Do you know the main differences between the two forms of vitamin D, D2 and D3? Let’s find out together what could be the best choice for integration.
Vitamin D is a fat-soluble vitamin that plays an essential role in our body, especially for the absorption of calcium, bone protection, muscle health and the correct functioning of the heart. Recently, studies have shown that vitamin D also has beneficial effects for the immune system and could have a protective role in several pathologies. However, there are two main forms of vitamin D – D2 and D3 – and while both are useful, they may have different effects on the body.
Vitamin D: a family of molecules fundamental for health
The vitamin D family includes five different molecules, but those that are most important for the human organism are the vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D2 is naturally present in some plant sources such as mushrooms and algae, while vitamin D3 is synthesized from cholesterol in the skin following exposure to the sun’s UVB rays and is found in animal products, such as fatty fish, egg yolk ‘fortified egg and milk.
What is the difference between vitamin D2 and D3
Both vitamin D2 and D3 remain inactive until the body converts them to their active form, known as calcitriol. This conversion process occurs in two stages: first in the liver, where vitamin D is transformed into calcidioland subsequently into the kidneys, where it becomes calcitriol, the form usable by most body tissues.
Research indicates that the two forms of vitamin D may affect the body in different ways. According to a study published in Frontiers in Immunologythe Vitamin D3 appears to have a more pronounced effect on the immune system compared to D2. The study found that vitamin D3 stimulates genes involved in immune defense more, suggesting that it may be more effective in supporting the immune system than D2. Another research, published on Nutrientsconfirmed that vitamin D3 more consistently increases vitamin D levels in the blood, thus being more effective in raising and maintaining stable vitamin D levels.
Why is it important to supplement vitamin D?
Today, vitamin D deficiency is extremely widespread, affecting approximately one billion people worldwide. This condition is linked to multiple factors, such as advanced age, dark skin (which reduces the synthesis of vitamin D), and lack of sun exposure due to climatic factors or time spent indoors. Vitamin D deficiency is linked to significant health issues, including increased risk of osteoporosis, cardiovascular disease, and, according to some research, an increased risk of respiratory infections and even some forms of cancer.
A 2022 study conducted by Brigham and Women’s Hospital highlighted that vitamin D can reduce the risk of autoimmune diseases by 22%, such as rheumatoid arthritis and psoriasis. In this VITAL study, participants taking 2,000 IU of vitamin D per day had a reduced risk of developing these diseases compared to those taking a placebo
Vitamin D and prevention: sun exposure and supplementation
For those who live in areas with low solar radiation, supplementation is often recommended. Even brief sun exposure – 15-30 minutes for people with light skin, longer for those with dark skin – can help maintain adequate levels of vitamin D. Supplements, especially in the D3 form, are a safe option and effective for those who cannot get enough vitamin D through diet and sun.
A recent study found that a Sufficient exposure to vitamin D could reduce the risk of death from Covid-19 by 64% . Another study published on Journal of Clinical Endocrinology & Metabolism indicates that adequate levels of vitamin D can help reduce the incidence of colorectal cancer.
Which vitamin D supplements to choose?
For those who decide to take supplements, the vitamin D3 it is considered the most effective form, as the human body uses it more efficiently. However, it is always advisable to consult a doctor to determine the correct dosage and type of supplementation best suited to your needs, especially if you have pre-existing health conditions.
The importance of vitamin D extends beyond bone health, becoming increasingly recognized as an essential vitamin for prevention and support of overall health.
Sources: Frontiers in Immunology / Nutrients/ National Institutes of Health (NIH)
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