Vitamin D is one of those fundamental nutrients you will find close to the top of the ingredients list in any multivitamin. But what actually is it, and why is it so important that we get enough? Vitamin D is in fact not a single substance but a group of five closely related ones, referred to, logically enough, as vitamin D1, D2, D3, D4 and D5. Vitamins D2 (ergocalciferol) and D3 (cholecalciferol) are the most important for human health and, unless specified otherwise, the term ‘vitamin D’ usually refers to these. Check out the difference between vitamin d and d3. Vitamins are organic compounds that are needed in small quantities to enable healthy metabolism and the proper functioning of our bodies. Without sufficient quantities of these vital substances, our health will decline in a variety of dramatic ways that can be subtle or painfully obvious. Our bodies cannot make these substances – they must be supplied by the food we eat. There is only one exception to this rule: vitamin D3. Cholecalciferol can be produced by the body – in the epidermis (outer layer of the skin) when exposed to sunlight. Sunlight is in fact the largest single source of vitamin D for most people.
Why we need vitamin D>Our bodies cannot function without an adequate supply of vitamin D: its role in our health is too central. The functions of this nutrient include:
- Maintaining normal blood levels of the minerals calcium and phosphorus.
- The absorption from food of calcium, enabling healthy bone growth.
- Stimulating immune cells to release antibodies and thereby encouraging a healthy, responsive immune system.
- Metabolising glucose to fuel our bodies.
- Controlling the growth of cells and nerves.
- Maintaining healthy muscles and joints.
- High blood pressure – also known as hypertension.
- Muscle pain or tremors.
- Tooth pain and gum inflammation.