by Craig Weatherby
Back in 2007, we reported on a finding that about 55 percent of adolescents in the northeastern U.S. – and most likely kids in other northerly states – were vitamin D deficient.
For more on that, see “Vitamin D Deters Diabetes and More: Northern Teens Deficient.”
Now, according to two new studies, millions of U.S. children have extremely low vitamin D levels, and that lack is tied to heart and diabetes risks.
In fact, some observers say that a lack of vitamin D in their childhoods may partly explain the epidemic of these diseases among adults in North America.
Study #1—National survey finds vitamin D shortfall common in kids and teens
And another 61 percent—50.8 million kids—have vitamin D levels that are higher but still deemed insufficient (Kumar J et al 2009).
According to the analysis of a nationally representative sample of more than 6,000 children, the lowest vitamin D levels were found among girls, adolescents, and people with darker skin, with 59 percent of African American teenage girls deemed vitamin D deficient.
Study #2—Federal agency sees D-related heart and diabetes risks for kids
Compared with teens with higher vitamin D levels, his team found that adolescents with the lowest D levels had more than double the risk of having high blood pressure and blood sugar and about four times the risk for the metabolic syndrome.
As his team concluded, “Low serum [blood] vitamin D [levels] in US adolescents is strongly associated with hypertension, hyperglycemia, and metabolic syndrome, independent of adiposity” (Reis JP et al. 2009).
By “adiposity” the Reis group meant excess body fat, which could not account for the risks seen in kids low in vitamin D.
Vitamin D experts speak out
In reaction to these new confirmations of the risks they've long highlighted, leading vitamin D researchers urged parents to ask doctors to test their children's vitamin D levels, increase kids' intake of vitamin D from foods and supplements, and make sure children spend enough time outdoors to let the youngster's bodies make vitamin D (20 minutes a day in strong sunlight; more for dark-skinned kids).
Vitamin D researchers universally point to ample evidence that the U.S. recommended daily allowances for vitamin D (400 IU) is much too low to maintain healthy levels among kids in northern latitudes, and especially in darker-skinned teens.
They suggest fortifying foods other than milk, since many children do not enough to meet their calcium or vitamin D needs.
Drinking 10 glasses of milk a day—the amount required to meet current intake advice from experts in the field (1000 IU per day)—would be a nutritionally knuckle-headed approach anyway.
Supplements and fatty fish are both much higher in vitamin D than milk, and fish such as wild sockeye salmon (687 IU per 3.5 oz serving) offer the benefits of very high protein and omega-3 content as well.
The Washington Post's coverage contained a cogent quote from vitamin D expert Michael F. Holick, M.D., of the Boston University School of Medicine: “The sun has been demonized for years and as a result, people have avoided any direct exposure to sunlight. I think that's the wrong message” (Stein R 2009).
- Botella-Carretero JI, Alvarez-Blasco F, Villafruela JJ, Balsa JA, Vazquez C, Escobar-Morreale HF. Vitamin D deficiency is associated with the metabolic syndrome in morbid obesity. Clin Nutr. 2007 Jul 9; [Epub ahead of print]
- Kumar J et al. Prevalence and Associations of 25-Hydroxyvitamin D Deficiency in US Children: NHANES 2001–2004. Pediatrics. Published online August 3, 2009. doi:10.1542/peds.2009-0051
- Pittas AG, Lau J, Hu FB, Dawson-Hughes B. The role of vitamin D and calcium in type 2 diabetes. A systematic review and meta-analysis. J Clin Endocrinol Metab. 2007 Jun;92(6):2017-29. Epub 2007 Mar 27. Review.
- Reis JP et al. Vitamin D Status and Cardiometabolic Risk Factors in the United States Adolescent Population. Pediatrics. Published online August 3, 2009. doi:10.1542/peds.2009-0213.
- Stein R. Millions of Children In U.S. Found to Be Lacking Vitamin D: Links to Diabetes, Heart Disease Examined. Washington Post. Monday, August 3, 2009. Accessed at http://www.washingtonpost.com/wp-dyn/content/article/2009/08/02/AR2009080202114.html
- Weng FL, Shults J, Leonard MB, Stallings VA, Zemel BS. Risk factors for low serum 25-hydroxyvitamin D concentrations in otherwise healthy children and adolescents. Am J Clin Nutr. 2007 Jul;86(1):150-8.