Ask your doctor about vitamin D
If you get little sun or few vitamin D foods, ask at your checkup whether testing or a supplement makes sense for you.
- How often
- Yearly
- Time
- Part of a checkup
- Recommended for
- 28 factors
How to do it
- At your yearly checkup, mention anything that limits your vitamin D, such as indoor or night work, long winters, darker skin, a plant-only diet, or a condition that affects absorption.
- Ask whether a blood test makes sense for you. Routine testing isn't recommended for everyone without symptoms, so your risk factors matter.
- Bring a list of any supplements you already take, including multivitamins.
- Work on food sources first, such as fatty fish, fortified milk and UV-exposed mushrooms.
Why it helps
Vitamin D keeps bones strong, and low levels can lead to soft, weak bones. Whether you need testing depends on your situation. The US Preventive Services Task Force found too little evidence to recommend screening adults who have no symptoms or risk factors, so it is a conversation to have with your doctor rather than a test for everyone.
Be careful
Don't start high-dose vitamin D on your own. Too much almost always comes from supplements and can raise calcium levels and harm the kidneys. The upper limit for adults is 4,000 IU (100 mcg) a day. Check with a doctor or pharmacist before supplementing.
Recommended for
Alaska
Months of low sun, deep cold and summer smoke from big wildfires.
placeConnecticut
The town Lyme disease is named for, plus short winter days.
placeDelaware
A high-Lyme state with humid summers on the coast.
placeIdaho
Mountain radon, smoky summers, cold winters and weak winter sun.
placeIllinois
High-radon soil, dark winters, cold snaps and deadly summer heat waves.
placeIndiana
High-radon soil, gray winters, humid summers and a lot of private wells.
placeIowa
Every county is high-radon country, and farm-country wells need testing.
placeMaine
One of the highest Lyme rates in the US, plus radon and arsenic in wells.
placeMaryland
High-Lyme suburbs, radon in the central counties and humid summers.
placeMassachusetts
Lyme country, cold winters and the original vitamin D winter study.
placeMichigan
Long gray winters, lake-effect cold and arsenic in some wells.
placeMinnesota
Deep cold, dark winters, high radon, Lyme ticks and arsenic in wells.
placeMontana
High-radon ground, smoky summers, bitter winters and a short winter sun.
placeNebraska
Radon under the house, mosquitoes in late summer, deep cold in winter.
placeNew Hampshire
Granite bedrock, tick-filled woods, and long, dark winters.
placeNew Jersey
Lyme ticks in the suburbs and radon in the northwestern hills.
placeNew York
Lyme country upstate and on Long Island, with long, gray winters.
habitNight shift work
Awake when your body expects to sleep, asleep when the world is loud.
placeNorth Dakota
Radon in every county, brutal wind chill, and West Nile in summer.
placeOhio
High radon across much of the state and a gray, low-sun winter.
placeOregon
Wildfire smoke in late summer and dim, cloudy winters.
placePennsylvania
Most counties in EPA's top radon zone, and plenty of Lyme ticks.
placeRhode Island
Small state, big Lyme numbers, and radon in the south.
placeSouth Dakota
Radon in the east, West Nile in summer, and hard Plains winters.
placeVermont
Lyme ticks in green summers, little sun and deep cold in winter.
placeWashington
Smoky late summers, dark gray winters, and radon in the northeast.
placeWest Virginia
Lyme ticks moving in, and radon in the eastern hills.
placeWisconsin
Lyme ticks in every county, nitrate in some wells, and long dark winters.