How to Improve Vitamin D Levels: Food, Sunlight, Testing, and Supplements

Written by Tarishi Shrivastava | April 6, 2022

Introduction

Even though India receives substantial sunlight, low vitamin D levels can still occur because of limited sun exposure, skin pigmentation, diet, certain medical conditions, and other factors. Vitamin D is important for calcium absorption, bone health, muscles, nerves, and normal immune function.

If you are looking for how to improve vitamin D, the safest approach is to consider your diet, usual sun exposure and individual risk factors rather than relying on one method. Foods containing vitamin D can contribute to intake, while supplements may be appropriate when recommended by a healthcare professional.

What Is Vitamin D?

Vitamin D is a fat-soluble vitamin that helps the body absorb calcium and supports normal bone, muscle, nerve and immune function. There are two main forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol).

D2 is commonly produced by fungi and is found in some fortified foods and supplements, while D3 is produced in the skin after sunlight exposure and is also found in some animal-derived foods and supplements. Both can raise blood vitamin D levels.

For daily intake, the current recommended amount is generally 400 IU for infants up to 12 months, 600 IU for children and teens, 600 IU for adults up to 70 years, and 800 IU for adults over 70. Individual needs may differ.

Vitamin D Test

When testing is clinically appropriate, the usual blood test is 25-hydroxyvitamin D [25(OH)D]. It measures the total amount of vitamin D in the blood, including vitamin D2 and D3 metabolites.

There is no single blood level that applies as a universal treatment target for every person. Test results should be interpreted using the laboratory's reference range and the person's health history.

Vitamin D Deficiency and Range

• Vitamin D results are usually reported in nanograms per millilitre (ng/mL) or nanomoles per litre (nmol/L). The interpretation of 25(OH)D levels can vary between guidelines and laboratories.
• The 2024 Endocrine Society guideline noted that outcome-specific blood-level thresholds for disease prevention have not been firmly established.
• Very low vitamin D can contribute to problems such as rickets in children and osteomalacia in adults, particularly when calcium or phosphate intake is also inadequate.

Why Are Some Indians at Risk of Low Vitamin D?

Skin Pigmentation

Higher melanin levels can reduce the skin's production of vitamin D from sunlight. However, skin tone alone does not mean that someone has a deficiency or automatically needs testing or supplements.

Limited Sunlight Exposure

Spending most of the day indoors, covering much of the skin outdoors or having little direct sun exposure can reduce vitamin D production. Sunlight exposure should not be prescribed using one universal time because vitamin D production varies with factors such as season, location, skin pigmentation, clothing and time of day.

Obesity

People with obesity can have lower circulating vitamin D because vitamin D can be distributed into body fat. However, obesity alone does not mean that a person needs routine vitamin D testing.

What Is the Safest Way to Improve Vitamin D Levels?

If deficiency is suspected, start with appropriate medical advice and testing when indicated, rather than taking high-dose supplements on your own. A healthcare professional can consider your symptoms, diet, sun exposure, medications, and medical history.

For people who need to improve their intake, options may include vitamin-D-containing foods, fortified products, sensible outdoor activity and clinician-recommended supplements. The right supplement dose depends on age, health status, and whether an actual deficiency is present.

Vitamin D Sources at a Glance

Who Is More Likely to Need Testing?

Testing may be considered when a person has risk factors or symptoms associated with low vitamin D rather than as a routine check for everyone.

People who may warrant clinical assessment include those with limited sun exposure, darker skin, obesity, problems absorbing nutrients, certain kidney or liver conditions, or medicines that affect vitamin D metabolism. Bone pain, muscle weakness, fractures, or other signs of bone problems may also prompt testing.

The 2024 Endocrine Society guideline does not recommend routine 25(OH)D screening for generally healthy adults without an established indication.

Foods to Improve Vitamin D

Seafood and Fatty Fish

Fatty fish such as salmon, tuna, trout and mackerel are among the best natural food sources of vitamin D. Include properly cooked fish as part of a balanced diet where appropriate.

Egg Yolk

Egg yolks contain vitamin D, although the amount can vary. Eggs can contribute to overall intake alongside other vitamin-D-containing foods.

Mushrooms

Mushrooms can provide vitamin D2, particularly varieties exposed to ultraviolet light. Their vitamin D content varies considerably depending on how they are grown and processed.

Fortified Foods

Fortified milk, breakfast cereals, some plant-based drinks and other products can provide vitamin D. Since fortification varies, check the nutrition label before assuming a product contains vitamin D.

Supplements

Vitamin D supplements may be recommended when dietary intake is inadequate or deficiency has been identified. Both D2 and D3 can raise vitamin D levels, although some evidence suggests D3 may raise levels more effectively in certain circumstances.

Food, Sunlight, and Supplements: A Combined Approach

There is no single method for improving vitamin D for everyone. A balanced diet can provide vitamin D and other nutrients, while sensible outdoor activity can support natural vitamin D production.

When supplementation is needed, the dose should be based on individual requirements and professional guidance. People with conditions affecting absorption, metabolism or bone health may need a personalised approach.

Customized Strategy

Vitamin D requirements and treatment needs vary with age, diet, sun exposure, medical conditions and medicines. A supplement that is appropriate for one person may not be appropriate for another.

If you have concerns about low vitamin D, discuss whether testing is appropriate with your healthcare professional. If a deficiency is confirmed, follow the recommended dose and duration rather than choosing a high-dose product independently.

Conclusion

Learning how to improve vitamin D starts with understanding the possible causes of low levels and choosing safe sources. A varied diet containing vitamin-D-rich and fortified foods, sensible outdoor activity, and appropriate supplementation can all contribute to maintaining vitamin D status.

If deficiency is suspected, the practical next step is to speak with a healthcare professional about whether testing is appropriate and what treatment, if any, is needed. Avoid high-dose supplements without guidance because excessive vitamin D can be harmful.

Frequently Asked Questions

How can vitamin D levels be improved naturally?

Include foods containing vitamin D, choose fortified products and maintain sensible outdoor activity while considering individual sun-exposure factors.

Which foods contain vitamin D?

Fatty fish are among the best natural sources. Egg yolks, mushrooms and fortified milk, cereals and plant drinks can also provide vitamin D.

When should vitamin D levels be tested?

Testing may be appropriate when deficiency is suspected, symptoms or risk factors are present, or a healthcare professional recommends it. Routine screening is not advised for every healthy adult.

Can too much vitamin D be harmful?

Yes. Excessive vitamin D, usually from supplements, can raise blood calcium and cause nausea, weakness, kidney problems, and other complications.