Boost Your Energy This Winter With Foods That Are High In Vitamin D
Because we tend to spend less time in the sun in the winter, it’s common to be warned that we may not be getting enough vitamin D. And there’s a reason we need that D: A lack of it can make us feel tired, so much so that we may want to hibernate for the season. It also affects our immune system and mood.
According to research, it could take about two hours’ worth of afternoon sun exposure, if not more, for the skin to produce enough vitamin D in the winter, when accounting for the types of clothing typically worn during the season. But prolonged sun exposure can put us at risk of skin cancer, and spending hours outside in the cold isn’t exactly fun.
But you can turn elsewhere to help get your daily dose of vitamin D. We spoke with nutrition experts about the types of food that can help, and how much of them to eat.
What is vitamin D?
“Vitamin D is an essential nutrient that has many critical functions in the body, including bone health, nerve function and immune health,” explained Hilary Walentuk, a registered dietitian and senior nutrition specialist at the New England Dairy nonprofit. “Vitamin D boosts the production of immune cells and helps the body fight off viruses and bacteria, making it an especially important nutrient during the cold and flu season.” The average adult needs 600 international units, or IU, of vitamin D per day, whereas older adults may need around 800 IU.
“I don’t necessarily think this [number] is what every individual feels optimal with, due to factors like age, gut health, sun exposure, skin tone, genetics and many other reasons why people might need different quantities of vitamin D than the standard 800 IU,” said Megan Lyons, who holds a doctorate in clinical nutrition and is double-board-certified as a clinical nutritionist and holistic nutritionist. She spoke about two major types of vitamin D: D2, or ergocalciferol, and D3, or cholecalciferol. “Vitamin D2 doesn’t convert as effectively [in the body] ... compared to vitamin D3,” she said. “When it comes to food, D3 — which is the form that converts better — is animal-based.”
Lauren Manaker, a registered dietitian nutritionist, outlined the effectiveness of D2 and D3 in food and supplements. “While both types can help improve vitamin D levels in the body, studies show that vitamin D3 is more effective at raising and maintaining those levels over time,” she said.
If you don’t receive an adequate amount of vitamin D, you may find yourself among the 35% of American adults who have a vitamin D deficiency. “The side effects are relatively mild at first and include nausea, vomiting, frequent urination and kidney issues,” said Trista Best, a registered dietitian at the Candida Diet. “It can lead to more serious effects, like ... kidney stones. Some vitamin D deficiency symptoms are commonly confused for symptoms of other conditions. The chronic fatigue associated with vitamin D may also be confused with the tiredness associated with aging or typical life stress.”
What foods contain vitamin D?
Fish, eggs, cheese, beef liver, mushrooms, fortified cereals and fortified milk — including nut and soy milks — are known for offering vitamin D.
“Almost all the U.S. milk supply is fortified with about 120 IU per cup,” Walentuk said.
Egg yolks contain about 40 IU, “so you probably can’t get your DRV just from egg yolks alone,” Lyons said in reference to dietary reference value, an estimate of daily nutrient requirements.
Because vitamin D is fat-soluble, “It needs to be paired with healthy fats, whether it comes from a supplement or a food source,” said Carla Hernandez, a registered dietitian who specializes in women’s health. “Examples include pairing it with avocado, olive oil, cheese or butter.” A tablespoon of cod liver oil would meet 170% of the recommended daily intake of vitamin D, and 3 ounces of rainbow trout would amount to about 81%.
“Cod liver oil is superior to other vitamin D sources, but quality matters. Choose a reputable brand that tests for heavy metals and contaminants, since organ meats can store toxins,” Hernandez said. Fish products that contain significant amounts of vitamin D include wild salmon, mackerel and canned tuna.
Because D2 is primarily plant-based, all kinds of mushrooms are the way to go. “When mushrooms are exposed to UV light (ultraviolet), they produce some D2,” Lyons said, while noting that “D2 doesn’t convert quite as well as D3.”
She said that 100 grams of portobello mushrooms contain “a little more than half” of the DRV of D2. “But we need to account for the lower conversion rate,” she noted. “If we’re eating something like salmon, the fat content helps with absorption. But mushrooms contain very little to no fat, so we would really need to pair them with a healthy fat to improve absorption.”
If you’re a vegan, you may have a difficult time absorbing enough vitamin D. And if you’re a vegan who dislikes mushrooms, you don’t have many options.
“For those who dislike mushrooms or want to explore alternative ways to get their vitamin D, consider fortified foods like cereals or orange juice, or explore taking a high-quality, vegan-friendly vitamin D supplement,” Manaker said. “Vitamin D2 supplements, for example, are often plant-derived and can help maintain proper levels in a vegan or vegetarian diet. Consulting with a health care professional can help determine the best source for your needs.”
Jordan Anthony, a registered dietitian nutritionist with the company Ahara, said that 1 cup of UV-treated mushrooms contains about 17% of the DRV. “Unless you want to eat 5 or 6 cups of mushrooms each day, you’ll want to diversify your sources of vitamin D,” she said.
As for soy milk and orange juice, they are often fortified with vitamin D. “It’s not uncommon for 1 cup of fortified OJ or soy milk to have about 40% of your recommended daily value, so 2 to 3 cups a day should give you what you need,” Anthony said. “You could also consider other fortified foods, like cereal. Again, if you’re a strict vegan, this may not be a good option for you, since the vitamin D in fortified foods and beverages is derived from animals.”
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