Vitamin D Deficiency: Symptoms, Causes and How to Fix It

Vitamin D deficiency is one of the most common and least noticed health problems in Pakistan. Surveys suggest that roughly seven in ten adults have low levels, even though the country gets plenty of sunshine. Many people only find out after a blood test for tiredness or body pain.

Vitamin D deficiency means the blood level of vitamin D is too low, usually below 12 to 20 ng/mL depending on the guideline. Common signs are tiredness, bone pain and muscle weakness, but many people feel nothing. A doctor confirms it with a blood test and treats it with supplements, safe sun exposure and vitamin D-rich foods.

What Is Vitamin D Deficiency, and Why Is It So Common in Pakistan?

Vitamin D helps the body absorb calcium and keeps bones, teeth and muscles strong. The skin makes it when exposed to sunlight, and small amounts come from food. Deficiency develops when the body gets too little from both sources, or cannot use what it gets.

The numbers in Pakistan are high. The National Nutrition Survey 2011 found deficiency in 70% of pregnant women and 66% of other women. A 2025 review of the 2018 survey reported that about 79.7% of women of reproductive age were deficient, with 25.7% severely so, and that urban rates were higher than rural ones. Pooled estimates from meta-analyses put adult prevalence at roughly 70% to 80%. Studies use different cut-offs, so exact figures vary, but the message is consistent.

It is not only a winter problem. Pakistani researchers report little seasonal difference, and doctors see deficiency throughout the year.

Vitamin D Deficiency Symptoms

Symptoms are often vague and develop slowly, so they are easy to blame on stress, age or a busy life.

Symptoms in adults

• Persistent tiredness and low energy

• Bone and joint pain, especially in the lower back

• Muscle weakness, aches or cramps

• Low mood or depression

• Bone loss over time, which raises the risk of fractures

Some people also report catching infections more often, but this link is less certain.

Symptoms in children

In children, severe deficiency causes rickets: soft bones, bowed or bent legs, delayed growth and joint deformities. Adults with long-term severe deficiency can develop osteomalacia, which means soft and painful bones.

Why many people have no symptoms

Do not wait for vitamin D deficiency symptoms to appear. A Pakistani study of outpatients at Aga Khan University Hospital found 92% were deficient, and almost half of them had no symptoms at all. Only a blood test can tell you.

Causes of Vitamin D Deficiency

The two most common causes of vitamin D deficiency are too little sun exposure and too little vitamin D in the diet. Other factors raise the risk further.

• Limited sun exposure: indoor work, covering most of the skin, regular sunscreen use, or avoiding midday sun.

• Darker skin: more melanin means the skin makes less vitamin D from the same sunlight.

• Low dietary intake: few foods naturally contain vitamin D.

• Obesity: a body mass index (BMI) of 30 or above is linked to lower blood levels.

• Kidney or liver disease: both reduce the enzymes that turn vitamin D into its active form.

• Digestive conditions: coeliac disease, Crohn's disease and other absorption disorders.

• Age: older adults make less vitamin D in the skin.

• Pregnancy: closely spaced pregnancies drain a mother's nutrient stores.

• Some medicines: certain anti-seizure drugs and long-term steroids can lower levels.

Pakistan is one of the world's sunniest countries, yet deficiency is widespread. Lifestyle matters as much as climate.

Which Blood Level Counts as Deficiency?

Guidelines do not agree on one number, which is why your lab report may say "low" while another source calls the same result adequate.

To convert ng/mL into nmol/L, multiply by 2.5. Levels above about 100 ng/mL carry a risk of vitamin D toxicity. Ask your doctor which range they follow.

How Is Vitamin D Deficiency Diagnosed?

The standard test is a 25-hydroxyvitamin D blood test. Symptoms alone cannot diagnose vitamin D deficiency. The Endocrine Society does not recommend routine testing for healthy people, so testing makes the most sense if you have symptoms or one of the risk factors above. If the cause is unclear, your doctor may also check calcium, kidney and liver function.

How to Fix Vitamin D Deficiency

Supplements under medical guidance

Supplements are the fastest and most reliable fix. Vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) are both used. For confirmed deficiency, doctors often prescribe a short high-dose course for several weeks, followed by a lower maintenance dose. One Pakistani clinical protocol describes 50,000 IU a week for levels under 20 ng/mL. Your dose depends on your level, age, weight, medicines and health conditions, so never copy someone else's prescription.

For general upkeep in healthy people, the US National Institutes of Health sets the recommended intake at 600 IU (15 mcg) a day for most adults, and 800 IU (20 mcg) after age 70. The upper limit without medical supervision is 4,000 IU (100 mcg) a day. Vitamin D dissolves in fat, so take it with a meal that contains some fat.

Safe sun exposure

Short, regular exposure helps. A commonly cited guide is about 5 to 30 minutes around midday, a couple of times a week, with the face, arms and legs uncovered. People with darker skin, or who keep most of their skin covered, need longer or another source. Glass blocks the UV rays that make vitamin D, so sitting by a window does not count. Move into shade before the skin turns pink, because sunburn raises skin cancer risk. Sunlight rarely fixes a confirmed deficiency on its own.

Vitamin D-rich foods

Food seldom corrects deficiency, but it helps prevent it:

• Oily fish such as salmon, sardines and mackerel

• Egg yolks (one large egg provides about 41 IU)

• Liver, in small portions

• Fortified foods: check labels for added vitamin D in milk, oils, cereals and juices

Retest and follow up

Doctors usually retest after about three months to confirm the level has risen, then adjust the dose. Do not continue high-dose treatment for longer than prescribed.

More is not better

Vitamin D toxicity is rare and comes from supplements, not sunlight. It raises blood calcium and can cause nausea, vomiting, weakness and kidney problems. Stay within your prescribed dose.

Vitamin D Myths and Facts

When to See a Doctor

Book a visit and ask about a vitamin D test if you notice any of these:

• Persistent bone or lower back pain

• Muscle weakness, such as trouble climbing stairs or rising from a chair

• Repeated fractures or falls

• Bowed legs or delayed walking in a child

• Pregnancy, or planning a pregnancy

• Kidney, liver or digestive disease

If you are already taking supplements, see a doctor promptly for nausea, vomiting, extreme thirst or confusion.

Conclusion

Vitamin D deficiency is common, easy to miss and straightforward to fix. Know the risk factors, get a 25-hydroxyvitamin D blood test if you have symptoms, and follow your doctor's dose. Add short midday sun exposure and vitamin D-rich foods, then retest after about three months.

Share this guide with family members who feel constantly tired or have unexplained body pain, and encourage them to get tested rather than guess.

Medical note: this guide is for general information and does not replace advice from a qualified doctor. Do not start high-dose supplements without medical advice.

Frequently Asked Questions

How long does it take to fix vitamin D deficiency?

Most people need several weeks to a few months of supplementation to reach an adequate level. Doctors usually retest after about three months and adjust the dose. Energy and muscle aches may improve gradually over that time, while bone strength recovers more slowly, so keep taking the dose your doctor recommends.

Can I get enough vitamin D from sunlight alone in Pakistan?

Often not. Despite the sunshine, most Pakistani studies find widespread deficiency, because indoor work, covered skin, darker skin and sunscreen reduce how much the skin makes. Short midday exposure helps, but a confirmed deficiency usually needs a supplement. Ask your doctor to test your level first.

Which is better, vitamin D2 or D3?

Both raise vitamin D levels, but D3 (cholecalciferol) tends to raise blood levels more effectively and is widely used. Your doctor may prescribe either one, depending on availability and your needs. Do not switch between them or combine brands without medical advice, because doses can add up.

Can vitamin D deficiency cause hair loss?

The evidence is limited and unclear. Hair loss has many other common causes, including low iron, thyroid problems, stress and genetics. If you are losing more hair than usual, ask a doctor to check vitamin D, iron and thyroid levels together rather than assuming one cause.

Should I take vitamin D with food?

Yes. Vitamin D is fat-soluble, so it is absorbed better with a meal that contains some fat, such as eggs, yogurt or nuts. Follow the timing on your prescription or the label. A weekly capsule should be taken on the same day each week.

Is it safe to take vitamin D every day without a test?

For most adults, daily intake up to 4,000 IU (100 mcg) is considered unlikely to cause harm, according to the US National Institutes of Health. Higher doses should only be taken under medical supervision. A blood test is the only way to know whether you need a supplement and how much.

Can children and pregnant women have vitamin D deficiency?

Yes. In the National Nutrition Survey 2011, 70% of pregnant women in Pakistan were deficient, and deficiency in children can cause rickets. Ask a doctor or paediatrician about the safe dose for pregnancy, infants and children. Do not guess the dose or share an adult's supplement.