A review published in the journal Nutrients discusses a great deal of research that indicates vitamin D provides protection against internal infection. It regulates both innate (inborn, quick acting, short lived) immunity and acquired (promoted by response to an invasive organism and producing a long-lasting effect) immunity.
The researchers extoll the virtues of vitamin D in increasing the strength of both forms of immunity, and state that vitamin D deficiency is associated with an increased risk for various infections, including HIV, respiratory tract and HCV infection. However, when discussing the efficacy of vitamin D supplementation, they state that “robust data from controlled trials investigating the use of vitamin D as a preventive or therapeutic agent are missing.”
Unfortunately, the researchers indicate that sun exposure would be a good way to obtain vitamin D in correct amounts, but then destroy that argument by stating that …”UVB radiation is also the main cause of human skin cancer, thus it is difficult, if not impossible, to make a general recommendation to expose the skin to the sun for sufficient vitamin D synthesis.”
They are wrong, of course. Common skin cancers cause very few deaths, and melanoma, the deadly cancer, is far less common in people who are regularly exposed to sunlight, compared to those who avoid the sun. Outdoor workers have about half the risk of contracting melanoma as do indoor workers.
Another problem that the researchers have with sun exposure as a vitamin D source is this: People who live at high latitudes do not produce any vitamin D from sun exposure in the winter, because there is no UVB light at that time of year. My response to this is the following: Use UVB lamps or sunbeds. Such a suggestion would probably cause the authors of this researchers to melt down. I can hear them screaming “melanoma!” already. I would then direct them to a 20-year study from Sweden, which showed that women who used sunbeds during that 20 years had a 23% reduction in all-cause death risk compared to those who avoided sunbeds. And, they were not at increased risk of melanoma. Also, the subjects in the study who avoided sun exposure were twice as likely to die of any cause compared to those who had the highest sun exposure.
At almost any place on earth, we now have either the sunshine or UVB lamps that can give us the vitamin D we need and the other photoproducts that protect us from myriad diseases, including various infections. It is a shame that too many fail to take advantage.
 Juliana de Castro Kroner, Andrea Sommer and Mario Fabri. Vitamin D Every Day to Keep the Infection Away? Nutrients 2015, 7, 4170-4188.
 Godar D, Landry, R, Lucas, A. Increased UVA exposures and decreased cutaneous Vitamin D3 levels may be responsible for the increasing incidence of melanoma. Med Hypotheses 2009;72(4):434-43.
 Pelle G. Lindqvist, Elisabeth Epstein, Mona Landin-Olsson, Christian Ingvar, Kari Nielsen, Magnus Stenbeck & Håkan Olsson. Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melanoma in Southern Sweden cohort. J Intern Med. 2014 Jul;276(1):77-86.
Sun exposure and health By Marc Sorenson, EdD, Sunlight Institute…
New research shows that sunlight boosts the effectiveness of T-cells, an integral part of the immune system. T-cells are a type of lymphocyte that recognizes and binds to foreign invaders, thereby rendering them harmless. This is an important new finding, which demonstrates another beneficial effect of sun—one that has no relationship to vitamin D.
The key player in this action is the blue-light spectrum of sunlight that stimulates hydrogen peroxide production. The hydrogen peroxide (HP) causes T-cells to move to the site of infection, and it (HP) is also involved in the killing of noxious bacteria. Dr. Gerard Ahern, one of the primary investigators, stated it in this way: “T cells, whether they are helper or killer, need to move to do their work, which is to get to the site of an infection and orchestrate a response. This study shows that sunlight directly activates key immune cells by increasing their movement.”
Also interesting is the fact that the skin has a large share of the total T-cells in humans, about twice the number circulating in the blood. Think about this magnificent body of ours! It is programmed to immediately respond to any invasions that may occur in the skin, and sun exposure, if we take full advantage of it, immediately accelerates the process. Then, when the t-cells are activated by the blue light, they can move rapidly to other body areas where they can be utilized.
Sun exposure has also been found to have an exceptionally important and positive effect on autoimmune diseases such as lupus, MS, rheumatoid arthritis and others, many of which have been found to associate with low solar radiation and vitamin D. In this case, a different type of T-cell, called a regulatory T-cell, attacks the body’s own tissue, mistaking it for a foreign invader, and causes severe damage. The mechanism of autoimmune disease prevention by sunlight may be the suppression of regulatory T cells, in a manner that impedes the immune system’s attacks on its own tissues. 
Sunlight is one of God’s (or Nature’s) greatest miracles. Be sure to receive your full contingent of wonderful, non-burning sun.
 Thieu X. Phan, Barbara Jaruga, Sandeep C. Pingle, Bidhan C. Bandyopadhyay, Gerard P. Ahern. Intrinsic Photosensitivity Enhances Motility of T Lymphocytes. Scientific Reports, 2016;6:39479
 Schwalfenberg GK. Solar radiation and vitamin D: mitigating environmental factors in autoimmune disease. J Environ Public Health. 2012;2012:619381.
ArtukovićM1, Ikić M, Kustelega J, Artuković IN, Kaliterna DM. Influence of UV radiation on immunological system and occurrence of autoimmune diseases. Coll Antropol. 2010 Apr;34 Suppl 2:175-8.
Marsh-Wakefield F, Byrne SN. Photoimmunology and Multiple Sclerosis. Curr Top Behav Neurosci. 2015;26:117-41.
By Marc Sorenson, EdD Sunlight Institute…
The obesity pandemic, brought about by horrendous eating patterns, lack of exercise and lack of sunlight, has spawned millions of nutritionally bizarre diet programs and numerous strange medical procedures. One of the strangest is gastric bypass surgery, a procedure that cuts calorie absorptions by bypassing part of the stomach and intestinal area that absorbs nutrients. It is another case, similar to open-heart bypass, of a surgery that “bypasses” the real problem: preposterous lifestyle habits.
Any thinking person realizes that a surgery that reduces the calorie absorption also reduces the absorption of calcium and dietary vitamin D. It is a recipe for osteoporosis and hip fractures; these nutrients are essential for optimal bone health. Research by Dr. J Fleischer and colleagues showed that one year after gastric bypass, bone loss at the hip was 8%.[i] Just how important is this finding? One assessment showed that the risk of fracture increases two to three times for every 10 percent drop in bone density,[ii] and another showed that for every loss of 0.12g (.043 oz) per square centimeter (.15 square inch) of bone mass, the risk of a fracture increased by 360% in women and 340% in men.[iii]
Remember that this bone loss was reported only one year after the bypass surgery. If this rate of bone loss continued for several years, it would weaken the skeleton to the point that the slightest movement would cause a fracture. The bypass procedure is a horror, and the bone loss brought on by lack of absorption of calcium and vitamin D is even worse.
In the case of decreased absorption of vitamin D, increased dietary intake of vitamin D may not work to improve bone strength; it is likely that only a very small quantity of the increased intake would be absorbed into the system, meaning that the only way to ensure adequate vitamin D levels in the blood is to expose the skin to sunlight around midday in summer or light from sunlamps in winter. Vast quantities of vitamin D are produced in this manner, and the entire quantity is delivered to the blood, where it can work to increase calcium absorption in both the intestine and the bone. Calcium absorption in the intestine, for example, is 65% higher in people whose vitamin D levels are at the high end of “normal” when compared with those who are at the low end of normal.[iv]
Osteoporosis is not inevitable, and it is to a certain extent reversible. It is a problem caused by sunlight deficiency, excessive protein consumption, smoking, and lack of activity. Now we have added another revolting cause: the doctor’s scalpel. I wonder just how many doctors advise their patients about bone loss, sunlight and vitamin D before performing this atrocity. Interestingly, however, sunlight exposure has a positive influence on gastric bypass. Adverse effects of these surgeries are directly associated with the season and latitude in which they occur.[v] Seasons or latitudes of low sunlight availability were inversely correlated to prolonged stays in the hospital (39.4% longer stay), increased dehiscence (bursting open of a surgically closed wound) and wound infection. This surgery is a horror to begin with, but if it must be done, it appears that one should have it done in a sunny season of the year, or at a sunny latitude.
An ounce of prevention is worth tons of cure in the case of obesity. Good nutrition and ample sunlight exposure is essential to optimal human health.
[i] Fleischer J, Stein EM, Bessler M, Della Badia M, Restuccia N, Olivero-Rivera L, McMahon DJ, Silverberg SJ. The decline in hip bone density after gastric bypass surgery is associated with extent of weight loss. J Clin Endocrinol Metab. 2008 Oct;93(10):3735-40.
[ii] Nguyen T, Sambrook P, Kelly P, Jones G, Lord S, Freund J, Eisman J. Prediction of osteoporotic fractures by postural instability and bone density. BMJ 1993;307:1111-15.
[iii] Nguyen ND, Pongchaiyakul C, Center JR, Eisman JA, Nguyen TV. Identification of high-risk individuals for hip fracture: a 14-year prospective study. J bone Miner Res 2005;20:1921-28.
[iv] Heaney RP, Dowell MS, Hale CA, Bendich A. Calcium Absorption Varies within the Reference Range for Serum 25-Hydroxyvitamin D. J Am Coll Nutr 2003;22:142-46.
[v] Petersen L, Canner J, Cheskin L, Prokopowicz G, Schweitzer M, Magnuson T, Steele, K. Proxy measures of vitamin D status—season and latitude, correlate with adverse outcomes after bariatric surgery in the Nationwide Inpatient Sample, 2001-2010; a retrospective cohort study. 2015;9:88-96.