NOTE: Please consult with your medical practioner before making any changes to your diet or taking supplements.
Vitamin D is a fat-soluble vitamin and also known as vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Because vitamin D is so important in skeletal growth and strong bones, many foods are fortified with this vitamin to ensure that children obtain adequate amounts
WHY YOU MAY NEED VITAMIN D
Rickets and osteomalacia are both directly related to vitamin D deficiency. Rickets affect children’s bones by causing retarded growth and skeletal abnormalities. The bones become weak and bend to support the body weight causing the most obvious sign of the disease – ‘bowed leg’. Osteomalacia occurs in adults where intake of calcium is low and exposure to sunlight is minimal. The bones of the legs soften, become bent and bowed leg. In addition, due to the importance of vitamin D on calcium absorption, osteoporosis can also develop.
HOW MUCH DO YOU NEED?
Recommended Daily Intake (RDI) An RDI has not been established in Australia. The National Health and Medical Research Council (NHMRC) of Australia recommend that vitamin D should be obtained by sunlight rather than from dietary sources. Their rationale is that compared to other countries such as England; Australia is sunnier and people tend to spend more time outdoors. The NHMRC do recommend that those who are housebound could benefit from an oral intake of 10 mcg (400 IU) vitamin D per day if they are not exposed (face, arms and hands) for 1–2 hours per week to direct sunlight in summer.
The major source of vitamin D is from exposure of the skin to ultraviolet (UV) rays, which results in the synthesis of vitamin D. About 15 minutes (depending on your skin pigmentation) of sunlight each dayis considered to be equivalent to the ingestion of 5 mcg (200 IU) of vitamin D. Choose a time of the day eg early morning or late afternoon when the sun’s rays are not so harsh. The use of sunscreens with a sun protection factor of 8 can prevent the synthesis of vitamin D in your skin. Considering the small amount of time necessary to self-synthesise vitamin D, this should not discourage the use of sunscreens. Best dietary sources include cod liver oil, egg yolks, butter, liver and fortified milk products.
Some conditions may be aggravated by vitamin D supplementation. These include hypercalcemia (high calcium in the blood), hyperparathyroidism, sarcoidosis, lymphoma, tuberculosis and kidney stones or kidney disease. Only take vitamin D under the supervision of your medical practitioner. Vegetarians – many supplements contain vitamin D3 (cholecalciferol) which is sourced from animal or fish. Vitamin D2 (ergocalciferol) is obtained from plant sources. There is no risk of vitamin D toxicity from prolonged exposure to sunlight. Just keep in mind that prolonged exposure to the sun can cause skin cancer and premature wrinkles. Excessive dietary intake leads to hypercalcaemia , fatigue, anorexia, diarrhoea, dry mouth and increased thirst, fatigue, headache, nausea vomiting, kidney stones and damage, abnormal heart rhythm and hypertension.