Why You Need More Vitamin D in the Winter
Winter is upon us and so is the risk of vitamin D deficiency and infections. Vitamin D, which is made in our skin following sunlight exposure and also found in oily fish (mackerel, tuna and sardines), mushrooms and fortified dairy and nondairy substitutes, is essential for good health. Humans need vitamin D to keep healthy and to fight infections. The irony is that in winter, when people need vitamin D the most, most of us are not getting enough. So how much should we take? Should we take supplements? How do we get more? And, who needs it most?
I am a medical microbiologist and immunologist who studies the functions of vitamin D in immune cells. My laboratory has been interested in figuring out why the immune system has vitamin D receptors that determine which cells can use vitamin D. In the immune system, vitamin D acts to improve your ability to fight infections and to reduce inflammation.
Where to Get Your Vitamin D
Vitamin D is called the sunshine vitamin since it is made in the skin after exposure to sun. The same UVB rays that cause a sunburn also make vitamin D. Sunscreen, darker skin pigmentation, clothing and reduced daylight in winter diminish the skin's ability to make vitamin D. The people who experience the biggest seasonal swings in vitamin D levels are fair-skinned individuals living in the northern regions of the U.S. and at higher latitudes around the globe where there is very little daylight in winter.
But those most at risk for low vitamin D levels are people of color and people living at higher latitudes. Dark-skinned individuals are more likely than fair-skinned individuals to be low for vitamin D year-round because the darker skin blocks the UVB rays from producing vitamin D. However, even in dark skinned individuals, vitamin D is lowest in the winter.
In the winter, in addition to high vitamin D food, adults should take additional vitamin D from foods and/or supplements to get at least 600 IU per day of vitamin D. People who have dark skin or avoid sunshine should eat more vitamin D year-round.
Vitamin D's Importance for Bones and Microbes
Originally, doctors thought that vitamin D was only important for bone health. This was because the vitamin D deficiency caused bone diseases like rickets in children and osteoporosis in adults. However, in the 1980s scientists discovered that immune cells had receptors for vitamin D.
My group's research has shown that vitamin D plays an important role in maintaining health in the gastrointestinal tract. Higher levels of vitamin D reduce susceptibility to inflammatory bowel disease and Crohn's disease, gut and lung infections in animals and people.
My colleagues and I have discovered that one of the ways vitamin D functions is by keeping the microbes in the gut healthy and happy. Vitamin D increases the number and diversity of microbes living in the gut, which together reduce inflammation throughout the body.
Low vitamin D levels are associated with inflammatory bowel disease in humans. Researchers have found that inflammatory bowel disease patients in Japan have more symptoms in winter than during other seasons.
Why is vitamin D more important in winter?
In the winter, humans are exposed to more infections and spend less time outside. Exactly how much vitamin D healthy adults should have is debated. Some authorities recommend from 200 IU per day to 2,000 IU per day. In the U.S., the Institutes of Medicine recommends 600-800 IU per day for adults, while the Endocrine Society states that optimal vitamin D status may require 1500-2,000 IU per day. In the winter, people have a reduced ability to make vitamin D when they go outside, so amounts of at least 600 IU per day of vitamin D from food or supplements would help maintain vitamin D status at summer levels.
But, just like many things, too much vitamin D can be harmful. Vitamin D toxicity does not result from too much sun or food. Because of the risk of skin cancer, dermatologists and other health professionals do not recommend unprotected sun exposure to boost your vitamin D. Instead they suggest supplements. But vitamin D toxicity can occur if an individual takes too many.
The experts that set the national intakes of vitamin D for the U.S. recommend that adult individuals take no more than 4,000 IU per day of vitamin D to avoid toxic side effects. Vitamin D helps you absorb calcium from your diet, but when vitamin D is too high, calcium levels in the blood go up and that can lead to kidney disease.
By consuming more vitamin D during the winter your gut microbes will be healthier and you'll be more resistant to infection and inflammation year-round.
Margherita T. Cantorna is a distinguished professor of molecular immunology at the Pennsylvania State University.
Reposted with permission from The Conversation.
- Redwoods are the world's tallest trees.
- Now scientists have discovered they are even bigger than we thought.
- Using laser technology they map the 80-meter giants.
- Trees are a key plank in the fight against climate change.
They are among the largest trees in the world, descendants of forests where dinosaurs roamed.
Pixabay / Simi Luft<p><span>Until recently, measuring these trees meant scaling their 80 meter high trunks with a tape measure. Now, a team of scientists from University College London and the University of Maryland uses advanced laser scanning, to create 3D maps and calculate the total mass.</span></p><p>The results are striking: suggesting the trees <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">may be as much as 30% larger than earlier measurements suggested.</a> Part of that could be due to the additional trunks the Redwoods can grow as they age, <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">a process known as reiteration</a>.</p>
New 3D measurements of large redwood trees for biomass and structure. Nature / UCL<p>Measuring the trees more accurately is important because carbon capture will probably play a key role in the battle against climate change. Forest <a href="https://www.wri.org/blog/2020/09/carbon-sequestration-natural-forest-regrowth" target="_blank">growth could absorb billions of tons</a> of carbon dioxide from the atmosphere each year.</p><p>"The importance of big trees is widely-recognised in terms of carbon storage, demographics and impact on their surrounding ecosystems," the authors wrote<a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank"> in the journal Nature</a>. "Unfortunately the importance of big trees is in direct proportion to the difficulty of measuring them."</p><p>Redwoods are so long lived because of their ability to <a href="https://www.nature.com/articles/s41598-020-73733-6" target="_blank" rel="noopener noreferrer">cope with climate change, resist disease and even survive fire damage</a>, the scientists say. Almost a fifth of their volume may be bark, which helps protect them.</p>
Carbon Capture Champions<p><span>Earlier research by scientists at Humboldt University and the University of Washington found that </span><a href="https://www.sciencedirect.com/science/article/pii/S0378112716302584" target="_blank" rel="noopener noreferrer">Redwood forests store almost 2,600 tonnes of carbon per hectare</a><span>, their bark alone containing more carbon than any other neighboring species.</span></p><p>While the importance of trees in fighting climate change is widely accepted, not all species enjoy the same protection as California's coastal Redwoods. In 2019 the world lost the equivalent of <a href="https://www.worldwildlife.org/threats/deforestation-and-forest-degradation" target="_blank" rel="noopener noreferrer">30 soccer fields of forest cover every minute</a>, due to agricultural expansion, logging and fires, according to The Worldwide Fund for Nature (WWF).</p>
Pixabay<p>Although <a href="https://c402277.ssl.cf1.rackcdn.com/publications/1420/files/original/Deforestation_fronts_-_drivers_and_responses_in_a_changing_world_-_full_report_%281%29.pdf?1610810475" target="_blank" rel="noopener noreferrer">the rate of loss is reported to have slowed in recent years</a>, reforesting the world to help stem climate change is a massive task.</p><p><span>That's why the World Economic Forum launched the Trillion Trees Challenge (</span><a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a><span>) and is engaging organizations and individuals across the globe through its </span><a href="https://uplink.weforum.org/uplink/s/uplink-issue/a002o00000vOf09AAC/trillion-trees" target="_blank" rel="noopener noreferrer">Uplink innovation crowdsourcing platform</a><span> to support the project.</span></p><p>That's backed up by research led by ETH Zurich/Crowther Lab showing there's potential to restore tree coverage across 2.2 billion acres of degraded land.</p><p>"Forests are critical to the health of the planet," according to <a href="https://www.1t.org/" target="_blank" rel="noopener noreferrer">1t.org</a>. "They sequester carbon, regulate global temperatures and freshwater flows, recharge groundwater, anchor fertile soil and act as flood barriers."</p><p><em data-redactor-tag="em" data-verified="redactor">Reposted with permission from the </em><span><em data-redactor-tag="em" data-verified="redactor"><a href="https://www.weforum.org/agenda/2021/03/redwoods-store-more-co2-and-are-more-enormous-than-we-thought/" target="_blank">World Economic Forum</a>.</em></span></p>
EcoWatch Daily Newsletter
- Offshore Wind Power Is Ready to Boom. Here's What That Means for ... ›
- American Skyscrapers Kill an Estimated 600 Million Migratory Birds ... ›
Kentucky is coping with historic flooding after a weekend of record-breaking rainfall, enduring water rescues, evacuations and emergency declarations.
<div id="0f31c" class="rm-shortcode" data-rm-shortcode-id="4290ab3e7ec4e142f8bce774bab39f03"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1366307788155219969" data-partner="rebelmouse"><div style="margin:1em 0">Just got back from my office... downtown Beattyville Kentucky is not a pretty sight. @KySportsRadio… https://t.co/6nXwyMKtRb</div> — Tom Jones (@Tom Jones)<a href="https://twitter.com/8atticus/statuses/1366307788155219969">1614588136.0</a></blockquote></div>
<div class="rm-shortcode" data-rm-shortcode-id="b41a2da6bf23cc19a5f38c2dc6c5f9fc"><div class="fb-post" data-href="https://www.facebook.com/dekalbtnfire/photos/a.924258171004562/3713119618785056/"></div></div>
Spring is coming. And soon, tree swallows will start building nests. But as the climate changes, the birds are nesting earlier in the spring.
- Spring Is Arriving Earlier Across the U.S. - EcoWatch ›
- Climate Change Leading to Fatal Bird Conflicts - EcoWatch ›
- The Unsettling Reason Why We're Seeing More Snowy Owls ... ›
Citigroup will strive to reach net-zero greenhouse gas pollution across its lending portfolio by 2050 and in its own operations by 2030, the investment group announced Monday.
- 20 Attorneys General Launch Climate Fraud Investigation of Exxon ... ›
- Exxon Plans to Increase Its Climate Pollution - EcoWatch ›
- Exxon to Slash 14,000 Jobs Worldwide as Oil Demand Drops ... ›