| What are the benefits? |
| Vitamin D is a fat-soluble vitamin necessary for the absorption and utilisation of calcium and phosphorus. It is important for the normal growth and development of bones and teeth, and may also help maintain healthy muscles. Vitamin D is important to the immune system. |
| What are the natural food sources? |
| Most of our daily requirements for vitamin D are satisfied by the vitamin D produced in our skin when it is exposed to sunlight. Small amounts may also be taken in through the diet. Natural food sources of vitamin D include oily fish, dairy products, eggs, cod liver oil and milk. |
| How much do you need? |
| The recommended daily allowance for vitamin D is 5 mcg, but a long-term intake of up to 20 mcg daily is not considered harmful. The form of vitamin D we receive through our diet or supplements is not fully active - it requires conversion by the liver and then the kidney before it becomes fully active. |
| Are you likely to be deficient? |
| People who don’t get enough sunshine, including those who live in northern climates such as the UK or northern Europe, and the elderly who don’t get out much may be prone to vitamin D deficiency. Severe vitamin D deficiency can cause rickets in children and osteomalacia in adults. A lesser deficiency could cause loss of appetite, a burning sensation in the mouth and throat, diarrhoea, insomnia, visual problems and weight loss. |
| Are you taking too much? |
| Vitamin D taken in large doses can result in calcium being reabsorbed from the bones and deposited in soft tissues such as the heart and lungs. This reduces their ability to function. |
| Are there any interactions? |
| Cholesterol lowering drugs, antacids, mineral oils and steroid hormones (cortisone) may interfere in vitamin D absorption. Thiazide diuretics such as chlorothiazide and hydrochlorothiazide (Esidrex) also disturb the body’s calcium to vitamin D ratio. |
