Vitamin D, also known as the “sunshine vitamin,” has become well known for its role in bone health, immunity, and mood. However, its role in other aspects of health is still emerging. Not worried about bone health you say? Keep reading as we research and answer five questions about other health benefits of Vitamin D you might not have been aware of.
Does Vitamin D Deficiency Cause Hair Loss?
Hair loss, known as alopecia, can occur for a multitude of reasons, including genetics, stress, medication, hormone alternations, and possibly, Vitamin D deficiency. But how?
There are three phases of the hair cycle: anagen, catagen, and telogen. The anagen phase is the growth phase where the follicular stem cells proliferate and differentiate into a mature hair follicle. The catagen phase is the transition phase when stimulation of the lower part of the hair follicle ends, and follicle growth stops. Finally, the telogen phase is considered the “rest” stage, and this lasts until another antigen phase is initiated again.
In vitro studies have found that Vitamin D receptors (VDR) are present on the follicular cells in varying degrees throughout the hair cycle, with numbers increasing during the late anagen and catagen phases to promote the progression of the hair cycle. The presence of VDRs on follicular cells suggests that Vitamin D does play a role in hair growth, development, and maintenance.
A growing body of evidence has also demonstrated a link between Vitamin D deficiency and hair loss. For example, a 2017 review found that low Vitamin D levels have been linked to excess hair shedding and alopecia, while a 2016 study found that among younger people who experienced hair loss, there was also a greater Vitamin D deficiency.
Conclusion: While causation has not been determined, the low levels of serum Vitamin D in patients with alopecia and the presence of VDRs on follicular cells suggest that Vitamin D does plays an active role in hair health. If hair loss is a concern, checking your Vitamin D status — ensuring you’re reaching optimal levels may be helpful.
Can Vitamin D Boost Energy?
Fatigue is a vague complaint but a common one nowadays. While there are many reasons a person could be tired, Vitamin D deficiency is one of them. Several case studies have demonstrated that low Vitamin D levels can cause pervasive fatigue, excessive daytime sleepiness and negatively impact quality of life. Fortunately, they also showed that supplementation with Vitamin D to achieve normal blood levels improved or entirely resolved these symptoms.
A study published in 2014 revealed that 77% of patients who presented with fatigue symptoms were Vitamin D deficient, and normalization of Vitamin D levels significantly improved fatigue symptoms. Another double-blind placebo-controlled trial published in 2016 found that Vitamin D treatment significantly improved fatigue in otherwise healthy people with Vitamin D deficiency compared with the placebo group.
While the mechanism behind these energy improvements is not fully known, several suggestions have been made about how this works. First, dopamine and serotonin imbalance have been found to influence mood and fatigue. Vitamin D is a key regulator of brain serotonin synthesis and has also been found to regulate dopaminergic neurons. These changes may lead to improved mood and physical function with adequate Vitamin D levels.
Secondly, correcting Vitamin D deficiency has been found to improve symptoms of muscle myopathy and fatigue. This occurs due to an enhancement of mitochondrial maximal oxidative phosphorylation. Put more simply, the parts of the cell that create energy could create it more efficiently. Again, these improvements were only seen in those who initially presented with Vitamin D deficiency.
Conclusion: If Vitamin D deficient, increasing Vitamin D intake via food or supplementation to normalize blood Vitamin D levels can improve feelings of fatigue and tiredness.
Can Vitamin D Help Sleep?
Although inconsistent, Vitamin D deficiency has been correlated with poorer sleep quality, sleep duration and efficiency, sleep maintenance, and lower scores on the Epworth Sleepiness Scale. A meta-analysis that discussed the relationship between Vitamin D deficiency and sleep disorders found that serum 25(OH)D levels were inversely associated with sleep. Furthermore, having levels below 20 ng/mL increased the risk of poor sleep quality by nearly 60%.
Although the mechanism is unknown, several possibilities have been suggested. VDRs are wildly distributed throughout the brain and can be found in all areas known to execute essential roles in sleep regulation. Vitamin D deficiency is also associated with bone demineralization and chronic nonspecific pain, which may also affect sleep.
Some epidemiologic evidence has verified that Vitamin D can improve sleep in those who are Vitamin D deficient. For example, research done to evaluate the effects of Vitamin D supplementation in outpatient veterans suffering from chronic pain and low serum 25(OH)D found that it can effectively improve their pain levels, sleep, and various aspects of quality of life. Another double-blind clinical trial showed that eight weeks of supplementation facilitated sleep duration and quality in people with sleep disorders.
Conclusion: If Vitamin D deficient, increasing Vitamin D intake via food or supplementation to normalize blood Vitamin D levels can improve sleep quality, duration, and quality of life.
Can Vitamin D Help You Lose Weight?
It turns out that obesity is a risk factor for Vitamin D deficiency, and percentage body fat content is inversely related to serum Vitamin D levels. Due to the dilution of Vitamin D in the larger fat mass of obese individuals, Vitamin D levels may need to be adjusted for body size in order to reach healthy serum levels. This means that even though obese and lean individuals might have similar total amounts of Vitamin D, in the obese person the Vitamin D is distributed into a larger volume making serum concentrations lower.
Ok, so clearly, there is a connection between obesity and Vitamin D deficiency, but can adequate intake support weight loss? Some evidence suggests so, although results are inconsistent. One study compared 12 months of Vitamin D supplementation with placebo on weight loss in women and found that those who reached normal serum levels experienced greater weight loss than those who did not. Another double-blind clinical trial on overweight and obese participants found that the group supplemented with Vitamin D experienced a significant decrease in weight, waist circumference, and body mass index (BMI) compared to the control group. Lastly, a systemic review and meta-analysis of 11 randomized controlled trials concluded that Vitamin D supplementation does have a desirable effect on weight loss by reducing BMI and waist circumference in overweight and obese individuals.
There are several hypotheses as to why this association occurs. First, Vitamin D plays a direct role in suppressing the parathyroid hormone (PTH). PTH promotes calcium influx into adipocytes (fat cells), enhancing lipogenesis (formation of fat) and leading to fat accumulation. Another hypothesis is that the active form of Vitamin D actually inhibits adipogenesis (creation of new fat cells) and suppresses the storage of fat cells, overall reducing fat accumulation. Lastly, a few other outcomes of Vitamin D should be considered when discussing weight loss. Low mood and lack of sleep have also been associated with both weight gain low levels of Vitamin D.
Conclusion: While the adequate dosages and duration of supplementation are unclear, maintaining a healthy Vitamin D status may support health factors that influence weight, support weight loss, and attenuate fat accumulation over time.
Does Vitamin D Boost Fertility?
Infertility is a multi-factorial problem that affects approximately 15% of the population. The etiology of infertility is attributed to several factors, some of which are out of our control. However, providing our bodies with proper and helpful nutrients is one area we can take charge of, and it may make all the difference.
Vitamins play an essential role in reproductive health, and VDRs are expressed throughout both male and female reproductive tracts. Animal studies have shown that Vitamin D deficiency reduces fertility success and supplementation restores it. Meanwhile, observational studies and fertility research in human populations express similar outcomes.
Although there is insufficient data to accurately evaluate the direct effects of Vitamin D on female fertility, there is evidence that Vitamin D plays a role in female reproduction and may influence pregnancy outcomes in cases of in vitro fertilization (IVF), polycystic ovary syndrome (PCOS), and endometriosis. Even in clinically healthy women, there appears to be an association between Vitamin D levels and progesterone and estradiol, two hormones that influence reproduction in a complex and dynamic dance.
There is a bit more information on male fertility, which accounts for 20-50% of infertility cases. Idiopathic male infertility, which indicates that the individual has an unexplained reduction of semen quality, is present in half of those numbers. Research has found that Vitamin D is significantly lower in patients with idiopathic infertility than in healthy fertile men and patients with secondary infertility. Moreover, significant improvements in progressive and total sperm motility were observed after Vitamin D treatment for two months.
Conclusion: Although results are inconsistent, there appears to be a positive association between total Vitamin D intake and the chance of conceiving a clinical pregnancy or live birth. To date, there are no specific guidelines regarding Vitamin D supplementation for individuals affected by infertility, but knowing your Vitamin D status and working with your medical provider to ensure Vitamin D levels are adequate may support your efforts.