Vitamin D, a hormone...

Vitamin D deficiency is one of the most common nutrient deficiencies in the world. Up to 42% of the adult population in the US has low vitamin D levels, which can cause health problems (1), (2), (3)

Vitamin D is an extremely important vitamin that has powerful effects on

several systems throughout your body. Unlike other vitamins, D functions like a hormone, and every single cell in your body has a receptor for it. Your body makes it from cholesterol when your skin is exposed to sunlight. By the way...; Testosterone is also made from cholesterol. One of vitamin D's most important roles is keeping your immune system strong so you're able to fight off viruses and bacteria that cause illness. Case studies have shown that very low D levels can cause fatigue and can have a severe negative effect on quality of life (4).

It`s a fat-soluble vitamin that functions like a steroid hormone in the body. You can get it from exposure to the sun. And some foods contain significant amounts; fatty fish like salmon , as well as fish liver oils. Egg yolks also contain small quantities.

Get some Sunshine in your life !

Summer sun exposure is the best way to get enough vitamin D. However, the amount of sunlight needed varies. Even though the sun may be shining, it is not necessarily strong enough to produce enough vitamin D. During wintertime in certain region no vitamin D is produced at all (5)

 D Supplementation is effective

A systematic review of  scientific literature was performed to investigate the effects of vitamin D supplementation on muscle strength in athletes. This showed a number of high-quality trials which lasted between 4 weeks to 6 months.

It was shown that vitamin D has a positive impact on muscle strength. In 2 studies, strength outcome measures were significantly improved after supplementation. In the other 2 studies  there were trends for improved muscle strength (6).

In another research the effect of D supplementation on Testosterone levels in men was compared to baseline values and significant increases in total Testosterone levels and free Testosterone levels was observed (7)

Complementary research showed that it is plausible that vitamin  D levels above the normal reference range might increase skeletal muscle function, decrease recovery time from training, increase both  force and power production, and increase testosterone production, each of which could potentiate athletic performance. Therefore, maintaining higher levels of vitamin D could prove beneficial for athletic performance (8).

The aim of another particular review was to assess the studies that evaluated the relationship between vitamin D and fertility in women and men as well as in animals. In men, vitamin D was positively associated with semen quality and androgen status. Moreover, vitamin D treatment increased testosterone levels (9).

In an Asian study, Vitamin D was associated with total testosterone and sex hormone-binding globulin. With a group of 382 men, their fasting blood was collected for serum testosterone. And levels were analyzed using multiple regression analysis. Vitamin D was significantly and positively associated with total testosterone. These values displayed an increasing trend from subjects with vitamin D deficiency to those with optimal level (10)

More D = More T