Sunlight and Vitamin D: Why So Many Indians Are Low, and What You Can Do Safely

What does vitamin D do?

Vitamin D helps the body use calcium, so it matters for strong bones. Your skin makes most of the vitamin D you need when sunlight falls on it.

How common is low vitamin D in India?

A 2018 review published in the Indian Journal of Medical Research collected studies from across India. It found low vitamin D, called hypovitaminosis D, in:

• 84.9 to 100 percent of school-going children
• 42 to 74 percent of pregnant women
• 44.3 to 66.7 percent of infants
• 70 to 81.1 percent of mothers who were breastfeeding
• 30 to 91.2 percent of adults

These ranges are wide, because studies used different groups of people and different cut-offs. The message is still clear: low vitamin D is common.

Why does it happen in a sunny country?

The review and a news report in The South First list several reasons:

• Indoor lives and city living. Many of us spend most of the day in offices, vehicles and air-conditioned homes, and tall buildings block direct sunlight.
• Clothing and sunscreen. Covering most of the skin, or using sunscreen, reduces how much vitamin D the skin makes.
• Air pollution. It can reduce the UVB rays that reach the skin.
• Skin colour. More melanin, the natural pigment in darker skin, slows vitamin D production. The South First report says darker skin may need roughly three to six times longer in the sun for the same amount.
• Diet. Foods rich in vitamin D, such as oily fish and egg yolks, are costly or eaten rarely. The review also lists vegetarian diets and low use of fortified foods as risk factors.

How much sun is enough?

The review says exposing your arms and face for about 30 minutes a day, between 10 am and 2 pm, without sunscreen, is considered adequate. This is the strongest sun of the day, so protect your skin from burning. The NHS says to cover up or protect your skin during long periods in the sun, to lower the risk of skin damage and skin cancer. It also says you cannot overdose on vitamin D from sunlight alone.

The NHS page does not give a number of minutes, so take the 30-minute figure as a guide from one review, not a rule for everyone. People with fair skin or skin problems should ask a doctor.

Which foods have vitamin D?

The NHS lists oily fish such as salmon, sardines and mackerel, red meat, egg yolks, and fortified foods such as some spreads and cereals. The review recommends fortifying staple foods, like milk, with vitamin D. If you are vegetarian, getting enough from food alone may be hard. Our guide to vegetarian protein covers other nutrients to watch.

Should you take a supplement?

A supplement may be helpful for some people, but this is a decision for a doctor. The NHS says that in the UK, 10 micrograms (400 IU) a day is the usual advice, and that too much over a long time can cause high calcium in the blood, which can weaken bones and damage the kidneys and heart. The upper daily limit for adults is 100 micrograms (4,000 IU). India's guidance is less clear. The South First report notes that recommendations range widely, from standard doses to very high "mega doses", so the right amount is unclear without advice.

So:

• Do not buy high-dose supplements by yourself.
• Ask for a blood test if you are worried, especially if you are pregnant, an older adult, or have bone pain or muscle weakness.
• Follow the dose your doctor gives you.

A simple, safe routine

1. Spend some time outdoors each day, with arms and face uncovered, avoiding sunburn.
2. Eat foods that contain vitamin D, and get tested if you have risk factors.

This article is general information, not medical advice. Always ask a doctor before starting a supplement.

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