At risk for heart disease? Eat more tuna, global study shows

David Heitz


If you’re not at risk for heart disease, eating a lot of fish probably isn’t going to keep you healthy and may have adverse effects. But if you are at risk for cardiovascular disease, a worldwide study published today shows eating more oily fish like tuna may save you from a fatal heart attack or stroke.

The massive study looked at global fish consumption. The original investigation appears in Journal of the American Medical Association and reviews previous research on the topic.

“Findings of this pooled analysis of four cohort studies indicated that a minimal fish intake of 175 grams (approximately two servings) weekly is associated with lower risk of major cardiovascular disease and mortality among patients with prior cardiovascular disease but not in general populations,” the authors concluded. “The consumption of fish (especially oily fish) should be evaluated in randomized trials of clinical outcomes among people with vascular disease.”

The collection of authors for the study shows the global scope of the research. Researchers hail from India, China, Canada, Brazil, Ireland, Argentina, Chile, Colombia, Poland, Turkey, Sweden, United Arab Emirates, Zimbabwe, Philippines, Saudi Arabia, and South Africa.

Almost 200,000 people participated in the research. It showed that while moderate fish intake showed protection against cardiovascular events in people at risk for heart disease, among the general population, it did not. In fact, too much fish can have negative health consequences in healthy people.

What’s the optimum level of fish intake?

In groups of patients with vascular disease, the hazard ratio for major cardiovascular disease and total mortality was lowest with fish intakes of at least 175 grams per week, or about two servings per week, compared with 50 grams per month or lower. Eating 350 grams per week or higher did not convey an even stronger protective effect.

Fish with higher amounts of ω-3 fatty acids such as tuna, mackerel, sardines, swordfish, and anchovies, to name a few, were strongly associated with a lower risk of cardiovascular disease. Other fish were neutral.

“A similar pattern of results was found for sudden cardiac death, with significant protective associations observed among patients with vascular disease, but neutral in general populations without vascular disease,” the authors explained. “Furthermore, the data available from one study on types of fish suggested that oily fish but not other types of fish were associated with greater benefits.”

Fish also has shown a protective effect in people with high triglycerides. “Short-term trials showed that two servings of fatty fish per week (roughly 112 grams or 4 ounces each) decreased triglyceride levels by 11.4 percent (and) also slightly increased LDL-C levels compared with the control diet,” the authors stated. “Our findings are consistent with this information, both among people with and among persons without vascular disease (8 percent decrease in triglyceride level with approximately two standard servings of fish per week but with slightly higher LDL-C level).

“The increase in LDL-C level associated with fish intake may not suggest an increased cardiovascular risk because this risk may be offset by the positive effects on lipoproteins.”

Is it safe to eat fish every day?

U.S. dietary guidelines call for healthy Americans to eat two servings of fish per week. According to government data, only 20 percent of adults in the U.S. consume that much.

On the other hand, too much fish reduces protective effects against heart disease in healthy people. Too much fish also can raise blood sugar. Other hazards include mercury levels and other contaminants found in fish.

According to Eric Rimm, a Harvard professor, “pregnant woman and children should avoid larger fish with longer lifespans—like swordfish and tuna—because those can have higher levels of toxins, such as mercury,” he says in a news release. “Even to get people eating fish two times a week we need to ramp up fish farming,” Rimm says, noting farmed fish can be more nutritious than those caught in the wild.

Is it safe to eat fish every day? “Most of the science isn’t looking at daily consumption,” Rimm explained. “But many, many studies have shown that those who have it a couple of times a week have a lower rate of fatal heart attacks compared to those who don’t eat any.”

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I have been in the news business more than 30 years, spending much of my career at some of the best local newspapers in the country. Today, I report on Denver City Hall, homelessness and other topics for NewsBreak, much like I did in my twenties covering Newport Beach, Calif. for the Daily Pilot. I consider myself a lucky guy to still be doing what I love after so many years.

Denver, CO

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