What it does in the body
- Calcium and phosphorus absorption from the intestine
- Bone mineralization and remodeling via osteoblast regulation
- Immune system modulation (innate and adaptive immunity)
- Insulin secretion regulation and glucose metabolism
- Muscle function and neuromuscular coordination
How much you need (Daily Value)
| Group | Recommended | Source |
|---|---|---|
| Adult male | 15 mcg (600 IU) | NIH/IOM |
| Adult female | 15 mcg (600 IU) | NIH/IOM |
| Pregnancy | 15 mcg (600 IU) | WHO/IOM |
| Children | 15 mcg (600 IU) ages 1-18 | WHO |
| Older adults | 20 mcg (800 IU) age 71+ | NIH/IOM |
Richest food sources
| Food | Amount | Where |
|---|---|---|
| Cod liver oil | 250 mcg (10,000 IU) per tablespoon | Northern Europe |
| Salmon (wild-caught) | 14.2 mcg (568 IU) per 100g | global |
| Sardines (canned) | 4.8 mcg (193 IU) per 100g | Mediterranean/global |
| Fortified milk | 2.5 mcg (100 IU) per 240ml | Americas/Europe |
| Egg yolk | 2.0 mcg (82 IU) per yolk | global |
| UV-exposed mushrooms (shiitake) | 18 mcg (720 IU) per 100g | East Asia |
| Fortified orange juice | 2.5 mcg (100 IU) per 240ml | Americas |
| Herring (pickled) | 17 mcg (680 IU) per 100g | Northern Europe/Scandinavia |
In our food database, per 100 g
Highest among our free foods — open the Food Explorer to compare.
If you don't get enough
Mild: Fatigue, muscle weakness, bone aches, increased susceptibility to infections
Moderate: Osteopenia, secondary hyperparathyroidism, proximal muscle weakness, increased fracture risk
Severe: Rickets in children (bowed legs, rachitic rosary), osteomalacia in adults (bone softening), severe immunodeficiency
Time to onset: Serum levels decline over weeks without sun/dietary intake; clinical rickets develops over months in growing children
Too much
Upper limit: 100 mcg (4000 IU)/day for adults; toxicity typically at >10,000 IU/day chronically
Hypercalcemia causing nausea, vomiting, confusion, polyuria, nephrocalcinosis, cardiac arrhythmias. Cannot occur from sun exposure alone.
How well you absorb it
55-99% of oral vitamin D absorbed in the small intestine with fat
Helped by: Dietary fat (take supplements with largest meal), UVB exposure (10-30 min midday sun), Magnesium (cofactor for vitamin D metabolism)
Hindered by: Obesity (sequestration in adipose tissue), Dark skin pigmentation (higher latitudes), Sunscreen SPF 30+ (blocks 95% UVB), Fat malabsorption disorders
Cooking & storage
Vitamin D is relatively heat-stable. Baking and frying retain 80-100% of vitamin D content. Boiling fish retains most vitamin D in the liquid.
Nutrisize Health totals every nutrient from what you actually eat, against targets set for your age and sex, and flags what's short — across 4,995 foods, on your device.
