Difference Between Vitamin D & Vitamin D3 in Sources & Functions
Vitamin D vs vitamin D3 conundrum comes up when trying to pick a supplement, or even just understand vitamin D levels. Several studies suggest that vitamin D insufficiency or deficiency is common in India.
Plant-based vitamin D3 supplements are available and may be suitable for individuals following vegetarian or vegan diets. This guide explains how vitamin D and D3 differ, including food sources, dosage, deficiency, and more.
Read on to learn more.
Is Vitamin D the Same as Vitamin D3, and What are Their Sources and Dosage?
Not exactly, as vitamin D is a general term for a group of fat-soluble vitamins, D2 and D3. And of those, vitamin D3, which is also known as cholecalciferol, is one specific type of vitamin D. Both types get converted by the body into a useful active form that helps the body absorb calcium and phosphorus and keeps the bones and muscles working properly.
The difference between vitamin D and D3 is about their forms and where they come from. Vitamin D3 gets made naturally in the skin after exposure to the sun, and it's also in fish like salmon and mackerel, plus egg yolks. Vitamin D2, on the other hand, is often found in mushrooms and fortified foods.
What Are the Sources of Vitamin D and Vitamin D3?
The body can get vitamin D from the sun, food, or supplements, but how much you get from the sun depends on factors like skin type, the time of year, and how much time is spent outdoors.
| Source | Vitamin D form | Examples |
| Sunlight | Vitamin D3 | Produced naturally in the skin after UVB exposure |
| Fatty fish | Mainly D3 | Salmon, mackerel and sardines |
| Egg yolk | D3 | Provides smaller amounts |
| Liver | D3 | Contains vitamin D along with other nutrients |
| UV-exposed mushrooms | Mainly D2 | A plant-based source |
| Fortified foods | D2 or D3 | Milk, plant-based milk, cereals and some other fortified foods |
People on a vegetarian diet can get vitamin D from fortified foods and mushrooms exposed to UV, and there are even some plant-derived D3 supplements available for those who don't eat meat.
How Much Vitamin D and Vitamin D3 Do You Need?
The recommended intake is generally given for vitamin D rather than separately for D2 and D3. According to age, the daily requirement is:
| Age group | Recommended daily intake |
| Infants 0 to 12 months | 400 IU or 10 mcg |
| Children 1 to 18 years | 600 IU or 15 mcg |
| Adults 19 to 70 years | 600 IU or 15 mcg |
| Adults over 70 years | 800 IU or 20 mcg |
The appropriate supplement dose can depend on factors like individual needs, existing vitamin D levels, age and health conditions, because too much D can cause problems as it is fat-soluble and accumulates in the body.
How Are Vitamin D2 and Vitamin D3 Different?
Vitamin D2, or ergocalciferol, is mostly found in plant and fungal sources, and you can get it from mushrooms that have been exposed to UV light or through fortified foods. Vitamin D3, or cholecalciferol, is produced in the skin when you get some sunlight, and you can also find it in foods like fatty fish, egg yolks and liver.
| Feature | Vitamin D2 | Vitamin D3 |
| Scientific name | Ergocalciferol | Cholecalciferol |
| Main sources | Mushrooms, yeasts and fortified foods | Sunlight, fatty fish, egg yolks and fortified foods |
| Sunlight production | Not produced in the body through sunlight | Produced naturally by the skin after UVB exposure |
| Molecular form | Different structure from D3 | Different structure from D2 |
| Supplements | Used in some vitamin D supplements | Commonly used in many vitamin D supplements |
The key difference between vitamin D and D3 really comes down to how the terms are used. Vitamin D is just a broad group, whereas D3 specifically refers to cholecalciferol.
What Happens When You Have a Vitamin D Deficiency?
Vitamin D deficiency can develop if you don't get enough Vitamin D from sunlight or food. At first, you might not even notice it's there, but prolonged low levels can start to affect the bones, muscles and overall well-being. People who spend a lot of time indoors, or have conditions that make it hard for their bodies to absorb nutrients, might be more at risk for deficiency.
Common signs can include:
- Fatigue or low energy
- Muscle pain or weakness
- Bone pain
- Frequent illness or infections
- Mood changes, including feelings of depression
In children, a severe deficiency can lead to rickets, which is bad for the bones. In adults, it can contribute to osteomalacia and weaker bones.
What Health Benefits Does Vitamin D Provide?
Vitamin D supports several of the body's normal functions, especially bone health and calcium absorption. It helps the intestines absorb calcium and phosphorus, which are needed for strong bones and teeth.
Vitamin D also plays a role in keeping the immune system healthy and helps the muscles function properly. Getting enough Vitamin D contributes to the normal functioning of the immune system. Vitamin D is involved in various physiological processes, including those related to nervous system function.
Conclusion
Vitamin D is a broad term that includes not just vitamin D2 and vitamin D3, but all the other forms. Vitamin D3, on the other hand, is the cholecalciferol form that gets produced by the skin after exposure to the sun. Both vitamin D2 and vitamin D3 contribute to calcium absorption and support bone health.
Although D3 is generally a bit more effective at maintaining vitamin D levels. When it comes to choosing a source or supplement, the right one for you is going to depend on individual needs and dietary circumstances.
Reader Information: The information shared is only for general educational purposes. Vitamin D contributes to the maintenance of normal bones, teeth, muscle function, and immune system function. Both vitamin D2 and vitamin D3 can help support vitamin D status when consumed appropriately. However, no vitamin or supplement can prevent, treat, or cure diseases on its own. Individual vitamin D requirements vary, and those concerned about deficiency or supplementation should consult a qualified healthcare professional.
