Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health. It is purportedly useful for healing wounds, sores, irritations of the respiratory tract and the alimentary canal and for lymph node swelling.^{[citation needed]} It is one of the active ingredients in hemorrhoid creams such as Preparation H.^[1]

Shark liver oil is rich in alkylglycerols, which are naturally found in mother's milk and in bone marrow.^{[citation needed]} It also contains pristane, squalene, vitamins A, D, omega-3 fatty acids, triglycerides, glycerol ethers, and fatty alcohols.^{[citation needed]}

[edit] Shark oil barometers

Bermudians rely on unique shark-oil based "barometers" to predict storms and other severe weather, even though electronic meteorological facilities are available.^[1] Small bottles of oil are hung outside. The appearance of the oil is said to alter consistently with changes in the weather.

While the mechanism of action is unknown, one theory states that electrical changes in the atmosphere affect the oil in order to alert the shark to move out to deeper water before a bad storm.^{[citation needed]}

[edit] Medicinal Use

Most shark liver oil supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.

Although many people have taken shark liver oil, the issue of potential toxicity at the usual doses has not been well studied. Some mild digestive problems such as nausea, upset stomach, and diarrhea have been reported. Some animal studies have found that shark liver oil and its components may raise blood cholesterol levels. A Japanese study ^[2] found some shark liver oil supplements to be contaminated with polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). PCBs can have harmful effects in humans, and may increase the risk of some types of cancer. People with seafood allergies may also react to shark liver oil.

Relying on this type of treatment alone, and avoiding or delaying conventional medical care, may have serious health consequences.

[edit] References

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