The sunshine vitamin may be good for male as well as female fertility according to a decade or so of research. Vitamin D - which is made in the skin when exposed to strong sunlight - may be one of the most under-rated male fertility vitamins - and it's a vitamin which is commonly deficient in men who are trying to conceive.

In a 2006 study (1) vitamin D receptors were first discovered in the head, nucleus and mid-pieces of human sperm pin-pointing how vitamin D’s may play an integral role in sperm health.

In the light of multiple studies confirming that most of us are vitamin D deficient - and that vitamin D receptors are replete in sperm - restoring optimal vitamin D levels could be important for male-factor infertility.

An Australian study (2) led by Dr. Ann Clark assessed the vitamin D levels of 794 men visiting an infertility clinic in Sydney, and found that even in this sun-drenched country over one third of the men were deficient. The men with vitamin D deficiency were also found to be more likely to be deficient in folic acid - another important nutrient for male fertility - and they were more likely to have higher levels of homocysteine.

Dietary sources of vitamin D are limited and predominantly include oily fish, eggs - if the chickens were outside - butter, hard cheeses and milk. Exposure to summer sunshine - without sunscreen - is the most reliable source, but many of us simply don't get enough..

A sub-group containing 123 vitamin D deficient men from the Australian study were followed for 3 months as they took a vitamin D containing multivitamin supplement, antioxidants and lost weight. Follow-up tests showed improvements in sperm morphology and a 75% drop in sperm DNA fragmentation. In a quarter of these men (31) pregnancy was successful.

Over 40 pregnancies were achieved in total - over half were conceived naturally or using low-tech reproductive medicine such as IUI, and miscarriage rates were unusually low (6%) pointing to a possible role for vitamin D in miscarriage prevention.

Dr Ann Clark, who led the study made the following remarks:

"Vitamin D and folate deficiency are known to be associated with infertility in women, but the outcomes of the screening among men in our study group came as a complete surprise. Men in the study group who agreed to make lifestyle changes and take dietary supplements had surprisingly good fertility outcomes."

A study (3) seeking to clarify to role of vitamin D in human sperm confirmed the presence of vitamin D receptors (VDR) in sperm and came to the following conclusion:

"Our data extended the role of 1,25(OH)2D3 beyond its conventional physiological actions, paving the way for novel therapeutic opportunities in the treatment of the male reproduction disorders."

A further Italian study (4) found vitamin D status may be an important determinant of sperm capacitation which is necessary for sperm to penetrate an egg. Vitamin D may also influence how well sperm freezes and may have an...

"...important role in sperm survival and the acquisition of fertilizing ability."

A 2017 study (5) on over a thousand infertile men found vitamin D deficiency may also be linked with semen quality and levels of sex steroids. Higher levels of vitamin D (above 75 nmol/l) were linked with
better sperm motility, higher numbers of motile sperm after a timed test and better, more fertile levels of male sex hormones (testosterone/estradiol).

If you have sub-fertile sperm, it may be wise to have your vitamin D levels checked with a 25-hydroxy-vitamin D test - also called a 25 OHD test - to see if you need a vitamin D boost.

The vitamin D reference range is very wide and it is thought to be ideal to have your levels sitting somewhere within mid-range.

Vitamin D3 supplements are thought to be very safe if used with care, and although the RDA for many years has been 400 IU a day recent studies have given pregnant women 4,000 IU a day with no side-effects of safety concerns.

I regularly post extra updates on new fertility research, tips and strategies, along with research on environmental toxins and fertility on my Facebook page

https://www.facebook.com/smartfertilitystrategies

This article is purely for informational and educational purposes only and is NOT intended to substitute for medical diagnosis or treatment for which you should consult a physician.

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2. Fertility Society of Australia conference in Brisbane - paper presented by D. Clark - research was part of a doctoral study by University of Sydney student Laura Thomson. News.com.au Oct 19 2008
1. Urology 2006 Dec;68(6):1345-9. Vitamin D receptor found in human sperm. Corbett ST, Hill O, Nangia AK.
3. Reprod Biol Endocrinol 2009 Nov 30;7:140. Human male gamete endocrinology: 1alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates different aspects of 4. human sperm biology and metabolism. Aquila S. et al.
(4) J Anat 2008 Nov;213(5):555-64. Human sperm anatomy: ultrastructural localization of 1alpha,25-dihydroxyvitamin D receptor and its possible role in the human male gamete. Aquila S et al.
(5) Hum Reprod. 2016 Aug;31(8):1875-85. doi: 10.1093/humrep/dew152. Epub 2016 Jun 19.
Vitamin D deficiency and low ionized calcium are linked with semen quality and sex steroid levels in infertile men. Blomberg Jensen M1, Gerner Lawaetz J2, Andersson AM2, Petersen JH2, Nordkap L2, Bang AK2, Ekbom P2, Joensen UN2, Prætorius L3, Lundstrøm P4, Boujida VH5, Lanske B6, Juul A2, Jørgensen N2.