Are you getting your Sunshine Vitamin?

Adequate levels of vitamin D are required to maintain calcium homeostasis in the body. The major role of vitamin D in the body is to increase the calcium, magnesium, and phosphate absorption in the intestine. This makes it really essential to get sufficient vitamin D in order to maintain proper bone health. Not only bone health, vitamin D has shown its benefits in improving immunity, neuromuscular functioning and overall quality of life.

Facts tell that nearly 1 billion people worldwide are Vitamin D deficient (<20 ng/ml) or insufficient (20-30 ng/ml) 

So, what is the reason for this vitamin D deficiency when it is readily available for free?

Our hectic work schedules and sedentary lifestyles have enclosed us inside offices and houses where we merely get to see the Sun during the daytime. Moreover, vitamin D synthesis also varies with other factors like geographical location, seasons, skin color etc. For example, people with darker skin absorb less sunlight than people with fair complexion. Vitamin D production is less in winter as compared to summer. This is the reason that people get more flues in winter than in summer.

Vitamin D, or as it is referred to as the Sunshine vitamin, is a fat-soluble vitamin that is synthesized by the skin when exposed to the Sun. The synthesis of vitamin D3 in the skin happens through cholesterol and depends upon the exposure to the Sun (specifically UV rays coming from the Sun). There are two major components of vitamin D: vitamin D3 and vitamin D2. While vitamin D3 is synthesized by animals, vitamin D2 (plant-based) is synthesized by yeast. Fatty fish, cod liver oil, and eggs are some dietary sources of vitamin D3, and mushrooms are good sources of vitamin D2.

Vitamin D is also consumed in supplemental form and through fortifying foods like milk, cheese, orange juice, etc. Vitamin D3 is found to be superior to vitamin D2 in terms of bioavailability in various studies.

The biologically inactive vitamin D synthesized by the skin is converted to a hormone by its enzymatic activation in the liver and kidneys. Vitamin D is converted to 25-hydroxyvitamin D or 25(OH)D in the liver. The serum concentration of 25(OH)D determines our Vitamin D levels. Then this 25(OH)D is converted to 25-dihydroxyvitamin D or 1,25(OH)2D in the kidney and becomes an active hormone. This is the most potent form of vitamin D.

Benefits of good Vitamin D Levels

 
The advantage of having sufficient vitamin D levels is not only limited to good bone health.

Vitamin D supplementation has been shown to improve follicular development and regulation of menstrual cycle in PCOD patients.

Hypovitaminosis D has been found to be common in patients with Fibromyalgia, a condition that is characterized by widespread musculoskeletal pain and other symptoms include fatigue, sleep and mood problems. Therefore, vitamin D supplementation might help in improving the condition. The relationship between sleep disorders and low vitamin D levels is also shown in a study.

Low vitamin D levels are also stated as one of the causes behind sarcopenia (age-related muscle loss) in a study. Another study related Hypovitaminosis D in postmenopausal women with a decrease in muscle mass and strength.

Maintaining good serum 25(OH)D levels is associated with better muscle recovery and hypertrophy. In a study, Vitamin D supplementation also leads to an improvement in quality of life and physical performance in people with osteoarthritis.

There are various other nonmusculoskeletal benefits of vitamin D like regulation of blood pressure, cardiovascular protection, improvement of immunity, suppressing inflammation, etc.[10] and the list seems endless.

But it is correctly said that too much of anything is bad. So is the case with vitamin D. This is because of vitamin D toxicity that results from hypervitaminosis, a condition that occurs when a person takes in too much vitamin D. One can never get enough vitamin D from exposure to sunlight because any amount of vitamin D produced by the skin above the equilibrium concentration is self-destroying.

Vitamin D toxicity usually happens because of excess vitamin D supplementation as it increases the serum concentration of vitamin D. The major consequence of this increased vitamin D concentration in the blood is hypercalcemia, that is, an increase in the serum concentration of calcium above the tolerable upper limit. This might pose a big threat of cardiac arrest by causing arterial calcification. Hypercalcemia is also one of the causes behind the development of kidney stones. Other symptoms include headache, frequent urination, and gastrointestinal disorders like diarrhea, constipation, nausea, etc.

The normal range of vitamin D lies approximately between 30-70 ng/ml. Vitamin D is considered to be potentially toxic above 150 ng/ml.

Now, there is enough evidence to prove that maintaining optimum vitamin D levels is extremely important for every individual. But this doesn’t mean that we should start supplementing it in any dosage without even knowing about the extent of its deficiency in our body.

So, what are you waiting for?

Go out and get your Vitamin D

Author: Akshita Arora, INFS Faculty 

References:
1. Naeem, Z. (2010). Vitamin D deficiency-an ignored epidemic. International journal of health sciences, 4(1), V.
2. Lehmann, U., Hirche, F., Stangl, G. I., Hinz, K., Westphal, S., & Dierkes, J. (2013). Bioavailability of vitamin D2 and D3 in healthy volunteers, a randomized placebo-controlled trial. The Journal of Clinical Endocrinology & Metabolism, 98(11), 4339-4345.
3. Fang, F., Ni, K., Cai, Y., Shang, J., Zhang, X., & Xiong, C. (2017). Effect of vitamin D supplementation on polycystic ovary syndrome: A systematic review and meta-analysis of randomized controlled trials. Complementary therapies in clinical practice, 26, 53-60.
4. Karras, S., Rapti, E., Matsoukas, S., & Kotsa, K. (2016). Vitamin D in Fibromyalgia: A Causative or Confounding Biological Interplay?. Nutrients, 8(6), 343.
5. Gominak, S. C., & Stumpf, W. E. (2012). The world epidemic of sleep disorders is linked to vitamin D deficiency. Medical hypotheses, 79(2), 132-135.
6. McKee, A., Morley, J. E., Matsumoto, A. M., & Vinik, A. (2017). Sarcopenia: an endocrine disorder?. Endocrine Practice, 23(9), 1143-1152.
7. Iolascon, G., Letizia, G. M., Fiore, P., Cisari, C., Benedetti, M. G., Panella, L., … & Gimigliano, F. (2017). Can vitamin D deficiency influence muscle performance in post-menopausal women? A multicenter retrospective study. European journal of physical and rehabilitation medicine.
8. Owens, D. J., Sharples, A. P., Polydorou, I., Alwan, N., Donovan, T., Tang, J., … & Close, G. L. (2015). A systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophy. American Journal of Physiology-Endocrinology and Metabolism, 309(12), E1019-E1031.
9. Manoy, P., Yuktanandana, P., Tanavalee, A., Anomasiri, W., Ngarmukos, S., Tanpowpong, T., & Honsawek, S. (2017). Vitamin D Supplementation Improves Quality of Life and Physical Performance in Osteoarthritis Patients. Nutrients, 9(8), 799.
10. Wimalawansa, S. J. (2016). Non-musculoskeletal benefits of vitamin D. The Journal of steroid biochemistry and molecular biology.