Vitamin D2 and D3, what's the difference?

Before talking about these different forms, let's talk about vitamin D in general.

Vitamin D, sometimes called the “sunshine vitamin,” is produced by our bodies when exposed to sunlight. It is also available in the form of food supplements and is found in certain foods. There are two main forms of vitamin D: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).

The essential function of vitamin D is to maintain the concentrations of phosphorus and calcium in the blood.

These concentrations are then redistributed to:

• - bones ;

• - immune system ;

• - cellular renewal;

• - and the hormonal regulation of the body.

To go further on the functions of Vitamin D , we have an article dedicated to its role. You will see, it is really essential for health.

According to statistics , it is estimated that a high proportion of the French population is deficient in vitamin D. Lack of sunshine, skin color, lack of physical activity would be factors aggravating this phenomenon.

However, a Vitamin D deficiency is not without consequences for the body. On the bone side, prolonged vitamin D deficiency can potentially lead to bone demineralization, muscle weakness and an increased risk of fractures, particularly in the elderly.

Studies have also linked vitamin D deficiency to an increased risk of autoimmune diseases, certain forms of cancer, cardiovascular disorders, depression, cognitive impairment, and infectious diseases.

Just that ! Faced with this non-exhaustive list of potential health problems, we better understand the importance of providing a sufficient quantity of Vitamin D to our body. And, this can be done through exposure to the sun, but also through diet.

Vitamin D found in food is in the form D2 and D3 . Vitamin D2 is ergocalciferol. Vitamin D3 is a molecule called cholecalciferol. Although they have a similar chemical structure, there are some important differences between the two.

Vitamin D2 is found mainly in plant food sources, such as mushrooms (morels, porcini mushrooms and white mushrooms), but also certain green vegetables, avocado, soy and its derivatives such as tofu.

Also note that commercially available drinks enriched with Vitamin D, such as semi-skimmed milk or vegetable drinks, are enriched with Vitamin D2.

The source of supply differs from one type of vitamin to another. However, once in the body, these two molecules have essentially the same function. Both are carried by the blood to the liver where they are transformed into calcifediol , in order to release calcitriol. Calcitriol is the hormone that stimulates the intestinal absorption of calcium and phosphates.

But if these two molecules have similar effects, where is their difference hidden?

Vitamin D2 is therefore mainly of plant origin . However, we note that it is present in very small quantities in the foods that contain it and plant-based foods alone are unfortunately not enough to meet the body's needs for Vitamin D.

Vitamin D2, when ingested through food or supplements, is metabolized by the body. It is converted to an inactive form in the liver, then converted to an active form in the kidneys.

However, it should be noted that vitamin D2 ( ergocalciferol ) is generally considered less effective than vitamin D3 ( cholecalciferol ) when it comes to absorption and utilization by the body. It is converted to active forms at a faster rate and has a shorter lifespan in the body compared to vitamin D3.

This also highlights the importance of regular intake of vitamin D2 to maintain adequate levels in the body.

As you will have understood, once we have compared Vitamin D2 and D3 , we understand why it is more relevant to supplement with Vitamin D3 .

Depending on our lifestyle, our age, our diet and our own particularities, we do not all have the same Vitamin D needs.

• - People living in areas with little sunlight or with olive or dark skin are more likely to develop Vitamin D deficiencies.

• - Elderly people whose metabolism has slowed down over time have a greater need for Vitamin D supplementation, particularly to combat the phenomenon of osteoporosis.

• - Babies are prescribed, almost systematically, Vitamin D supplementation, in order to contribute to their bone growth.

• - People with a specific diet, who consume little or no food of animal origin, can also supplement with Vitamin D.

• - More generally, anyone interested in improving their well-being and stimulating their immune defenses and regulatory functions can take Vitamin D3 as a supplement.

However, attention must be drawn to the dangers of overdose. For the most fragile populations such as babies and the elderly, medical advice with or without blood testing is preferable in order to avoid taking any risks.

Daily requirements for Vitamin D are on average around 15 mg per day, for people not suffering from a deficiency.

Vitamin D is a fat-soluble molecule that is found in significant quantities in fatty fish. This is why, historically, Vitamin D food supplements were in the form of fish oil drops to be diluted.

Today, there are pharmaceutical forms that are easy to ingest, non-greasy and of plant origin (no more sickening fishy smell).

We recommend that you choose a plant-based vitamin, which is suitable for vegetarians and vegans and is easily assimilated.

Although Vitamin D3 is digested in just a few hours, it generally takes 2 to 3 weeks to replenish abnormally low levels in the body.

Of course, supplementing with Vitamin D2 or D3 will never replace a healthy lifestyle: a balanced diet and regular physical activity. However, you now have all the cards in hand to choose the right formula, and no longer lack Vitamin D!