Vitamin D

Iguanas NEED, specifically UV-B rays in which to aid in the production of the vitamin D-3 which aids in the absorption of CALCIUM. Without UV-B to help create the D-3 Vitamin Iguanas can not absorb Calcium and thus develop weak and brittle bones often termed as Metabolic Bone Disease, Fibrous Osteodystrophy and/or Nutritional Secondary Hyperparathyroidism. You can provide this UV-B quite simply by adding a Vita-Lite to the enclosure and allowing about 12 hours of exposure to it per day. If this can happen to Iguanas then without light it can happen to our bodies. Suspect we will need to stock up on vitamin D-3 or supply UV-B light to our bodies in the proper minimum quantities.

The following is from:
Bi 231 Anatomy & Physiology
Lecture: Integument Dr. Walters PCC
Much of this is from Tortora & Marieb

1. In sunny areas, 1 hour/week of arm/face exposure to sun enough for making adequate vitamin D3, so no dietary supplement would be required. Aging reduces ability to make vitamin D3; have 4-fold reduction after age 70. Topical sunscreens may prevent vitamin D3 synthesis. Latitude is important: at our latitude, the sun's angle is low in the winter months and the ozone absorbs photons so well that no vitamin D is made in the skin between November & February
2. Milk has vitamin D3 added, so can go without sun. Other foods: fatty fish like salmon, eggs, butter, liver
3. vitamin D deficiency: if drink no milk &completely cover skin in sun or don't go outside
4. if get enough sun to cause mild sunburn, equivalent to taking 10,000 to 25,000 international units (IU) of vitamin D.
5. If no skin production of vitamin D, should take 400-600 IU/day, otherwise 200 IU/day is recommended.
6. If liver or kidney disease, get calcitriol deficiency. Ingesting vitamin D3 or synthesizing it in skin is ineffective. Need take Rocaltrol (calcitriol) 1,25(OH)2VitD3

The major role of vitamin D is calcium homeostasis - it does this by integrating absorption of calcium from the intestine with mobilsation and deposition of bone and its excretion in the kidney. Vitamin D : What happens if you don’t get enough? A deficiency of vitamin D is known as hypovitaminosis D. Hypovitaminosis D causes decreased intestinal absorption and bone resorption of calcium, leading to low levels of blood calcium. Low levels of blood calcium stimulate compensatory parathyroid hormone production. This results in demineralisation of bone which presents as rickets in young growing mammals and osteomalacia in adult mature mammals. In mammals other symptoms include : loss of appetite, slow growth, general weakness, digestion problems and stillbirths. In fowl, symptoms include retarded growth, lameness, abnormal bone development, thin shelled eggs and fertility problems. Rickets is a disease of growing bones in which the deposition of calcium and phosphorus is abnormal. This results in the bones being weak, easily broken and the legs may be bowed. It may also result in convulsions and tetany.

Offered by Mike.