A human body produces vitamin D as a response to exposure to sunlight.
A person can also increase their vitamin D levels through diet or supplements.
Vitamin D is an important nutrient your body requires for many critical processes, including building strong bones and keeping them solid.
Low intake of vitamin D is a significant public health concern across the globe, and it affects 13% of the world’s population (1).
Luckily, there are some strategies and ways to increase your vitamin D levels.
Table of Contents
1. Get Some Sunshine
Vitamin D is called a “sunshine vitamin” because the sun is one of the major sources of this nutrient.
Your skin contains cholesterol, which acts as a precursor to vitamin D.
Once the compound in your skin is exposed to UV-B rays, it becomes vitamin D.
Sun-derived vitamin D can, in fact, circulate twice as long as vitamin D that comes from food or supplements (1).
The amount of vitamin D that your body can produce depends on many variables.
- Skin type and age: People with darker skin will meet to spend more time in the sun developing vitamin D than people with lighter skin. That’s because more melanin is found in darker skin, a compound that can inhibit vitamin D production. Aging may also influence your vitamin D levels. As you get older, your skin is less effective in producing vitamin D from the sun (2, 3).
- Geographical location: The closer you live to the equator, the more vitamin D you will get because of your physical closeness to the rays of the sun. In comparison, the chances of sufficient sun exposure decrease proportionally if you live far from the equator (4).
- Sunscreen and clothing: Some types of clothing and sunscreen can block the production of vitamin D from the sun. While protecting yourself from skin disease by preventing overexposure to sunlight is also important. However, vitamin D needs very little sun exposure for your body (1, 5).
While there is no formal guideline, reports say that as little as 8–15 minutes of exposure is enough for lighter-skinned individuals to make enough vitamin D. People with darker skin can need to spend more time in the sun.
2. Consume Egg Yolks
Another way to increase vitamin D is through egg yolks, which you can easily add to your diet. Like many other natural sources of food, yolks have a variable content of vitamin D.
Conventionally raised chickens that have no exposure to the outdoors usually produce only eggs that harbor 2–5% of the RDI (6).
The study, however, shows that eggs from pasture-raised or free-range chickens provide four times more vitamin D, which is 20% of the RDI.
However, this depends on how much time the chicken spends outdoors. Chicken feed can also influence the amount of vitamin D in eggs (7).
Grain-fed chicken can produce yolks that contain over 100% of RDI.
3. Consume Fatty Fish
Fatty fish is among the best vitamin D food sources. For example, a canned salmon serving of 3.5 ounces (100 grams) will provide up to 386 IU of vitamin D, which is about 50% of the RDI.
The exact content of vitamin D in seafood will differ depending on the form and species.
For instance, some research shows that farmed salmon contain only 25% as much vitamin D as wild-caught salmon (8).
This means wild-caught salmon contains 75% more vitamin D than farmed salmon. Other forms of seafood rich in vitamin D are tuna, mackerel, shrimp, oysters, sardines, and anchovies.
In addition, seafood is also high in omega-3 fatty acids, which will further prevent heart disease (8).
4. Consume Fortified Foods
There are a variety of natural foods that contain high levels of vitamin D. However, some foods are processed, and they add nutrients to them in a process known as fortification.
You should remember that the availability of vitamin D in fortified foods varies by region, and the amount added to the food can vary by brand and form.
Some foods, such as cow milk, soy milk, almond milk, hemp milk, fruit juice powder, cereals, yogurt, and tofu, are fortified.
If you’re unsure whether a particular food has been fortified with vitamin D, search for the label and read the list of ingredients.
5. Eat Mushrooms
Mushrooms are the only plant based source of vitamin D. Humans can produce vitamin D upon exposure to UV light. Similarly, mushrooms can produce their own vitamin D.
The only difference is that humans produce a vitamin D called D3 (cholecalciferol), while mushrooms make D2 (ergocalciferol) (9).
Both D2 and D3 can increase vitamin D levels, but evidence shows that D3 can increase levels more rapidly than D2 (10).
Although the amount of vitamin D depends on the mushroom type, such as wild maitake mushrooms, they can provide as much as 2,348 IU per 3.5 ounces (100 grams). That is nearly 300% of RDI (11).
That’s said, wild mushrooms have more vitamin D than commercially grown varieties because of their exposure to sunlight.
You should purchase wild mushrooms from a reputable supplier, such as a grocery store or farmers’ market, to avoid poisonous varieties.
6. Take Vitamin D Supplement
Taking a vitamin D supplement is the best way to ensure a sufficient intake.
There are two primary sources of vitamin D: D2 (ergocalciferol) and D3 (cholecalciferol). Usually, D2 originates from plants and D3 comes from animal sources.
Research shows that D3 may significantly increase overall levels of vitamin D compared to D2 (10).
Buying high-quality supplements that have been independently tested is important.
You need to take supplements if you are not getting adequate vitamin D from food or sunlight, and the best way is to have your vitamin D levels checked before supplementation.
7. Try a UV Lamp
Lamps that provide UV-B radiation can also boost your levels of vitamin D. However, these lamps are very expensive.
When the sun exposes the skin to UV-B radiation, the skin will produce its own vitamin D. UV lamps replicate the sun’s behavior and can be especially beneficial if you don’t have access to the sun.
For decades, UV radiation has been used therapeutically for various skin disorders, but it has only recently been marketed to increase vitamin D levels (12).
Safety with these devices is a major concern, as too much exposure could burn your skin. Usually, it’s recommended that you limit your skin exposure to only 15 minutes at a time to prevent any obstacles.
How Does Vitamin D work?
Vitamin D is a fat-soluble vitamin that helps the bones absorb calcium, promoting growth and mineralization. It also has immune, digestive, circulatory, and nervous systems, among various other functions.
Emerging evidence shows that vitamin D can help prevent several diseases, including depression, diabetes, heart disease, and more (13, 14, 15, 16, 17, 18, 19, 20).
However, the relationship between vitamin D and those conditions is not crystal clear.
How Much Vitamin D You Need?
According to the guidelines, 600–800 IU per day is adequate for most people (21).
The Endocrine Society recommends 1,500–2,000 IU a day (22).
However, the Reference Daily Intake (RDI) for adults based in the US is 600–800 IU of vitamin D, and the optimal blood vitamin D level is not concretely determined, but is likely to fall between 20 and 50 ng/mL.
The National Academy of Medicine in the United States suggests a daily intake of 4,000 IU per day is safe for most people.
However, much higher doses may be required temporarily in order to raise blood levels in some people with vitamin deficiency (23, 24, 25).
Keep in mind that too much vitamin D can lead to hypervitaminosis D, which is a type of toxicity that could be very dangerous or even life-threatening. Therefore, it is important to take vitamin D in the proper dosage recommended by your doctor (26, 27).
Conclusion
Vitamin D is a necessary nutrient that many people do not get enough of.
However, you can increase your vitamin D levels by getting more sun exposure, eating vitamin D-rich foods, or taking supplements.
If you suspect you’re deficient in this essential nutrient, see a doctor to have your blood levels checked.