Why is Vitamin D and sunshine important for our health?
A few facts about Vitamin D
Vitamin D is a fat-soluble vitamin that plays an important role in many functions in the body. Other fat-soluble vitamins are A, E and K. They are absorbed into the body and transported the same way as fat. Since these vitamins will be stored in our livers and fat tissue, they are prone to be toxic if they are over consumed, mostly through supplements. Regarding over-the-counter commercial vitamins, we can find them in different forms, the most common ones used are Vitamin D2 and Vitamin D3. One is more potent than the other and the reason taking one over the other can vary depending on a particular condition your doctor might be treating. Vitamin D3 is only found in animal-sourced foods, whereas D2 mainly comes from plant sources and fortified foods.Vitamin D is also produced in the skin under the influence of sunlight (UVB) and it’s maximized at levels of sunlight exposure that do not burn the skin. (1) You do not need an overall tan to get the benefits of natural Vitamin D production. What does Vitamin D do in the body?
One of Vitamin D’s main function is to help absorb calcium in the gut. It also balances calcium and phosphate levels in the blood, which protects us against diseases like rickets, and conditions like osteoporosis and risk of bone fracture (2). In a general way it also regulates immune function, cell growth, and proper muscle function. (3)Even though we have the option to obtain Vitamin D from diet and supplements, it is always best to balance a healthy combination of producing our own with the help of sunlight. What are the benefits and dangers of Sunlight?
When we are exposed to sunlight, we receive mainly 2 types of ultraviolet lights, UVA and UVB. Both types of ultraviolet light have been linked to skin cancer when exposed in excess.UVA light: These types of ultraviolet lights start to appear at sun rise and are barely noticeable. They can bounce off surfaces like water and ice. They are present all year round and does not cause much risk for sunburn. An excess of UVA lights can cause premature aging and wrinkles. UVA exposure has also shown a few benefits when taking the necessary precautions. It can increase the release of nitric oxide which dilates blood vessels, this helps reduce blood pressure.UVB light: UVB lights can cause painful sunburns, and it is mostly harmful between 10:00 am and 4:00 pm in summer and winter. These ultraviolet lights are the ones that play a key role in the production of vitamin D in the skin.What are the symptoms for low Vitamin D?
Fatigue.Bone pain.Muscle weakness, muscle aches, or muscle cramps.Mood changes like depression.
Since vitamin D is a fat-soluble vitamin and it is stored in the body fat and liver, it takes a long time for your body to run out. It would always depend on age, ethnicity and current levels before presenting symptoms of very low Vitamin D levels. Normal Vitamin D levels depends on many factors
Conventional lab ranges are between 20 and 40 ng/mL. Optimal ranges recommend between 35 and 60 ng/mL. Lower than this has shown to start exhibiting symptoms of low Vitamin D.Studies have shown it can vary from different ethnicities, gender, and skin color. (4) Darker skin has more melanin, which is the skin protein that gives us our color and protects from UVB. They may need more sun exposure for Vitamin D synthesis. Also, African descent have higher bone mineral density and may need less Vitamin D levels than Caucasians.Nutritional status may also influence Vitamin D. Vitamins A, K, potassium, and Magnesium help avoid Vitamin D toxicity. (5)What is Vitamin D toxicity?
It is usually caused by excess Vitamin D supplement intake, not diet or sun exposure. You can get sunburned or an overall tan, but it will not cause Vitamin D toxicity.Calcium builds up in the blood, causing symptoms like nausea and vomiting, weakness, and frequent urination. (6) It may progress to bone pain and kidney problems, like calcium stones.Foods that contain Vitamin D
Cod liver oil, 1 tablespoon 1360Swordfish, cooked, 3 ounces 566Salmon (sockeye) cooked, 3 ounces 447Tuna, canned in water, drained, 3 ounces 154Orange juice fortified with vitamin D, 1 cup 137Milk, vitamin-fortified, 1 cup 115-124Yogurt, fortified with 20% of the daily value of vitamin D, 6 ounces 80Sardines, canned in oil, drained, 2 sardines 46Liver, beef, cooked, 3 ounces 42Egg yolk, 1 large 41Cereal, fortified with 10% of the daily value of vitamin D, 1 cup 40Cheese, Swiss, 1 ounceSource: Vitamin D. Health Professionals. Dietary Supplement Fact Sheet. National Institutes of Health. Office of Dietary Supplements. August 7, 2019.
Recommendations
Don’t supplement without the supervision of a qualified practitioner.Vitamin D3 is better than D2.Make sure to always get tested and retested.Optimum level should be between 35 and 60 ng/mL.Your main source of Vitamin D should be through sunlight or UV exposure.Don’t leave out micronutrients when supplementing with Vitamin D. Vitamin A, K, potassium and magnesium are also important to prevent Vitamin D toxicity.Get sunlight or UV exposure as your primary form of vitamin D.Spend about 15 to 30 minutes, or about half the time it takes your skin to turn pink, in direct sunlight.Darker skin may need more time, from 30 to 40 minutes.
References
https://www.ncbi.nlm.nih.gov/books/NBK278935/
https://www.jbc.org/article/S0021-9258(18)85783-0/pdf
https://pubmed.ncbi.nlm.nih.gov/18458986/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821804/
https://pubmed.ncbi.nlm.nih.gov/15579526/
Marcinowska-Suchowierska E, et al. Vitamin D toxicity — A clinical perspective. Frontiers in Endocrinology. 2018; doi:10.3389/fendo.2018.00550.
