Being Thankful for Good Nutrition
We’re officially less than 24 hours away from Thanksgiving and people are clearly excited by the thought of going into tryptophan-induced turkey comas*. Another nutrient found in turkey that is involved in tryptophan metabolism is vitamin B6. And did you know that, according to the CDC, vitamin B6 deficiency is the most common nutrient deficiency in the United States?
Vitamin B6 plays essential roles in the body such as supporting protein metabolism, maintaining the function of the nervous system, and supporting the production of healthy red blood cells. The best dietary sources of vitamin B6 include Thanksgiving staples like turkey and potatoes, but also fortified breakfast cereals. The Institute of Medicine has set a Recommended Dietary Allowance (RDA) of 1.3 mg/day for adult men and women.
Despite the much greater fanfare about the suboptimal intakes of nutrients like vitamin D and vitamin E, data put forth by the CDC actually indicates that vitamin B6 deficiency is the most prevalent deficiency observed in the United States – affecting 10.5% of males and females 1 year of age and older, or just over 30 million Americans. To put that in perspective, that’s bigger than entire population of the state of Texas.
Even if you just consider naturally occurring sources of vitamin B6, dietary inadequacy (that is, consuming less than the Estimated Average Requirement) is on the lower end, affecting 21.7% of Americans. Including fortified foods and dietary supplements significantly reduces this prevalence, of course. However, with >90% of Americans consuming inadequate amounts of vitamin D from food yet the prevalence of vitamin D deficiency is slightly lower than that of vitamin B6, that demonstrates how many gaps in our knowledge of the biology of these vitamins still exists even 100 years after their discovery.
I think this story teaches us two lessons. First, that despite the common belief among consumers and the media that nutrient deficiencies are rare in the modern day United States, vitamin B6 deficiency alone affects 30 million Americans. That doesn’t even include the deficiencies of any other nutrients, which similarly affect millions of Americans. Second, despite all the scientific advances we have made in the 102 years since the discovery of vitamins, there are still so many unknowns as it relates to the biology of these nutrients. In a world of decreased research funding, we need to remember that if deficiencies remain so common then understanding the biology of these vitamins is a public health priority.
This Thanksgiving, while we should first be thankful for our time with family and friends, we can also use this feasting opportunity to recognize the importance that nutrition plays in our lives, and how improving our understanding of nutrition continues to be a public health priority.
*Author’s note: As a nutrition scientist, I feel compelled to mention that the story of tryptophan inducing sleepiness is thought to be more of a myth than reality. Experts believe the sleepiness we experience after Thanksgiving is more related to the size of the meal and the carbohydrate content more so than the tryptophan - sorry mashed potato and stuffing lovers! Happy Thanksgiving!
US Centers for Disease Control and Prevention. Second National Report on Biochemical Indicators of Diet and Nutrition in the US Population. Atlanta (GA): CDC; 2012. Available from http://www.cdc.gov/nutritionreport
Fulgoni VL 3rd, Keast DR, Bailey RL, Dwyer J. Foods, fortificants, and supplements: where do Americans get their nutrients? J Nutr 2011; 141: 1847-1854.