Before we dig into Vitamin D, let’s take a quick refresher 101 about vitamins in general. Vitamins are micronutrients and we only need them in tiny amounts. Instead of grams, they are measured in smaller units: milligrams (mg) or micrograms (μg).
Types Of Vitamins Needed By Human Body
The body needs 13 different vitamins to support specific functions that promote growth, repair, and the maintenance of life. They can be divided into two main groups: fat-soluble and water-soluble. The difference between these groups determines how each vitamin acts in the body.
Water soluble vitamins C and B-complex are found in a wide variety of foods, though in relatively small amounts. Our body does not have a storage facility for these vitamins, which means you pee out any excess. Saying this reminds me of the vitamin C effervescent tablets or the energy multi-vitamin Berocca that will make your wee bright yellow. Don’t panic — it’s just your body flushing out the excess.
Fat-soluble vitamins A, D, E, K (easy to remember thanks to the mnemonic: All Dogs Eat Kibble) are found in a variety of fatty foods, some of them in pretty high concentrations. Liver, for example, contains a large amount of vitamin A.
Now that the basics are covered, lets do a deep dive into Vitamin D, shall we?
All About Vitamin D
Why do we need it? Well, it helps to regulate the amount of calcium and phosphate in our body, which is vital for strong bones, teeth, and muscle. I know its normal to think of calcium when you say bones and teeth, and you are not entirely wrong. It’s just that no matter how much calcium-sufficient you are, without vitamin D, your body cannot absorb and use that calcium. In that sense, vitamin D becomes even more important for strong bones and teeth.
Over the years, we’ve come to understand that its benefits extend beyond bone health — it is now recognised to have a broad impact on the body as a whole. From improving the immune system (there’s some evidence suggesting that sufficient levels of vitamin D may reduce your risk of getting COVID and dial down the severity of the infection itself) to helping reduce depressive symptoms, it can potentially improve strength and fat loss goals. Vitamin D deficiency is also associated with cardiovascular disease, cancer, inflammatory bowel disease, and autoimmune disorders — all the more reason to ensure we are keeping an eye on vitamin D levels.
Vitamin D Types
Now that you know its importance, you need to know the sources of vitamin D. To understand this better, it’s important to know that Vitamin D comes in three forms.
Calciferol
This occurs naturally in fish oils and egg yolk. In many countries, it is mandatorily added to fat spreads (since it’s a fat-soluble vitamin, adding it to high fat foods makes it easier for the body to absorb it), and voluntarily added to breakfast cereals and some dairy products.
Cholecalciferol
This is created when sunlight hits your skin and ultraviolet rays react with steroid chemicals in body fat just underneath. Sunlight is your main source of vitamin D even if you live in a country known for its grey weather.
Ergocalciferol
This is made in plants that are exposed to sunlight. For example, sunbathe your mushrooms for 30 minutes to get a decent dose of vitamin D. This is a science-backed hack, and now you know why.
Cholecalciferol and ergocalciferol justify vitamin D’s nickname The Sunshine Vitamin. Both of these forms are biologically inactive when consumed in foods until they have been converted into the active form by the liver and the kidneys.
Sources of Vitamin D
Most of the world’s population relies on natural exposure to sunlight to maintain adequate levels of vitamin D. If you’re worried whether excessive sun exposure could lead to vitamin D toxicity, the answer is a resounding no. Prolonged exposure to sunlight degrades the vitamin D precursor in the skin, preventing its conversion to the active form, which basically means you are safe; even lifeguards out all day on sunny beaches are safe from vitamin D toxicity from the sun.
In fact, toxicity through sun exposure should not be a concern even otherwise. Considering the reality of modern lifestyles that are continually moving indoors, vitamin D insufficiency is being reported fairly worldwide. Risk of vitamin D deficiency may be higher amongst the elderly, especially those in care homes or who are house-bound. Those who completely cover skin with clothes as part of religious or cultural requirements are also at risk and may have to consider supplementation.
Prolonged deficiency in children results in rickets and leads to osteomalacia and osteoporosis in adults. It can work both ways — high dietary intake can result in hyper (high) vitaminosis D, which can result in dangerously high levels of calcium entering the blood, but you won’t get it from too much sunbathing.
On the same note, for most people, exposing hands, face, and arms on a clear summer day for 10 to 15 minutes a few times a week should be sufficient to maintain vitamin D nutrition. However, it is standard recommendation to take a supplement during autumn and winter (10µg per day for adults), when you’re not getting enough sunlight. Ideally, get your blood tested and supplement accordingly — 2,500-4,000IU/day. Corrective bolus doses should only be with a doctor’s consent.
Challenges With Vitamin D Nutrition
When it comes to vitamin D, the tricky part is that only a few foods supply significant amounts of it, and it’s notably derived from animal sources: egg yolks, liver, fatty fish, butter, dairy products. Unlike other vitamins that are easy to get through food, it’s not the same for vitamin D. For example, if the reference nutrient intake for vitamin C is 40mg/day, you can easily get that by eating 45g of broccoli, one small green pepper, and one small orange. Now, to get 2,500IU of vitamin D you’d have to drink 6,250ml of whole milk and eat 143 large eggs. This is where supplementation comes to the rescue, especially in the case of a vitamin D deficiency.
If you’re someone who loves using digital apps, there are various comprehensive vitamin D-tracking apps available; Dminder, Sola, and Qsun are a few. Personally, I’ve heard good reviews about Dminder. These apps use your phone’s location data to figure out where you are on the planet, then compute when you can get your vitamin D through sunlight and how much of it you can make in your body. It also gives you a timer.
Takeaway
Vitamin D can be synthesised in the body with the help of sunlight or obtained from animal foods. Considering modern lifestyles and diets, especially the vegan diet, it is ideal to monitor your vitamin D levels and go for supplementation under the guidance of your doctor.
Lovely Ranganath is a licensed clinical dietician in Dubai. Visit @good.food.guru for more information.
This article is for informational purposes only. It is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. To the extent that this article features the advice of physicians or medical practitioners, the views expressed are the views of the cited expert and do not necessarily represent the views of The Gaggler.
