Vitamin D deficiency in India: what your test result means

Vitamin D is the most common gap we see on Indian blood reports. Pooled studies from across India put low vitamin D at around 3 in 5 people, in cities and villages, in the north and the south. That surprises a lot of people in a country with this much sunshine.

Why vitamin D is low in a sunny country

Your skin makes vitamin D when midday sun (UVB light) falls on bare skin. Several things get in the way:

• Indoor lives. Office work, study and commutes keep most of us out of the sun between 10 am and 3 pm, when UVB is strongest.
• Covered skin. Clothing, sunscreen and staying in the shade all block UVB.
• Darker skin. More melanin means more time in the sun to make the same amount.
• Air pollution. Smog in many cities filters out UVB before it reaches the ground.
• Food. Few Indian staples have much vitamin D. Fatty fish, egg yolks and fortified milk help, but rarely enough on their own.

What the test measures

The test on your report is usually called 25 hydroxy vitamin D, 25(OH)D or "Vitamin D Total". It shows how much vitamin D your body has stored over the past few weeks. Indian labs report it in ng/mL; some labs abroad use nmol/L (divide by 2.5 to get ng/mL).

Most labs and the US National Institutes of Health read it like this:

• Under 20 ng/mL: deficient. Under 10 is severely low.
• 20 to 29 ng/mL: insufficient, or low normal.
• 30 to 100 ng/mL: the range most labs call sufficient.
• Over 100 ng/mL: above range. This almost always comes from taking a lot of vitamin D, and it's worth stopping and talking to a doctor.

Don't mix this up with 1,25 dihydroxy vitamin D, a different test that isn't used to check your stores.

How much vitamin D adults usually take

The US daily need for adults is 600 IU (800 IU over 70), and the safe upper limit is 4,000 IU a day. When a blood test shows a low level, reference doses are higher than the daily need, but stay at or under that upper limit:

• Under 10 ng/mL: 4,000 IU a day
• 10 to 19 ng/mL: 2,000 IU a day
• 20 to 29 ng/mL: 1,000 IU a day

These are the doses in our rules table. A doctor may suggest a different plan, such as a weekly 60,000 IU sachet for a few weeks, which is common in India. Very low levels, under 5 ng/mL, are worth a doctor's visit before you start anything.

Getting the most from a vitamin D supplement

• Take it with a meal that has some fat, like breakfast with milk, eggs, curd or nuts. Vitamin D dissolves in fat and is absorbed better that way.
• D3 (cholecalciferol) is the usual form. Vegan D3 made from lichen exists if you avoid animal products.
• Retest after about 3 months. Levels rise slowly, and 12 weeks is long enough to see where you have settled.

Sun still counts

10 to 30 minutes of midday sun on your arms and legs a few times a week helps, especially with lighter skin. It is not a reliable fix on its own for a low level, but it's free and it adds up.

Check yours

Upload your lab report PDF and Beyond Humans reads your vitamin D value for you, shows where it sits, and gives you a daily dose from a fixed reference table, every one at or under the US upper limit.