By Marc Sorenson, EdD, Sunlight Institute
An August 15, 2015 review of research on sunlight, vitamin D and food allergy makes some interesting statements.[1] First, the researchers state that since 2007, most epidemiologic studies have supported low sunlight, as measured by season of birth and latitude, as a risk factor for food allergy. They then note that studies that looked directly at vitamin D status as measured by serum vitamin D levels are not nearly as consistent as the sunlight studies. They state: “Although conflicting, the vitamin D studies suggest a more complicated association than a linear dose response in all individuals, with some studies indicating different associations based on host characteristics (e.g. concomitant eczema, genetic polymorphisms, country of birth).”
Their summary is telling: “Many studies have linked sunlight with the development of food allergy but whether this is directly related to vitamin D status or a myriad of other sunlight-derived, seasonal and/or geographic factors remains uncertain. More studies are needed to investigate the role of sunlight and vitamin D status in food allergy because of their potential for primary prevention and disease modification.”
This is another of those scientific papers that illustrates that whereas sunlight exposure is nearly always protective against the studied disease, there is much more room for argument when vitamin D serum levels are used.
My takeaway? Get sufficient exposure to sunlight on a regular basis. That provides plenty of vitamin D when it is needed, but also provides nitric oxide, endorphins, serotonin, dopamine and other photoproducts that may yet be named. We must cease to equate sunlight exposure only with vitamin D production or we do a disservice to other healthful effects of sunlight.
[1] Rudders SA, Camargo CA Jr. Sunlight, vitamin D and food allergy. Curr Opin Allergy Clin Immunol. 2015 Aug;15(4):350-7.