What can I eat to increase vitamin D?

Vitamin D supports bone health, immune function and calcium metabolism. While skin synthesis from sunlight is the primary source for many people, diet and supplements are important to maintain steady levels—especially in winter, at high latitudes, or when sun exposure is limited. This article reviews the most reliable dietary sources, differences between forms of vitamin D, and practical tips to improve absorption.

Key dietary sources

Animal-based foods typically provide vitamin D3 (cholecalciferol), which raises serum vitamin D more effectively than vitamin D2. The highest natural sources include fatty fish such as salmon, mackerel, trout and sardines. For example, a 100 g portion of wild salmon can supply several hundred IU of vitamin D. Egg yolks and certain organ meats (notably beef liver) contain modest amounts, while many dairy products and cereals are fortified with either D2 or D3.

Fungi such as maitake and UV-exposed shiitake mushrooms synthesize vitamin D2 (ergocalciferol) when exposed to ultraviolet light. Although D2 is less potent than D3 on a per-unit basis, sun-exposed mushrooms and fortified plant milks can be meaningful options for vegetarian and vegan diets.

Improving absorption and utilization

Vitamin D is fat-soluble, so consuming vitamin D-rich foods with dietary fat improves intestinal absorption. Pairing fortified cereal with milk, eating salmon with olive oil–based dressings, or including avocado or nuts in a meal are simple ways to enhance uptake. Cofactors such as magnesium and vitamin K2 also influence vitamin D metabolism: magnesium is required for enzymatic activation, and K2 helps direct calcium into bone rather than soft tissues.

Omega-3 fatty acids from fatty fish or algae may support the anti-inflammatory environment that allows fat-soluble vitamins to function effectively, though they do not directly increase vitamin D content.

Practical meal strategies

To distribute intake throughout the day, include at least one dietary source of vitamin D at a main meal: a fortified breakfast option, a fish-based lunch or eggs for breakfast. For plant-based eaters, combine fortified plant milks, UV-exposed mushrooms and fortified cereals to reach recommended intakes. Regular consumption of fortified foods helps offset seasonal variability in sunlight-derived vitamin D.

Testing and supplementation considerations

Because dietary intake alone may be insufficient for some individuals, measurement of 25(OH)D blood levels is the most reliable way to assess status. When supplementation is indicated, cholecalciferol (D3) is generally preferred for efficacy; dosing should be guided by baseline levels and clinical context. For additional reading about nutrient absorption and supplement strategies, see this overview of B12 absorption and guidance on maximizing supplement benefits, which discuss related principles of micronutrient uptake.

For a concise external summary about nutrient absorption approaches, consult this Telegraph overview of B12 absorption. For a focused review of dietary and supplemental vitamin D in the context of this topic, see the related resource at What can I eat to increase vitamin D? and general information on the main site at Topvitamine.

Summary

Prioritize fatty fish, egg yolks, liver and fortified foods to increase dietary vitamin D, consume these foods with healthy fats to improve absorption, and consider measurement of serum 25(OH)D to determine whether supplements are needed. Addressing cofactors such as magnesium and vitamin K2 can further support appropriate vitamin D metabolism.