By Ansley Hill
Vitamin D is an essential nutrient that your body needs for many vital processes, including building and maintaining strong bones.
Low vitamin D intake is considered a major public health concern across the globe. In fact, vitamin D deficiency is estimated to affect 13% of the world's population (1).
Here are 7 effective ways to increase your vitamin D levels.
What is Vitamin D?
Vitamin D is a fat-soluble vitamin that primarily aids calcium absorption, promoting growth and mineralization of your bones. It's also involved in various functions of your immune, digestive, circulatory, and nervous systems (1).
Emerging research suggests that vitamin D may help prevent a variety of illnesses, such as depression, diabetes, cancer, and heart disease. However, vitamin D's relationship to these conditions is still poorly understood (1).
How Much Do You Need?
There is significant debate within the scientific community about how much vitamin D your body needs.
While the U.S. National Academy of Medicine considers 600–800 IU of daily vitamin D to be sufficient for the majority of the population, the U.S. Endocrine Society recommends 1,500–2,000 IU per day (2, 3).
The Reference Daily Intake (RDI) is currently set at 600-800 IU of vitamin D for adults, based on the U.S. National Academy of Medicine's recommendations (2).
The U.S. National Academy of Medicine further suggests that a daily intake up to 4,000 IU of vitamin D per day is safe for most people, although much higher doses may be temporarily necessary in order to raise blood levels in some individuals (4).
Although toxicity is rare, it is best to avoid long-term vitamin D doses in excess of 4,000 IU without supervision from a qualified healthcare professional.
Vitamin D is necessary for calcium absorption and bone health. While there is no set guidance, dosage recommendations range from 600–2,000 IU per day — but some people may need heavier doses to reach and maintain healthy blood levels.
1. Spend Time in Sunlight
Vitamin D is often referred to as "the sunshine vitamin" because the sun is one of the best sources of this nutrient.
Your skin hosts a type of cholesterol that functions as a precursor to vitamin D. When this compound is exposed to UV-B radiation from the sun, it becomes vitamin D.
In fact, sun-derived vitamin D may circulate for twice as long as vitamin D from food or supplements (1).
However, the amount of vitamin D your body can make depends on several variables.
Skin Tone and Age
People with darker skin need to spend more time in the sun to produce vitamin D than those with lighter skin. That's because darker skin has more melanin, a compound that can inhibit vitamin D production (7).
Age can have an impact as well. As you get older, vitamin D production in your skin becomes less efficient (8).
Geographical Location and Season
The closer you live to the equator, the more vitamin D you'll be able to produce year-round because of your physical proximity to the sun's rays.
Conversely, your opportunities for adequate sun exposure decreases proportionally the farther away from the equator you live (9).
Sunscreen and Clothing
Certain types of clothing and sunscreen can hinder — if not completely block — vitamin D production (1).
While it's vital to protect yourself from skin cancer by avoiding overexposure to sunlight, it takes very little unprotected sun exposure for your body to start producing vitamin D.
Although there's no official recommendation, sources suggest that as few as 8–15 minutes of exposure is enough to make plenty of vitamin D for lighter-skinned individuals. Those with darker skin may need more time (10).
Your skin can produce large quantities of vitamin D on its own when exposed to the sun's UV-B rays. However, many factors affect this process.
2. Consume Fatty Fish and Seafood
Fatty fish and seafood are among the richest natural food sources of vitamin D.
The exact vitamin D content of seafoods may vary depending on the type and species in question. For example, some research suggests that farmed salmon may contain only 25% of the amount of wild-caught salmon (12).
Other kinds of fish and seafood rich in vitamin D include:
Fatty fish and seafood are among the foods highest in vitamin D, though exact vitamin content may vary depending on the type and source of the food in question.
3. Eat More Mushrooms
Mushrooms are the only completely plant-based source of vitamin D.
Like humans, mushrooms can make their own vitamin D upon exposure to UV light. Humans produce a form of vitamin D known as D3 or cholecalciferol, whereas mushrooms produce D2 or ergocalciferol(14).
While vitamin D content depends on the type of mushroom, certain varieties — such as wild maitake mushrooms — provide as much as 2,348 IU per 3.5-ounce (100-gram) serving. That's almost 300% of the RDI (11, 16).
Due to their exposure to sunlight, wild mushrooms usually have more vitamin D than commercially grown types. However, you can also purchase mushrooms treated with UV light.
However, you should always take care to meticulously identify wild mushrooms or purchase them from a trusted supplier — such as a grocery store or farmers market — to avoid exposure to poisonous varieties.
Much like humans, mushrooms produce vitamin D when exposed to UV light. Wild mushrooms — or commercially grown ones treated with UV light — have the greatest vitamin D levels.
4. Include Egg Yolks in Your Diet
Egg yolks are another source of vitamin D that you can easily add to your routine.
Like many other natural food sources, yolks have variable vitamin D content.
Conventionally raised chickens that don't have access to the outdoors typically only produce eggs harboring 2–5% of the RDI (17).
Chicken feed can also affect the vitamin D content of eggs. Those fed vitamin-D-enriched grain may produce yolks that boast well over 100% of the RDI (18).
Free-range and pastured eggs are a great source of vitamin D, as chickens with access to sunlight produce more vitamin D in their eggs than those that remain indoors.
5. Eat Fortified Foods
Because few foods naturally contain high levels of vitamin D, this nutrient is often added to staple goods in a process known as fortification.
Still, you should keep in mind that the availability of vitamin-D-fortified foods varies by country, and the amount added to foods may differ by brand and type.
Some commonly fortified goods include:
- cow's milk
- plant-based milk alternatives like soy, almond, and hemp milk
- orange juice
- ready-to-eat cereals
- certain types of yogurt
If you're unsure whether a particular food has been fortified with vitamin D, check its ingredients list.
Vitamin D is often added to food staples — such as milk and breakfast cereals — to increase intake of this nutrient.
6. Take a Supplement
For many people, taking a vitamin D supplement may be the best way to ensure adequate intake.
Vitamin D exists in two main biological forms — D2 (ergocalciferol) and D3 (cholecalciferol). Typically, D2 comes from plants and D3 from animals (15).
Research suggests that D3 may be significantly more effective at raising and maintaining overall vitamin D levels than D2, so look for a supplement with this form (15).
Additionally, it's important to purchase high-quality supplements that have been independently tested. Some countries — such as the United States — don't regulate nutritional supplements, which can negatively impact supplement quality.
It's best to choose supplements tested for purity and quality by a third party, such as the U.S. Pharmacopeia (USP), Informed-Choice, ConsumerLab.com, or the Banned Substances Control Group (BSCG).
Vitamin D supplements vary in dosage. That said, the amount you need depends on your current vitamin D levels.
However, you may need a much larger dose in certain circumstances — and especially if your current levels are very low or you have limited exposure to sunshine (4).
For this reason, it's ideal to have your vitamin D levels tested by your medical professional to ensure you're taking the most appropriate dose.
Vegan Supplement Options
The majority of vitamin D supplements are derived from animal sources — and thus inappropriate for vegans. However, a few vegan D supplement options exist.
Because vitamin D2 is plant-derived, D2 supplements are typically vegan-friendly and widely available.
Vegan D3 is significantly less common than D2 but can be made from lichens. You're most likely to find them in specialty health stores or online.
Supplements are often needed if you don't obtain enough vitamin D from food or sunlight. Having your vitamin D levels checked before supplementing is the best way to pick the appropriate dose.
7. Try a UV Lamp
Lamps that emit UV-B radiation may also boost your vitamin D levels, though these lamps can be costly.
When your skin is exposed to UV-B radiation from the sun, it's able to produce its own vitamin D. UV lamps mimic the action of the sun and can be especially helpful if your sun exposure is limited due to geography or time indoors.
Safety is an important concern with these devices, as too much exposure could burn your skin. You're typically recommended to limit your exposure to no more than 15 minutes at a time.
You can purchase lamps that emit UV-B radiation to stimulate vitamin D production. However, they can be expensive and dangerous if used for more than 15 minutes at a time.
The Bottom Line
Vitamin D is an essential nutrient that many people around the world don't get enough of.
That said, you can boost your vitamin D levels by getting more sun exposure, eating foods rich in vitamin D, and/or taking supplements.
If you suspect you're low in this essential nutrient, consult with a health professional to get your levels checked.
Reposted with permission from our media associate Healthline.
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The bright patterns and recognizable designs of Waterlust's activewear aren't just for show. In fact, they're meant to promote the conversation around sustainability and give back to the ocean science and conservation community.
Each design is paired with a research lab, nonprofit, or education organization that has high intellectual merit and the potential to move the needle in its respective field. For each product sold, Waterlust donates 10% of profits to these conservation partners.
Eye-Catching Designs Made from Recycled Plastic Bottles
waterlust.com / @abamabam
The company sells a range of eco-friendly items like leggings, rash guards, and board shorts that are made using recycled post-consumer plastic bottles. There are currently 16 causes represented by distinct marine-life patterns, from whale shark research and invasive lionfish removal to sockeye salmon monitoring and abalone restoration.
One such organization is Get Inspired, a nonprofit that specializes in ocean restoration and environmental education. Get Inspired founder, marine biologist Nancy Caruso, says supporting on-the-ground efforts is one thing that sets Waterlust apart, like their apparel line that supports Get Inspired abalone restoration programs.
"All of us [conservation partners] are doing something," Caruso said. "We're not putting up exhibits and talking about it — although that is important — we're in the field."
Waterlust not only helps its conservation partners financially so they can continue their important work. It also helps them get the word out about what they're doing, whether that's through social media spotlights, photo and video projects, or the informative note card that comes with each piece of apparel.
"They're doing their part for sure, pushing the information out across all of their channels, and I think that's what makes them so interesting," Caruso said.
And then there are the clothes, which speak for themselves.
Advocate Apparel to Start Conversations About Conservation
waterlust.com / @oceanraysphotography
Waterlust's concept of "advocate apparel" encourages people to see getting dressed every day as an opportunity to not only express their individuality and style, but also to advance the conversation around marine science. By infusing science into clothing, people can visually represent species and ecosystems in need of advocacy — something that, more often than not, leads to a teaching moment.
"When people wear Waterlust gear, it's just a matter of time before somebody asks them about the bright, funky designs," said Waterlust's CEO, Patrick Rynne. "That moment is incredibly special, because it creates an intimate opportunity for the wearer to share what they've learned with another."
The idea for the company came to Rynne when he was a Ph.D. student in marine science.
"I was surrounded by incredible people that were discovering fascinating things but noticed that often their work wasn't reaching the general public in creative and engaging ways," he said. "That seemed like a missed opportunity with big implications."
Waterlust initially focused on conventional media, like film and photography, to promote ocean science, but the team quickly realized engagement on social media didn't translate to action or even knowledge sharing offscreen.
Rynne also saw the "in one ear, out the other" issue in the classroom — if students didn't repeatedly engage with the topics they learned, they'd quickly forget them.
"We decided that if we truly wanted to achieve our goal of bringing science into people's lives and have it stick, it would need to be through a process that is frequently repeated, fun, and functional," Rynne said. "That's when we thought about clothing."
Support Marine Research and Sustainability in Style
To date, Waterlust has sold tens of thousands of pieces of apparel in over 100 countries, and the interactions its products have sparked have had clear implications for furthering science communication.
For Caruso alone, it's led to opportunities to share her abalone restoration methods with communities far and wide.
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Check out all of the different eco-conscious apparel options available from Waterlust to help promote ocean conservation.
Melissa Smith is an avid writer, scuba diver, backpacker, and all-around outdoor enthusiast. She graduated from the University of Florida with degrees in journalism and sustainable studies. Before joining EcoWatch, Melissa worked as the managing editor of Scuba Diving magazine and the communications manager of The Ocean Agency, a non-profit that's featured in the Emmy award-winning documentary Chasing Coral.