Vitamin D
Helps your body absorb calcium and supports bone and muscle health.
Why it matters
Vitamin D helps your body absorb calcium and phosphorus, which makes it central to healthy bones and teeth. It also supports muscle function, nerve signaling, and immune health.
- Helps absorb calcium and phosphorus.
- Supports bone strength and muscle function.
- Contributes to immune and nerve function.
If intake is too low
Low vitamin D can weaken bones over time. In children, severe deficiency causes rickets, and in adults it can contribute to osteomalacia, bone pain, and muscle weakness.
- Soft or weak bones over time.
- Rickets in children.
- Bone pain and muscle weakness in adults.
If intake is too high
Vitamin D toxicity almost always comes from supplements, not from sun exposure. Too much can raise calcium levels in the blood and damage the kidneys and other tissues.
- Nausea, vomiting, weakness, and confusion.
- High blood calcium, which can damage the kidneys.
- Kidney stones or tissue calcification with prolonged excess.
Adult upper limit: 100 mcg/day (4,000 IU/day)
Toxicity is usually tied to high supplemental intake rather than the vitamin D your body makes from sunlight.
Common food sources
Vitamin D is harder to get from food alone than many vitamins, so fortified foods and sunlight exposure often matter.
- Fatty fish such as salmon, trout, and tuna
- Fortified milk, plant milks, cereals, and some yogurts
- Egg yolks and cod liver oil
Who may need closer attention
Low vitamin D is common when sun exposure is limited, skin pigmentation is darker, or absorption is reduced.
- Older adults
- People with little sun exposure or consistently covered skin
- People with darker skin, obesity, or fat-malabsorption disorders
Use extra caution if
Small details change the risk picture with nutrients more than most people expect.
You take high-dose vitamin D for long periods or have conditions that affect calcium balance. A clinician can help interpret bloodwork and dose decisions.
Supplement and label notes
Useful context when this nutrient shows up across more than one product.
- Labels may show vitamin D in micrograms or IU; 1 mcg equals 40 IU.
- Vitamin D often stacks across multivitamins, calcium blends, bone formulas, and stand-alone softgels.
- Vitamin D2 and D3 are both used on labels, but long-term dosing decisions should still be guided by overall intake and labs when relevant.
Daily Value targets in SuppMap
These are the same label-style Daily Value targets used in the app.
Official references
These pages were used to draft the summaries on this guide.
Educational only. These pages are not a diagnosis or a substitute for personal medical care.
More guides
Keep moving through the rest of the Daily Value chart from here.