Each Seven Seas cod liver oil product contains a different mixture of cod liver oil and other ingredients, including fish oil and various vitamins and minerals. As of July 2016, the Seven Seas website notes that all of its cod liver oil products contain omega-3 fatty acids, and vitamins D and E. Vitamin A, which is normally present in raw cod liver oil, is noted only in the cod liver oil plus garlic supplement. The nutrients in Seven Seas cod liver oil products can potentially promote heart and musculoskeletal health, among other possible benefits.
Seven Seas cod liver oil products are rich in the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While fatty fish consumption in the diet is associated with a decreased risk of heart disease, studies examining the effects of EPA and DHA supplements -- such as cod liver oil -- have yielded mixed results. Some studies have shown benefit while others have not. Similarly, studies examining the effects of EPA and DHA supplements on people who already have heart disease have shown mixed results.
A research article published in October 2012 in "Circulation: Cardiovascular Quality and Outcomes" pooled the results from 20 studies involving more than 60,000 people. The authors found that people with higher omega-3 fatty acid consumption -- through diet or supplements -- had a slightly decreased risk of dying from a heart attack or stroke, although the overall risk of death was not reduced. The American Heart Association recommends 1 g of EPA plus DHA daily for people with heart disease, and higher amounts for those with elevated blood triglycerides. Food is the best source of omega-3 fatty acids but supplements may be helpful, if your doctor recommends them.
Vitamin D is a fat-soluble vitamin found in Seven Seas cod liver oil products. It can be formed in the skin with exposure to the sun. It occurs naturally in only a few foods, including fatty fish and egg yolks. Vitamin D supports many important functions in the body but is best known for its critical role in bone health. The nutrient is essential for strong bones and protects against the development of osteoporosis.
Vitamin D is also essential for muscle health. A deficiency can lead to muscle weakness and pain. As with all vitamins, minerals and other nutrients, foods are the best source. But for people who may not get enough vitamin D in their diet, cod liver oil may be a good alternative to promote musculoskeletal health.
Other Potential Benefits
A number of other potential benefits of cod liver oil have been suggested, primarily based on the high concentration of omega-3 fatty acids. While these possible benefits have yet to be proven, the National Institutes of Health notes preliminary evidence showing that omega-3 fatty acid supplements might:
-- decrease morning stiffness and pain in people with rheumatoid arthritis
-- reduce the risk for an eye condition called age-related macular degeneration
Researchers are also looking at the potential for omega-3 fatty acid supplements to influence diseases such as multiple sclerosis, depression, autism, Crohn disease, diabetes, lupus and others. However, it remains unclear as of July 2016 whether supplements or a diet rich in omega-3 fatty acids benefits people with or at risk for these conditions.
Talk with your doctor if you are considering taking a cod liver oil supplement to be sure it's safe for you. This is especially important for women who are pregnant or might become pregnant as too much vitamin A might might harm a developing baby. An imbalance between vitamin A and D intake associated with cod liver oil might also be detrimental to bone health in both children and adults. Finally, cod liver oil supplementation might interfere with the effectiveness of blood thinners, such as warfarin (Coumadin).
Reviewed and revised by Tina St. John, M.D.
- Oregon State University Linus Pauling Micronutrient Information Center: Essential Fatty Acids
- Circulation: Cardiovascular Quality and Outcomes: Omega 3 Fatty Acids and Cardiovascular Outcomes Systematic Review and Meta-Analysis
- Tanaffos: Omega-3 Supplements and Cardiovascular Diseases
- American Heart Association: Vitamin Supplements: Healthy or Hoax?
- National Institutes of Health Office of Dietary Supplements: Vitamin D
- Oregon State University Linus Pauling Micronutrient Information Center: Vitamin D
- National Center for Complementary and Alternative Health: Omega-3 Supplements: In Depth