Certain foods can naturally enhance your vitamin D levels, helping to address deficiency more effectively than supplements. These include fatty fish and fortified cereals.123

1. Fatty Fish 

Fatty fish, such as salmon, mackerel, and sardines, are among the richest natural sources of vitamin D3, Morgan Walker, MS, RD, LDN, a sports nutritionist and adjunct professor at Lebanon Valley College, told Health.

One 3-ounce serving of rainbow trout contains 645 IU of vitamin D, while the same amount of sockeye salmon has 570 IU. Canned tuna and salmon are convenient and economical options as well.3

2. Egg Yolks

Egg yolks contain vitamin D3, though not nearly as much as fatty fish. One large egg has 44 IU.3 

There are plenty of ways to enjoy eggs, but deviled eggs put the yolks front and center, said Jen Hernandez, RDN, CSR, a registered dietitian nutritionist focusing on renal health and founder of Plant-Powered Kidneys.

3. UV-Exposed Mushrooms

Mushrooms that have been exposed to ultraviolet light contain lots of vitamin D.4 A 1/2 cup of sliced white UV-exposed mushrooms provides about 366 IU. Look for labels that say “High Vitamin D” or “UV-Exposed.”3

Shiitake, button, oyster, and other mushrooms contain a precursor to vitamin D called ergosterol. When UV rays hit the mushrooms, ergosterol converts to vitamin D2, similar to how sunlight triggers vitamin D production in our skin.4

"Because vitamin D is fat-soluble, it is important to include some type of fat to help absorb the vitamin D,” Hernandez told Health.

4. Fortified Dairy Products and Plant Milks

Fortified dairy products, such as cow's milk and yogurt, typically provide vitamin D3, while most fortified plant-based milks and non-dairy yogurts are fortified with vitamin D2, Walker said. 

One cup of fortified 2% reduced-fat milk contains 120 IU. A cup of fortified soy, almond, or oat milk has between 100 and 144 IU, depending on the type.3

5. Fortified Cereals

Many breakfast cereals are fortified with vitamin D. While the amount varies by brand, they typically provide around 80 IU per serving.3

Frank Dumont, MD, FACP, an internal medicine physician and executive medical director at Virta Health, doesn’t recommend getting the bulk of your vitamin D intake through processed fortified cereals, but they can be a good way to increase vitamin D if you don't eat other vitamin D-rich foods.

When You Might Need a Vitamin D Supplement

If you regularly spend time outdoors (research suggests that sunscreen doesn’t block vitamin D production) and have a diet full of foods rich in vitamin D, you probably don’t need a supplement, Dumont said.5

However, experts noted that people who live in areas with limited sun exposure, spend most time indoors, have darker skin, or follow a vegan or vegetarian diet may benefit from supplementation. Many people with a vitamin D deficiency don't have symptoms, but possible signs include muscle weakness, bone pain, and fatigue.6 A simple blood test—which Hernandez recommends people get twice a year, around daylight savings time—can confirm your levels.

Before taking vitamin D, it's a good idea to consult your physician to ensure it won’t interact with other medications or existing health conditions.