Global Study Supports Eating Fish for Heart Health

Steven Reinberg wrote . . . . . . . . .

For people with heart disease, eating fish twice a week may be a lifesaver.

New worldwide research shows that two 6-ounce servings a week of oily fish, like salmon, might help prevent cardiovascular disease in high-risk people, such as those who have heart disease or who have experienced a stroke.

“Eating at least two servings of fish each week appears to lower your risk of future cardiovascular events and death if you have preexisting cardiovascular disease,” said lead researcher Andrew Mente, an associate professor of health research methods, evidence and impact at McMaster University in Hamilton, Canada.

“If you’re generally healthy, there’s no clear protection, although fish is probably a safe choice for them as well,” he said.

This study, however, can’t prove that fish boosts heart health, only that there seems to be a connection.

It’s the omega-3 fatty acids in fatty fish that is associated with a lower risk of heart attacks and strokes, by roughly 17%, Mente said.

“The protection of fish is seen mainly for fish that contain high amounts of omega-3 fats, or so-called oily fish, such as herring, mackerel, sable, salmon, tuna [steak or canned] and sardines. Other types of fish that contain low amounts of omega-3 fats are generally neutral,” he said.

For the study, Mente and his colleagues collected data on nearly 192,000 people from five continents who took part in four studies, including about 52,000 who had cardiovascular disease.

It’s actual fish that seems to confer the benefit, not supplements, Mente noted.

“Some trials have shown that omega-3 supplements in high-risk individuals with high triglyceride levels may achieve a benefit, but a higher dose of omega-3 supplements might be needed to achieve a benefit. Trials with small-dose omega-3s found little or no benefit,” he said.

The report was published online March 8 in the journal JAMA Internal Medicine.

Dr. Dariush Mozaffarian is a professor of nutrition at the Friedman School of Nutrition Science and Policy at Tufts University in Boston. He noted that past research efforts have not always been conclusive. “Not all studies have shown benefits, creating uncertainty and controversy over the role of fish for heart health,” he said.

Some of the differences in findings could be due to different types of fish studied or how the fish was cooked. Also, some studies looked at different types of heart disease that might not benefit from fish or different amounts of fish or supplements consumed, said Mozaffarian, who authored an editorial that accompanied the study.

“Modest fish consumption — two servings a week — appears to contribute to a healthy heart,” he said. “There are probably bigger benefits from eating non-fried dark meat fish, which have more omega-3 fatty acids. The preponderance of global evidence to date suggests that people who eat more fish generally have better health outcomes. Or put more simply, include some fish in your diet each week — your heart will thank you.”

One dietitian says that foods other than fish may be a better choice for your and the planet’s health.

“With our seas being overfished and several species of fish on the verge of extinction, we and the planet can all benefit from adding more plant foods and fewer animal foods to our daily plates,” said Samantha Heller, a senior clinical nutritionist at NYU Langone Health in New York City.

Consuming fish a few times a week is considered a healthy alternative to red or processed meat, but she pointed out there are also plant-based foods such as tofu, edamame, legumes like lentils, chickpeas, kidney beans, nuts, whole grains and seitan, a wheat gluten protein, that offer an array of health benefits.

“A plethora of studies have found that consuming a diet rich in plant foods decreases the risk of many chronic diseases, including cardiovascular disease, type 2 diabetes, certain cancers, obesity and cognitive decline,” Heller said.

Source: Healthday

Study: Mercury Released by Permafrost Thaw Puts Yukon River Fish at Risk

Yereth Rosen wrote . . . . . . . . .

If carbon emissions continue at current rates, so much mercury will leach from thawing permafrost that fish in the Yukon River could become dangerous to eat within a few decades, according to a study published Wednesday in the journal Nature Communications.

Current emissions rates threaten to trigger enough thaw release to drive mercury levels in Yukon River fish above federal safety guidelines by 2050, according to the study.

Mercury concentration in the Yukon is expected to double by the end of the century if carbon emissions continue at present rates, according to the study.

But if emissions are reduced in line with the 2015 Paris Agreement, mercury concentrations will increase by only 14% by the end of the century, keeping levels in fish at or below safety guidelines, according to the study.

“A lot will depend on what we do in terms of response to climate change,” said Kevin Schaefer of the Colorado-based National Snow and Ice Data Center, the study’s lead author.

The study has implications beyond the indigenous communities in Alaska and Canada that depend on Yukon River fish for their income, diets and culture, Schaefer said.

The nearly 2,000-mile river is “a bellwether or a canary-in-the-coal mine kind of thing, an indicator of what might happen over the whole Arctic,” he said. Thaw-released mercury will work its way from the land to the river and ultimately, into the oceans, and thaw-released mercury in gaseous form will encircle the world, he said.

“What happens in the Yukon is going to affect the entire globe, not just the people who live on or around the Yukon River,” he said.

A 2018 study co-authored by Schaefer, in collaboration with partners from the U.S. Geological Survey and other institutions, estimated that Northern Hemisphere’s permafrost soils hold nearly twice as much stored mercury as is in all the rest of the world’s soils, the oceans and the atmosphere combined.

Source: Reuters

Girl Power in the Deep Blue Sea: World’s Largest Fish are Female

Will Dunham wrote . . . . . . . . .

Male and female whale sharks – filter-feeding marine behemoths – grow at different rates, with females doing so more slowly but getting much larger than the guys, according to research that offers deeper insight into the biology of Earth’s largest fish.

Researchers said on Wednesday they had tracked the growth of 54 whale sharks over a 10-year period in the vast Ningaloo Reef off Australia’s west coast, where hundreds of these slow-swimming endangered fish migrate annually.

Whale sharks of both sexes were found to have their fastest growth as juveniles, about 8-12 inches (20-30 cm) annually.

Overall, males were found to grow slightly more quickly than females, plateauing at around 26 feet (8 meters) long after reaching sexual maturity at about 30 years old. Females plateaued at around 14 meters (46 feet) when they reached sexual maturity at about age 50.

It is believed whale sharks may live 100-150 years. The longest-known whale shark reached about 60 feet (18 meters).

“Whale sharks are remarkable in that females have massive litters of pups, up to 300 at one time. Being very large is almost certainly a prerequisite for carrying this many young inside a female’s body,” said Australian Institute of Marine Science marine biologist Mark Meekan, who led the research published the journal Frontiers in Marine Science.

These sharks have a brownish-grayish color on the back and sides with white spots, with a white underside.

“Our study provides the first evidence that male and female whale sharks grow at different rates,” Meekan said. “Previously, researchers had to rely on estimates of growth and age extracted from the vertebrae of dead sharks that had either stranded on shore or been killed by a fishery. Samples were very limited and didn’t cover a very wide size range of animals, confounding attempts to produce reliable estimates of growth patterns.”

They are filter feeders, swimming great distances through the world’s tropical oceans to find enough plankton to sustain themselves.

“Our study has important implications for conservation,” Meekan said. “If it takes many years, 30 or more, for these animals to become mature, there are lots of threats such as hunting and ship-strike that they may succumb to before they get a chance to breed, making conservation strategies for these animals an urgent task.”

Source: Reuters

When It Comes to Healthy Protein, Fish is the Dish

When it comes to healthy sources of protein, fish is the dish. An entrée like grilled white fish with avocado relish is tasty, easy to cook and good for your heart.

“We recommend people to eat fish at least two times a week. It makes for a satisfying entrée that’s relatively low in saturated fat compared to something like a hamburger or quiche,” said Alice H. Lichtenstein, senior scientist and director of the Cardiovascular Nutrition Laboratory at Tufts University in Boston.

Each serving of this grilled white fish recipe boasts 21 grams of protein. Fish also is a good source of omega-3 fatty acids, which promotes heart health. If you want to up your omega-3 intake, substitute salmon for white fish in this recipe, Lichtenstein said.

The mix of avocado, pineapple, red onion and cilantro gives the dish a dash of color and flavor, and provides dietary fiber. “It looks good from a visual perspective as well as a health perspective,” she said.

One more attractive thing is fish fillets are fairly easy and quick to cook.

“Fish doesn’t require long cooking times, and there are a lot of different ways to prepare it,” Lichtenstein said. “Fish is very flexible when it comes to preparation techniques and combination with other ingredients.”

Source: American Heart Association


Today’s Comic

Does Eating Fish Protect Our Brains from Air Pollution?

Older women who eat more than one to two servings a week of baked or broiled fish or shellfish may consume enough omega-3 fatty acids to counteract the effects of air pollution on the brain, according to a new study published in online issue of Neurology®, the medical journal of the American Academy of Neurology.

Researchers found that among older women who lived in areas with high levels of air pollution, those who had the lowest levels of omega-3 fatty acids in their blood had more brain shrinkage than women who had the highest levels.

“Fish are an excellent source of omega-3 fatty acids and easy to add to the diet,” said study author Ka He, M.D., Sc.D., of Columbia University in New York. “Omega-3 fatty acids have been shown to fight inflammation and maintain brain structure in aging brains. They have also been found to reduce brain damage caused by neurotoxins like lead and mercury. So we explored if omega-3 fatty acids have a protective effect against another neurotoxin, the fine particulate matter found in air pollution.”

The study involved 1,315 women with an average age of 70 who did not have dementia at the start of the study. The women completed questionnaires about diet, physical activity, and medical history.

Researchers used the diet questionnaire to calculate the average amount of fish each woman consumed each week, including broiled or baked fish, canned tuna, tuna salad, tuna casserole and non-fried shellfish. Fried fish was not included because research has shown deep frying damages omega-3 fatty acids.

Participants were given blood tests. Researchers measured the amount of omega-3 fatty acids in their red blood cells and then divided the women into four groups based on the amount of omega-3 fatty acids in their blood.

Researchers used the women’s home addresses to determine their three-year average exposure to air pollution. Participants then had brain scans with magnetic resonance imaging (MRI) to measure various areas of the brain including white matter, which is composed of nerve fibers that send signals throughout the brain, and the hippocampus, the part of the brain associated with memory.

After adjusting for age, education, smoking and other factors that could affect brain shrinkage, researchers found that women who had the highest levels of omega-3 fatty acids in the blood had greater volumes of white matter than those with the lowest levels. Those in the highest group had 410 cubic centimeters (cm3) white matter, compared to 403 cm3 for those in the lowest group. The researchers found that for each quartile increase in air pollution levels, the average white matter volume was 11.52 cm3 smaller among people with lower levels of omega-3 fatty acids and 0.12 cm3 smaller among those with higher levels.

Women with the highest levels of omega-3 fatty acids in the blood also had greater volumes of the hippocampus.

“Our findings suggest that higher levels of omega-3 fatty acids in the blood from fish consumption may preserve brain volume as women age and possibly protect against the potential toxic effects of air pollution,” said He. “It’s important to note that our study only found an association between brain volume and eating fish. It does not prove that eating fish preserves brain volume. And since separate studies have found some species of fish may contain environmental toxins, it’s important to talk to a doctor about what types of fish to eat before adding more fish to your diet.”

A limitation of the study was that most participants were older white women, so the results cannot be generalized to others. Also, researchers were only able to examine exposures to later-life air pollution, not early or mid-life exposures, so future studies should look at exposures to air pollution across a person’s lifespan.

Source: American Academy of Neurology