7 unexpected advantages of vitamin D that extend beyond bone health

Vitamin D, often called the sunshine vitamin, contributes far more than just bone strength. This essential nutrient influences multiple body functions, including immunity, brain health, and more. Unlike many vitamins, it is not abundant in most foods; the body primarily produces it when the skin is exposed to sunlight under the right conditions. Ongoing research continues to uncover additional ways vitamin D supports overall wellness.

Despite its importance, vitamin D deficiency remains widespread. A 2023 study in Frontiers of Nutrition reported that 15.7% of people worldwide lack adequate vitamin D, with higher rates in women and those living at higher latitudes. In the U.S., a 2022 NHANES study found that up to 40% of adults may not meet their daily vitamin D requirements.

Heres a closer look at the ways vitamin D can enhance your health and how to ensure youre getting enough.

1. Supports Immune Function

Vitamin D is critical for a strong immune system. It helps the body combat infections and boosts production of antibacterial proteins. A 2023 Nutrients review found that vitamin D activates immune cells to protect against illness, while low levels are linked to increased inflammation and higher susceptibility to infections. Adequate vitamin D may also influence the risk of autoimmune conditions such as rheumatoid arthritis, lupus, and inflammatory bowel disease. Supplements can help those who are deficient, though excess intake doesnt necessarily prevent common colds or flu.

2. Heart Health

Emerging research indicates vitamin D may support cardiovascular health by regulating blood pressure, maintaining healthy blood vessels, and reducing chronic inflammation. A 2025 Nutrients review suggests that optimal vitamin D levels could lower heart disease risk factors and potentially reduce the risk of major cardiovascular events, such as heart attack or stroke, by up to 17%. Personalized vitamin D therapy in adults with heart disease showed a 52% lower risk of heart attack in a preliminary study presented at the American Heart Association 2025 Scientific Sessions.

3. Bone and Muscle Health

Vitamin D facilitates calcium absorption, essential for strong bones and teeth. Insufficient vitamin D can lead to weaker bones and higher fracture risk. Additionally, vitamin D supports muscle health by aiding protein synthesis and reducing inflammation. A 2023 review reported that 2,000 IU daily for at least a week reduced muscle damage and inflammation after exercise.

4. Hair and Skin Support

Vitamin D is linked to healthier hair and skin. It strengthens hair follicles, potentially reducing hair loss, and protects skin from oxidative stress and inflammation. A 2024 review noted vitamin D deficiency is common in certain hair loss conditions, such as female pattern baldness and alopecia areata. Vitamin D also promotes wound healing by activating skin stem cells, though exceeding recommended doses wont enhance these effects.

5. Brain Health

Vitamin D regulates neurotransmitters, reduces inflammation, and protects neurons, supporting memory and cognitive function. A 2025 Journal of Alzheimers Disease review found higher vitamin D levels were associated with improved memory in adults over 60. Observational studies suggest adequate vitamin D may lower dementia risk by reducing inflammation and regulating calcium in the brain.

6. Gut Health

Vitamin D may help maintain a balanced gut microbiome. Research shows it strengthens the intestinal barrier, preventing harmful bacteria and toxins from entering the bloodstream, and can positively influence gut bacterial diversity. A 2025 review indicated healthy vitamin D levels might reduce gut inflammation and support digestive health.

7. Aging and Longevity

Vitamin D supports healthy aging by maintaining muscle, bone, and brain health. Early research suggests it may slow aging; a 2025 randomized trial found that 2,000 IU daily for four years reduced telomere shortening, a marker of cellular aging. Its anti-inflammatory and immune-supporting properties may help preserve cellular function over time.

Recommended Intake

The Recommended Dietary Allowance (RDA) varies by age and condition. For pregnancy and breastfeeding, it is 15 mcg (600 IU). Individual needs may differ, especially for those with darker skin or limited sun exposure. Consulting a healthcare provider is the best way to determine personal requirements.

Sources of Vitamin D

Vitamin D can be obtained from sunlight, foods, and supplements. Rich dietary sources include fatty fish (salmon, mackerel, sardines), egg yolks, beef liver, and cheese, as well as fortified foods like milk, plant-based alternatives, orange juice, and cereals. Vitamin D3 (cholecalciferol) from animal sources is more effective than D2 (ergocalciferol) from plant sources at maintaining optimal blood levels.

Supplement Guidance

Supplements can help meet vitamin D needs, especially when dietary intake or sun exposure is insufficient. Nordic Naturals offers a vitamin D3 softgel with 2,000 IU vitamin D3 and 90 mcg vitamin K2, supporting calcium utilization. All supplements are third-party tested for purity and potency.

Deficiency and Safety

Vitamin D deficiency can be subtle and is confirmed only by blood testing. Excess vitamin D can be harmful, causing elevated calcium, fatigue, bone pain, nausea, or kidney issues. It can also interact with medications. Regular monitoring and adherence to Tolerable Upper Intake Levels are essential.

Conclusion

Vitamin D is crucial for immune function, heart, bone, muscle, hair, skin, brain, gut health, and aging. Ensuring adequate intake through a combination of sunlight, food, and supplements can provide wide-ranging health benefits while avoiding risks of excess.

Sources cited include research reviews from Nutrients and the Journal of Alzheimers Disease, along with insights from registered dietitians Helen Tieu, Sapna Peruvemba, and Anne Murray.

Author: Sophia Brooks