Health Risks from Excessive Vitamin D

Vitamin D toxicity can cause nonspecific symptoms such as nausea,
vomiting, poor appetite, constipation, weakness, and weight loss. More
seriously, it can also raise blood levels of calcium, causing mental
status changes such as confusion and heart rhythm abnormalities The use
of supplements of both calcium (1,000 mg/day) and vitamin D (400 IU/day)
by postmenopausal women was associated with a 17% increase in the risk
of kidney stones over 7 years in the Women's Health Initiative .
Deposition of calcium and phosphate in the kidneys and other soft
tissues can also be caused by excessive vitamin D levels . A serum
25(OH)D concentration consistently >200 ng/mL (>500 nmol/L) is
considered to be potentially toxic . In an animal model, concentrations
?400 ng/mL (?1,000 nmol/L) were not associated with harm