What ethnicity has the lowest vitamin D?

October 24, 2025 •

3 min read

According to data from the National Health and Nutrition Examination Surveys, non-Hispanic Black individuals often have the lowest mean vitamin D levels in the United States. This complex topic explores why specific ethnic groups have lower vitamin D and what factors are involved, such as melanin content and geographical location.

Quick Summary

This article examines the biological and environmental reasons why non-Hispanic Black and some South Asian populations typically show lower circulating vitamin D levels. It explores the role of melanin, migration, and other factors, addressing the 'vitamin D paradox' and the differing health implications across ethnic groups.

Key Points

Lowest Levels: Non-Hispanic Black Americans typically have the lowest mean circulating vitamin D levels in the United States, based on NHANES data.
Role of Melanin: The primary biological reason for this disparity is higher skin melanin content, which acts as a natural UV-B blocker and reduces the skin's ability to produce vitamin D from sunlight.
Geographical Mismatch: Dark-skinned populations living far from the equator receive insufficient UV-B radiation, leading to lower vitamin D synthesis, especially in winter.
Cultural Factors: In addition to skin tone, cultural clothing practices and habits that limit sun exposure also contribute to low vitamin D in some populations, such as South Asians.
The Vitamin D Paradox: Despite lower levels, some ethnic groups like African Americans exhibit better bone health outcomes, suggesting that standard deficiency definitions may need re-evaluation for different populations.
Actionable Steps: Individuals with risk factors, including darker skin, should discuss testing and supplementation with a healthcare provider to ensure optimal vitamin D intake, especially with limited sun exposure.

Understanding Vitamin D Synthesis

Vitamin D is a fat-soluble nutrient essential for bone health and many other biological processes. The primary natural source for most people is synthesis in the skin, which occurs when exposed to ultraviolet B (UV-B) radiation from sunlight. The body converts 7-dehydrocholesterol into vitamin D3, which is then metabolized by the liver and kidneys into its active form. Dietary intake of fortified foods and fatty fish also contributes, but is often insufficient on its own.

The Role of Melanin and Skin Pigmentation

Skin pigmentation significantly influences vitamin D production. Melanin, which gives skin its color, absorbs UV-B radiation, protecting against sun damage and skin cancer. However, this reduces the skin's ability to synthesize vitamin D from the sun. Individuals with darker skin tones, such as those of African descent, require more sun exposure to produce the same amount of vitamin D as those with lighter skin.

Disparities in Vitamin D Levels by Ethnicity

Studies consistently show disparities in vitamin D levels across ethnic groups. Non-Hispanic Black Americans frequently exhibit the lowest levels in the U.S.. Contributing factors include higher melanin content, which limits vitamin D synthesis from sunlight, geographical location shifts from high-UV regions to areas with less sun, and cultural practices that reduce sun exposure, as seen in some South Asian and Middle Eastern populations. Dietary habits, such as lower intake of fortified foods, can also play a role.

The "Vitamin D Paradox" in African Americans

Despite often having lower circulating vitamin D levels, African Americans may show better bone health outcomes, like higher bone mineral density and fewer fractures, compared to white Americans. This leads to questions about whether standard vitamin D deficiency definitions, largely based on white populations, are universally applicable. Possible explanations involve genetic differences affecting vitamin D use, more efficient calcium absorption and retention, and parathyroid hormone (PTH) regulation. This paradox highlights the need for more research on race-specific optimal vitamin D levels.

Comparison of Vitamin D Deficiency by Ethnicity (U.S.)

Data from NHANES surveys provides insight into vitamin D status among U.S. ethnic groups. For example, NHANES data from 2001–2010 for non-supplement users indicated a 75% prevalence of deficiency (<20 ng/mL) in Non-Hispanic Black individuals, compared to 20% in Non-Hispanic White individuals. Prevalence of severe deficiency (<10 ng/mL) was 17% in Non-Hispanic Black individuals and 1% in Non-Hispanic White individuals. Hispanic individuals had a 44% prevalence of deficiency, while Asian healthy adults showed a 63% prevalence of deficiency.

Strategies for Improving Vitamin D Status

Addressing low vitamin D is important. Strategies include considering supplementation, especially for those with darker skin at higher latitudes (consult a doctor); safe, moderate sun exposure, keeping in mind skin cancer risks; increasing dietary intake of vitamin D-rich foods and fortified items; and managing associated medical conditions or medications.

Conclusion

Non-Hispanic Black populations and some South Asian groups frequently exhibit the lowest circulating vitamin D levels due to a combination of biological, environmental, and social factors. The higher melanin content in darker skin reduces vitamin D synthesis from sunlight. However, the 'vitamin D paradox,' where groups like African Americans show good bone health despite lower levels, suggests that optimal vitamin D requirements might differ across populations. Further research is needed, and a personalized approach to supplementation and sun exposure is advisable for maintaining adequate vitamin D.

For more detailed information, consult resources like the {Link: NCBI article https://pmc.ncbi.nlm.nih.gov/articles/PMC7913332/} and the {Link: National Institutes of Health Vitamin D Fact Sheet https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/}.

Frequently Asked Questions

People with darker skin have more melanin, a pigment that protects against UV radiation. While this is beneficial for reducing skin cancer risk, it also blocks the UV-B rays necessary for the skin to produce vitamin D, resulting in lower levels.

No. Studies show high rates of vitamin D deficiency even in sunny countries, particularly in the Middle East and South Asia. Factors like limited outdoor activity, use of sun-blocking clothing, and air pollution can hinder vitamin D synthesis despite ample sun.

The 'vitamin D paradox' refers to the phenomenon where certain populations, like African Americans, have lower circulating vitamin D levels but better bone health (e.g., higher bone mineral density) compared to white populations. This suggests that genetic and metabolic differences may alter vitamin D requirements.

It is difficult for most people to meet their vitamin D requirements from natural food sources alone. While foods like fatty fish and fortified milk help, most vitamin D is synthesized through sun exposure, and supplementation is often recommended for at-risk individuals.

Besides individuals with darker skin, other high-risk groups include breastfed infants, older adults (due to reduced skin synthesis), people with limited sun exposure (e.g., homebound or institutionalized), and those with certain health conditions like obesity or fat malabsorption disorders.

Many healthcare professionals recommend that individuals with darker skin, particularly those living far from the equator, discuss supplementation with their doctor. Studies have shown that supplementation can improve vitamin D status in these populations.

The official dietary reference intakes (DRIs) are generally universal, but research continues to suggest that optimal vitamin D levels and responses to supplementation might vary by ethnicity. Individualized medical assessment is crucial for determining adequate levels and dosages.