TMI warning: how fish oil did not work for me

When I was in my late twenties, I started taking fish oil supplements for the first time. I tolerated them well and they, in conjunction with my other supplements and lifestyle changes, led to an amazingly healthy period for me—I actually went weeks without a migraine.

As I do, I fell off the wagon and climbed back on. I’ve done this many times over the years, but I didn’t reincorporate fish oil again until about six months ago when my neurologist was displeased with my migraine improvement (or lack thereof) and wanted me to add an extra dose of magnesium as well as daily omega-3 and omega-6 fatty acids, in the form of fish oil capsules.

(If you don’t want to read more about poo, it’s probably time for you to dip out—we’re definitely entering #TMI land.)

I started noticing something weird about my once- or twice-daily trips to the bathroom: my poop smelled like my cat’s poop. A putrid, acrid smell. What in the world?

I stuck with the fish oil capsules even after that, not quite sure what was up. My alarmist, hypochondriac side thought, I guess Satchel and I have the same deadly illness that makes our poop smell so awful. Luckily that side doesn’t usually have a very loud voice, and it shuts up quickly.

A few days later, I opened a can of wet food for the cat and tried to avoid breathing in the smell of what the pet food company calls “Seafood Deluxe Dinner.” But I couldn’t help but catch a whiff. That smell was…familiar. That smell made me think of my bathroom, where not only I but my cat use the restroom (he in a litter box, mind you—we aren’t clever enough to have toilet-trained him).

OMG, I thought. Duh. Satchel started eating canned food with a ton of fish in it right when I started taking daily fish oil. That’s why we both have this awful-smelling #2! (Luckily he was spared the diarrhea.)

I had bought the same brand I’d used before with no problems, so didn’t even consider that the fish oil was the reason behind my GI issues.

The longer I stuck with the twice-daily capsules I realized I hadn’t changed much else in my life or diet since adding them in. I decided to use freshly ground flaxseed (a great source for omega-3) in my then-daily smoothies instead of the fish oil capusles, and the problem went away.

Later, at my appointment, my neurologist seemed quite surprised to hear that the fish oil was making me have diarrhea or soft stools most of the time—apparently she doesn’t have other patients who've had that same issue. She told me the flaxseed was fine for now as long as I made sure to grind it fresh and keep it refrigerated (which I do).

Have you ever had a weird side effect from fish oil capsules? Along those lines, are their any drugs or treatments you’ve tried that gave you weird symptoms that the doctor didn’t recognize? 

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