In such cases, the blood raids the skeleton for the calcium it needs, thus raising the risk of osteoporosis. These and other findings indicate that dietary sources of vitamin D become increasingly important as we age. According to the National Institute on Aging, the current Dietary Reference Intake Guidelines recommend 600 IU for those over age 70. By law, a quart of milk must contain 400 IU of vitamin D, but studies have shown that 80 percent of milk samples nationwide have more or less than that and 14 percent had no detectable vitamin D at all. Some breakfast and nutrition bars and drinks provide 100 to 140 IU of vitamin D per serving.
Vitamin D is also available in multivitamins and calcium supplements.
According to the Mayo Clinic Health Letter, ingesting more than 2,000 IU a day for a prolonged period poses the risk of toxic side effects. Symptoms of vitamin D poisoning may include nausea, headache, excessive urination, hypertension, kidney stones, kidney damage, and other problems. The text presented on these pages is for your information only. It is not a substitute for professional medical advice. It may not represent your true individual medical situation.