FACTS Men’s Health Series
The Effects of Vitamin D3 Supplementation in Infertile Men
By Abby Koski
Editor’s Note: At FACTS, we recognize that fertility is a vital sign of health and studies show men’s long-term health and well-being is tied to healthy fertility. Therefore, as a continuation of our series during National Men’s Health Month, we are featuring research that evaluated the impact of Vitamin D3 on sperm parameters in infertile men. Abby Koski, a medical student who participated in the FACTS elective, summarized a 2021 study published in Reproductive Biology and Endocrinology by Maghsoumi-Norouzabad L, Javid AZ, et al.
Introduction
Often in discussing infertility, it is the female’s contribution to infertility that is the focus. Failure to acknowledge and investigate male factor infertility is a disservice to the couple, and to the general health and wellness of the man. Infertility is due to male related factors about 40% to 50% of the time [1].Oxidative damage is a potential contributor to male factor infertility. Meanwhile, vitamin D is an antioxidant that protects against oxidative damage, and deficiency in vitamin D has been found to contribute to male infertility in animal models and small-scale studies [1]. Worldwide vitamin D deficiency is the most common vitamin deficiency; thus, it has a potentially significant impact on infertility globally [1] The study, The effects of Vitamin D3 supplementation on Spermatogram and endocrine factors in asthenozoospermia infertile men: a randomized, triple blind, placebo-controlled clinical trial, assessed the impact of vitamin D3 supplementation on sperm quality in a population of men with infertility related to sperm motility.
Methodology
This study was a randomized, triple-blind, controlled trial of 86 infertile men with vitamin D3 levels of less than 30 ng/mL and asthenozoospermia (reduced sperm motility) seen at an infertility clinic in Iran [1]. Inclusion criteria for the study participants included: inability to conceive after one year of unprotected intercourse with a fertile female; no medical history contributing to infertility; no drug or alcohol abuse; no environmental exposure to toxins impacting fertility; a BMI less than 30, and no medical therapy within three months of the trial [1]. The participants were randomly allocated to two groups: one that received 4000 IU of vitamin D3 daily for three months and another that received an identical placebo for the same amount of time [1].
Baseline labs and semen samples were collected from the participants before and after the intervention. Lab workup included semen volume, sperm count, motility, percent normal sperm morphology, serum 25(OH)VD3, testosterone, estradiol, follicle stimulating hormone, luteinizing hormone, sex hormone binding globulin, prolactin, parathyroid hormone, osteocalcin, calcium, and phosphorus. The intervention was in place for three months after which the bloodwork and semen analysis was repeated [1].
Results
When comparing the two study groups, there was no statistically significant difference in the study participants’ including age, marriage duration, infertility duration, education, race, weight, physical activity, and sun exposure [1]. The group that received vitamin D3 supplementation was found to have an increase in serum 25(OH)vitamin D3, a decrease in PTH, and a significant increase in serum and seminal calcium concentration [1]. Overall, total and progressive sperm motility both increased after intervention in the group receiving vitamin D3, while semen volume, sperm count and morphology were not significantly impacted.
Discussion
The study found that supplementation with vitamin D3 for three months improved the sperm motility in men struggling with infertility. After the intervention period, the average vitamin D3 level of the participants receiving supplementation was 32 ng/mL compared to 18 ng/mL in the placebo group [1]. Vitamin D3 levels between 20 and 30 are considered insufficient, and levels below 20 are classified as a deficiency.
“Supplementation with vitamin D3 for three months improved the sperm motility in men struggling with infertility.”
As previously stated, vitamin D deficiency is common worldwide. Interestingly, deficiency is common even in areas of the world receiving sun year-round. One study in Saudi Arabia found that over 50% of subjects had low vitamin D3 levels [2]. Given the prevalence of vitamin D3 deficiency globally and its influence on sperm quality, it is crucial for health care providers to be aware.
One proposed mechanism to improve sperm quality is with vitamin D supplementation due to its antioxidant properties. Several studies have shown that use of a variety of antioxidants can improve quality of semen by reducing oxidative stress [3] which is thought to damage cell membranes, impair sperm mobility, cause DNA damage in sperm, and impair the ability of sperm to fertilize an oocyte [3].
Another potential mechanism to improve sperm motility is the increase in serum and seminal calcium in tandem with vitamin D supplementation [1]. Calcium has a role in numerous cell-signaling pathways that influence sperm motility, capitation, cell volume and osmolarity, and numerous other cellular reactions [1]. All of these cellular processes affect the overall sperm health and fertility.
This study had several limitations. The sample size was small and the participants were all patients at an infertility clinic in Iran, which makes the results less generalizable. Additionally, the participants were all free of other health conditions impacting fertility, thus further limiting the ability to generalize the study findings to patients who suffer from chronic health conditions.
Male infertility is associated with poor health outcomes and decreased life expectancy [3]. Though the mechanism behind this is not completely clear, studies have found associations between low vitamin D levels and chronic health conditions, such as cardiovascular disease, metabolic syndrome, and type 2 diabetes [3].
“Male infertility is associated with poor health outcomes and decreased life expectancy.”
Despite the limitations of the study, it did discover statistically significant results that have implications for clinical practice. Supplementation with vitamin D is a low-cost, low-risk intervention associated with improved health and fertility outcomes in men. Larger scale, more generalizable studies need to be conducted to further clarify the impact of vitamin D on fertility and live birth rates.
References
[1] Maghsoumi-Norouzabad L, Javid AZ, et al. The effects of Vitamin D3 supplementation on Spermatogram and endocrine factors in asthenozoospermia infertile men: a randomized, triple blind, pacebo-controlled clinical trial. Reproductive Biology and Endocrinology. 2021; 19 (102).
[2] Al-Rowaily MA. Vitamin D Supplementation: Optimal Dose, Real Benefits, and Potential Side Effects (A Review). Bulletin of High Institute of Public Health. 2009; 39 (4).
[3] Katz DJ, Teloken P, Shoshany O. Male infertility-The other side of the equation. Australian College of General Practitioners. 2017; 47 (9) 641-646
[4] Karavolos S, Panagiotopoulou N, et al. An update on the management of male infertility. The Obsteterician & Gynecologist. 2020.
ABOUT THE AUTHOR
Abby Koski
Abby Koski is a fourth-year medical student at Des Moines University. She is pursuing a residency in pediatrics. She has a passion for women’s health and ensuring that adolescents have the knowledge to make informed decisions about their lives and bodies.
