By Marc Sorenson, EdD Sunlight Institute…
Leukemia is a cancer of the bone marrow that prevents the normal manufacture of red blood cells, white blood cells and platelets. It can lead to infection, impaired blood clotting and anemia. The good news is that embracing the sun may have a profoundly protective effect against this deadly disease.
Consider this research by Dr. Timo Tomonen and his colleagues that showed a very close relationship between sun deprivation and acute myeloid leukemia.[1] The researchers stated that “During the light season, the incidence decreased by 58% (95% confidence interval, 16–79%) per 1,000 kJ/m2/d increase of solar radiation.” In Finland, It has also been shown that deficiency of sunlight (and perhaps cold weather) was associated with excessive diagnoses when compared to diagnoses in in the sunlit, warm season. Other research has indicated that sun exposure during mothers’ pregnancies reduced the risk of leukemia and other cancers in their children.[2]
Finally, in a laboratory study using UVA irradiation of leukemia cells, it was found that such radiation caused rapid apoptosis (natural cell death) in the exposed cells.[3] UVA, of course, is the major ultraviolet component of the solar radiation that reaches the earth. UVA also has been shown to cause a marked decline in the proliferation of leukemia cells.[4] Proliferation is the process of rapid growth and multiplication of cancer cells. So it appears that sun exposure has two more positive attributes for preventing cancers: it has the ability to hasten the death of cancer cells and to retard the tendency of cancer cells to grow and multiply out-of-control. It is also interesting to note, although the researchers did not mention it, that UVA exposure does not cause the production of vitamin D, which means that some other mechanism of sun exposure was responsible for the positive results. Vitamin D is a wonderful photoproduct of sun exposure, but positive benefits of other photoproducts are available. When we substitute vitamin D supplements for sun exposure we may make a critical mistake and increase our risk of leukemia and other diseases. Nothing is a match for habitual, safe sun exposure, but sun lamps would be a close second.
The sun is a natural protector against leukemia. What more need we say?
[1] Timo Timonen, Simo Näyhä, Tapani Koskela, Eero Pukkala. Are sun deprivation and influenza epidemics associated with the onset of acute leukemia? Haematologica 2007; 92 (11):1553-56.
[2] Christina Lombardi, Julia E. Heck, Myles Cockburn, and Beate Ritz. Solar UV Radiation and Cancer in Young Children. Cancer Epidemiol Biomarkers Prev 2013;22:1118-1128.
[3] Zhuang S, Kochevar IE. Ultraviolet A radiation induces rapid apoptosis of human leukemia cells by Fas ligand-independent activation of the Fas death pathways. Photochem Photobiol. 2003 Jul;78(1):61-7.
[4] Leszczynski D, Fagerholm S, Leszczynski K. The effects of the broadband UVA radiation on myeloid leukemia cells: the possible role of protein kinase C in mediation of UVA-induced effects. Photochem Photobiol. 1996 Dec;64(6):936-42.
Sunlight and Vitamin D associate with a reduced risk of Leukemia. Or is it really only Sun Exposure?
By Marc Sorenson, EdD Sunlight institute…
Recent research shows that there is a higher risk of leukemia in countries that are at high latitudes in the north or low latitudes in the south. The risk is twice as high at these latitudes as at latitudes closer to the equator.[1] Dr. Cedrick Garland, one of the authors of the research, stated that “these results suggest that much of the burden of leukemia worldwide is due to the epidemic of vitamin D deficiency we are experiencing in winter in populations distant from the equator.” Since persons living far from the equator have much less exposure to the sun’s rays, due to shorter sunlight seasons and more cloudiness, the statement regarding vitamin D deficiency makes sense; UVB from sun exposure, or another source such as tanning lamps, is necessary to stimulate the skin to produce vitamin D—hence the association between latitude and vitamin D.
However, Dr. William B Grant sent me an interesting paper that leads me to believe that some things that seem to make sense may not necessarily be true. The paper showed that there was little difference among vitamin D levels in countries at different latitudes,[2] with levels being close to 20 ng/ml on average. This would lead me to believe that vitamin D was not the factor that caused the reduced risk of leukemia among the countries that received more sunlight.
We are then left to determine the cause of the reduced risk of leukemia in the sunny countries. There are really only two factors that come to mind. First, sunlight, through the eyes, stimulates the production of serotonin/melatonin, which have been associated with protection against cancer in some studies. Sunlight also stimulates the skin to produce nitric oxide and endorphin, which could have an impact. Second, populations residing in areas closer to the equator are likely to have access to year-round fruits and vegetables, which have been shown to associate to a lower risk of cancer. Whatever the reason, this is one more example of better health among people who receive more sunlight. And remember, even those fruits and veggies need sunlight to thrive. So let’s safely embrace the sun.
[1] Cuomo RE, Garland CF, Gorham ED, Mohr SB. Cuomo RE, Garland CF, Gorham ED, Mohr SB. Low Cloud Cover-Adjusted Ultraviolet B Irradiance Is Associated with High Incidence Rates of Leukemia: Study of 172 Countries. PLoS One. 2015 Dec 4;10(12).
[2] Jennifer Hilger, Angelika Friedel, Raphael Herr, Tamara Rausch, Franz Roos, Denys A. Wahl, Dominique D. Pierroz, Peter Weber and Kristina Hoffmann. A systematic review of vitamin D status in populations worldwide. Br J Nutr. 2014 Jan 14;111(1):23-45.