Benefits: Treats low blood calcium in kidney disease, necessary for proper bone growth and development, prevents rickets, treats post-operative muscle contractions.
Good food sources: Vitamin D fortified milk, egg yolks, fortified cereals, cod liver oil, salmon, sardines, herring, mackerel.
Cautions: Consult your doctor if you have epilepsy, heart or blood-vessel disease, kidney, liver, or pancreatic disease, intestinal problems or diarrhea, sarcoidosis, or if you are pregnant or planning on becoming pregnant.
Substance interactions: These medications may reduce the effects of vitamin D: antacids with aluminum, anti-convulsants, barbiturates, cholestyramine, colestipol, hydantoin, primidone. Antacids with magnesium may cause too much magnesium in the bloodstream of people with kidney problems. Mega-doses of calcium, diuretics and thiazide increases the risk of hypercalcemia. Vitamin D reduces the effect of calcitonin when treating hypercalcemia. Digitalis preparations increases the risk of heartbeat irregularities. Phosphorous-containing medicines may release too much phosphorous into the body.
Signs of toxicity: High blood pressure, irregular heartbeat, nausea, weight loss, seizures, diarrhea, mental confusion, vomiting. Long-term mega-doses can lead to kidney and cardiovascular damage. Doses of 1800 IU daily can cause stunted growth in children.
* Unfiltered sunlight is another source of vitamin D. UV light
is processed in the cholesterol within the skin and made into vitamin
D. Growing children on vegetarian diets and those living in extreme
climates (winter darkness) may want to consider supplementing.
Most elderly people have deficiencies, making osteoporosis worse.
* Newborns are born with a 9 month supply of vitamin D. Vitamin
D is stored in the body's fat cells during the summer for use during dark winter months, providing an adequate diet is followed.
* Because of toxicity, don't exceed 600 IU per day without a doctor's specific instructions.