The Role of Omega-3s in Overall Health

Lucy Jones, RD09/29/16

Omega-3 fatty acids are often making the news for their widespread health benefits.

There are three important types of omega-3 fatty acids for our health; α-linolenic acid (ALA) (found in plant oils), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) (both commonly found in marine oils).

In Europe, the shorter chain ALA has approved health claims for reducing cholesterol levels1 and brain development2 while the longer chain EPA and DHA have approved health claims for reducing blood pressure3, reducing triglycerides (a type of blood fat)3, overall heart function4 and in the case of DHA; normal brain function, vision and brain development5. DHA is the major structural fat in the brain and during the first two years of life, the brain needs to accumulate large amounts of DHA5.

Omega-3 fatty acids are therefore essential nutrients for health. Humans can’t make long chain omega-3 fatty acids, so we have to get them from our diet. We can however, convert the shorter chain ALA into those more important longer chain omega 3s6. Studies have shown that while this is possible, we aren’t particularly good at it, with conversion rates are only around 4-6 percent of our ALA6.  Because of this poor conversion rate, food sources of EPA and DHA are really important for meeting our needs.

Unfortunately, as well as being very important, the food sources of these two nutrients are also pretty restricted. EPA and DHA are only found in oily fish and other marine sources like algae and as such, intakes tend to be wholly dependent on people’s consumption of oily fish, which includes salmon, fresh tuna, mackerel, sardines, trout, and herring.

Studies have shown omega-3 supplementation may improve reading age in school aged children7 and even helping dry eye syndrome in adults8. In terms of heart health, the latest research to be reported in the journal JAMA Internal Medicine has shown that omega-3 fatty acids may significantly lower our chances of dying from a heart attack9. The new analysis study was the largest of its kind — from an international consortium comprising 19 studies from 16 countries with more than 45,000 participants — and found that higher circulating blood levels of omega-3 fatty acids were associated with a nearly 10 percent lower risk of a fatal heart attack, on average, compared with lower levels. Those with the highest level of omega-3s in their blood had the greatest risk reduction — a more than 25 percent lower risk of having a fatal heart attack, the study found.

Heart disease and heart attacks are a leading cause of death throughout the world, accounting for one in four of all deaths in the United States, according to the Centers for Disease Control and Prevention10. One of the authors of the study, Dr. Mozaffarian, reported that the reduction in risk of 25 percent on fatal heart attacks is quite meaningful and offers a similar effect size to statins (without the side effects). The findings were true despite differences in age, sex, race, presence or absence of diabetes and even use of aspirin or cholesterol lowering medications, meaning intakes of omega-3 fatty acids appear to be protective for all of us.

 

Read more about our expert Lucy Jones, RD

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