Vitamin D is an essential nutrient. Our body does not make it on its own and therefore has to get it from outside sources.
The best way we can get vitamin D naturally is from sunlight exposure. Other natural ways we can get it is from food sources such as vegetables, fruits, and animal foods.
We can also obtain this vitamin from supplements in the form of tablets and injections.
Recommended daily intake
How much vitamin D you require per day depends on your age:
• For children up to age 12 months, it is 400 international units (IU) (10 mcg also written as μg)
• For people between the age of one year to 70 years, the daily requirement is 600 IU (15 mcg).
• For pregnant or lactating women, it is 600 IU (15 mcg)
• For people over 70 years, the requirement is 800 IU (20 mcg)
Insufficient intake of vitamin D among the public is a global health concern. Its deficiency is diagnosed in 13% of the world’s population
How to get your vitamin D requirement from the sun?
When you expose yourself to sunlight, your skin makes vitamin D with the help of cholesterol present in the skin cells.
During exposure to sunlight 7-dehydrocholesterol (a form of cholesterol) in the skin absorbs UV B radiation from the sunlight and gets converted to pre-vitamin D3, which consequently changes into vitamin D3.
This is possible only if the sun hits your skin directly. The sun’s UVB rays cannot penetrate through the glass. Therefore, exposure through a window’s glass or the car’s glass pane will not help.
Sunscreens too will not allow the sun’s UVB rays to reach your skin.
The best time to expose your skin to sunlight is midday (12 noon) for your body to manufacture vitamin D most efficiently in less time. At this time, the risk of getting cutaneous malignant melanoma (CMM) is minimal if exposed for the prescribed time as described below.
How much time you need to expose yourself to the skin varies on your skin color and the part of the world you live in.
Dark-skinned people need to spend a longer period in the sun than fair-skinned people to produce the same amount of vitamin D. This is because dark skin contains higher amounts of the pigment melanin, which acts as a type of natural sunscreen.
According to studies, dark-skinned people may need anywhere from 30 minutes longer to get adequate vitamin D, compared to fair-skinned people. This is the main reason why dark-skinned people are at a higher risk of suffering from vitamin D deficiency.
Further, people who live farther from the equator receive less amount of UV radiation because they hardly receive sufficient sunlight during the winter months.
During this period, they should get their vitamin D quota from foods and supplements.
Cod liver oil is a good supplement. One tablespoon (14 grams) of it contains more than three times the recommended daily amount of vitamin D
It is estimated that more than 40% of American adults have a vitamin D deficiency. People should ensure that they get their daily quota of this vitamin through the sun or through food or supplements.
You can also get your sunshine vitamin through a host of foods such as fatty fish, certain vegetables, fruits, and fortified foods.
Food sources of vitamin D
You can get vitamin D from some foods that are natural sources of this vitamin. Among them, the best sources are the flesh of fatty fish and fish liver oils.
Smaller amounts of this vitamin are found in egg yolk, cheese, and beef liver.
Then there are some foods like dairy products, orange juices, and cereals that are fortified with vitamin D.
Here is a list of foods that will give you a good amount of this vitamin.
• Cod liver oil
• Tuna fish
• White mushroom exposed to sunlight
• Orange juice fortified with vitamin D
• Dairy and plant milk fortified with vitamin D
• Beef liver
• Pork chops
• Egg yolk
• Fortified cereals
Foods High in Vitamin D2
• Portobellos exposed to sunlight. It is a type of mushroom native to grasslands in Europe
• Oyster mushrooms
• White button mushrooms
• Fortified soy milk
• Fortified almond milk
• Fortified rice milk
Foods High in Vitamin D3
• Rainbow trout
• Canned sardines
• Whole milk
• Fortified orange juice
• Canned Tune
Vegetarians can get their vitamin D requirement from milk, vegetables, and fruits, while vegans can get their requirement from the following vegetables and fruits:
Vitamin D-rich vegetables include:
• Mushrooms naturally produce vitamin D from sunlight exposure. They are also a good source of fiber and selenium.
• Spinach is one vegetable that contains both vitamin D and calcium. One cup of spinach also gives you about 25% of your daily requirement of vitamin A, calcium, iron, and fiber.
Vitamin D-rich fruits:
Unfortunately, no fruits are high in vitamin D.
• Fortified orange juice. An 8-ounce glass of fortified orange juice gives you about one-third of your body’s daily requirement of calcium. Besides, it is equally effective as a vitamin D supplement in maintaining its status in adults, providing you with 100 IU. It also provides you with vitamin C, folate, potassium, and thiamine.
• Bananas do not contain vitamin D, but they are a good source of magnesium, which is necessary to activate the synthesis of vit D from exposure to sunlight and from dietary sources.
Vitamin D supplements
Very few foods can give you enough vitamin D to reach recommended daily intake. Besides, sunshine can be insufficient in cold climates.
On average, your intake from diet alone does not exceed 300 IU a day. Even drinking an 8-ounce glass of milk will provide you with only 100 IU.
With the help of supplements, you can fill in the deficit and achieve the required 600 IU per day. This will help prevent deficiency and the problems associated with it
Supplements are available in the form of tablets, liquids, injectables, and powder. The doses are best fixed by your physician, who will prescribe them according to your vitamin D levels in the blood.