By Balveer Singh Rathore, Editor · Last updated: September 26, 2026 · How we write
Vitamin D deficiency often has no symptoms at first. When it’s more severe, it can cause bone pain, muscle weakness and soft bones (osteomalacia) in adults and rickets in children. A blood test for 25-hydroxy vitamin D confirms it: below 12 ng/mL is deficient and 12–20 ng/mL is inadequate. Adults need about 600 IU a day.
This article is general information, not medical advice. If you have a health condition, are pregnant or take medication, talk to your doctor before changing your diet, exercise or supplements. Read our disclaimer.
What does vitamin D do?
Vitamin D helps your body absorb calcium and build strong bones. It also supports muscle function. Your skin makes vitamin D in sunlight, and a small amount comes from food.
Vitamin D deficiency symptoms
- Often none: many people find out only from a blood test.
- Bone pain or aching, especially in the lower back, hips or legs
- Muscle weakness or cramps, and difficulty climbing stairs
- Tiredness (common, but it has many other causes)
- Frequent falls or fractures in older adults
- In children: rickets, with bowed legs, delayed growth and soft bones
Why is vitamin D deficiency common in India?
- Indoor jobs and study, with little sun on bare skin
- Darker skin needs more sun exposure to make the same vitamin D
- Clothing that covers most of the skin
- Air pollution that blocks UV light
- Few vitamin D-rich foods in vegetarian diets
- Older age and obesity (BMI 30+)
Vitamin D test levels explained
| 25(OH)D level | ng/mL | nmol/L |
|---|---|---|
| Deficient | below 12 | below 30 |
| Inadequate | 12 to under 20 | 30 to under 50 |
| Adequate for most people | 20 or above | 50 or above |
| Possibly too high | above 50 | above 125 |
Cut-offs from the US NIH Office of Dietary Supplements. Some labs and doctors use different ranges, such as 30 ng/mL as a target; follow your doctor’s interpretation.
How much vitamin D do you need?
| Group | Recommended intake |
|---|---|
| Adults (ICMR-NIN 2020) | 600 IU (15 mcg) per day |
| Adults over 70 (US NIH) | 800 IU (20 mcg) per day |
| Upper safe limit for adults (US NIH) | 4,000 IU (100 mcg) per day, unless prescribed |
Vitamin D foods
| Food | Serving | Vitamin D (approx.) |
|---|---|---|
| Trout, cooked | about 85 g | 645 IU |
| Salmon, cooked | about 85 g | 570 IU |
| UV-exposed mushrooms | ½ cup | 366 IU |
| Fortified milk | 1 cup | about 120 IU (check label) |
| Sardines, canned | 2 fish | about 46 IU |
| Egg yolk | 1 large | about 44 IU |
Food alone rarely provides enough, especially for vegetarians. That’s why sunlight and, when needed, supplements matter.
Sunlight: getting vitamin D safely
Short, regular periods of sun on the arms and legs help your skin make vitamin D. Glass blocks the UV rays that are needed, so sitting by a window doesn’t count. Avoid sunburn and long unprotected exposure in peak Indian summer heat; ask your doctor what’s sensible for your skin type and health.
Supplements: use with care
- Take vitamin D supplements only after testing, at the dose your doctor advises.
- Very high doses (such as repeated large injections or weekly mega-doses without monitoring) can raise calcium to harmful levels.
- Take vitamin D with a meal that contains some fat for better absorption.
- Get enough calcium from dairy, ragi, sesame or leafy greens too.
For more nutrient guides, see iron-rich foods and vitamin B12 foods for vegetarians.
Frequently asked questions
What are the first signs of vitamin D deficiency?
Often there are no early signs. When symptoms appear, they commonly include bone pain, muscle weakness or cramps and tiredness. In children, severe deficiency causes rickets. Because symptoms are vague, a blood test for 25-hydroxy vitamin D is the only way to confirm deficiency.
What level of vitamin D is considered deficient?
According to the US NIH, a 25-hydroxy vitamin D level below 12 ng/mL (30 nmol/L) is deficient, 12–20 ng/mL is inadequate, and 20 ng/mL or above is adequate for most people. Some doctors aim higher. Always discuss your report with your doctor.
Why do so many Indians have low vitamin D despite sunshine?
Many Indians spend most daylight hours indoors, cover most of their skin, and have darker skin that needs more sun to make vitamin D. Pollution, vegetarian diets with few vitamin D foods, older age and obesity add to the risk.
Which foods are rich in vitamin D?
Fatty fish like trout, salmon and sardines, egg yolks, UV-exposed mushrooms and fortified milk are the main food sources. Salmon provides about 570 IU per 85 g serving. Vegetarians get little vitamin D from food and usually depend on sunlight or supplements.
How much vitamin D should I take daily?
ICMR-NIN recommends 600 IU a day for Indian adults. If you’re deficient, your doctor may prescribe a higher dose for a period and then a maintenance dose. Don’t exceed 4,000 IU a day long-term without medical advice, as too much can be harmful.
Can vitamin D deficiency cause hair fall or weight gain?
Low vitamin D has been linked in some studies with hair loss and obesity, but it hasn’t been shown to directly cause weight gain or hair fall in most people. If you have these problems, see a doctor to check vitamin D, iron, thyroid and other causes.