However, vitamin D helps your body absorb calcium and maintain sufficient concentrations of serum magnesium and phosphate. These nutrients are essential to your teeth, muscles, and bones. Vitamin D also plays an important role in the growth of your brain, heart function, and the immune system. Vitamin D deficiencies are common around the world. Symptoms of deficiency include fatigue, muscle pain, weak muscles, and stunted growth in children. However, getting enough Vitamin D from food sources can be difficult, particularly if you are vegetarian or vegan.
Exposing your skin to the ultraviolet B (UVB) rays of the sun for 5–30 minutes twice a week without sunscreen is usually enough to produce adequate levels of vitamin D.
However, this depends on your geographical location, your age, skin color, and the ability of your skin to produce sufficient vitamin D. Some factors such as a rainy day, smog, for example, can reduce the intensity of UV rays by up to 60%.
Older adults and those with darker skin may need over 30 minutes of sun exposure to produce enough vitamin D. That said, over-exposure to the sun may increase your risk of skin cancer. The American Academy of Dermatology therefore advises people not to rely on the sun as their primary source of vitamin D.
2. Egg yolks
Eggs specific amount of vitamin D rely heavily on the diet and outdoor access of the chicken. For example, chicken that have access to sun exposure or fed with vitamin-D-enriched feed can provide up to 6,000 IU (150 mcg) per yolk, while regular feed eggs contain only 18–39 IU (0.4–1 mcg) per yolk.
Likewise, outdoor roaming chickens are exposed to sunshine and usually lay eggs that contain 4 times more vitamin D than chickens raised indoors. Free-range or organic eggs appear to have a greater vitamin D content.
Mushrooms can produce vitamin D when exposed to UV light. This makes them the only plant based vitamin D source. Mushrooms can provide about 154 to 1,136 IU of vitamin D per 100 grams serving.
Also, their vitamin D content stays high for the rest of their shelf life and is as effective as VD supplements. That said, most commercial mushrooms are grown in the dark, and are not exposed to UV light, meaning they possibly contain very little vitamin D.
Specific mushrooms can be a choice for vegetarian or vegan. Some types of mushroom have a high vitamin D content.
Raw maitake mushrooms: These comprise 562 IU per 50 grams, which is 94 percent RDA.
Dried shiitake mushrooms: These comprise 77 IU per 50 grams, which is 12 percent of RDA.
Read the label which mentions the content of vitamin D while buying. Know that all wild mushrooms are not edible. Eating poisonous can cause symptoms from mild indigestion to organ damage and even death.
Cheese is a natural vitamin D source, but in very limited amounts. Most varieties produce 8–24 IU (0.2–0.6 mcg) per 2-ounce (50-gram) serving. Levels vary according to how the cheese is produced. The cheddar and fontina boast more, while the mozzarella has less. Weak types such as cottage, ricotta, or cream cheeses do not provide vitamin D.
5. Fortified foods
Since few foods naturally contain the highest levels of vitamin D, they add this nutrient in a process known as fortification to the staple foods. Remember, the availability of VD in fortified food varies from region to region, and the amount added to the food can vary by brand and form.
Common food sources containing added vitamin D and other nutrients include:
Cow milk, soya milk, almond milk, hemp milk, fruit juice powder, cereals, yogurt, and tofu. If you are unsure about a particular food has been fortified with vitamin D, search the ingredients list on the product label.
You may not get enough vitamin D from your diet alone. Therefore, supplements can serve as safe and consistent source. These supplements come in two forms:
Vitamin D3: usually extracted from fish oil or sheep’s wool. Vegan forms recently produced from lichen.
Vitamin D2: usually harvested from yeast or UV-exposed mushrooms.
If taken in large doses of 50,000 IU (1,250 mcg) or more, vitamin D3 is more effective in sustaining good levels of vitamin D than D2. However, if taken in smaller doses, the benefit of D3 over D2 appears to be much lower.
Most D3 supplements are derived from lichen and add vegan certification. Since vitamin D is fat soluble, consuming it with fatty foods will help make it more absorbent.
The Average Daily Intake (RDI) is 400–800 IU (10–20 mcg), depending on factors such as age. It is not recommended to exceed this dose for prolonged periods, as this can cause toxicity.
Symptoms of vitamin D toxicity may include confusion, concentration problems, insomnia, stomach pain, vomiting, high blood pressure, hearing loss, hallucinations and, in severe cases, kidney failure and coma.
While vitamin D plays many crucial roles in your body, it is naturally found in few food sources. Therefore, vegetarian or vegan sources are limited. Spending time in the sunshine is a brilliant way to boost your vitamin D levels. You should try foods such as wild mushrooms, egg yolks or vitamin D-enriched products. If you are worried about your vitamin D levels, you may have low levels of this nutrient. Talk to your health care provider.
Vitamin D. U.S. Department of Health & Human Services.
The vitamin D questions: how much do you need and how should you get it? J Am Acad Dermatol. 2006.
Natural vitamin D content in animal products. Adv Nutr. 2013.
Cheese, cream. U.S. DEPARTMENT OF AGRICULTURE.
Dietary fat increases vitamin D-3 absorption. J Acad Nutr Diet. 2015.
Vitamin D Toxicity-A Clinical Perspective. Front Endocrinol (Lausanne). 2018.