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Can Cod Liver Oil Strengthen Your Immune System?

Giving children cod liver oil may help them fight off respiratory viruses that cause colds and flu. Can it do the same for adults?

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?

Spoonfuls or Capsules to Prevent Colds:

Q. Mom always gave us cod liver oil in the winter, especially for colds. It tasted awful, but it kept colds down.

As an adult, I stopped taking it until recently. I started getting a cold nearly every month. It finally occurred to me to take cod liver oil capsules. I take them as needed, and they work along with my vitamins C and D. Together, they strengthened my immune system, and the colds stopped.

A. Many readers agree that this can help prevent colds.

One person wrote:

“I believe that cod liver oil has been effective in fighting off colds. Our harvest season can drag on for two months in wet, cold weather with 16-hour days.

“I would always catch a bad cold every season until I started taking a spoonful every day at least 10 years ago. Now I very rarely catch a cold.”

Cod liver oil is an excellent source of vitamin D. Grandmothers in northern Europe, where there is little sunshine in the winter, often dosed the family with this yucky-tasting stuff.

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, it 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 this to us by the spoonful when we were kids, long ago. The tablets I take now 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 else to be done to strengthen your immune system. 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 drlowdog.com.

You can also read what we have written about other popular supplements that people use to prevent colds. These include zinc and vitamin C. To learn more about vitamin D and its benefits for the immune system, you may wish to read our eGuide to Vitamin D and Optimal Health.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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