A Complete Guide on How to get vitamin D: Sources, Supplements, and Safety

October 4, 2025 •

3 min read

According to the National Health and Nutrition Examination Survey (NHANES), nearly one-third of the US population has inadequate levels of vitamin D. Known as the "sunshine vitamin," vitamin D is crucial for absorbing calcium and plays a vital role in bone density, muscle function, and immune health. Understanding how to get vitamin D safely is essential for maintaining your overall health and well-being.

Quick Summary

This guide details the primary sources for obtaining vitamin D, including natural sunlight exposure, food sources like fatty fish and fortified products, and supplements. It explains how to maximize your intake, differentiate between D2 and D3, and prevent deficiency-related health issues.

Key Points

Sunlight is Key: Brief, safe sun exposure, especially around midday, is the most natural way to boost your vitamin D, but factors like location and skin tone affect production.
D3 is Often More Effective: Vitamin D3 from animal sources and supplements is generally considered more potent and effective at raising blood levels than plant-based D2.
Dietary Sources are Important: Incorporate fatty fish like salmon and mackerel, egg yolks, and UV-exposed mushrooms, along with fortified foods like milk and cereals, into your diet.
Supplements Ensure Consistency: For those with limited sun exposure, supplements, particularly D3, are a reliable option to maintain adequate levels, especially when taken with a fat-containing meal for better absorption.
Deficiency Poses Serious Risks: Lack of vitamin D can lead to bone disorders like rickets and osteoporosis, as well as fatigue, muscle pain, and weakened immunity.

The Sun: Your Primary Source for Vitamin D

Sunlight is the most natural way for your body to produce vitamin D through exposure to ultraviolet B (UVB) rays on bare skin. However, balancing sufficient sun exposure for vitamin D with protection from harmful UV radiation to prevent skin cancer is crucial.

Factors Influencing Sun-Derived Vitamin D

Several factors affect how much vitamin D your skin can produce from the sun:

Geographic Location and Season: Your distance from the equator and the time of year significantly impact UVB effectiveness. In higher latitudes, minimal vitamin D production occurs during winter months.
Time of Day: Midday, when the UV index is highest, is the most efficient time for vitamin D synthesis. A short amount of exposure during this time may be sufficient for some. You can use the 'shadow rule' – if your shadow is shorter than your height, UVB is adequate.
Skin Tone: More melanin in darker skin acts as a natural sunblock, requiring more sun exposure compared to lighter skin for the same amount of vitamin D.
Sunscreen and Clothing: Sunscreen with SPF 8 can significantly reduce vitamin D production. Brief unprotected exposure before applying sunscreen may be beneficial.

Food Sources: Naturally Occurring and Fortified

Dietary intake of vitamin D is important, especially when sun exposure is limited. While few foods naturally contain high amounts, many are fortified.

Natural Food Sources

Good natural sources include:

Fatty Fish: Salmon, tuna, mackerel, and sardines are rich in vitamin D3.
Fish Liver Oils: Cod liver oil is a potent source of vitamin D3.
Egg Yolks: Especially from pasture-raised chickens.
Mushrooms: The only significant plant source, producing vitamin D2 when exposed to UV light.
Beef Liver: Contains smaller amounts.

Fortified Food Sources

Fortified foods are a key source for many:

Milk and Milk Alternatives: Cow's milk and plant-based options are often fortified.
Cereals and Orange Juice: Many brands are fortified.
Yogurt and Margarine: Can also be fortified.

Supplements: A Reliable Alternative

Supplements are often the most reliable way to maintain adequate vitamin D, particularly for those with limited sun exposure or absorption issues.

Vitamin D2 vs. Vitamin D3

Vitamin D comes as D2 (plant-based) and D3 (animal-based and sun-produced).


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Source	Plants and fungi (mushrooms) exposed to UV light	Animal products (oily fish, egg yolks) and human skin exposed to sunlight
Availability	Prescription-only in high doses, found in some fortified foods	Over-the-counter supplements, naturally in animal-based foods
Effectiveness	Increases vitamin D levels, but may be less effective at sustaining them long-term	More effective at raising and maintaining blood vitamin D levels over time
Absorption	Absorbed effectively, but metabolized differently by the liver	Absorbed well, especially with fat-containing meals

How and When to Take Supplements

With Food: Take supplements with a meal containing fat for better absorption.
Consistency: Regular intake is key to maintaining stable levels.
Guidance: Consult a healthcare provider for personalized advice, as individual needs vary.

The Health Risks of Deficiency

Vitamin D deficiency is common and linked to health problems. It causes rickets in children (soft, deformed bones) and osteomalacia/osteoporosis in adults (soft/brittle bones, increased fracture risk). Other symptoms include:

Fatigue and tiredness
Bone and muscle pain/weakness
Depressed mood
Increased infections
Slower wound healing
Hair loss

Conclusion

Maintaining adequate vitamin D is vital for bone and immune health. A combination of safe sun exposure, dietary sources like fatty fish and fortified foods, and D3 supplements during less sunny periods is often the best approach. Individuals at higher risk, such as those with darker skin, older adults, or certain medical conditions, should seek personalized advice from a healthcare provider, potentially including a blood test for vitamin D levels. Proactive measures ensure sufficient intake of this essential nutrient year-round.

Frequently Asked Questions

For most fair-skinned adults during the summer, exposing your face, arms, and legs for a short period around midday a few times a week may be sufficient. People with darker skin or those living far from the equator will need more time.

The best natural sources are fatty fish like salmon, sardines, and tuna, as well as cod liver oil, egg yolks, and certain UV-exposed mushrooms.

While both forms increase blood levels, studies suggest that vitamin D3 is more effective at raising and maintaining those levels for a longer period. Many healthcare providers recommend D3 for supplementation.

As a fat-soluble vitamin, D is best absorbed with a meal or snack containing fat, regardless of the time of day. Consistency is the most important factor, so pick a time that works for your daily routine.

Symptoms can be subtle and include fatigue, bone or muscle pain, muscle weakness, mood changes like depression, frequent illnesses, and hair loss.

No, your skin regulates the amount of vitamin D it produces and prevents toxicity from overexposure. However, excessive sun exposure increases the risk of skin damage and skin cancer, so moderation and sun protection are key.

For many, fortified foods can help, but they may not be enough, especially during winter months or for those with increased needs. A balanced approach combining diet, sun, and potentially supplements is often recommended.

Individuals with darker skin, older adults, people with limited sun exposure, those with malabsorption syndromes (like Celiac disease), and those with obesity are at higher risk.