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Is krill oil better than fish oil for omega-3?

Krill oil and fish oil supplements are two sources of omega-3 fatty acids including DHA and EPA. While oil from both krill and fish provide health benefits, there are differences in their origin, price, and benefits.

Fish oil comes from oily fish, such as tuna, herring, or sardines. Krill oil comes from a small, shrimp-like animal called krill.

Krill oil has a distinctive red color while fish oil supplements are typically yellow or gold. Krill oil is usually more expensive than fish oil.

While each supplement type contains omega-3 fatty acids, there are various risks and benefits in taking each supplement type. Read on to find out more.

Benefits of krill oil and fish oil Krill oil versus fish oil
Omega-3 fatty acids are present in krill oil and fish oil.

Both krill oil and fish oil contain omega-3 fatty acids. Some of the most popular and beneficial omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

When consumed in fish, these fatty acids have been shown to boost a person's overall heart health and reduce the risks of heart attack and coronary artery disease. However, while research has shown eating whole fish can have heart-protecting benefits, scientific studies have not yet proven that taking omega-3 supplements offers the same benefits as eating fish.

However, the National Institutes of Health (NIH) state that the specific benefits of taking omega-3 supplements include:

Reducing high triglyceride levels. High triglyceride levels are associated with an increased risk for heart disease. Relieving rheumatoid arthritis. Evidence suggests that omega-3 supplements may help relieve the symptoms of rheumatoid arthritis. Relieving dry eye symptoms. Some studies have indicated that omega-3 supplements help to improve eye moisture and reduce the symptoms of dry eye disease. However, other large-scale studies have found that taking omega-3 supplements are no better than a placebo for eye dryness, so more research is needed.

Drug stores and online supermarkets sell both fish oil and krill oil supplements.

Thank you for supporting Medical News Today What does the research say? A study from 2011 compared the effects of fish and krill oil, finding that they resulted in similar blood levels of EPA and DHA. However, people took 3 grams (g) of krill oil and only 1.8 g of fish oil, which may suggest that a person needs to take almost twice as much krill oil as fish oil to get the same benefits. However, the amount and concentration of omega-3 in krill and fish oil vary depending on the product. Some krill oil manufacturers claim that the krill oil omega-3s are better absorbed than fish oil omega-3s, so a lower concentration works just as well. However, there is no current proof that this statement is true. According to the study's authors, 30–65 percent of krill oil's fatty acids are stored as phospholipids, while the fatty acids in fish oils are instead stored primarily as triglycerides. The researchers suggest that the body may able to use fatty acids stored as phospholipids more easily. However, despite this possibility, a person may still have to take more krill oil capsules than fish oil to get an equivalent amount of omega-3s. Another small-scale study published in 2013 found that after 4 weeks of taking only one of the supplements, krill oil led to higher levels of EPA and DHA in a person's blood compared with fish oil. Although both supplements increased levels of healthful omega-3 fatty acids, they also increased levels of low-density lipoprotein (LDL) cholesterol, which is the 'bad' cholesterol. Studies are not consistent, though. A study from 2015 found no differences in krill oil and fish oil in the blood after 4 weeks of taking supplements. So, while some research suggests that the body might better absorb krill oil, other studies find no difference between fish and krill oil. More research is therefore needed. The above research only looks effects of the oil on blood levels, which is just one marker of their potential benefits. No study has compared these products to see if one works better than the other for the specific uses that people are interested in, such as bodybuilding or promoting heart health. Risks of krill oil and fish oil Krill oil versus fish oil - both can cause bad breath
There is no significant risk in taking omega-3 supplements, but a person may experience bad breath as a result. Taking omega-3 supplements in the forms of krill oil and fish oil does not appear to carry any significant side effects, but minor side effects may include: Also, omega-3 supplements, such as krill oil and fish oil, have the potential to interact negatively with blood-thinning medications, such as warfarin (Coumadin). This is because omega-3 fatty acids have mild anticoagulant or blood-thinning effects. However, a person must usually take between 3 and 6 g of fish oil a day for these adverse interactions to occur. Thank you for supporting Medical News Today Dosage recommendations The Office of Dietary Supplements (ODS) reports there is no established upper limit for taking omega-3 supplements. However, taking dosages of more than 900 milligrams (mg) of EPA and 600 mg of DHA a day can reduce a person's immune system by suppressing natural inflammatory responses. According to the ODS, daily intakes for omega-3 fatty acids are about 1.6 g per day for men and 1.1 g per day for women. The ODS also recommend not exceeding 2 g of EPA and DHA a day from dietary supplements. A person should read supplement labels carefully to determine how much of each substance is in each capsule. Takeaway Krill oil versus fish oil - both can reduce arthritis symptoms
Omega-3 may help to reduce rheumatoid arthritis symptoms. According to the ODS, an estimated 7.8 percent of adults and 1.1 percent of children in the United States take omega-3 fatty acid supplements in the forms of fish oil, krill oil, or animal-free alternatives, such as algal oil or flaxseed oil. The evidence is still inconclusive about whether krill oil works as well as or better than fish oil. So far, most of the research on the benefits of omega-3 fatty acids has been carried out using fish oil. There is not a lot of research on krill oil. Taking omega-3 supplements can offer benefits in terms of lowering triglyceride levels and reducing rheumatoid arthritis symptoms. However, the evidence is inconclusive regarding whether they can reduce heart disease or improve overall cardiovascular health to the same extent as eating whole fish. According to the NIH, eating oily fish, including tuna and salmon, can offer a greater variety of nutrients than supplements, and has been shown to improve heart health. On balance, taking either krill oil or fish oil supplements can help to boost a person's overall levels of omega-3 fatty acids, though it is unclear whether one is better than the other.
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Novel gel regrows brain tissue after stroke

A new study paper describes a groundbreaking bioengineered gel that can help stroke-damaged brain tissue to regrow.
Brain stroke gel photomicrograph
Photomicrograph of stroke-damaged tissue with gel (explained in text).
Image credit: UCLA Health

A stroke occurs when blood supply to a certain part of the brain is significantly reduced, resulting in brain cell death.

Following a stroke, many people will be left with cognitive impairments, motor impairments, or both because of the brain tissue that is destroyed in the process.

In fact, stroke is the leading cause of long-term disability in the United States.

Unlike most other tissues in the body, the brain cannot regenerate; once brain tissue dies, it is absorbed, leaving a cavity that is not refilled.

For many years now, researchers have been trying to find ways to encourage the central nervous system to regenerate — but this has proven challenging.

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New approach to stroke damage

Recently, researchers from the University of California, Los Angeles set about the problem using a novel, bioengineered gel. They were led by Dr. Tatiana Segura — now a professor at Duke University in Durham, NC — who created the innovative gel.

The compound is designed to thicken once it enters the brain, acting as a scaffolding for fresh neuronal and vascular growth.

The gel contains compounds intended to stimulate the growth of blood vessels. It also contains anti-inflammatory compounds. This is important because inflammation causes scarring, which hinders new growth.

Using a mouse model of stroke, they squirted the gel into the cavities left by stroke damage. At the 16-week mark, they assessed the cavities for activity and new growth.

They discovered that the gel was slowly absorbed into the body, and regions that had previously been empty spaces were now filled with new tissue. The findings were recently published in the journal Nature Materials.

"This study indicated that new brain tissue can be regenerated in what was previously just an inactive brain scar after stroke."

Dr. S. Thomas Carmichael, researcher

The image at the top of the article is a photomicrograph. It shows new tissue growing into the gel-filled cavity in a stroke-damaged mouse brain.

The red tubes are blood vessels, the green strings are axons — which grow along the blood vessels as they creep into the cavity — and the blue spots are cell nuclei.

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Motor recovery

When assessing the mice's recovery, the scientists found that motor behavior improved in the mice that had been treated with the gel. However, it is not exactly clear how this improvement was achieved.

Segura explains, "The new axons could actually be working, or the new tissue could be improving the performance of the surrounding, unharmed brain tissue."

The findings are exciting, although preliminary. Of course, more work will need to be done on a much larger scale — but, in principle, this could be a gamechanger.

Carmichael and Segura are eager to continue testing their gel in new situations. For instance, the new study used a mouse model that replicates an intervention roughly 5 days after a stroke.

Next, they want to examine how the gel might perform in brain tissue that was injured longer ago.

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One egg per day may keep stroke at bay

Popular knowledge has it that eggs, due to their high cholesterol content, are quite bad for us. New research, however, suggests we would do well to indulge in more egg consumption: about one per day could help us to steer clear of cardiovascular conditions.
carton of eggs
We might think of eggs as unhealthful, but could they protect against cardiovascular events?

If you've ever heard that eating more than two or three eggs per week is bad for your health, you're not alone.

Some studies have suggested that, due to yolks' high cholesterol content, eggs can be a harmful food — particularly for people already at risk of cardiovascular events.

The idea that eggs may pose danger to health has also been spread widely by many popular websites and magazines.

However, despite being rich in cholesterol, eggs are also a great source of healthful nutrients, such as protein, vitamins, phospholipids, and carotenoids.

And, recent research has increasingly gathered evidence showing that eggs don't really influence the risk of cardiovascular disease (CVD).

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One study published in 2013 in The BMJ, for example, concluded that eating up to one egg per day was not tied to a heightened risk of heart disease or stroke.

Another study, published earlier this month in the American Journal of Clinical Nutrition, suggested that a "high-egg diet" of up to 12 eggs per week did not increase cardiovascular risk.

But recent research from the School of Public Health at Peking University Health Science Center in Beijing, China, goes even further.

Lead investigators Prof. Liming Li and Dr. Canqing Yu have now found that a diet in which eggs are consumed on a regular basis may actually protect cardiovascular health.

The team's findings were published yesterday in the journal Heart.

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About 84 million people in the United States have some form of CVD, and about 2,200 people die each day due to their condition. And, in China, the rates for cardiovascular conditions are even higher.

In China in 2014, an estimated "837,300 urban residents and 1,023,400 rural residents died from cerebrovascular diseases," according to recent data. And the most widespread conditions are stroke — both hemorrhagic and ischemic — and ischemic heart disease, in that order.

These numbers motivated the researchers involved in the new study to investigate what role — if any — egg consumption plays in modifying the risk for CVD.

In order to do so, they analyzed data sourced via the China Kadoorie Biobank, which is an ongoing prospective study investigating the genetic and environmental causes of chronic diseases among the Chinese population.

In this study, Prof. Li and team analyzed health-related information from 416,213 adult participants recruited in 2004–2008. They were all free of cancer, CVD, and diabetes at baseline.

At recruitment, the participants reported how often they ate eggs — 13.1 percent of them admitting to daily consumption (about 0.76 eggs per day) and 9.1 percent saying that they only indulged in eggs rarely (0.29 eggs per day) or not at all.

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There was a median follow-up period of 8.9 years, during which new health diagnoses and deaths were recorded. During that time, 83,977 participants received a CVD diagnosis, and 9,985 people died due to CVD-related causes. Moreover, 5,103 major coronary events were recorded.

The researchers' analysis revealed that individuals who usually ate about one egg per day had a 26 percent lower risk of experiencing hemorrhagic stroke, a 28 percent lower risk of death due to this type of event, and an 18 percent lower risk of CVD-related mortality.

Almost daily egg consumption — or around 5.32 eggs per week — was also linked to a 12 percent lower risk of ischemic heart disease, compared with people who never or rarely ate this food (amounting to approximately 2.03 eggs per week).

"The present study finds that there is an association between moderate level of egg consumption (up to 1 egg/day) and a lower cardiac event rate," the study authors explain.

Prof. Li and team warn that this was an observational study, so it would be unwise to conclude that there is necessarily a causational effect between egg consumption and a lower risk of CVD.

However, the large population sample size with which the researchers worked, as well as the fact that they adjusted for confounding factors — both known and potential CVD risk factors — imply that this is a strong possibility.

"Our findings," the researchers conclude, "contribute scientific evidence to the dietary guidelines with regard to egg consumption for the healthy Chinese adult."

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This 'natural antioxidant' may protect heart health

Bilirubin is a pigment and natural antioxidant. Often, an excess of bilirubin is a sure indicator of disease, but emerging research suggests that high levels of this compound may actually help to sustain cardiovascular health.
colorful letters spelling bilirubin
Could higher bilirubin levels help to improve the risk of cardiovascular events?

This pigment has a yellowish tint, which causes the yellow tinge of the skin in jaundice.

It is a natural byproduct of the breakdown of red blood cells, which takes place when blood cells age or become faulty.

Bilirubin is then processed by the liver; some of it is reabsorbed into the bloodstream, while the rest is eventually excreted through urine or feces.

Sometimes, due to various dysfunctional biological mechanisms, excess bilirubin is not processed and eliminated from the body. When this happens, it can lead to jaundice; sometimes, it indicates that there is a problem with the liver or pancreas.

Yet, according to researchers from a range of reputable institutions in the United States — including the Atlanta Veteran Affairs Medical Center in Georgia, Yale University in New Haven, CT, Vanderbilt University in Nashville, TN, and Boston University in Massachusetts — blood levels of bilirubin may also be used to determine a person's risk of cardiovascular problems.

Their findings, now published in the Journal of the American Heart Association, indicate that people with higher levels of bilirubin in the blood may be better protected against conditions and events such as heart failure, heart attack, or stroke.

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Previous research suggests that bilirubin levels could predict cardiovascular risk, but the investigators involved in the current study were interested in seeing whether the relationship was different in HIV-positive versus HIV-negative individuals.

They were interested in this because people living with HIV are often at a higher risk of cardiovascular disease. At the same time, the HIV drug ataznavir is known to elevate serum bilirubin levels.

"We sought to determine whether increased total bilirubin levels were associated with reduced [cardiovascular] events in [Veterans Aging Cohort Study] and to determine if those associations differed by HIV status, atazanavir use, and liver disease," the authors explain in their paper.

For this purpose, they worked with 96,381 participants with an average age of 48. Of these, 31,418 were HIV-positive, and 66,987 were HIV-negative. Ninety-seven percent of these were men, and 48 percent identified as African-American.

"We initially wanted to see if bilirubin and cardiovascular disease had a different relationship in people who were HIV positive, compared to HIV negative," says first author Vincent Marconi, from the Atlanta Veterans Affairs Medical Center.

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Marconi and team split the participants into four groups, or quartiles, based on their levels of serum bilirubin. Those in the highest bilirubin category were found to have a lower risk of heart attack, stroke, and heart failure.

In other words, the higher the bilirubin levels, the lower the risk for cardiovascular events, and vice versa. The risk decreased "by 8 percent for each increase in total bilirubin quartile," the authors write.

Moreover, the risk trends were similar among the HIV-positive and the HIV-negative cohort, though they remained slightly higher for the former.

The researchers also note that "high levels" of the compound did not mean "off the charts," and that the concentration of serum bilirubin always stayed within healthy ranges.

"Large increases in bilirubin were not required to see an effect on [cardiovascular] risk reduction," explains Marconi, adding, "Most of the change happened well within the normal physiologic range and specifically from the first to the second quartile."

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The study did not find an independent effect of ataznavir on cardiovascular health outcomes, but the researchers note that previous analyses have suggested that the drug could have a positive impact in this respect.

In their conclusion, Marconi and team note that a better understanding of the underlying mechanisms set in motion by bilirubin may help to improve therapies for individuals at high risk of cardiovascular events, as well as various inflammatory diseases.

"It is important to determine whether incorporating bilirubin levels into current risk stratification models could improve prognostication of inflammatory diseases."

"In addition," the authors conclude, "further exploration into the mechanisms related to the antioxidant properties of bilirubin could provide new insights into therapeutic strategies."

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Increasing exercise over 6-year span protects the heart

With heart failure, the cardiac muscle is unable to pump blood at the normal rate, resulting in persistent tiredness, breathlessness, and swollen legs. The condition can appear with age and tends to worsen over time.
older individuals exercising
Can increasing exercise protect heart health? And how much would you need to increase it by to benefit? A new study investigates.

Heart failure affects about 5.7 million adults in the United States.

The most salient risk factors for this condition, according to the Centers for Disease Control and Prevention (CDC), are: hypertension, a history of coronary heart disease or heart attacks, and diabetes.

Since this condition, once acquired, has to be managed for life, healthcare professionals recommend preventive strategies.

These usually involve making more healthful lifestyle choices by acquiring good dietary habits and exercising regularly.

But how do fluctuations in a person's levels of physical activity influence their risk of experiencing heart failure? That is what Dr. Chiadi Ndumele and colleagues, from Johns Hopkins University in Baltimore, MD, and other institutions set out to clarify.

In a new study — the findings of which have now been published in the journal Circulation — Dr. Ndumele and team investigate whether individuals who are active until middle age, but then become more sedentary, are more exposed to heart failure and vice versa.

"The population of people with heart failure is growing," says first study author Dr. Roberta Florido, "because people are living longer and surviving heart attacks and other forms of heart disease."

"Unlike other heart disease risk factors like high blood pressure or high cholesterol, we don't have specifically effective drugs to prevent heart failure," she notes, "so we need to identify and verify effective strategies for prevention and emphasize these to the public."

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It's never too late to exercise more

The research team analyzed data sourced from 11,351 people using the long-term Atherosclerosis Risk in Communities (ARIC) study. The participants had an average age of 60 at the point of recruitment, and 57 percent of them were women.

They were monitored over a period of 19 years, on average, and records were kept about instances of cardiovascular disease events — including heart failure, stroke, and heart attack — on a yearly basis.

Moreover, each participant was asked to delineate their exercise habits on two ARIC study visits — first at baseline, and then again after 6 years. The researchers then used this information to rate everyone's levels of physical activity.

Measuring the study participants' exercise habits against the American Heart Association's (AHA) recommendations, they were categorized as:

poor, if the individual did not typically exercise intermediate, if exercise levels corresponded to those outlined by the AHA — that is, a minimum of 75 minutes of "vigorous" exercise per week, or at least 150 minutes of "moderate" exercise per week

Dr. Ndumele and his collegues noted that the participants that met recommended exercise levels both at baseline and at the 6-year mark appeared to enjoy the greatest benefits to heart health, with a 31 percent lower risk of heart failure, compared with their peers who had poor physical activity habits during the same timeline.

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But those participants who increased their levels of physical activity over that 6-year period also experienced benefits. Heart failure risk decreased by 12 percent among individuals who upped their fitness levels from poor to intermediate.

And the reverse was also true — participants who gave up exercise during those 6 years saw an 18 percent increase in heart failure risk.

"In everyday terms," notes Dr. Ndumele, "our findings suggest that consistently participating in the recommended 150 minutes of moderate to vigorous activity each week, such as brisk walking or biking, in middle age may be enough to reduce your heart failure risk by 31 percent."

"Additionally," he says, "going from no exercise to recommended activity levels over 6 years in middle age may reduce heart failure risk by 23 percent."

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At what rate must we up our exercise levels?

The research team also wanted to ascertain by how much an individual would need to increase their levels of physical activity in order to lower their risk of experiencing heart failure.

To do so, they calculated physical activity as "metabolic equivalents" (METs) and described one MET as 1 kilocalorie per kilogram per hour, which was equivalent to a passive activity, such as sitting down and watching TV.

Different activities corresponded to different MET levels; for instance, walking fast would be 3 METs, jogging 7 METs, and jumping rope 10 METs.

They determined that every increase of 750 MET minutes per week over a 6-year period would reduce the risk of heart failure by 16 percent. Also, every increase of 1,000 MET minutes per week would result in a 21 percent lower risk of heart failure.

That being said, Dr. Ndumele and his team also warn that their study was observational, and so the relationship between physical activity levels and the decreased risks to heart health should not be automatically taken as causational.

Even so, they note that the trends they observed are consistent enough to indicate that individuals may benefit from adhering to exercise guidelines in middle age.

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