Common beliefs assert that testosterone makes men more masculine, and Vitamin D strengthens bones. However, recent research indicates that these two famous biomarkers don’t just have one purpose in the body and may, in fact, impact each other’s levels. There are key reasons to optimize both vitamin D and testosterone, and research has shown a fascinating relationship between the two.
Some Background on Vitamin D
Vitamin D is an important fat-soluble nutrient naturally found in a limited number of foods, such as mushrooms and fatty fish (i.e., sardines, salmon, and mackerel). Some other foods contain vitamin D, such as milk. The body can produce high amounts of vitamin D when skin is exposed to the sun. This is why it’s sometimes referred to as the “sunshine vitamin.” However, too much sun exposure may increase the risk of skin cancer. Vitamin D is often prescribed in supplement form by dietitians and doctors, as it can be difficult to obtain through diet alone, and prolonged sun exposure carries health risks.
The liver converts vitamin D to 25-hydroxyvitamin D before it is used in the body. Blood levels of this compound are the best way to measure someone’s Vitamin D levels. The kidneys produce 1,25-dihydroxy vitamin D, which is the active form of vitamin D. Calcitriol is the form of vitamin D that is responsible for regulating calcium metabolism in the body.
Testosterone and Vitamin D Concentrations in Military Personnel Following Traumatic Brain Injury
TBI can have long-term consequences, including physical disabilities and behavioral, cognitive, and psychological defects. This can prevent military personnel from performing to their fullest potential and have a negative impact on their long-term health. Neuroendocrine dysfunction, characterized by hormone imbalances, is common in cases of TBI and is directly related to the hypothalamus and pituitary gland. Disruptions to the endocrine axes are caused by an inadequate supply of hypothalamic-releasing hormones or by the pituitary gland’s inability to produce hormones. Either of these can result in pituitary dysfunction. Low testosterone concentrations are a common symptom of hypopituitarism with gonadotropin deficiency, a neuroendocrine disorder often seen in people who have suffered a traumatic brain injury.
Immediately after a TBI, up to 80% of people have low testosterone levels, but in most cases, the levels return to normal after 3 months. There is evidence that suggests vitamin D deficiency may be associated with TBI sequelae. However, the role of vitamin D in neuroendocrine disorders is not well understood. The role that vitamin D plays in protecting the brain following a traumatic brain injury (TBI) has been explored in several studies, most of which have used animal models. There is no clear evidence to suggest that TBI either causes low vitamin D levels or that low vitamin D levels make TBI worse.
A number of studies have found that people who have suffered a traumatic brain injury have lower levels of testosterone or vitamin D. Clinical hypopituitarism has been observed in all TBI severities. Hypogonadism, a deficiency of the hormone that controls sexual development and function, is the most common pituitary abnormality. Growth hormone deficiency is also common, but testosterone concentrations vary depending on the severity of the injury.
There have been four studies conducted on testosterone levels in military personnel who have suffered from varying degrees of blast-related traumatic brain injuries, but no significant differences were found between the severities of the injury. These studies found that testosterone levels were low following an injury, and one study found that there was a significant decrease in testosterone levels three years after an injury compared to levels in people who had not been injured. One researcher found that people with more severe cases of TBI tend to have lower levels of vitamin D.
Some studies have found that there is a positive relationship between the amount of testosterone in a man’s body and the amount of vitamin D. This may be because the cells in the testes that produce testosterone also have receptors and enzymes that process vitamin D. Pilz et al. found that vitamin D supplementation in deficient males significantly increased testosterone compared to a placebo group. The data indicate that vitamin D may help to regulate testosterone production.
There is no research that has looked at both testosterone and vitamin D levels in people who have had a TBI, even though it is possible that having low levels of these hormones could make post-concussion symptoms worse. There is also little research on the use of testosterone replacement therapy for people who have suffered a traumatic brain injury. The point of this study was to see if there was a difference in testosterone and vitamin D levels between people who had a history of TBI and those who didn’t, as well as to find out how many people who had a history of TBI were getting testosterone replacement therapy. Identifying the number of military personnel who experience TBI-related hypogonadism and vitamin D deficiency helps clinicians know who may need therapeutic treatments to improve long-term recovery.
A recent study has found that military personnel who have suffered from a traumatic brain injury have lower concentrations of testosterone and vitamin D. This is the first study to investigate both of these hormones in military personnel with TBI. Analyzed rates of pituitary dysfunction and vitamin D deficiency in military personnel with and without a history of TBI and found no difference between the two groups.
In our dataset, it was found that active-duty men who had suffered a TBI had testosterone levels that were, on average, lower than those of active-duty men who had not suffered a TBI. However, the difference between the two groups was small and would not be considered clinically significant. There was no significant connection between TBI and vitamin D deficiency. The dataset we looked at showed that a lot of service members, both active and retired, have a deficiency in vitamin D, regardless of whether they have a TBI. There was a weak positive correlation between testosterone and vitamin D concentrations in men. Maybe the findings are due to the low number of TBIs that have been reported by medical professionals.
More conservative military treatment facilities have stopped prescribing testosterone replacement therapy. Too little sleep, being tired all the time, and too much physical stress from things like deployment and training can cause testosterone levels to go down in military personnel. The study found that active-duty men with TBI had lower testosterone concentrations than active-duty men without injury. This may explain why veterans with TBI did not have this result. The production of testosterone may be reduced after suffering a traumatic brain injury due to the presence of inflammatory proteins that suppress the function of the Leydig cells in the testes, resulting in a dysfunction of the hypothalamic-pituitary-gonadal axis. The veterans with a TBI had higher testosterone levels than the veterans without a TBI. However, there were several veteran men without a TBI who had very low testosterone levels (<10 ng/dl). According to the NHANES data, there is a drastic age-related decline in testosterone concentration, with a concentration at age 80 being 30% less than at age 20. Although these veterans showed low levels of testosterone, they were not given testosterone replacement therapy, possibly because they did not have any symptoms relating to androgen deficiency. The Endocrine Society’s recommendations say that this finding would be normal.
A study done on humans found that patients who were deficient in vitamin D had worse three-month Glasgow Outcome Scores than patients who had enough vitamin D. A different study discovered that vitamin D supplementation would improve long-term performance and cognitive abilities in patients who were vitamin D deficient and had mild to moderate traumatic brain injuries. The dataset as a whole indicates that there is a high incidence of vitamin D deficiency. Military personnel are at high risk for suffering a TBI, and the tactical gear they wear limits their exposure to adequate sunlight. For these reasons, it is recommended that their vitamin D status be assessed biannually. It would be beneficial to supplement people who have insufficiency and deficiency of vitamin D according to Endocrine Society Guidelines to maintain optimal vitamin D levels as a preventive measure to improve resiliency post-TBI. Since the gonadotroph function may improve on its own within 3 to 12 months after an injury, the hormone levels should be checked at 3 to 6 months after the TBI occurred and then again at 12 months. Testosterone replacement therapy has been shown to increase lean body mass and strength while reversing cachexia in diseased populations, and it can easily reverse symptoms of neuroendocrine dysfunction once they have been identified.
Vitamin D in the Body
Vitamin D is vital for keeping bones healthy and helping the body to absorb minerals such as calcium and magnesium. However, recent research has found that this biomarker also regulates cell growth and the immune system while maintaining neuromuscular and cardiovascular health. Maintaining optimal levels of vitamin D is crucial for athletes as it stimulates muscle growth, increases power, and cuts unnecessary body fat.
Although vitamin D has many benefits, deficiency is still common. It was estimated in 2011 that 8% of Americans were deficient in vitamin D (serum 25(OH)D <30 nmol/L) and that 25% were at risk for inadequacy (serum 25(OH)D 30-49 nmol/L).
Other potential problems associated with too much vitamin D include kidney problems and nausea. Laura Ingalls, for example, has reported joint pain as a result of taking in too much vitamin D. InsideTracker users are not doing well in terms of vitamin D levels, with only 14% having optimal levels.
Testosterone: Critical for Performance and Health
Testosterone is a steroid hormone that is produced by both men and women. It is considered to be crucial for many bodily functions. The hormone testosterone is responsible for the changes that occur in boys during puberty. Testosterone levels increase during puberty and stimulate the production of sperm and the formation of secondary sexual characteristics such as body hair and a deeper voice. Both men and women have increased bone strength, muscle mass and strength, and libido when testosterone is present. Testosterone is important for both male and female athletes. It helps the body recover from injuries and produces red blood cells.
Testosterone is found in the bloodstream in two forms. Testosterone can be attached to proteins such as albumin or sex hormone-binding globulin, which transport it throughout the body. This form of testosterone is known as “bound testosterone.” However, it does not affect body cells as it typically would. Almost all testosterone is bound to one of these proteins.
The other 2-3% of the hormone circulates in the blood and can therefore have an impact on the body. This portion is known as “free testosterone” (FT). Although it is small compared to the other muscles, the FT muscle is essential for keeping the body’s performance and health at its best. Total testosterone is the combination of bound and free testosterone. InsideTracker’s Ultimate Panel measures four crucial biomarkers of health and fitness – SHBG, free testosterone, albumin, and total testosterone.
Vitamin D and Testosterone: Not Just for Men
There is a direct correlation between vitamin D and testosterone levels in women, according to scientists. In a recent cross-sectional study of women, researchers observed a positive, significant correlation between serum 25(OH)D concentrations and total testosterone levels.18 This suggests that increasing levels of vitamin D may restore healthy levels of testosterone, though more research investigating the mechanism through which this happens needs to be done.
Does Supplementation with Vitamin D Boost Testosterone?
The researchers found that the group of men given a daily high-dose vitamin D supplement saw a significant increase in their total testosterone, while the group given a placebo showed hardly any change. The findings suggest that men who are deficient in vitamin D and take a vitamin D supplement may improve testosterone levels.
Analysis: Can vitamin D treat low testosterone?
Let’s recap the evidence for the relationship between Vitamin D and testosterone:
- Several studies in men show an independent association between Vitamin D intake and testosterone.
- A cross-sectional study observed a correlation between Vitamin D and testosterone in women.
- One study shows an increase in levels of testosterone after providing high-dose, long-term vitamin D supplements to Vitamin D-deficient men.
- Another study observed no increase in testosterone after providing Vitamin D-deficient men with short-term Vitamin D supplementation.
Provided with this inconsistent evidence, what do we recommend? We encourage you to conduct your own experiment. First, monitor your Vitamin D and testosterone levels using InsideTracker and follow the science-based recommendations to optimize them. If you are low in vitamin D and testosterone, you may want to try taking a vitamin D supplement on a regular basis to see if it increases your testosterone levels. Vitamin D supplements will not improve your testosterone levels if you are already getting enough vitamin D, and this could even lead to too much vitamin D in your body.
Putting it into perspective
It is crucial that you monitor levels of vitamin D and testosterone regularly to ensure that they are optimized. Some research indicates that there may be a relationship between sufficient amounts of vitamin D and testosterone levels. Supplementation will only help you boost testosterone if you are already deficient in both testosterone and vitamin D.