nutrition

Omega-3 Fatty Acids 101

Here’s how to answer patients who object to taking fish oil supplements.

Kimberly K. Reed, O.D., F.A.A.O.

I recently conducted an interactive nutrition program with a group of eighth grade science students. While most did not know that table sugar was “naturally” a fat-free food, nearly all knew that fish oil was “healthy” for them. Fish oil, or more precisely the omega-3 fatty acids that make up the bulk of fish oil, has taken a front-and-center position in the layperson’s nutrition world. And although the eighth graders didn’t know why fish oil was a good thing, we do: The anti-inflammatory effects of omega-3 fatty acids are well-known to provide significant benefit in several ocular and systemic diseases, such as dry eye and cardiovascular disease.

So, it should be easy for us to convince patients who could benefit from omega-3s to take supplements, as appropriate — especially those who have dry eye syndrome, for which omega-3s have been unequivocally shown to be beneficial. Yet it’s easier said than done, as it turns out.

When I mention fish oil capsules to my dry eye patients, I typically get one of two responses: more often is a vigorous shaking of the head and, “Oh, no, doc. I tried those, and I couldn’t stand the aftereffects.” Or, “I take a fish oil capsule every day — I have for years — and my eyes are still dry.”

Let’s look at these two common “push-back” issues from patients a little more closely and examine how we can respond.

“Repeat” business

It’s true that many fish oil products cause unpleasant side effects, including an unpleasant smell and taste, indigestion and “fishy burps” for hours after taking the supplement. I’ve discovered that in general, these side effects occur more frequently with low quality fish oil products. High-quality, high-potency products are more expensive, but in the long run, they are often more cost-effective for two reasons: (1) The patient has to take fewer capsules to reach a therapeutic level, and (2) with unpleasant side effects minimized or eliminated, the patients actually take the capsules. Remember, bioavailability and effectiveness amount to zero if the supplement isn’t ingested.

Why are the low-potency supplements often unpleasant? To understand this, we need to know more about the various products available. Remember, there are no real FDA regulations about what supplement labels may claim. Fish oil (with the exception of the prescription fish oil product), fish body oil, omega-3 capsules, omega 3-6-9 capsules, liquid omegas, krill oil, Docosahexaenoic acid (DHA) — these are all related to each other, but unless you look at the fine print on the label, you can’t easily compare products.

Omega fatty acids are named based on their molecular structure — an omega-3 fatty acid has its first double carbon bond at the third carbon atom. But there are several different omega-3 fatty acids, each with varying lengths and numbers of atoms. The health benefits of omega-3s are attributed primarily to the long-chain omega-3s, such as Eicosapentaenoic acid (EPA) and DHA. You can get EPA and (DHA) in two ways: Either ingesting them as EPA and DHA (which makes up the bulk of most fish oil), or eating the shorter-chain omega-3s that are prevalent in flax seeds, certain tree nuts, or some low-quality fish oil supplements, and rely on your body’s enzymes and multiple biochemical reactions to convert the short-chain into long-chain molecules. That conversion process is inefficient in most people, and one result is the production of intermediate chain omega-3s. The health benefits of these (if any) are unknown — and in the case of fish oil supplements, they may contribute significantly to the aforementioned side effects.

To help with these side effects, suggest patients buy enteric-coated products, and to store the fish oil in the refrigerator or freezer to delay the onset of potential “repeating.” Taking the supplement at night is another suggestion, although this may cause sleep disruption in very sensitive people.

Evaluating formulations

In evaluating a fish oil supplement, it’s critical to identify the breakdown of omega-3 fatty acids. Look for the amount of “total omega-3 fatty acids” which usually appears near the top of the label, and in most fish oil supplements is an amount somewhere in the range of 1 gram, or 1,000 mg. Then look for EPA and DHA, which are usually located near the bottom of the label, if they are included at all. Ideally, the total amount of EPA+ DHA shouldn’t be less than half of the total omega-3 fatty acids — and most of the high-quality supplements have 75% to 80% or more EPA+DHA.

Often, I am asked about the difference between the triglyceride form and the ethyl ester form of fish oil. Again, this is a controversial topic. The prescription brand omega-3 and most store-brand or health food store products are in ethyl ester form. Many authorities instead recommend the triglyceride formulation, as the medical literature suggests bioavailability is higher with the triglyceride form. But, this may vary depending upon each patient’s diet.

“It's not working”

The second complaint that’s common is that patients don’t feel any noticeable benefit from the supplement they might already be taking. This is often a matter of inadequate dosing. Although dosing is still fairly controversial, many experts advise that for a dry eye patient, a minimum of 1,500mg DHA + EPA is required, at least in initial therapy, to break the inflammatory ocular surface disease cycle. In my experience, patients who are “already taking fish oil” may be taking a 1,000mg capsule a day that often has about 300mg total EPA+DHA. That is a woefully inadequate dose — but telling the patient to take five of those capsules may end up causing unwanted side effects, and may increase the risk of bleeding (although this is also difficult to predict).

So the solution to both of the objections from patients is the same: Switch the patient to a highquality/high-potency fish oil product in a high enough dose to have an effect. For pregnant or breastfeeding patients, or patients on blood thinning medications or with bleeding disorders, always consult with the patient’s health care provider — no matter what dose you recommend. OM