Don’t Fear Heart Disease: Oily Fish is Here!

Oily fish such as salmon and mackerel are rich sources of heart-healthy Omega-3 fatty acids. There is strong scientific evidence showing that people who consume more oily fish are less likely to suffer from heart attacks and other cardiovascular events.

Heart (cardiovascular) disease is the number one cause of death in both men and women worldwide. Large scientific studies have reported that Omega-3s present in oily fish, known as EPA and DHA, are beneficial for the heart because they reduce many risk factors that increase the chances of suffering from cardiovascular disease. Some of the risk factors decreased by EPA and DHA are cholesterol levels and blood pressure. The only bad thing about oily fish is mercury contamination, however, experts state that the benefits far outweigh the risks. Plus you can always avoid fish that are high in mercury like tuna and opt for the low mercury options such as salmon.

oily1

Figure 1. Try to choose oily fish with a low mercury content such as salmon, although occasionally eating a bit of tuna isn’t going to hurt you. Either way, whether you choose high or low mercury oily fish, you will still be getting Omega-3s that are beneficial for the heart. Adapted from http://www.healthcastle.com/tuna-food-month  

Omega-3s found in fish seem to be of particular benefit at reducing the risk of heart attacks by stabilising atherosclerotic plaques. These are fatty tissue deposits that build up in arteries across the body, a condition called atherosclerosis. Sometimes, plaques can rupture, travelling in the blood until they block a narrower artery. If an artery that supplies the heart with oxygenated blood gets blocked, this will result in a heart attack. If the heart muscle does not receive oxygen and nutrients, it quickly starves and dies.

Research has identified that certain white blood cells knows as macrophages can up-regulate inflammatory processes which makes plaques more likely to break off. Scientists found out that individuals who consumed two or more portions of oily fish on a weekly basis, had fewer numbers of macrophages in atherosclerotic plaques than those who rarely ate oily fish. When EPA and DHA get incorporated into plaques, they cause the production of anti-inflammatory molecules, which reduces infiltration of macrophages into arterial plaques. Additionally, Omega-3s get incorporated into the cell membranes of macrophages, directly lowering their activity. These effects reduces arterial plaque inflammation, decreasing the likelihood that the clot will come off.

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Figure 2. Summary of the proposed mechanism that explains how oily fish consumption makes atherosclerotic plaques more stable. Based on Calder and Yaqoob (2010)

Consuming oily fish not only stabilises atherosclerotic plaques, but getting enough EPA and DHA in the diet from an early age can slow down atherosclerosis. Having high levels of bad cholesterol (LDL) increases deposition of fatty deposits in arteries, which may result in heart disease after many years. Luckily, EPA in oily fish reduces the build up of plaques by raising HDL, usually known as good cholesterol. Furthermore, omega-3s in oily fish appear to be effective at lowering blood pressure, a major risk factor in atherosclerosis. Studies in humans showed that the biggest blood pressure lowering effects were observed in older and hypertensive patients, while blood pressure in non-hypertensive individuals was not reduced. Due to the many advantages that omega-3s have in heart health, doctors and nutritionists now advise individuals to eat two portions of oily fish every week.

References

Calder, P.C. & Yaqoob, P. (2010). Omega-3 (n-3) fatty acids, cardiovascular disease and stability of atherosclerotic plaques. Cellular and Molecular Biology, 56(1), 28-37.

Galli, C. & Rise, P. (2009). Fish consumption, omega 3 fatty acids and cardiovascular disease. The science and the clinical trials. Nutrition and Health, 20(1), 11-20.

 

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9 thoughts on “Don’t Fear Heart Disease: Oily Fish is Here!

  1. You can also choose the only FDA approved EPA only drug Vascepa. Unlike generic lovazza, Vascepa does not increase LDL cholesterol because of the presence of DHA. It also has a safety profile equal to or better than aspirin and lacks the other side effects such as bloating and or fishy taste found with DHA and over the counter fish oil supplements. You can read up on EPA by going to epadruginitiative.com or read more about Vascepa at Vascepa.com. I take the drug and it really helped to lower my statin dose and minimize the muscle ache from taking statins.

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    1. Thank you for your comment Mark. It is certainly true that DHA raises LDL, but it is also more effective at raising good HDL than EPA. I think that if it’s possible, it is always better to get these omega-3s through the diet, rather than by taking supplements or prescription drugs. The beneficial effects of consuming oily fish for the heart may extend beyond Omega-3s, and nutrients such as selenium may play a role. But Vascepa as you said, has been shown in clinical trials to be more effective than lovazza at reducing cholesterol levels. I will try to write a blog entry about vascepa in the future.

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      1. There has been a recent study that showed that increasing HDL has no effect on CVD. Also, if you get EPA from diet only, you would have to eat soooooo much fish, more than your body needs, and the mercury inside it is bad for you. Vascepa doesn’t have mercury.

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      2. Hi Ralph. You are quite right that some scientific studies showed no real link between HDL and CVD. But science is more conflictive than people usually think. When it comes to cholesterol and heart disease there have been many studies that have looked at the effects of HDL and LDL. Some studies have shown that a subtype of HDL known as simply HDL2, is antiatherogenic. In other words, it may reduce the risk of suffering from heart disease in the future by preventing plaque building up in arteries. Meanwhile other subtypes of HDL may not help at all in heart disease. As for your second question, it is true that we would have to eat a lot of oily fish to get EPA and other Omega3 and in doing so we would put mercury into our systems. However, salmon has much higher levels of EPA compared to other oily fish, plus it has very low mercury levels. The American Heart Association recommends 2 portions of oily every week as a primary prevention against cardiovascular disease.

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  2. Thank you for the reply, I actually have a condition where I have low HDL despite diet and exercise. Fishy diet, Lovazza and Vascepa were not effective in increasing my HDL and I am unaware of any fish oil study where the sole use of fish oil increased HDL. I have increased my HDL by taking high dose statin. However, the science is now mixed on HDL and instead my cardiologist maintains a ratio, low trigs and low ldl is ok with HDL under 40. With regards to diet, I would agree if our food supply was all natural and free of bad fats and preservatives. I believe in order to achieve a therapeutic dose of fish oil you would need to eat 2lbs of salmon per day. To back this, you should take a look at this Japanese study JELIS: http://www.medscape.org/viewarticle/518574, despite a diet rich in fish and optimal, satin therapy.the addition of EPA reduced risk of further cardiac events.

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    1. Hi Mark. What I also think is that nowadays we consume far more Omega-6 than Omega3s. The Omega-3s in fish are far more beneficial than the Omega-3s in flaxseed for example. The body is then capable of synthesising EPA from Omega-3s found in flaxseed, But unfortunately, very little EPA is usually produced. Our body uses the same enzymes to convert Omega-6 and Omega-3s into other fatty acids. Because we have much higher levels of Omege-6 in our bodies, the enzymes are always saturated with Omega-6s instead of Omega-3s. If we reduced Omega-6 intake, our body would then be capable of producing far more EPA, which would protect our heart. Many studies point out that reducing the Omega6: Omega3 ratio reduces heart disease.

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