Understanding Which US Population Group is at Highest Risk for Vitamin D Deficiency?

October 17, 2025 •

4 min read

According to a 2005–2006 analysis of the National Health and Nutrition Examination Survey (NHANES), 82.1% of Black adults in the US had a vitamin D deficiency. This data underscores why African Americans are identified as the US population group at highest risk for vitamin D deficiency, a disparity linked to biological and socioeconomic factors.

Quick Summary

Vitamin D deficiency affects several US groups, with African Americans having the highest prevalence. This is largely due to increased melanin content in darker skin, which reduces vitamin D production from sunlight. Other factors include limited sun exposure, age, obesity, malabsorption conditions, and diet.

Key Points

Highest Risk Group: African Americans have the highest prevalence of vitamin D deficiency in the US, with over 80% at risk, primarily due to higher skin melanin content.
Melanin's Effect: Increased melanin in darker skin tones blocks UVB radiation, significantly reducing the skin's ability to synthesize vitamin D from sunlight.
Other Risk Populations: Hispanic individuals, older adults, people with obesity, and those with malabsorption disorders also face a high risk of deficiency.
Health Impacts: Untreated deficiency can lead to severe health issues, including osteomalacia, osteoporosis, muscle weakness, and impaired immune function.
Prevention Strategies: Solutions include dietary sources (fatty fish, fortified foods), controlled sun exposure, and, most importantly for high-risk individuals, supplementation.
Health Equity Concern: The disproportionate prevalence of vitamin D deficiency among minority groups represents a significant health disparity that requires targeted public health interventions.

The Highest Risk Population: African Americans

Data from health surveys consistently show African Americans face the highest risk of vitamin D deficiency in the US. The main biological reason is the higher concentration of melanin in darker skin tones. Melanin absorbs ultraviolet B (UVB) radiation, protecting against sun damage but reducing the skin's ability to produce vitamin D from sunlight. People with darker skin need more sun exposure for the same vitamin D production as those with lighter skin. This, combined with other factors, makes deficiency common in this group.

Other At-Risk Population Groups and Contributing Factors

Beyond African Americans, other groups also have a higher risk of low vitamin D levels, often due to overlapping factors.

Hispanic Individuals

Data also indicates a high prevalence among Hispanic adults. The 2005–2006 NHANES found 62.9% were deficient, second only to Black adults. This is linked to factors similar to those affecting African Americans, such as higher skin pigmentation and possibly dietary or lifestyle differences.

Older Adults

Older age increases risk as the skin's ability to make vitamin D from sun declines, and seniors often spend more time indoors. A significant number of older adults in care facilities are deficient. Kidney function changes with age can also affect vitamin D activation.

People with Obesity

Individuals with a BMI of 30 or higher often have lower vitamin D levels. Body fat stores vitamin D, reducing its circulation. Higher supplement amounts may be needed for those with obesity.

Individuals with Limited Sun Exposure

Anyone with minimal sun exposure is at risk, including those who are homebound, live in northern areas, cover their skin, or frequently use sunscreen. Lack of sun significantly impacts vitamin D status.

People with Malabsorption Disorders

Conditions impairing fat absorption, such as celiac disease, cystic fibrosis, Crohn's disease, and short bowel syndrome, can hinder vitamin D absorption.

Health Consequences of Deficiency

Vitamin D is vital for bone health, muscles, immune function, and cell growth. Deficiency can cause:

Bone issues: Softening of bones (osteomalacia/rickets) and osteoporosis, increasing fracture risk.
Muscle weakness: Can increase fall risk, especially in older adults.
Immune function: May increase susceptibility to infections.
Chronic diseases: Research is exploring links to heart disease, diabetes, and certain cancers.

Comparison of Risk Factors for Vitamin D Deficiency


Risk Factor	Higher Risk: Dark-Skinned Individuals (e.g., African/Hispanic)	Higher Risk: Light-Skinned Individuals
Melanin Content	Higher melanin significantly blocks UVB, slowing synthesis.	Lower melanin allows efficient UVB absorption and rapid synthesis.
Sun Exposure Required	Needs substantially longer sun exposure for equivalent vitamin D.	Requires less time in the sun for sufficient vitamin D.
Sunsynthesis Efficiency	Less efficient, raising baseline risk, particularly in winter or higher latitudes.	More efficient, but still at risk in winter or with limited exposure.
Health Disparities	Disproportionately affected, often facing additional socioeconomic and dietary factors.	Lower baseline risk but susceptible due to age, obesity, or limited sun exposure.

Strategies for Prevention and Management

A combination of approaches is key for high-risk groups to maintain adequate vitamin D.

Dietary Sources: Include fatty fish (salmon, mackerel, tuna), fish liver oils, and egg yolks.
Fortified Foods: Many US foods are fortified, including milk, some cereals, and juices.
Supplements: Often needed, especially for high-risk individuals. Higher amounts may be recommended for those with obesity or malabsorption. Supplements are available as D2 and D3, with D3 generally considered more effective. Consult a doctor for personalized guidance.
Sensible Sun Exposure: Brief sun exposure without sunscreen can help, balancing benefit with skin cancer risk.

Conclusion

A large portion of the US population has low vitamin D, with African Americans facing the highest risk. This is mainly due to melanin's impact on synthesis, compounded by socioeconomic factors. Addressing this requires targeted strategies combining diet, supplements, and informed sun exposure to promote health equity. High-risk individuals should consult a healthcare provider to check their levels and discuss options.

The Role of Genetic and Environmental Factors

Genetic differences in how the body handles vitamin D can affect deficiency risk. Variations in vitamin D-binding protein may play a role in people of African descent, though research continues. Environmental factors like where one lives (latitude), diet, and spending time indoors also contribute, particularly seasonally.

The Need for Personalized Nutritional Guidance

A personalized approach is essential. Public health efforts must recognize the higher prevalence and unique challenges for the US population group most at risk for vitamin D deficiency. This means improving access to fortified foods in underserved areas and providing clear, tailored supplement advice based on factors like race, age, and health. Consulting a dietitian or endocrinologist can help develop a plan.

Supporting Overall Health

Correcting a vitamin D deficiency enhances bone and muscle health and contributes to general well-being, potentially boosting energy, mood, and immune function. Given possible links to chronic diseases, managing vitamin D is a valuable strategy, especially for high-risk groups like African Americans.

Frequently Asked Questions

Melanin, the pigment responsible for darker skin, absorbs UVB radiation from the sun. Since UVB is necessary for the skin to produce vitamin D, higher melanin content reduces the amount of vitamin D synthesized, leading to a higher risk of deficiency.

Yes, older adults are a high-risk group. Their skin's ability to synthesize vitamin D decreases with age, and many spend less time outdoors, limiting their sun exposure.

Vitamin D is fat-soluble and can be sequestered in body fat. In individuals with obesity, a greater amount of the vitamin is stored in fatty tissue, making less of it available for biological functions in the bloodstream.

Medical conditions that cause fat malabsorption, such as celiac disease, cystic fibrosis, and Crohn's disease, can interfere with vitamin D absorption. Chronic liver or kidney disease also impairs the body's ability to activate vitamin D.

It is difficult to get sufficient vitamin D from unfortified food sources alone, as very few foods contain it naturally in significant amounts. Many people rely on fortified foods, supplements, and sun exposure to meet their needs.

Severe vitamin D deficiency can cause rickets in children and osteomalacia in adults, leading to soft bones and deformities. It is also linked to muscle weakness, fatigue, a weakened immune system, and increased risk of fractures.

High-risk individuals can prevent deficiency through a combination of strategies, including increasing intake of dietary vitamin D and fortified foods, using supplements (as advised by a healthcare provider), and getting sensible sun exposure while protecting against sunburn.