Cod liver oil is extracted from cod, which is a cold-water fish. This oil has a long history of use and great cultural importance for the people of Ireland, Scotland, northern Europe, and Iceland, where it is consumed to treat rickets, rheumatism, and a variety of diseases. Cod liver oil is extracted from cod livers, whereas fish oil is extracted from the body flesh of fish. Cod liver oil contains much more vitamins A and D per unit weight than regular fish oil. The types of omega-3 oils are the same for both products.
Cod Liver Oil Benefits and Researches
Cod liver oil contains omega-3 fatty acids, vitamin A, and vitamin D. The vitamin A in cod liver oil supports immune system. This vitamin regulates critical functions such as cell division and bone growth and helps keep the skin healthy.Vitamin A deficiency is a important cause of blindness in the world.
Vitamin D is necessary to keep a balance between phosphorus and calcium in the body. Vitamin D affects DNA through vitamin D receptors, which bind to specific locations of the human. Researchers have mapped the points at which vitamin D interacts with our DNA – and identified over two hundred genes that it directly influences. Deficiency of vitamin D is associated to rickets, bone softening, osteoporosis, prostate cancer, colorectal cancer, and autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and type 1 diabetes. Several findings indicate that adequate levels of vitamin D may reduce the risk of developing osteoporosis, some cancers, high blood pressure and autoimmune disorders. A individual’s vitamin D level is gauged by measuring the blood level of 25-hydroxyvitamin D. When levels go below 20 nanograms per milliliter (ng/mL) the person has vitamin D deficiency.
Cod liver oil is rich in DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). EPA is the precursor of important prostaglandins, localized tissue hormones that help the body deal with inflammation; and DHA is very important for the development and function of the brain and nervous system. In several studies, the elongated omega-3 fats found in cod liver oil have been shown to improve brain function, memory, immune response, asthma, allergies, learning and behavioral disorders.
Rickets is a disease caused by a deficiency of vitamin D, calcium, or phosphate. Insufficiency of vitamin D can lead to rickets in children (soft bones that can be painful and deformed) and osteomalacia in adults (soft bones, bone pain, and muscle weakness). Vitamin D can prevent and treat some bone problems such as rickets in children and osteomalacia in adults. By clinical studies conducted in Vienna between 1919 and 1922, Dr Harriette Chick and her coworkers were able to confirm the preventive and therapeutic value of cod liver oil and sunlight against rickets in young infants. With the discovery of vitamin D and the delineation of the antirachitic effects of cod liver oil by the 1930s, it became possible to not just treat but also eradicate rickets in the United States.
Vitamin D deficiency, which is usually seen in older people, can lead to osteoporosis and is associated to an increased risk for broken hips. The vitamin D in cod liver oil helps build bone density in adolescents to lower the risk of osteoporosis and other bone related problems later in life. In a animal-based study, the effect of cod liver oil was investigated in the prevention of bone loss in the ovariectomized female rats. One group of ovariectomized rats received an estrogen implantation at the time of operation and the second group was supplemented orally with cod liver oil daily for eight weeks. It was found that estrogen implantation as well as cod liver oil supplementation in ovariectomized rats increased the calcium level in femur. Therefore, cod liver oil may benefit postmenopausal women at risk of osteoporosis.
Cod liver oil has anti-inflammatory effects that help quell the inflammation of arthritis. Some researches have shown that cod liver oil may help with the symptoms of arthritis. Cod liver oil likely works in two different ways in preventing arthritis. It is a rich source of Omega-3 fatty acids and of vitamin D. These substances modify immune reactions in the body and help to prevent the body being attacked by itself in what is called an autoimmune reaction.
A pilot study studied the efficacy of cod liver oil supplements on symptoms of rheumatoid arthritis. Forty three participants with rheumatoid arthritis took 1g of cod liver oil daily for three months. Supplementation significantly reduced morning joint stiffness for 52 % of patients. Joint pain was reduced in 42% of patients and joint swelling was reduced in 40% of patients. Intensity of pain was reduced in 67.5% of patients. Results of the Cardiff study of 25 arthritis patients awaiting knee replacement surgery demonstrated that 86% of patients who took 2,000 mg of cod liver oil capsules daily had absent or significantly reduced levels of one of the enzymes that cause cartilage damage. Also, the result demonstrated a marked reduction in some of the enzymes that cause joint pain in those people taking the cod liver oil.“The data suggests cod liver oil has a dual mode of action, potentially slowing down the cartilage degeneration inherent in osteoarthritis, and also reducing factors that cause pain and inflammation,” Professor Bruce Caterson said.
Non-steroidal anti-inflammatory drugs (NSAIDs) are the most common prescribed medications worldwide. The most frequently known NSAIDs are ibuprofen and asprin. The ibuprofen and other NSAIDs prescribed to millions of patients each year have been linked to a range of adverse effects. A study reported in the March 2008 Rheumatology investigated the effectiveness of cod liver oil on reducing reliance on non-steroidal anti-inflammatory drugs. Approximately 40 % of the patients in the cod liver oil group were able to wean themselves off of NSAIDs, compared to only 10% in the control group. Deficiency of vitamin D has been associated with osteoarthritis and rheumatoid arthritis. A study at “Malmo University” found recently that babies that began breast feeding in hospital were more likely to suffer from rheumatoid arthritis later in life than babies that did not begin breast feeding in hospital and probably went on to bottle feeding.
Cod liver oil significantly improves heart function. Pure cod liver oil is a important source of these Omega-3. Omega-3 exert a protective property on the heart, by making the heart cells that generate the electric impulses that cause the heart to beat less prone to developing abnormal rhythms. Several researches have showed that Omega-3 fatty acids can significantly reduce the mortality rate of people who have suffered heart attacks. Cod liver oil helps to reduce stickiness in the blood and helps lower high triglyceride levels. Taking cod liver oil can reduce triglyceride levels by 20% to 50% in individuals with high triglyceride levels.
Otitis media (middle ear infection), is an infection of the middle ear common in younger children. In a study at the New York Eye and Ear Infirmary, researchers found that youngsters prone to otitis media had lower than normal levels of EPA, selenium and vitamin A. When they gave the youngsters cod liver oil, selenium, and a multivitamin, they found the children suffered fewer ear infections.“This study provides preliminary evidence that otitis media may be prevented and that the reliance on antibiotics may be reduced among young children by using nutritional supplements,” said Dr. Linday. The results were reported in the July 2002 edition of the Annals of Otology, Rhinology & Laryngology.
With respect to type 1 diabetes, cod liver oil has been shown to potentially lower the likelihood of developing the disease if taken within the first year of life. Studies conducted out by researchers in Norway showed that infants regularly given a spoonful of the oil during their first year were 25 % less likely to develop the disease.
Lab and animal studies and observational epidemiologic studies demonstrate that higher levels of vitamin D in the body may be linked to lower cancer risk. Higher vitamin D levels in the blood have been associated to lower risk for some types of cancer, particularly colorectal cancer. The International Agency for Research on Cancer, reviewed this topic and concluded in a 2008 report that vitamin D may reduce risk of colorectal cancer. According to a 2009 study performed by Norwegian scientists and reported in the International Journal of Cancer, daily supplementation of cod liver oil associated with a higher survival rate among lung cancer patients and cancer patients with solid tumors. A population-based case-control study studied the correlation between vitamin D and breast cancer. Women with newly diagnosed invasive breast cancer and women without breast cancer participated in the study. Increasing sun exposure between ages 10 and 19 was associated with reduced breast cancer risk. Use of cod liver oil and consumption of milk were also correlated with reduced breast cancer risk.