Dietary Sources and Supplementation of Vitamin D

Introduction to Vitamin D Sources

The American College of Nutrition and the Proceedings of the Nutrition Society suggest that vitamin D occurs naturally in very few foods, with oily fish and eggs being the primary natural dietary sources, but these alone are insufficient to meet daily requirements, making fortified foods and supplementation essential for most people 1, 2

Fatty fish, such as salmon and sardines, are rich in vitamin D, containing 5-25 μg/100g, according to the American Journal of Clinical Dermatology and Circulation Research 3, 4, 5
Eggs, particularly egg yolks, are a moderate source of vitamin D, containing 1.3-2.9 μg/100g, as stated by the American Journal of Clinical Dermatology and Circulation Research 3, 4, 5

The Proceedings of the Nutrition Society and the Ca-A Cancer Journal for Clinicians recommend that fortified foods, such as breakfast cereals, milk, and orange juice, are critical for achieving adequate vitamin D intake since natural sources are insufficient 1, 2, 6, 7
The American Heart Association and Circulation Research suggest that supplementation is essential for older adults, with a daily recommendation of 15 μg (600 IU) vitamin D supplement year-round, and 600 IU daily for general adults aged 1-70 years, and 800 IU for those 71+ years 1, 2, 5, 6

The Ca-A Cancer Journal for Clinicians identifies high-risk groups for vitamin D insufficiency, including individuals with dark skin, those living in Northern latitudes, and those who stay indoors, requiring particular attention to supplementation 7
The Circulation Research states that the safe upper limit for vitamin D intake is 4000 IU daily 5