child and medicine spoon, measure kids' medicine, cod liver oil

As cold and flu season sets in, it makes sense to do what we can to strengthen the immune system and ward off these respiratory infections. Will cod liver oil help?

To protect yourself from the flu, public health officials advise getting vaccinated. We don’t yet know how well the flu shot will match the flu viruses that will be circulating this year. We only find that out after the fact.

In any event, there is no vaccine for colds. The standard advice is to wash your hands frequently. We should all do that, though it doesn’t cover the spread of flu viruses through the air. Are there any other ways to boost the immune system so it can fight off the cold viruses you can’t avoid?

Cod Liver Oil for the Immune System:

Q. I started taking cod liver oil ten years ago and have only had one cold over that time. I am convinced that, together with parsley and cinnamon, cod liver oil has strengthened my immune system.

Warding Off Colds:

A. Cod liver oil has a long-standing reputation for warding off winter colds. Most of the studies of this supplement have been done in young children, however. Cod liver oil seems to reduce the number of upper respiratory tract infections in kids (Journal of the American College of Nutrition, Dec., 2010; Annals of Otology, Rhinology and Laryngology, Nov., 2004). We couldn’t find any research on cod liver oil to prevent colds in adults.

We have written previously about cod liver oil for preventing colds, since it was a favorite home remedy during the 20th century and even earlier in many places. Here is what we wrote:

A History of Cod Liver Oil:

Q. I’d like your take on a home remedy. During cold season I take cod liver oil tablets.

My mother used to give us liquid cod liver oil when we were kids, long ago. These tablets not only seem to successfully treat colds, but also to prevent them. Has anyone else mentioned this?

The Old Wives’ Favorite:

A. Cod liver oil has a traditional reputation for reducing upper respiratory tract infections during the winter. Families from Nordic countries seem to have been especially partial to this old-fashioned remedy. Many readers have reminisced about their mothers or grandmothers administering spoonfuls of it. Few of them enjoyed the taste.

Children who take this form of fish oil do seem to suffer fewer infections (Journal of the American College of Nutrition, Dec., 2010). Whether that is due to the vitamin D and vitamin A that is found in the oil or to some other quality isn’t known. But we are pleased to hear it is working for you. We don’t know how well it might work for other adults. Because cod liver oil can become rancid, keep it in a tightly closed container, preferably in the refrigerator.

What Else Can You Take for Your Immune System?

That doesn’t mean there is nothing to be done to strengthen your immune system, though. Getting adequate sleep and making sure your diet is top-notch are the first and most basic steps toward a healthy immune system. You might also consider taking an immune-boosting herb such as the Chinese herb astragalus. Tieraona Low Dog, MD, recommends putting a piece of astragalus root in your soup, stew or rice two or three times a week during cold season.

To listen to her explain its use and other ways to boost immunity such as taking reishi or maitaki mushroom extracts, you may want to listen to the mp3 of Show 1057: How Can You Improve Your Immune Response? Dr. Low Dog is one of the country’s leading experts on botanical medicines and the evidence for their use. National Geographic has published three of her books: Life Is Your Best Medicine; Healthy at Home: Get Well and Stay Well Without Prescriptions; and Fortify Your Life: Your Guide to Vitamins, Minerals and More. Her website is

You can also read what we have written about other popular supplements that people use to prevent colds. These include zinc and vitamin C.

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  1. Michelle

    The cod liver oil is very effective in fighting my colds. I can feel my cold symtom leaving within hours of taking cod liver oil, and it stay gone. One time I had a cold, but it only lasted one day instead of a week as usual. I couldn’t figure why it went away so fast; until it dawn on me that I had just taken cod lliver oil. I was very impressed.

  2. Berryman

    Everyday at breakfast I have plain yogurt mixed with an equal volume of fruit or berries, preferably fresh or fresh frozen, preferably from my garden, safe from chemicals to control bugs or weeds. I cycle through blackberries, blueberries, elderberries, raspberries, strawberries, avocado or bananas. I still get a runny nose every few years that may last as long as a day or two, but none so severe as before I started this regimen.

  3. Lisa

    What about mercury? Is that a problem with cod liver oil?

  4. Keith

    My mother used to give my siblings and I called liver oil for colds growing up I’ve been taking the tablets or gel caps and it seems to help ward off and even destroy cold symptoms as a matter of fact I find it more effective than over the counter remedies such as Tylenol Cold and safer because it’s natural

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