July 28, 2016

Vitamin D Deficiency

What are symptoms and signs of an excessive vitamin D intake (Daily Limits Chart)?

In United States, the sales of vitamin D supplements went from $75 million in 2006 to $550 million in 2010; it is likely even higher today. This can be a case of too much of a good thing. Not many people realize that there is a limit to how much vitamin D you can safely take. This can build up in your fat cells and cause health problems. Tolerable upper limits (UL) are set to help avoid this.

Excessive intakes of vitamin D can lead to high levels of calcium (hypercalcemia). The symptoms of this are weakness, confusion, constipation, loss of appetite, and development of painful calcium deposits. Research has shown that very high doses can actually increase the risk of falls and fractures. A study of 2,256 community-dwelling women, aged 70 years or older, found that over five years, those given very high doses of vitamin D experienced 15% more falls and 26% more fractures then those in the placebo group.

To avoid this, keep your supplement intake below the UL:

  1 to 3 years 4 to 8 years 9 to 18 years 19+ years
IOM 2,500 IU/day 3,000 IU/day 4,000 IU/day 4,000 IU/day
Endocrine Society 4,000 IU/day 4,000 IU/day 10,000 IU/day 10,000 IU/day

This limit is set as the most that a person can consume safely. The arguments against these levels stem from the fact that you can get 10,000-25,000 IU from exposure to the sun in one day. Studies have shown that supplementation over 10,000 IU/day can cause kidney and tissue damage. A recent study found that high-dose vitamin D supplementation (20,000-40,000 IU/week) caused a slight but significant increase in hemoglobin A1C and C-reactive protein, and a decrease in serum HDL. Currently, there are not enough credible studies to support the safety or necessity of taking a supplement in a dose that exceeds the current tolerable upper limits.

There is no disputing that fact that vitamin D plays many vital roles in our well-being. Changes to our lifestyle, diet, and supplementing when needed are the keys to curbing the vitamin D deficiency pandemic. Continue Reading

Reviewed on 6/9/2016