Vitamin D Sources, Benefits, Dosage, And Side Effects

Vitamin D 101 - Sources, Dosage & Side Effects


Vitamin D is an essential vitamin that comes with ample health benefits and can be produced by the body!

After sun exposure, the human body’s natural response is to produce Vitamin D. You need to intake this vitamin from sunlight and through certain foods. Also, there are different vitamin D supplements that you can take consulting your doctor.

Vitamin D comes with various health benefits such as maintaining bones and teeth health. Also, it protects against various diseases. Scarcity of this vitamin can cause some severe illness in people

What is Vitamin D?

Vitamin D is a group of vitamins mostly found in fatty fishes, liver, and fish oils. This vitamin is very essential to maintain the health of the bones and teeth. It helps to absorb calcium and prevents rickets in kids and osteomalacia in adults. There are two types of vitamin D has been found!

  • Vitamin D2, also known as calciferol.
  • Vitamin D3 or Cholecalciferol.

Sources of Vitamin D

The body produces vitamin D when it gets exposed to the sun. However, you don’t always get enough sun that can enhance the production of vitamin D. Thus you need to consume this vitamin through various foods.


Sunlight is the main source of vitamin D! The ultraviolet ray B within the sunrays is the one that can induce our cells to produce vitamin D. To get Vitamin D from the sunlight you need to stay outside in the sun’s exposure for 10 minutes at least 2-3 times a week in summer and 5-6 times in winter.

2. Salmon Fish

Well, salmon is a great source of vitamin D and omega 3 fatty acids. Normal salmon fish comes with at least 536 IU per 100 g. Whereas, wild salmon comes up to 1200 IU per 100 g. 

3. Sardines and Herrings

Fatty fishes like sardines and herrings are rich with Vitamin D. These fishes come with 215 IU vitamin D/100g.

3. Egg Yolks

Well, egg yolk is filled with vitamin D. An egg yolk comes with 37 IU of vitamin D which will provide almost 5% of your daily recommended value! 

4. Cod Liver Oil

Cod liver oil is a popular supplement that comes with various nutrients. Despite its seriously fishy taste and smell it is the powerhouse of vitamin D. 5 ml of cod liver oil comes with almost 450 IU of Vitamin D or almost 56% of the daily required value!

5. Mushrooms

For vegans, finding vitamin D in foods can be a tedious job. Only mushrooms come with a little vitamin D2. But to get vitamin D3 you need to consume animal proteins. Remember that some of the wild mushrooms can provide you with 2300 IU/100 g of vitamin D2 that is almost thrice the DV (daily value).

6. Cows Milk

Cow milk is a good source of vitamin D. Apart from it, milk also contains calcium, phosphorus, and riboflavin. 

Deficiency of Vitamin D

Well, Vitamin D deficiency is also called hypovitaminosis D. This is a condition where the Vitamin D level in the body decreases severely. Generally, this condition occurs mostly in people who do not have much sunlight exposure. Also, inadequate intake of vitamin D rich foods can cause the deficiency of Vitamin D. 

We can measure Vitamin D deficiency by measuring the quantity concentration of 25-hydroxyvitamin D in the blood. 

ConditionVitamin D level (ng/mL)
Insufficient 20-29
DeficiencyLess than 20
Severe Deficiency Less than 12

Vitamin D deficiency can cause some severe problems.

  • Osteomalacia: This Vitamin D deficiency condition occurs exclusively in adults. In osteomalacia, the bone gets thinner and the proximal muscles get weakened.
  • Ricket: This Vitamin D deficiency condition occurs exclusively in kids. In ricket, the bones get deformed and the growth stops. The mineral density of the bones decreases (a condition called osteoporosis).
  • The risk of fractures increases with sudden muscle aches and weakness.
  • Fasciculations or muscle twitching.
  • Loss of tooth or periodontitis.

The quantity of vitamin D is measured in the international unit (IU) or micrograms (mcg). 1 mcg of vitamin D = 40 IU.

The recommended daily dosages of vitamin D are –

Infants (1-12 months): 10 mcg (400 IU)

Children (1-18 years): 15 mcg (600 IU)

Adults (Up to 70 years): 15 mcg ( 600 IU)

Adults (Over 70 years): 20 mcg (800 IU)

Pregnant and Lactating Women: 15 mcg (600 IU)

Well, to get the vitamin D from sun exposure, you need to be out in the sunlight for 5-10 minutes at least 3 times per week. However, in winter you need to be out at least 5-6 times a week.

Benefits of Vitamin D

Vitamin D or the ‘sunshine vitamin’ can be absorbed by the skin through the sunlight. This group of 2 vitamins comes with ample benefits and very essential for a healthy body. Vitamin D promotes calcium absorption, thus helps to grow bones and teeth. Also, vitamin D comes with some other benefits as well. It helps your mental wellbeing and also supports the immune system!

Let’s check the various health benefits that Vitamin D provides!

1. Strengthens the Bones

Vitamin D promotes the absorption of calcium, thus it helps to strengthen the bones and teeth. The calcium which is necessary to maintain bones and teeth growth gets absorbed by the gut with the help of vitamin D. This vitamin induces the normal mineralization of the bones. Thus vitamin D prevents diseases like osteoporosis (a disease where the bones become brittle).

2. Promotes Muscle Health

Along with strengthening the bones, vitamin D promotes healthy muscles. Deficiency of vitamin D can weaken the muscles and thus it increases the risk of brittle bones and osteosarcoma. In the case of older adults, deficiency of vitamin D can lead to substantial disability and even death. 

3. Supports Teeth

As we have said earlier, vitamin D helps the gut to absorb calcium. Thus it plays a critical role in supporting the health of your teeth. Vitamin D is essential for a proper enamel coating to your teeth. Thus a vitamin D supplement can support your oral health. 

4.  Prevents Diabetes

Though more studies need to be done on this matter, Vitamin D helps to prevent diabetes. It helps to increase the production of insulin hormone in the pancreas. Thus vitamin D also helps in metabolism. 

5. Treats Hypertension

Vitamin D can also improve your cardiovascular health and treat the problem of hypertension. The deficiency of vitamin D can cause a rise in blood pressure thus the target organs get damaged.

6. Helps To Lose Weight

Severe obesity can damage bone and muscle health. Vitamin D helps to lose weight by increasing metabolism.

7. Battles Depression

Low vitamin D levels or deficiency of vitamin D can cause anxiety and depression. This vitamin D is significantly related to the production of endorphins that can make you happy and fight off depression.

8. Supports Immune System

Vitamin D helps to build immunity and fights off inflammation. Some studies show that vitamin D supplements can help people with respiratory infections. In this time of the Covid 19 pandemic, it is essential to incorporate Vitamin D supplements in your diet.

Side Effects of Excessive Intake of Vitamin D

Well, according to the healthcare personalities the daily recommended dosage of Vitamin D is 4000 IU daily. If you consume an excessive amount of more than 10,000 IU of vitamin D a day then it can cause some problems, such as over-calcification of bones, hardening of bones, problems in kidney, heart, and lungs! Symptoms of over intake of Vitamin D are-

  • Nausea
  • Headache
  • Appetite loss
  • Dry mouth
  • Vomiting
  • Constipation 
  • Diarrhea

Also Read: Best Calcium Supplements in India

Bottom Line

To have proper calcium density and maintain bone health vitamin D is an essential element. Apart from sunlight, or natural food sources you can get vitamin D from supplements as well. Just contact a doctor before incorporating a Vitamin D supplement in your diet. We have written everything that you need to know about vitamin D in this article!

Did you like this article? Did we miss anything? Should we write something more? Do tell us your valuable feedback in the comments section below!

Photo of Sraya Samaddar
Sraya is Health & Nutrition Content Writer at Zotezo since 2019. Her master's in Zoology has helped her to pull out critical scientific aspects of health and nutrition into user-friendly and easy to understand language for the readers. You can find her articles on medium and wordpress!

Leave a Reply