”
To understand how the findings support the idea of universal vitamin D fortification, consider as a point of comparison the public health benefits that have accrued due to mandatory folic acid fortification of enriched grains since 1998. The program has been credited with reducing neural tube birth defects by roughly 25%.
In absolute numbers, folic acid fortification has lowered the number of neural tube birth defects annually in the United States by about 1,000, a reduction described by the National Institutes of Health as one of the great public health achievements of its time.
How would vitamin D compare? The researchers found bringing vitamin D intake to adequate levels could reduce the number of prediabetics who become diabetic by 15%. About 1.2 million prediabetics “graduate” to diabetes each year. The 15% reduction could mean 180,000 fewer cases of diabetes annually. Importantly, the researchers said 80% of prediabetics do not know they are prediabetic. Universal fortification with vitamin D would be far more effective at reaching prediabetics than promoting supplementation.
For children, the researchers pointed to evidence vitamin D provides many benefits, including promoting bone health and reducing the risk of respiratory infection, the most common infectious cause of death for small children. For pregnant women, vitamin D appears to slightly reduce the risk of stillborn births, neonatal mortality, pre-term birth, low birthweight and gestational diabetes. While the researchers were not able to quantify the reduced risk of stillborn babies and to children that would result from vitamin D supplementation, 21,000 babies in the United States are stillborn annually and respiratory illness causes hundreds of deaths among children (almost a million globally) . If vitamin D supplementation reduced these numbers by even a few percentage points, the lives of hundreds, perhaps thousands, of babies and children would be saved each year. Again, the study described as trivial the risks from vitamin D supplementation.
While discussing fortification passingly, the researchers did not examine the relative merits of increasing vitamin D intake through supplements versus fortification. Still, when the study is viewed through this filter, it becomes clear universal fortification of enriched grains with vitamin D deserves a fresh and serious look.
