Vitamin D: what it does and which foods have it

What it does

Vitamin D promotes calcium absorption in the gut and keeps calcium and phosphate at the levels needed for normal bone mineralization. (NIH) It is also needed for bone growth and remodeling.

Where you find it in food

Vitamin D is found naturally in only a few foods, such as fatty fish, fish liver oils, beef liver, egg yolks and cheese. (NIH)

Amounts are from the NIH Office of Dietary Supplements food table. "Servings to reach the daily value" is the daily value (20 mcg) divided by the amount per serving.

How much you absorb

• Fat in the gut at the same time enhances vitamin D absorption, but some is absorbed even without dietary fat. (NIH)

Food, and where an IV fits

Food comes first. Most people get what they need from a varied diet, and a nutrient in food comes with fiber, protein and everything else the food carries.

An IV takes a different route. It delivers a nutrient straight into the bloodstream, so none of it depends on absorption in the gut. That can matter for people who absorb less, and your provider decides whether it is appropriate for you.

Vitamin D is available at RESRV as an injection (cholecalciferol, $30), not in the drips.

Who tends to run low

In US national data, 5% of people were at risk of vitamin D deficiency and another 18% at risk of inadequacy. (NIH)

The NIH lists these groups among those more likely to fall short:

• Older adults
• People with limited sun exposure
• People with dark skin
• People with conditions that limit fat absorption

A lab panel ordered by your provider can show your own levels. See lab testing before IV therapy.