What Country Has the Worst Vitamin D Deficiency?

November 12, 2025 •

4 min read

According to international health research, paradoxically, some of the highest rates of vitamin D deficiency are found in sunny regions like the Middle East and South Asia, challenging the assumption that limited sunlight exposure is the sole cause. This article investigates what country has the worst vitamin D deficiency and explores the complex underlying factors.

Quick Summary

This analysis reveals that countries in the Middle East and South Asia experience the highest prevalence of vitamin D deficiency, often due to cultural practices, diet, urbanization, and lifestyle factors.

Key Points

High-Prevalence Regions Are Often Sunny: Contrary to popular belief, regions with abundant sunshine like the Middle East and South Asia exhibit some of the highest rates of vitamin D deficiency.
Cultural Practices Limit Sun Exposure: Traditional clothing that covers most of the body, combined with sun avoidance in hot climates, is a primary driver of deficiency, especially in women.
Dietary and Lifestyle Factors Play a Major Role: Low dietary intake of vitamin D, lack of food fortification, and a shift towards urban, indoor lifestyles contribute significantly to the problem.
Darker Skin Increases Risk: Higher melanin content in darker skin reduces its ability to produce vitamin D from sunlight, making individuals with darker skin more susceptible.
Effective Interventions Exist: Strategies like targeted supplementation, mandatory food fortification, and culturally sensitive educational campaigns have proven successful in improving vitamin D status in various countries.
A Problem Beyond Latitude: The global data demonstrates that vitamin D status is determined by a complex interplay of geography, culture, and public health policies, not just a country's location.

The Global Picture: High-Prevalence Regions

For many, the first thought might be that countries with cold climates and limited sunlight would suffer the most from vitamin D deficiency. However, a significant body of research indicates that the highest prevalence rates are often concentrated in regions with abundant sunshine, particularly the Middle East and South Asia. A meta-analysis published in The Lancet Global Health in 2019 suggested that Africa could be the continent with the highest frequency of severe vitamin D deficiency, a finding that challenges conventional wisdom. Meanwhile, other studies have highlighted the extreme rates in the Middle East, with some reports showing very high deficiency rates in children, adolescents, and women, especially. Specific countries frequently mentioned for their high deficiency rates include Iran, Saudi Arabia, and Turkey, where percentages can be alarmingly high. Similar issues plague South Asia, where India and Pakistan also show high prevalence. This complex picture underscores that the cause of deficiency is not a simple matter of latitude.

The Complex Factors Behind Deficiency

Several interconnected factors contribute to the paradox of high vitamin D deficiency in sunny countries. The issue is a blend of cultural habits, dietary choices, and population demographics that override the benefits of plentiful solar radiation.

Why Sun-Drenched Regions Suffer

While sun exposure is the primary way humans produce vitamin D, several factors limit its effectiveness even in sunny climates. The first is human behavior, specifically related to sun avoidance. In many very hot regions, people tend to stay indoors during the peak hours of sunlight to avoid the heat, drastically cutting down on potential sun-induced vitamin D synthesis. The widespread use of sunscreen, while important for skin cancer prevention, also blocks the ultraviolet B (UVB) rays necessary for vitamin D production, adding another layer of complexity to public health recommendations. Furthermore, air pollution in large urban centers can scatter UVB radiation, further reducing its availability for skin synthesis.

Cultural Practices and Limited Exposure

Cultural and religious clothing practices play a dominant role in certain regions, particularly in the Middle East and South Asia. Full-body coverings significantly block skin exposure to the sun, regardless of how much time is spent outdoors. This is a key reason why deficiency rates are often higher among women in these countries. In Lebanon, for instance, a survey revealed that vitamin D deficiency was common, particularly in veiled women.

Diet and Lifestyle Factors

Dietary intake is another crucial piece of the puzzle. The natural diet in many of these regions lacks sufficient vitamin D sources like fatty fish. Moreover, many countries lack comprehensive food fortification programs, a strategy that has successfully improved vitamin D status in other parts of the world, like Finland and Canada. The global trend of urbanization also contributes, as urban dwellers tend to have more sedentary, indoor lifestyles than rural populations. This shift impacts sun exposure and can lead to higher obesity rates, as body fat can sequester vitamin D and reduce its availability. Finally, darker skin pigmentation, a genetic adaptation to intense sun, makes it harder for individuals to produce vitamin D in their skin, further increasing their vulnerability.

Global Prevalence: A Comparative Table

To illustrate the global disparity, the table below compares vitamin D deficiency rates across different regions, based on various studies using a threshold of <50 nmol/L (or <20 ng/mL) for deficiency/insufficiency.


Region	Prevalence of Deficiency/Insufficiency (<50 nmol/L)	Key Contributing Factors
Middle East	Very High (Often >50%, up to 90% in some groups)	Cultural clothing, sun avoidance, low fortified food consumption
South Asia	Very High (Often >50%, especially in urban women and children)	Cultural clothing, urbanization, darker skin, low dietary intake
Europe	Moderate (Around 40% overall, but varies greatly)	Seasonal sun variation, dietary habits, and differing supplementation policies
Africa	Moderate (Around 34% overall, but higher in northern and southern regions)	Skin pigmentation, urbanization, and potential calcium deficiency
North America	Low to Moderate (Around 20-30%, higher in darker-skinned individuals)	Supplementation, food fortification, but also sun avoidance and skin pigmentation

Addressing the Epidemic: Global and Local Strategies

As the prevalence of vitamin D deficiency has risen, so has the need for effective public health interventions. Addressing the problem requires a multi-pronged approach that goes beyond simply advocating for more sun exposure.

Public Education: Widespread awareness campaigns can help educate the public about the risk factors and the importance of adequate vitamin D intake, especially in regions where traditional beliefs or practices might contribute to the deficiency.
Mandatory Food Fortification: Government-led programs to fortify staple foods like milk, dairy products, and cereals with vitamin D have been highly effective in countries like Finland. This approach can significantly boost population-wide levels without requiring individual behavioral changes.
Targeted Supplementation: High-risk groups, including breastfed infants, pregnant women, older adults, and those with limited sun exposure, should be encouraged and provided with supplements to ensure adequate intake.
Cultural Sensitivity: Health campaigns need to be culturally sensitive and offer solutions that work within existing social norms. For example, providing indoor UV-B light therapy or promoting supplementation can be effective for individuals whose clothing practices limit sun exposure.
Addressing Underlying Issues: Healthcare strategies should also address underlying health issues like obesity and malabsorption disorders that impact vitamin D metabolism.

The Path Forward: A Call for Awareness

Ultimately, pinpointing a single country as having the “worst” vitamin D deficiency is less accurate than recognizing a regional public health crisis affecting the Middle East and South Asia. The data reveal that a confluence of cultural practices, urbanization, genetics, and diet creates a complex environment where deficiency can thrive despite abundant sunshine. Addressing this global health issue requires a nuanced understanding of these regional differences and a commitment to implementing tailored and effective public health strategies. Awareness is the first step toward change, and empowering individuals with knowledge about their risk factors and options for supplementation is critical.

For more in-depth medical analysis, consult the comprehensive overview on Vitamin D Deficiency and Related Disorders provided by Medscape.

Frequently Asked Questions

In many sunny regions, particularly the Middle East and South Asia, high rates of deficiency occur due to cultural clothing practices limiting skin exposure, sun avoidance during peak heat, and low dietary intake, despite the abundant sunlight.

Yes. Darker skin contains more melanin, which acts as a natural sunscreen and reduces the skin's ability to produce vitamin D from sunlight. This means individuals with darker skin require more sun exposure to produce the same amount of vitamin D as someone with lighter skin.

The main causes include insufficient sun exposure (due to lifestyle, location, or clothing), inadequate dietary intake (as few foods naturally contain enough vitamin D), malabsorption disorders, certain medications, and chronic kidney or liver disease.

In many high-risk regions, especially in the Middle East, studies show vitamin D deficiency is significantly more common among women, which is often linked to cultural clothing styles that limit skin exposure.

It is very difficult for most people to get sufficient vitamin D from diet alone, as few natural foods are rich in it. Fortified foods and supplements are often necessary, especially when sun exposure is limited.

Not necessarily. Despite limited sunlight, many Northern European countries have relatively lower rates of deficiency compared to sunny regions due to widespread food fortification programs and the high use of supplements.

High-risk groups can improve their levels through controlled, safe sun exposure, increasing consumption of fatty fish and fortified foods, and taking supplements. Public health programs often focus on targeted education and supplementation for these populations.