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Ear infections, cod liver oil, and selenium

NEW research indicates that VITAMIN D is essential for the health of the body's innate immune system, which helps protect against infection.


Ear Infections are a common and costly problem in infants and young children. (The medical term for ear infections is "otitis media.") Pneumococcus is a bacteria that causes many ear infections; however, it is becoming resistant to the antibiotics commonly used to treat this disorder. Doctors are trying to find ways to use fewer antibiotics to treat ear infections. Prevnar , the pediatric vaccine against the pneumococcus bacteria, is effective against blood-stream infections. However, there was only a 6% decrease in the overall number of ear infections from any cause in the studies of this vaccine.


Free Radicals are molecules, or parts of molecules, that are highly reactive chemicals. Free radicals can damage lipid (fatty) membranes by a process known as lipid peroxidation; they can also damage proteins and DNA, and they are important in inflammation. Research has shown that free radicals and inflammation are involved in ear infections. Inflammation is also important in the infections caused by some of viruses and bacteria that cause ear infections.

There are special enzymes in the body whose job is to "clean up" free radicals. These enzymes are known as FREE RADICAL SCAVENGING ENZYMES. TRACE METALS are important parts of these enzymes. Trace metals include SELENIUM, zinc and copper; they are present in the body in very small or "trace" amounts. If the body does not have adequate amounts of trace metals, it cannot make enough free radical scavenging enzymes.


Lipids (also called fats) make up a large part of the membrane that surrounds each cell in the body; they are particularly important in the brain and the eye. Some fatty acids are "essential," meaning that they cannot be made in the body; they must come from outside the human body, usually in food. OMEGA-3 FATTY ACIDS are a special kind of fat. The parent omega-3 fatty acid is an essential fatty acid; it has 18 carbon molecules and 3 double bonds. This fatty acid may be metabolized by adding more carbon molecules and/or adding more double bonds, resulting in long-chain, polyunsaturated fatty acids (LCPUFA), such as EPA (EICOSAPENTAENOIC ACID) and DHA (DOCOSAHEXAENOIC ACID). EPA is important in decreasing inflammation, and DHA is important in the eye and brain. It is unclear how much EPA or DHA the body can make from the parent omega-3 fatty acid. Therefore, taking fish oil or cod liver oil can provide these important fatty acids. (Fish oil contains EPA and DHA; in addition to these important omega-3 fatty acids, cod liver oil also contains vitamins A and D).


In the USA from the 1920s through the 1940s, children were routinely given a teaspoon of cod liver oil every day, often in orange juice. There were no synthetic vitamins at this time. Cod liver oil was therefore given as a source of both vitamin D (to prevent rickets, a bone disorder) and vitamin A (the "anti-infective" vitamin). Although it was not known at that time, cod liver oil was also an important source of omega-3 fatty acids. Orange juice was given to provide vitamin C (to prevent scurvy). However, these older preparations of cod liver oil did not have a pleasant taste, and giving orange juice to such young children may cause allergies. Thus, when synthetic vitamins became available, they soon replaced cod liver oil and orange juice. However, there are NO omega-3 fatty acids in synthetic vitamins, and children therefore lost a significant source of these important fatty acids.

In this research, we used cod liver oil that had a pleasant, lemon flavor. For adults, who can swallow capsules, the taste of cod liver oil can hidden by putting it in capsules. However, young children cannot swallow capsules; they must take the oil as a liquid, and taste is therefore particularly important for them.

Over the years, our environment has become increasingly polluted. For example, from the 1930s to the 1970s, chemicals known as polychlorinated biphenyls (PCBs) and dioxins were widely used for industrial purposes. Although their use is now severely restricted, these chemicals last for a long time and they are therefore still present in our environment, including our oceans, where they can accumulate in fish. There are now strict criteria for the amount of these chemicals that are allowed in fish oil and cod liver oil to be consumed by people. The lemon-flavored cod liver oil we used in this research met these strict criteria. Flavor and purity are important considerations when choosing a cod liver oil preparation, especially for young children.

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The information on this web site is provided for educational purposes only; it is a general reference for healthcare consumers and providers; it is not a prescription for any individual person. It is important that you consult your childís qualified healthcare provider before implementing any of the research discussed on this web site.


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