Fatty fish like salmon, mackerel, trout, and sardines are among the best natural sources of vitamin D. For example, a 3.5-ounce (100-gram) serving of cooked salmon can provide around 570-590 IU (International Units) of vitamin D.
Cod liver oil is derived from the liver of codfish. It is incredibly rich in vitamin D, with just one tablespoon (about 15 ml) containing over 1,300 IU of vitamin D.
Some varieties of mushrooms, such as shiitake and maitake, can synthesize vitamin D when exposed to ultraviolet (UV) light. This makes them one of the few plant-based sources of vitamin D. The exact vitamin D content can vary based on the type and how they're grown.
Egg yolks contain small amounts of vitamin D. The vitamin D content can vary depending on the diet of the hens. Eggs from chickens raised in environments with access to sunlight or fed with vitamin D-enriched feed tend to have higher vitamin D levels.
Many dairy products like cow's milk, yogurt, and cheese are fortified with vitamin D. Additionally, some plant-based milk alternatives like soy milk, almond milk, and oat milk are also fortified with vitamin D.
Certain breakfast cereals, instant oatmeal, and other grain products are often fortified with vitamin D. Always check the product labels for specific vitamin D content.
Pork, particularly pork liver, contains decent amounts of vitamin D. However, it's worth noting that the exact vitamin D content can vary depending on the cut of meat.
Some tofu and tempeh products are fortified with vitamin D. Be sure to check the labels to confirm the exact content.