Marc Sorenson, EdD
IBD consists of two primary diseases, ulcerative colitis (UC) and Crohn’s disease (CD). UC is a chronic inflammatory condition characterized by relapsing and remitting episodes of inflammation limited to the mucosal layer of the colon.  Crohn’s however, can involve any part of the gastrointestinal tract from the mouth to the anus but most commonly affects the small intestine or the colon or both. The most common symptoms of IBD are abdominal pain, weight loss, fever, rectal bleeding, skin and eye irritations and diarrhea.
In a 12-year year investigation of hundreds of thousands of IBD patients, measuring both UC and CD, hospitalizations and prolonged hospitalizations for both diseases were higher among those who had low sunlight exposure compared to those with very high sunlight exposure. The same relationship was shown between sunlight, bowel surgeries and deaths; more surgeries were needed for those patients who experienced the lowest sunlight exposure compared to those who had the highest sunlight exposure, and more deaths occurred among those with low exposure.
An interesting side note to this investigation was that a large number of non-IBD patients were also analyzed for sunlight exposure amounts. As with the IBD patients, low sunlight exposure was associated with prolonged hospitalizations and more deaths when compared with high exposure.
French research has shown that high residential sun exposure is associated with a low risk of CD, but not UC. Women who were in the highest third of sunlight exposure had only half the risk of CD compared to those in the lowest third, but UC was increased 21% by high sunlight exposure. This study was the only one I have seen—other than studies on non-melanoma skin cancer—that indicated a positive association of sunlight exposure with disease risk. None of the other studies mentioned here showed that relationship with UC. Another interesting side note to this research was that vitamin D intake was not associated with decreased risk of CD.
It has also been shown that in both Europe and the US, there is a north-south gradient for IBD, meaning that the risk of developing IBD is significantly lower for the southern latitudes (where sunlight exposure is greater). And finally, another French study has demonstrated that low sunlight exposure is associated with an increased incidence of Crohn’s disease.
So for a healthy gut, sunlight exposure plays a vital role.
 Mark A Peppercorn, Adam S Cheifetz, Paul Rutgeerts, Shilpa Grover. Definition, epidemiology, and risk factors in inflammatory bowel disease. Uptodate http://www.uptodate.com/contents/definition-epidemiology-and-risk-factors-in-inflammatory-bowel-disease. Accessed July 1, 2015.
 Web MD http://www.webmd.com/ibd-crohns-disease/crohns-disease/inflammatory-bowel-syndrome. Accessed July 1, 2015.
 Limketkai BN1, Bayless TM, Brant SR, Hutfless SM. Lower regional and temporal ultraviolet exposure is associated with increased rates and severity of inflammatory bowel disease hospitalization. Aliment Pharmacol Ther. 2014 Sep;40(5):508-17.
 Jantchou P1, Clavel-Chapelon F, Racine A, Kvaskoff M, Carbonnel F, Boutron-Ruault MC. High residential sun exposure is associated with a low risk of incident Crohn’s disease in the prospective E3N cohort. Inflamm Bowel Dis. 2014 Jan;20(1):75-81.
 Schultz M1, Butt AG. Is the north to south gradient in inflammatory bowel disease a global phenomenon? Expert Rev Gastroenterol Hepatol. 2012 Aug;6(4):445-7.
 Nerich V1, Jantchou P, Boutron-Ruault MC, Monnet E, Weill A, Vanbockstael V, Auleley GR, Balaire C, Dubost P, Rican S, Allemand H, Carbonnel F. Low exposure to sunlight is a risk factor for Crohn’s disease. Aliment Pharmacol Ther. 2011 Apr;33(8):940-5.
Marc Sorenson, EdD, Sunlight Institute
The Daily Mail, from the UK, recently posted an article regarding sunlight and fertility that should catch some interest.
Infertility is a problem that causes some couples to seek help from in vitro fertilization (IVF). New research shows that sunlight exposure for a month prior to the procedure increase the odds of success by 35%. Dr. Frank Vandekerckhove, who reported the research, looked at the IVF results of about 6,000 women and compared the dates of their treatment with weather conditions. The more sunshine, the greater likelihood of becoming pregnant. Dr. Vandekerckhove said that sunshine a month before conception probably helped a woman’s eggs to mature. He also mentioned that there is no reason to think that a burst of sunshine won’t also help women trying to get pregnant naturally.
There is nothing really new about the effects of sunlight on fertility, and this work by Vandekerckhove is not the first to establish the link of sunlight to IVF. Much has also been studied regarding natural, non- laboratory fertility. Low vitamin D, which is primarily a result of low sunlight exposure, is closely related to the ability to conceive in both women and men. Couples spend thousands of dollars on fertility clinics and IVF when perhaps all they need is some time in the sun.
In an article posted on Emax health, entitled Sex in the Sun May Increase Your Fertility it is pointed out that approximately 15% of couples who want to conceive are plagued by problems of fertility. Drs. Elisabeth Lerchbaum and Barbara Obermayer-Pietsch, in 2012, conducted a review of articles on vitamin D and fertility and came to these conclusions: “VDR knockout mice [mice whose vitamin D doesn’t work due to inability to link to receptors at the cellular level] have significant gonadal insufficiency, decreased sperm count and motility, and histological abnormalities of testis, ovary and uterus.” They also point out that vitamin D is involved in female reproduction—including IVF outcome, so it is a bit surprising that the article in the Daily Mail gave the impression that the research by Vandekerckhove was a totally new concept.
The review also stated that in men, higher vitamin D levels are positively associated with semen quality and androgen (male hormone) status, and that vitamin D treatment might increase testosterone levels.
One thing that is missing in these excellent studies is any discussion of the production of nitric oxide (NO) by sunlight exposure. NO is a potent vasodilator that is essential for proper erection in men, meaning it relaxes the blood vessels, allowing the blood to pass more easily through the vessels. Without it erectile dysfunction (ED) occurs. Viagra, Cialis and other such ED drugs work through a Nitric Oxide pathway and act by keeping NO in circulation for a longer period. But they don’t work in about one-third of the cases, and the effect diminishes over time, not to mention the side effects such as headaches, body aches and pains, gastrointestinal distress, dizziness, vision changes, flushing, congestion and runny nose. Since sunlight exposure increases NO, it is probably a better choice. For those who wish to produce a pregnancy, ED could be a devastating problem, and sunlight may be the answer.
Sunlight exposure has so many positive properties that we may never know them all. Use non-burning sunlight safely. Here’s to a successful pregnancy and a sunny family life!
Vandekerckhove, F. Presentation at the European Society of Human Reproduction and Embryology (ESHRE) annual conference in Lisbon, Portugal, from June 14 to 17.
 Lerchbaum E1, Obermayer-Pietsch B. Vitamin D and fertility: a systematic review. Eur J Endocrinol. 2012 May;166(5):765-7.
 Burnett AL. The role of nitric oxide in erectile dysfunction: implications for medical therapy. J Clin Hypertens (Greenwich). 2006 Dec;8(12 Suppl 4):53-62.