By Ryan Raman
Cod liver oil is a type of fish oil supplement.
It also contains vitamins A and D, both of which provide many other health benefits.
Here are nine scientifically supported benefits of cod liver oil.
High in Vitamins A and D
Most cod liver oil is extracted from the liver of Atlantic cod.
Cod liver oil has been used for centuries to relieve joint pain and treat rickets, a disease that causes fragile bones in children (3).
Although cod liver oil is a fish oil supplement, it's quite different than regular fish oil.
Regular fish oil is extracted from the tissue of oily fish like tuna, herring, anchovies and mackerel, while cod liver oil is extracted from the livers of cod.
The liver is rich in fat-soluble vitamins like vitamins A and D, which give it an impressive nutrient profile.
One teaspoon (5 ml) of cod liver oil provides the following (4):
- Calories: 40
- Fat: 4.5 grams
- Omega-3 fatty acids: 890 mg
- Monounsaturated fat: 2.1 grams
- Saturated fat: 1 gram
- Polyunsaturated fat: 1 gram
- Vitamin A: 90 percent of the RDI
- Vitamin D: 113 percent of the RDI
Cod liver oil is incredibly nutritious, with a single teaspoon providing 90% of your daily requirements for vitamin A and 113 percent of your daily requirements for vitamin D.
Summary: Cod liver oil is very nutritious and provides nearly all of your daily requirements for vitamins A and D.
May Reduce Inflammation
Inflammation is a natural process that helps the body fight infections and heal injuries.
Unfortunately, in some cases, inflammation can continue at a low level for long periods of time.
Summary: The omega-3 fatty acids in cod liver oil may help suppress proteins that promote chronic inflammation. Cod liver oil is also a great source of vitamins A and D, both of which have antioxidant properties.
May Improve Bone Health
It's incredibly important to maintain healthy bones as you age.
Cod liver oil is a great dietary source of vitamin D and may reduce age-related bone loss. That's because it helps your body absorb calcium, which is a necessary mineral for strong bones, from the gut (7, 19).
In fact, studies show that when accompanied by a diet high in calcium, taking a vitamin D supplement like cod liver oil can reduce bone loss among adults and strengthen fragile bones in children (20, 21, 22).
Getting enough vitamin D from foods and supplements like cod liver oil is especially important for people who live far from the equator, a their skin doesn't get enough sunlight to synthesize vitamin D for up to six months of the year (23).
Summary: Cod liver oil is rich in vitamin D, which helps with maintaining strong and healthy bones. It is especially important for people who live far from the equator.
May Reduce Joint Pain and Improve Rheumatoid Arthritis Symptoms
Rheumatoid arthritis is an autoimmune disease that's characterized by damage to the joints.
There is currently no cure for rheumatoid arthritis, but studies suggest that cod liver oil may reduce joint pain and improve symptoms of rheumatoid arthritis like joint stiffness and swelling (24, 25).
In one study, 43 people took a 1-gram capsule of cod liver oil daily for three months. They found it reduced symptoms of rheumatoid arthritis, such as morning stiffness, pain and swelling (24).
In another study in 58 individuals, researchers investigated if taking cod liver oil would reduce pain from rheumatoid arthritis enough to help patients reduce their use of anti-inflammatory medications.
By the end of the study, 39% of people who took cod liver oil comfortably reduced their use of anti-inflammatory medication by over 30% (25).
Summary: Thanks to cod liver oil's ability to reduce inflammation, it may help reduce joint pain in those who suffer from rheumatoid arthritis.
May Support Eye Health
Vision loss is a huge health problem, affecting over 285 million people worldwide (26).
There are many reasons why people lose their vision, but two of the leading causes are glaucoma and age-related macular degeneration (AMD).
Both of these diseases can result from chronic inflammation.
In another study in 666 people, researchers found those who ate the most omega-3 fatty acids had a 17% lower risk of early AMD and 41% lower risk of late AMD (27).
In one study in 3,502 people aged 55 and over, researchers found that people who consumed the most vitamin A had a much lower risk of glaucoma than those who ate the least vitamin A (6).
Although vitamin A is great for eye health, it's not recommended to take high doses of it, as it may cause vitamin A toxicity.
Summary: Cod liver oil is a great source of omega-3 and vitamin A, both of which may protect against vision loss from inflammatory eye diseases like glaucoma and age-related macular degeneration (AMD).
May Reduce Heart Disease Risk
Heart disease is the leading cause of death worldwide, affecting over 17.5 million people annually (33).
Omega-3s have been shown to have many benefits for your heart, including:
- Reducing triglycerides: Omega-3 fatty acids in cod liver oil may reduce blood triglycerides by 15–30% (36, 37, 38).
- Lowering blood pressure: Many studies have found that omega-3 fatty acids may lower blood pressure, especially in people with high blood pressure and high cholesterol (2, 39).
- Increasing HDL cholesterol: Omega-3 fatty acids in cod liver oil can raise good HDL cholesterol, which is linked to a lower risk of heart disease (40, 41).
- Preventing plaque formation: Animal studies have found that cod liver oil may reduce the risk of plaques forming in the arteries. Plaque buildup can narrow the arteries and lead to a heart attack or stroke (42, 43).
While taking fish oil supplements like cod liver oil may reduce risk factors for heart disease, there is little evidence that it can prevent heart disease or strokes (44).
Unfortunately, few studies have specifically examined the association of cod liver oil and heart diseas, as many studies classify cod liver oil as regular fish oil.
Thus, more specific research on cod liver oil and heart disease risk factors are needed to make a clear link between the two.
Summary: Cod liver oil may help reduce risk factors for heart disease. Studies specifically on cod liver oil and heart disease risk factors are needed, as most studies group cod liver oil with regular fish oils.
May Improve Symptoms of Anxiety and Depression
Anxiety and depression are common illnesses that together affect over 615 million people worldwide (45).
A large study including 21,835 individuals found that people who took cod liver oil regularly had fewer symptoms of depression alone or combined with anxiety (50).
Nevertheless, while omega-3 fatty acids help reduce symptoms of anxiety and depression, their overall effect seems small.
In an analysis of 26 studies including 1,478 individuals, omega-3 supplements were only slightly more effective than placebos at reducing symptoms of depression and anxiety (51).
How it reduces symptoms of depression is still unclear, but some studies suggest that vitamin D can bind to receptors in the brain and stimulate the release of mood-improving hormones like serotonin (53, 54, 55).
Summary: The omega-3 fatty acids and vitamin D in cod liver oil may help reduce symptoms of anxiety and depression, but more studies are needed.
May Help Heal Stomach and Gut Ulcers
Ulcers are small breaks in the lining of the stomach or gut. They may cause symptoms of nausea, upper abdominal pain and discomfort.
They are often caused by bacterial infections, smoking, excess use of anti-inflammatory medications or too much acid in the stomach (56).
Animal studies indicate that cod liver oil may help treat ulcers, particularly in the stomach and gut.
In one animal study, researchers found that low and high doses of cod liver oil helped heal ulcers in both the stomach and gut (57).
Another animal study found that cod liver oil suppressed genes that are linked with gut inflammation and reduced inflammation and ulceration in the gut (58).
While the use of cod liver oil to help heal ulcers seems promising, more studies in humans are needed to make clear recommendations.
Summary: Cod liver oil may help treat ulcers in the stomach and gut, but more human studies are needed before making recommendations.
Easy to Add to Your Diet
Cod liver oil is incredibly easy to add to your diet. It comes in many forms, but liquid and capsule forms are the most common.
There are no set guidelines for cod liver oil intake, so most recommendations are based on safe intake levels of omega-3 fatty acids, vitamin A and D.
A common dose is often 1–2 teaspoons, but taking up to one tablespoon per day is usually safe. Higher doses are not recommended, as they would result in excess vitamin A intake (52).
Although cod liver oil is extremely healthy, some people need to be cautious about their intake since cod liver oil can act as a blood thinner.
So check with your doctor before taking cod liver oil if you take blood pressure or blood thinning medications.
Also, pregnant women should check with their doctor before taking it, as high levels of vitamin A may cause harm to the baby.
Summary: Cod liver oil is easy to add to your diet. Stick with recommended amounts, as excess cod liver oil may be harmful.
The Bottom Line
Cod liver oil is an incredibly nutritious type of fish oil supplement. It's very convenient and contains a great combination of omega-3 fatty acids, vitamin A and vitamin D.
Cod liver oil may provide you with health benefits like stronger bones, reduced inflammation and less joint pain for those with rheumatoid arthritis.
If you want to try supplementing, a common dose is 1–2 teaspoons of liquid cod liver oil per day. You can also try the capsule form.
If you struggle with the fishy taste of either, try taking it on an empty stomach before your first meal or with a few sips of water.
Reposted with permission from our media associate Authority Nutrition.
By Tara Lohan
Our plastic pollution problem has reached new heights and new depths.
Scientists have found bits of plastic on the seafloor, thousands of feet below the ocean's surface. Plastic debris has also washed ashore on remote islands; traveled to the top of pristine mountains; and been found inside the bodies of whales, turtles, seabirds and people, too.
1. There’s a lot of it.<p>In a September study published in <em>Science </em>about the growth of plastic waste, an international team of researchers estimated that 19 to 23 million metric tons — or 11% of plastic waste generated — ended up in aquatic ecosystems in 2016. And even with countries pledging to help cut waste or better manage it, the amount of plastic pollution is <a href="https://science.sciencemag.org/content/369/6510/1515" target="_blank" rel="noopener noreferrer">likely to double</a> in the next 10 years.</p><p>A <a href="https://science.sciencemag.org/content/369/6510/1455" target="_blank">study</a> about solutions to plastic waste, published in the same issue, attributed the plastic pollution epidemic to a rise in single-use plastic and "an expanding 'throw-away' culture." The researchers also found that waste-management systems simply can't deal with the onslaught of plastic, which is why so much of it ends up in the environment. We now know that only <a href="https://www.nationalgeographic.org/article/whopping-91-percent-plastic-isnt-recycled/" target="_blank">9% of the plastic products</a> we use actually get recycled.</p>
2. The United States is a big culprit.<p>Plastic pollution is a global problem, but the United States plays an outsized role. In 2016 the United States was responsible for more plastic waste than any other country, a <a href="https://advances.sciencemag.org/content/6/44/eabd0288" target="_blank">new study</a> in <em>Science Advances</em> found. Some of that waste was dumped illegally within the country and some was shipped to other countries that lacked the necessary infrastructure to handle it.</p><p>"The amount of plastic waste generated in the United States estimated to enter the coastal environment in 2016 was up to five times larger than that estimated for 2010, rendering the United States' contribution among the highest in the world," the researchers concluded. Part of that is because the United States ranks second in exporting plastic scrap.</p>
3. It threatens wildlife and ecosystems.<img lazy-loadable="true" src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDg3MTUwMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMzE1MzM2MH0.YL5C-5GF2mq9OZBLSkcAnreq2Mai20DweKSNqeUSWM4/img.jpg?width=980" id="20233" class="rm-shortcode" data-rm-shortcode-id="3db4a05d5d417d925a770cf309db1db1" data-rm-shortcode-name="rebelmouse-image" />
A giant otter plays with a plastic bottle. Paul Williams / CC BY-NC 2.0<p>Out of sight (for Americans) is <em>not </em>out of mind — and definitely not out of our waterways. An estimated 700 marine species and 50 freshwater species have either ingested plastic or been entangled in it.</p><p>"If we don't get the plastic pollution problem in the ocean under control, we threaten contaminating the entire marine food web, from phytoplankton to whales," George Leonard, the Ocean Conservancy's chief scientist and coauthor of the September <em>Science </em>study about plastic waste's increase, <a href="https://www.nationalgeographic.com/science/2020/10/plastic-pollution-huge-problem-not-too-late-to-fix-it/" target="_blank">told <em>National Geographic</em></a>. "And by the time the science catches up to this, perhaps definitively concluding that this is problematic, it will be too late. We will not be able to go back. That massive amount of plastic will be embedded in the ocean's wildlife essentially forever."</p><p>Microplastics have also been found in terrestrial animals, soil, drinking water and, not surprisingly, <a href="https://www.forbes.com/sites/victoriaforster/2020/08/18/microplastics-found-in-human-organs-for-the-first-time/?sh=42994a4e16f2" target="_blank" rel="noopener noreferrer">in our own bodies</a>, although it's not clear yet just how dangerous that is for people.</p>
4. The fracking boom is producing a plastic boom.<p>Despite the known risks of plastic pollution and concern over its mounting presence in the environment, plastic production — driven by fossil fuels like fracked gas and its component chemicals — is on pace to increase by 40% in the next 10 years.</p><p>The American Chemistry Council <a href="https://www.americanchemistry.com/Shale-Infographic/" target="_blank" rel="noopener noreferrer">boasted that shale gas drilling is driving a surge</a> in plastic production, including the investment of more than $200 billion to fund new and expanded operations at 343 production plants in the United States.</p><p>On the ground this means more harmful pollution along the Gulf Coast's "Cancer Alley," where petrochemicals have been manufactured for decades in low-wealth communities of color. And it means the build-out of new facilities in Rust Belt states such as Ohio, Pennsylvania and West Virginia.</p><p>Fracking also causes harmful greenhouse gas emissions, like methane, to be released into the atmosphere — amplifying the climate crisis. The refining process and the incineration of plastic waste also further drives greenhouse emissions and hazardous pollution.</p>
A petrochemical plant in Houston's ship channel. Louis Vest / CC BY-NC 2.0
5. Solutions are multifaceted.<p><a href="https://www.dw.com/en/plastic-pollution-do-beach-cleanups-really-make-a-difference/a-46196975" target="_blank" rel="noopener noreferrer">Beach cleanups</a> tend to make headlines, but it's a losing battle as long as petrochemical companies keep producing so much plastic and we keep using plastic for products we're meant to toss after a single use.</p><p>The September study in <em><a href="https://science.sciencemag.org/content/369/6510/1455" target="_blank">Science</a></em> on plastic solutions found that it's possible to cut plastic pollution — perhaps as much as 80% by 2040 — but it will take systemic change both in reducing the amount of plastic produced and in better managing the waste stream.</p><p>Regulatory efforts can help this process, including by regulating plastic as a pollution source under the Clean Water Act.</p><p>Efforts to ban single-use plastics, as the European Union aims to do by 2021, are another positive step. So too are "<a href="https://therevelator.org/california-plastic-legislation/" target="_blank" rel="noopener noreferrer">circular economy laws</a>," which have been <a href="https://www.congress.gov/bill/116th-congress/house-bill/5845?q=%7B%22search%22%3A%5B%22H.R.5%22%5D%7D&s=1&r=5" target="_blank" rel="noopener noreferrer">introduced, but not yet passed</a>, in the United States.</p><p>These laws would halt the production of new petrochemical facilities and encourage businesses to take responsibility for the full lifecycle of the products they produce by requiring them to be reused, adequately recycled or composted.</p><p>Getting circular economy laws enacted, though, will mean enough public and political will to counter the petrochemical, fossil fuel and plastic industries.</p><p>At <em>The Revelator</em>, we'll keep covering the push for solutions to the plastic problem and new science to better understand the threats. And if you want to know more about how wildlife has already been affected, what laws could help, whether industry will be held accountable and more, check out these stories from our archives:</p><p><strong>Laws and Regulations</strong></p><p><strong></strong><a href="https://therevelator.org/plastic-pollution-warnings/" target="_blank">Plastic Pollution: Could We Have Solved the Problem Nearly 50 Years Ago?</a></p><p><a href="https://therevelator.org/clean-water-plastic/" target="_blank" rel="noopener noreferrer">How an Old Law Is Helping Fight New Plastic Problems</a></p><p><a href="https://therevelator.org/california-plastic-legislation/" target="_blank" rel="noopener noreferrer">New California Bill Could Revolutionize How the U.S. Tackles Plastic Pollution</a></p><p><a href="https://therevelator.org/plastic-pollution-laws/" target="_blank" rel="noopener noreferrer">What Laws Work Best to Cut Plastic Pollution?</a></p><p><a href="https://therevelator.org/plastic-illegal/" target="_blank" rel="noopener noreferrer">Can Plastic Ever Be Made Illegal?</a></p><p><strong>Impacts</strong></p><p><a href="https://therevelator.org/toxic-plastic-pollution-food-chain/" target="_blank" rel="noopener noreferrer">Something Fishy: Toxic Plastic Pollution Is Traveling Up the Food Chain</a></p><p><a href="https://therevelator.org/plastic-pollution-ship-shore/" target="_blank" rel="noopener noreferrer">Plastic Pollution: From Ship to Shore</a></p><p><a href="https://therevelator.org/plastics-fracking-climate/" target="_blank" rel="noopener noreferrer">Plans to Turn America's Rust Belt Into a New Plastics Belt Are Bad News for the Climate</a></p><p><a href="https://therevelator.org/trash-galapagos-ecotourism/" target="_blank" rel="noopener noreferrer">Trash in the Galápagos Reveals the Dark Side of Ecotourism</a></p><p><a href="https://therevelator.org/elephant-seals-diving-garbage/" target="_blank" rel="noopener noreferrer">Elephant Seals: Diving Through Garbage</a></p><p><strong>Taking Action</strong></p><p><em><a href="https://therevelator.org/story-plastic-review/" target="_blank" rel="noopener noreferrer">The Story of Plastic: </a></em><a href="https://therevelator.org/story-plastic-review/" target="_blank" rel="noopener noreferrer">New Film Exposes the Source of Our Plastic Crisis</a></p><p><a href="https://therevelator.org/plastic-movie-stuff/" target="_blank" rel="noopener noreferrer">How to Win the Fight Against Plastic</a></p><p><a href="https://therevelator.org/cities-zero-waste/" target="_blank" rel="noopener noreferrer">Can Cities Go Zero-waste? One Japanese Town Tried</a></p><p><a href="https://therevelator.org/secret-value-trash/" target="_blank" rel="noopener noreferrer">The Secret Value of Trash</a></p><p><a href="https://therevelator.org/junk-raft-polluted-ocean/" target="_blank" rel="noopener noreferrer">Junk Raft: A Journey Through a Polluted Ocean</a></p><p><a href="https://therevelator.org/bioplastics-environment/" target="_blank" rel="noopener noreferrer">Are Bioplastics a Better Environmental Choice?</a></p><p><a href="https://therevelator.org/plastic-straws-problem-solution/" target="_blank" rel="noopener noreferrer">Plastic Pollution Is a Problem — These Kids Are Working for a Solution</a></p><p><a href="https://therevelator.org/thai-activists-fight-trash-taboo/" target="_blank" rel="noopener noreferrer">Thai Activists Fight Trash Taboo</a></p><p><em><a href="https://therevelator.org/author/taralohan/" target="_blank">Tara Lohan</a> is deputy editor of The Revelator and has worked for more than a decade as a digital editor and environmental journalist focused on the intersections of energy, water and climate. Her work has been published by The Nation, American Prospect, High Country News, Grist, Pacific Standard and others. She is the editor of two books on the global water crisis.</em></p><p><em>Reposted with permission from <a href="https://therevelator.org/plastic-pollution-archives/" target="_blank">The Revelator</a>. </em></p>
EcoWatch Daily Newsletter
Hundreds of endangered sea turtles were stranded on beaches after suffering "cold stunning" in the waters off Cape Cod, Mass. Local rescuers and wildlife rehabilitators stabilized the turtles at the New England Aquarium (NEAQ) and National Marine Life Center and began treatment. Many of the sea turtles were transported by land or air to partner facilities around the Eastern Seaboard for longer-term care to make room for more incoming, cold-stunned animals.
Rehabilitators at The Turtle Hospital in the Florida Keys assess critically endangered, cold-stunned Kemp's ridley sea turtles flown in after rescue in New England. The Turtle Hospital<p>NEAQ and local rescuers begin seeing turtles every fall when water temperatures drop to that 50 degrees F threshold, and typically expect to find them into early January. After that, <a href="https://www.ecowatch.com/sea-turtle-cape-cod-weather-2621527394.html" target="_self">temperatures are so cold that any animals found are usually no longer alive</a>.</p><p>Merigo estimated that this year's cold season "looks very busy" and noted that local rescue efforts had already surpassed 400 turtles.</p><p>"It is a lot of animals. They're still coming in," she told EcoWatch as she surveyed 39 rescued turtles that day and 20 the day prior. "So far, this is a huge year."</p><p>At NEAQ, the turtles are gradually warmed up about five to 10 degrees F a day. More aggressive warming can cause serious damage and the turtle might not survive, Merigo said. Emergency treatments also include providing replacement fluids, balancing electrolytes and addressing pneumonia. Assessments take place for other serious problems too, such as shell or limb fractures, frostbite, emaciation and eye damage.<span></span></p><p>As local aquariums don't have the capacity to care for all the injured turtles, a group of private pilots called <a href="https://www.turtlesflytoo.org/" target="_blank">"Turtles Fly Too"</a> donated planes, fuel and time to transport some to various partner facilities around the country. Other turtles were driven to closer care facilities.</p><p>"We have a huge network of really great partners working with us, so if we can spread out the care, we can give better care to all the animals," Merigo said.</p><p>The 40 Kemp's ridley sea turtles recovering in The Turtle Hospital will continue to be treated and rehabilitated anywhere from 30 days to a year, depending on the severity of injuries, Zirkelbach said.</p><p>The turtle expert noted that while she's treated cold-stunned turtles from the north before, the newest arrivals were the most cold-stunned Kemp's ridleys ever received at one time.</p>
After rescue, cold-stunned sea turtles received immediate emergency care and assessments at the New England Aquarium. Caitlin Cunningham / New England Aquarium<p>In the past decade, the Gulf of Maine, which spans from Cape Cod to Nova Scotia, has warmed 99 percent faster than the rest of the ocean, Zirkelbach said. The warm water encourages turtles that migrate north along the Gulf Stream in warmer months to stay in the bay longer.</p><p>"Turtles that fail to migrate south get stuck in the unique horseshoe-shaped topography of the Cape Cod peninsula, and when temperatures drop, the bay becomes a death trap," she added.</p><p>Before ocean temperatures warmed, the waters of Maine were too cold for many of these sea turtles, Merigo echoed. Now, with warming sea surface temperatures, Maine can reach the high 70s to low 80s, which is "perfect turtle temperature," she said. The potential for more turtles getting trapped in the bay and then cold-stunned is nerve-racking for Merigo.</p><p>In addition to shifting habitats as waters warm, warming global temperatures also disrupt natural gender balance in sea turtles, Merigo warned. Gender is determined by the temperature of eggs in nests, and as the planet warms, it will result in all females at some point, she said.</p><p>"The turtles we work with are all endangered and threatened," Merigo said. "For sea turtles in general, the future is a little grim. Climate change is real; it does impact them."</p>
- 9 Super Cool Facts About Sea Turtles - EcoWatch ›
- Sea Turtles Often Get Lost for Miles, but Always Find Their Destination ›
- 100% of Sea Turtles in Global Study Found With Plastics in Their ... ›
The night sky has a special treat in store for stargazers this winter solstice.
- NASA Satellites Enable Scientists to Observe Climate Change ... ›
- Why Scientists Are Searching for Life in 'Alien Oceans' - EcoWatch ›
- To Save Endangered Species, Scientists Point Stargazing Software ... ›
By Dena Jones
The U.S. Department of Agriculture (USDA) was sued three times this past summer for shirking its responsibility to protect birds from egregious welfare violations and safeguard workers at slaughterhouses from injuries and the spread of the coronavirus.
By Julia Conley
Conservation campaigners on Thursday accused President Donald Trump of taking a "wrecking ball" to the Arctic National Wildlife Refuge as the White House announced plans to move ahead with the sale of drilling leases in the 19 million-acre coastal preserve, despite widespread, bipartisan opposition to oil and gas extraction there.
The Sheenjek River in the Arctic National Wildlife Refuge. Alexis Bonogofsky / USFWS
- Bipartisan Bill Seeks to Ban Drilling in Arctic National Wildlife Refuge ›
- Bank of America Promises It Won't Fund Arctic Drilling - EcoWatch ›
- Trump's Drilling Leases on Public Lands Could Lead to 4.7B Metric ... ›
- Trump Administration's Alaska Oil and Gas Lease Sale a 'Major Flop ... ›
- Will Oil Companies Drill in the Arctic National Wildlife Refuge ... ›