All About Fish Oil

by Ryan Andrews (Precision Nutrition), May 31st, 2010.

 

What is fish oil?

Fish oil is, well, oil from fish.

It’s rich in two specific groups of omega-3 fatty acids known as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). DHA and EPA, along with alpha-linolenic acid (ALA), found in things like flax and walnuts, fall under the subheading of omega-3 fatty acids.

EPA and DHA are often cited as being the beneficial components of fish oil. EPA and DHA actually originate in algae, which is the base of the food chain for fish. Fish consume these algae and thus concentrate high amounts of the beneficial fats.

Why is fish oil so important?

 

Overall health

 

Omega-3s are very important for health, including:

• cardiovascular function
• nervous system function and brain development
• immune health

Research shows that low DHA consumption (and blood levels) is associated with memory loss, difficulty concentrating, Alzheimer’s disease and other mood problems.

Cell membranes

 

Essential fats have an integral role in promoting cell health.

Cells in the human body have a fatty membrane (known as the lipid bilayer). This membrane is semi-permable: It regulates what gets into the cell and what goes out of it. The fluidity of cell membranes depend on the fatty acid composition of the diet.

• If the fatty membranes surrounding brain cells are relatively fluid, as they are with lots of omega-3s, then messages from neurochemicals such as serotonin can be transmitted more easily.
• On the other hand, if people eat too many saturated fats (which are solid at room temperature), without enough omega-3s, then these membranes become more rigid, and stuff can’t get through.

 

Fatty membrane of cells

Cells also require these good fats for repair and regeneration.

With lots of omega-3s, muscle cells become more sensitive to insulin, while fat cells decrease. This may mean that the body can divert more nutrients to muscle tissue.

 

Metabolic health

Finally, DHA and EPA can increase metabolism by increasing levels of enzymes that boost calorie-burning ability.

 

What you should know

We can’t make omega-3 and omega-6 fatty acids in our bodies, so we need to get them from our diets.

 

Omega-3 to omega-6 ratio

It’s easy for us to get omega-6 fatty acids. These are found in plant oils, for instance, and factory-raised animals (which are fed a lot of corn and soy) will usually have a lot of omega-6 too.

But it’s hard for people in Western countries to get omega-3 fats from dietary sources. We eat a lot more processed foods and a lot less wild game and plants than our ancestors did. And we don’t usually eat things like snails and insects, which are also high in omega-3s, although many folks worldwide still eat these as part of traditional diets. We rely heavily now on omega-6 vegetable oils.

We evolved with a fat intake ratio of about 1:1 omega-3 to omega-6 fatty acids. Now, it’s closer to 1:20.

Because omega-3s and omega-6s compete with each other for space in cell membranes and the attention of enzymes, the ratio matters more than the absolute amount consumed of either fat.

 

Fat heads

When it comes to fat intake, you (and your cells) really are what you eat.

Years of research has linked lower fat diets with aggression, depression, and suicidal ideation. Over time, the cells in your brain take on the dietary fat you consume. DHA is the active fat in the brain, and especially important throughout developmental stages.

 

Depletion of fish oil resources

About 1/3 of the world’s total fish catch goes toward fish meal/oil for farmed fish and other animals. Many open ocean fish like menhaden, anchovies, herring and mackerel are caught mainly for this purpose. Competition for fish meal/oil can drive up the price of fish, which pushes this food source out of reach for many of the world’s poorest.

 

Summary and recommendations

Aim for 6-12 daily grams of total fish oil (about 3-6 grams of EPA + DHA) per day from a supplement company that doesn’t contribute directly to the depletion of fish (e.g., they use primarily fish discards). We suggest liquid fish oil, because it’s hard to take so many capsules, and because some supplement companies put lower-quality oil into capsules (or secretly cut it with soy oil). Buy from a reputable company.

Look for small-fish-based formulations (e.g. herring, mackerel). Small fish are lower on the food chain and less likely to accumulate environmental toxins. Or choose krill oil or algae oil

Add up the amounts of EPA & DHA listed on the back of the product and make sure the total is at least 300 mg per 1000 mg capsule. This will make it easier to get the suggested dose.

Avoid cod liver oil.

Find a fish oil supplement that you can tolerate the taste of, otherwise you won’t use it (unless it’s in capsule form).

Fish oil can taste much better when combined with your favorite protein powder in a super shake.

Avoid trans fats; they can interfere with EPA & DHA in the body.

Use fewer omega-6 rich vegetable oils, which will negatively alter your fatty acid ratio.

 

For extra credit

The amount of DHA in a woman’s diet determines the amount of DHA in her breast milk.

Omega-3 fats are not typically used in processed foods because of their tendency to oxidize.

NIH researchers have said that the billions we spend on anti-inflammatory drugs such as aspirin, ibuprofen, and acetaminophen is money spent to undo the effects of too much omega-6 fat in the diet.

It’s hypothesized that populations may drift toward a lower omega-3 intake because a faster metabolism (from high omega-3 intake) increases the need for food and the possibility of hunger.

Fish oil seems to be safe (except for those on blood thinning medications).

References

 

Borer KT. Exercise Endocrinology. Human Kinetics. Champaign, IL. 2003.

Mahan LK & Escott-Stump S. Eds. Krause’s Food, Nutrition, & Diet Therapy. 11th ed. Saunders Publishing, Philadelphia, PA. 2004.

Groff JL & Gropper SS. Advanced nutrition and human metabolism. 3rd ed. Wadsworth Thomson Learning. 2000.

Barnard ND, et al. Nutrition Guide for Clinicians. 1st ed. PCRM. 2007.

Hibbeln J, et al. Health intakes of n-3 and n-6 fatty acids: estimations considering worldwide diversity. Am J Clin Nutr 2006;83 (suppl):1483S-1493S.

Daviglus ML. Fish consumption and the 30-year risk of myocardial infarction. NEJM 1997;336:1046-1053.

Arterburn LM, et al. Bioequivalence of docosahexaenoic acid from different algal oils in capsules and in a DHA-fortified food. Lipids 2007;42:1011-1024.

Church MW, et al. Abnormal neurological responses in young adult offspring caused by excess omega-3 fatty acid (fish oil) consumption by the mother during pregnancy and lactation. Neurotoxicol Teratol 2009;31:26-33.

Nair GM & Connolly SJ. Should patients with cardiovascular disease take fish oil? CMAJ 2008;178:181-182.

Lee KW, et al. Effects of dietary fat intake in sudden death: reduction of death with omega-3 fatty acids. Curr Cardiol Rep 2004;6:371-378.

Jacobson TA. Beyond lipids: the role of omega-3 fatty acids from fish oil in the prevention of coronary heart disease. Curr Atheroscler Rep 2007;9:145-153.