What to avoid while taking fish oil?

The six things to avoid, three of timing and posture, one of storage and two of stacking

What to avoid while taking fish oil, and the variant about fish oil capsules, is a question that the shelf answers with a long list of vague cautions and the honest page answers with six specific things and then a long list of things a reader need not avoid, because the second list is the one that saves worry. The first three are timing and posture. Avoid taking it fasted: a softgel on an empty stomach, or just before a meal that has not arrived, dissolves in minutes and its oil floats beneath the sphincter, which is the fishy burp and the occasional nausea, the reflux-and-posture literature's mechanism, so the softgel goes in the middle of a meal after several mouthfuls, which removes most of what a reader would otherwise avoid. Avoid lying down within two hours of it: the sofa or the bed rests a full stomach against the oesophageal junction and refluxes what standing holds, so a bedtime softgel is the one to move. Avoid peppermint after it: the mint, the mint tea or the peppermint capsule a reader reaches for after a fishy burp relaxes the lower oesophageal sphincter and opens the door the burps come through, the peppermint and reflux literature's finding, so water, a slice of lemon or plain gum instead. The fourth is storage. Avoid heat, light and an open lid for the tub: fish oil oxidises, and an oxidised oil carries the aldehydes that smell of paint and repeat all day whatever the timing, the oxidation literature's account, so the tub lives somewhere cool and dark with the lid closed and is finished within a couple of months of opening, checked by biting a softgel for a paint or old-nut taste, and the fridge is fine for an opened liquid. The fifth and sixth are stacking. Avoid gram doses of EPA and DHA on an anticoagulant or dual antiplatelet therapy without the clinician told, since bleeding time lengthens slightly at a gram or more, minor in the trials but a variable the clinician wants to know, with a standard softgel usually unremarkable. Avoid stacking cod liver oil with a multivitamin or a vitamin A supplement: cod liver oil carries vitamin A, the multivitamin often does too, and the two add toward the adult upper level of 3000 micrograms a day, the cod liver oil pages' standing note, which a body fish oil with no vitamin A does not raise. A seventh, for the reader on it: orlistat blocks the absorption of the oil, so the two are separated in time.

The long list you need not avoid, why it is long, the reader who asked because of a warning, and the six filed

The list a reader need not avoid is long, and its length is the point. Alcohol in moderation: there is no interaction between a fat and a drink, the alcohol pages' finding, and the only note is that alcohol raises the LDL and the triglycerides that a high-dose reader is trying to lower, which is a reason to drink less, not a reason to avoid the softgel. Coffee and caffeine: no interaction, and the pre-workout can stay. Creatine, protein powder, vitamin D, magnesium, zinc, a multivitamin without vitamin A, collagen: no interaction with any of them, the fat neither helping nor hindering their absorption, with vitamin D absorbing better alongside a fatty meal that the softgel happens to share. Statins, blood pressure tablets, metformin, thyroid replacement, antidepressants, the contraceptive pill, inhalers, antihistamines: no interaction at a standard dose, the medications pages' finding that the interactions live at gram doses with anticoagulants and almost nowhere else, with the clinician told as a matter of a complete list rather than because anything needs changing. Training on the day: no timing rule beyond the meal's, a months-long pool not caring when it is fed, so the softgel goes with whichever meal is fatty and reliable and the session goes when it goes. Fish on the plate: two portions of oily fish a week alongside a softgel is around two and a half softgels' worth, inside every line, and a reader who eats that much fish needs no softgel at all rather than needing to avoid one. Grapefruit, dairy, iron, calcium, fibre, the things other supplements carry warnings about: nothing for fish oil. The reader who asked because of a warning, a label, a forum or a relative, has usually been warned about one of the six, most often fasted timing or the anticoagulant stacking, and can file the rest. The six filed: not fasted, not lying down within two hours, no peppermint after, no heat, light or open lid, no gram doses on an anticoagulant untold, no cod liver oil stacked with a multivitamin's vitamin A, orlistat separated, and everything else on the long list left alone, with the worked example being a body oil with no vitamin A taken mid-meal from a closed tub, £14.99 for 90 at 17p.

The verdict, six specific things and a long list of things left alone

What to avoid while taking fish oil: six things, taking it fasted, which floats the oil beneath the sphincter and burps it, lying down within two hours, which refluxes it, peppermint after it, which relaxes the sphincter, heat, light and an open lid for the tub, which oxidise the oil into paint-smelling aldehydes, gram doses of EPA and DHA on an anticoagulant without the clinician told, since bleeding time lengthens slightly at a gram or more, and cod liver oil stacked with a multivitamin's vitamin A, which adds toward the vitamin A ceiling, with orlistat separated in time, while alcohol in moderation, coffee, creatine, protein, vitamin D, magnesium, statins, most medicines, training on the day and fish on the plate need no avoiding at all. A body oil with no vitamin A taken mid-meal from a closed tub: Futuro Labs Omega 3 Fish Oil, one mid-meal, 180mg EPA and 120mg DHA, lab-tested purity, 90 for £14.99 at 17p a day.

What to check on the label

Questions people also ask

Can I drink alcohol while taking fish oil?

In moderation, yes: there is no interaction between a fat and a drink, and the only note is that alcohol raises the triglycerides and LDL that a high-dose reader is trying to lower, which is a reason to drink less rather than a reason to avoid the softgel.

Can I take fish oil with coffee or a pre-workout?

Yes: caffeine and fish oil do not interact, and the only timing rule for the softgel is the meal's, mid-meal with something fatty, so a coffee or a pre-workout goes when it goes and the softgel goes with whichever meal is reliable.

What supplements should not be taken with fish oil?

Almost none: creatine, protein, vitamin D, magnesium, zinc, collagen and a multivitamin without vitamin A all sit alongside it without interaction, the one stacking caution being cod liver oil with a multivitamin or a vitamin A supplement, which adds toward the vitamin A upper level, and which a body fish oil with no vitamin A does not raise.

What medications should not be taken with fish oil?

At a standard softgel, none: the interactions live at gram doses with anticoagulants and dual antiplatelet therapy, where bleeding time lengthens slightly and the clinician is told, and with orlistat, which blocks the absorption of the oil and is separated in time, while statins, blood pressure tablets, metformin, thyroid replacement and the rest do not interact.

What foods should I avoid with fish oil?

None: fish on the plate adds to the count rather than clashing with it, dairy, iron, calcium and fibre carry no warning for fish oil, and the only food-adjacent rule is that the softgel goes in the middle of a meal rather than on an empty stomach, with peppermint after it the one thing to skip.

Sources

1. The reflux and posture literature: lying flat within an hour or two of eating, and of taking an oil, increases reflux because the stomach's contents sit against the oesophageal junction, so a fish oil softgel taken at the pillow refluxes more than the same softgel taken with an upright meal. PubMed record
2. The reflux trigger literature: peppermint, chocolate, alcohol and large fatty meals relax the lower oesophageal sphincter and worsen reflux, while chewing gum, staying upright and a small starchy snack are among the simple measures that reduce it after the event. PubMed record
3. The fish oil oxidation literature: oxidation is measured by peroxide value, anisidine value and their combination as TOTOX, with the industry monograph setting limits of 5, 20 and 26 respectively, and surveys of retail fish oils finding a meaningful share above those limits, freshness being a quality dimension a label rarely shows and a certificate does. PubMed record
4. The cod liver oil and vitamin A literature: cod liver oil carries preformed vitamin A at hundreds of micrograms per teaspoon or capsule, the adult upper level for preformed vitamin A being 3000 micrograms a day and pregnancy advice being to avoid liver oils, so a cod liver oil stacked with a multivitamin or a vitamin A supplement is the one combination in which a fish oil can push a vitamin over its limit. https://www.gov.uk/government/publications/sacn-vitamin-a-and-health

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