This article was written by Marc Barton, who is a 2nd degree Jiu-Jitsu Black Belt under Mauricio Gomes. Marc is the head instructor at Kingston Jiu Jitsu and is also a qualified medical doctor. Marc has also contributed articles for a medical education website.
A few years back, I noticed that I was overwhelmingly tired, especially for a day or two after training. At the time, I also worked 50 hours a week as an Emergency Medicine doctor, and I initially attributed my tiredness to this. As the weeks went by, I decided to get my bloods checked, just to be safe, and was surprised to find out that my Vitamin D levels were very low and that this was, at least partially, responsible for my tiredness.
After doing some further reading, I discovered that I was not alone. Around 70% of people are deficient in this crucial vitamin. Despite having been through 6 years of medical school and having worked as a doctor for almost a decade at that point in time, I was completely unaware of this fact. Amazingly, after talking to many of my colleagues about the same thing at work, many other doctors were unaware of this. Awareness has improved over recent years, though, and this is something tested for more frequently now.
I have taken Vitamin D almost every day since then, in one form or another. Not only did my tiredness resolve, but I have also experienced numerous other benefits.
What is Vitamin D?
Vitamin D is not a single vitamin but instead a group of five fat-soluble vitamins. In humans, Vitamin D3 appears to be the most important of these. Vitamin D is actually considered to be a steroid hormone and plays a vital role in gene expression, controlling the action of over 1,000 genes in the human body. It also controls an enormous variety of vitally important physiological functions. Very few foods contain Vitamin D3, and the primary source is UV radiation from exposure to sunlight. The UV radiation converts a type of cholesterol in the skin into vitamin D3, which is then converted into a more active form, called 25-hydroxyvitamin D, in the liver.
Boost your energy levels
A mild lack of Vitamin D often goes unnoticed but is a well-recognised cause of muscle fatigue and general aches and pains. As I did, many people experience these symptoms and simply attribute them to the general stresses of work, life and training.
One recent study at Newcastle University in the UK demonstrated that good Vitamin D levels are necessary for making muscles work efficiently and can also help to boost energy levels1.
Vitamin D is thought to do this by enhancing the activity of mitochondria within cells. Mitochondria are essentially the ‘power stations’ of our cells and are responsible for generating the energy needed for them to function properly.
The study looked at a group of patients with low Vitamin D levels and symptoms of muscle fatigue. Improving the Vitamin D levels of these patients improved their symptoms of muscle fatigue and their muscle efficiency significantly.
Strengthen your bones
Vitamin D plays a critical role in maintaining healthy bones by promoting calcium absorption from our diet and facilitating healthy bone formation and turnover.
A more severe lack of Vitamin D can cause serious problems relating to bone health, such as osteomalacia. In osteomalacia, the bones become weakened due to reduced density, and sufferers frequently experience bone pain. It can also increase the risk of bone fracture and cause deformities of the bones.
Increase testosterone production and athletic performance
Vitamin D has been used to improve athletic performance for decades. It has long been accepted that athletes perform better in the summer months. A study on Russian sprinters in the 1930s showed that 100 metre sprint times improved in athletes that were exposed to ultraviolet radiation2. Another study in the 1960s demonstrated an improvement in speed, strength and endurance in women treated with a single dose of ultraviolet radiation3.
Several recent studies have shown that men with good Vitamin D levels also tend to have significantly higher testosterone levels. It is not fully understood why Vitamin D causes an increase in testosterone levels, but it is known that there are Vitamin D receptors in the testes, where testosterone is produced. Experiments on mice have shown that those without Vitamin D receptors suffer from low testosterone levels4.
Vitamin D and the ageing athlete
If you, like me, are a little on the older side (I am 47 years old), then you will almost certainly benefit from Vitamin D supplementation. As we age, our body becomes less able to produce Vitamin D from UV light, and a 70-year-old produces four times less vitamin D from sunlight than a 20-year-old.
Vitamin D also plays an important role in offsetting some of the effects of ageing. Each strand of DNA in our bodies is capped by something called a telomere. Telomeres are a little like the cap at the end of a shoelace that protects the shoelace from fraying, but instead of protecting the shoelace, they protect DNA strands from damage. As we get older, our telomeres shorten, and telomere length is considered to be an excellent biological marker of age. Studies have shown that telomere length is longer in people taking Vitamin D supplements. In essence, this means that people with higher Vitamin D levels are biologically younger than their vitamin D deficient counterparts.
The moral of the story is that if you want to be still training and keeping fit in your 50s, 60s or even 70s, it is a good idea to ensure you are getting plenty of Vitamin D!
Other health benefits
Vitamin D deficiency is also associated with a wide variety of diseases, including numerous different types of cancer, immune system dysfunction, depression and dementia. Much research is still needed to look into these associations further, but it is clear that Vitamin D plays an essential role in staying healthy.
Getting enough vitamin D
There are numerous reasons why people tend to be low in Vitamin D levels. Most people, very wisely, monitor their exposure to sunlight and wear sunblock to reduce the risk of skin cancer. Unfortunately, this also prevents the production of Vitamin D in the skin. People with darker skin pigmentation are also less able to make Vitamin D. Their higher melanin levels act as a type of natural sunblock.
The further north you live, the more likely you are to be Vitamin D deficient. The 37th parallel north is effectively the last point where the skin can produce a meaningful amount of Vitamin D from sunlight, so if you are not taking any vitamin D supplementation and live further north than this, you may be Vitamin D deficient. The 37th parallel isn’t as far north as you would think; it runs through Santa Cruz in California!
Being overweight can also negatively impact your Vitamin D levels. It is a fat-soluble vitamin and, as a result, is stored in body fat. If you have a large quantity of body fat, then this means that more Vitamin D will be stored there, and less will be circulating in your bloodstream. In effect, less Vitamin D will be available to your cells.
The best dietary source of Vitamin D is probably oily fish, such as salmon, tuna and mackerel. Vitamin D is also present in certain mushrooms, some fortified cereals, and milk. It can be challenging to obtain enough Vitamin D, even if you eat a lot of these foods and the easiest way to ensure that you are getting enough is by taking a Vitamin D supplement.
What’s the correct dose?
The best way to check if you are deficient in Vitamin D is to talk to your doctor about arranging a blood test. I would particularly recommend this if you are experiencing unexplained tiredness, fatigue or any of the other symptoms I have discussed.
The UK’s National Institute for Clinical Excellence (NICE) currently advises that all adults living in the UK should take a daily supplement containing 400 IUs of Vitamin D throughout the year, including in the winter months5. Higher doses than this are required to treat established vitamin D deficiency. Your doctor will be able to guide you if you are found to be deficient, as I was. The optimum levels seem to be between 40 and 60 ng/ml, and people with these levels appear to be generally healthier, have better energy levels and live longer.
The bottom line: If you are an athlete or training regularly in some form of sport or exercise, you should be seriously thinking about taking a Vitamin D3 supplement or checking your levels.
- Sinha, A., Hollingsworth, K., Ball, S., & Cheetham, T. Improving the vitamin D status of vitamin D deficient adults is associated with improved mitochondrial oxidative function in skeletal muscle. Endocrine Abstracts (2013) 31 OC1.6
- Gorkin, Z., Gorkin, MJ., Teslenko, NE. The effect of ultraviolet irradiation upon training for 100m sprint. Fiziol Zh USSR. (1938) 25:695-701
- Cheatum BA. Effects of a single biodose of ultraviolet radiation upon the speed of college women.Res Q. 1968;39(3):482-485.
- Cannell JJ, Hollis BW, Sorenson MB, Taft TN, Anderson JJ. Athletic performance and vitamin D.Med Sci Sports Exerc. 2009;41(5):1102-1110.