Is Fish The Only Source Of Omega3 Fat For Heart Disease Prevention?

Omega-3 fatty acids are polyunsaturated fats that that may reduce inflammation throughout the body. Inflammation in the body can damage the blood vessels and lead to heart disease and strokes. 

Research has shown that omega-3 fatty acids decrease risk of arrhythmias (abnormal heartbeats) that can lead to sudden death, decrease triglyceride levels, slow growth rate of atherosclerotic plaque, and lower blood pressure (slightly). Hence, omega-3 fatty acids are not only essential for the brain and nervous system function properly but also good for heart disease prevention.

When talking about omega-3 fatty acids, people usually think of fish. Being a good source of protein, fish are some of the richest sources of 2 forms of omega-3 fatty acids called docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Fatty fish, such as salmon, lake trout, halibut, herring, sardines and tuna, contain the most omega-3 fatty acids.

Despite of the health benefits of fish, people should not eat too much fish. This is because most fish come from ocean, and many parts of the ocean are contaminated by pollution. Some types of fish may contain high levels of mercury, PCBs (polychlorinated biphenyls), dioxins and other environmental contaminants. Consumption too much of these fish may be harmful for the body.

According to health experts, the risk of getting too much mercury or other contaminations from fish is generally outweighed by the health benefits that omega-3 fatty acids have if people consume fish in moderation. That is why the American Heart Association (AHA) recommends eating 2 servings of fish every week for adults. A serving size is 3.5 ounces (99 grams).

Eating a variety of fish will generally help minimize any potentially adverse effects due to environmental pollutants. 5 of the most commonly eaten fish or shellfish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish. Avoid eating shark, swordfish, king Mackerel, or tilefish because they contain high levels of mercury. Nevertheless, any fish can be unhealthy depending on how it is prepared. For example, broiling or baking fish is a healthier option than is deep-frying.

For people who do not like or are sensitive to fish, there are other non-fish options. Plants like flaxseed oil, chia seeds, walnuts, soybeans and spinach do contain high omega-3 fatty acids. These plants create alpha-linolenic acid (ALA. Although human body can convert ALA to DHA or EPA as needed, fish are probably still the best source of omega-3s. 

Meanwhile, there are health supplements containing omega-3 fatty acids. However, the evidence of heart-healthy benefits from eating these foods is not as strong as it is from eating fish.

Can Eating Fish Prolong Life?

American Heart Association (AHA) recommends that people who have no coronary heart disease (CHD) should eat a variety of fish, preferably oily fish such as salmon and tuna, at least twice a week.  

Eating fish is good for the health because of omega-3 fatty acids, particularly EPA (Eicosapentaenoic acid) and DHA (Docosahexaenoic acid), These fatty acids have been shown to benefit the heart of healthy people and those at high risk for or who already have cardiovascular disease.

In a study released on April 2, 2013 in the journal ‘Annals of Internal Medicine’, researchers from the Brigham and Women's Hospital, Harvard Medical School, Harvard School of Public Health, University of New Mexico, Fred Hutchinson Cancer Research Center and University of Washington reported that people, who were 65 and older and ate fish, may live an average of 2 years longer than people who did not consume the omega-3 fatty acids.

While other studies have found link between omega-3 fatty acids and lower risk of heart disease, this study aimed to determine the link between fish eating and mortality risk.

Researchers analyzed records of older people by scanning 16 years of data on about 2,692 American adults aged 74 years (plus or minus 5 years) without prevalent CHD, stroke, or heart failure. These participants were not taking fish oil supplements.

Their findings indicated that those with the highest blood levels of omega-3 fatty acids had the lowest risk of dying from any cause, and lived an average of 2.2 years longer than those with low levels. Omega-3 fatty acids were found mainly in fish like salmon, tuna, halibut, sardines, herring and mackerel.

DHA was found to be the most strongly linked to lower risk of CHD death. EPA, on the other hand, was strongly related to lower risk of nonfatal heart attack and DPA (docosapentaenoic acid) was most strongly associated with lower risk of dying from a stroke. Even after adjusting for demographic, lifestyle and diet factors, the results persisted.

Importance of adequate blood omega-3 levels for cardiovascular health was indeed supported by the findings, which also suggested that in life these benefits could extend the years of remaining life.

According to AHA, people who had CHD are advised to consume about 1 gram of EPA and DHA per day, preferably from oily fish, though EPA & DHA supplements could be taken as well but should be in consultation with their doctors. People who have elevated triglycerides require 2 to 4 grams of EPA and DHA provided as capsules on a daily basis under doctor’s care.

How To Lower Irregular Heartbeat Risk?

According to some estimates, up to 9 percent of Americans will develop atrial fibrillation (AF) by the time they reach their 80s. AF is the most common heart arrhythmia (irregular heartbeat). Though it may cause no symptoms, it is often associated with palpitations, fainting and chest pain. It could eventually lead to stroke and heart failure.

AF might be treated with medications to either slow the heart rate to normal range (range control) or revert the heart rhythm back to normal (rhythm control). People with AF are often prescribed with blood-thinning drugs to prevent stroke.

A new study by researchers from the Harvard School of Public Health reported on January 26, 2012 in the journal ‘Circulation’ that older adults who had the highest blood levels of omega-3 fatty acids were 30 percent less likely to later develop an irregular heartbeat than those with the lowest blood levels of omega-3.

The omega-3 fatty acids measured in the study were eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). They can be found in oily fish and some enriched foods like eggs and in fish oil supplements.

While some previous studies have suggested that people who ate a lot of fish had a lower risk of developing AF, these studies relied on questionnaires answered by participants about how much fish they ate, which could only estimate the amount of omega-3s they consumed.

To get a more accurate measurement, the researchers sampled blood from 3,326 adults aged over 65. These participants’ health was tracked over the next 14 years (1992-2006) and 789 were found to develop AF.

Researchers’ analysis showed that those with the top 25 percent omega-3 levels in the bloodstreams at the beginning of the study were about 30 percent less likely to develop AF, comparing with those with the bottom 25 percent blood levels. Of the 3 omega-3 fatty acids, high DHA levels were linked to a 23 percent lower risk for AF, but no reduced risk was found for EPA and DPA.

Other heart experts not involved in the study cautioned that the study did not prove eating fish could lower AF risk. The study, however, did provide some idea that the fatty acids found in fish could work by stabilizing the excitability of heart muscle cells. Meanwhile, they also suggested further studies should be carried out to find out how fish oil might be used as a potential preventive measure against AF.