Cod Liver Oil Side Effects - The Added Benefit of Cod Liver Oil Is Also the Major Problem

Fish oil supplements have become enormously popular in recent years because of all their proven health benefits.

Vitamin D has become enormously popular in recent years because of all its proven health benefits.

Are there any Cod Liver Oil Side Effects?

And cod liver oil, which provides both the omega-3 fatty acids found in fish oil plus natural vitamin A and D, is making a comeback as a health food. It's possible, however, to get too much of a good thing.

The vitamin A and vitamin D in a fish is concentrated in its liver. Fish oil is steamed out of the whole fish and is not as high in vitamins A and D.

In the early twentieth century, cod liver oil was very popular as a supplement for children in teens. A recent study of American teens found that 42% did not have optimum levels of vitamin D for good health and 24% had so little vitamin D in their bloodstreams that they were in serious damage of bone and tooth disease.

Vitamin D is also an issue for older adults, especially women. Bone breaks, especially hip fractures, are commonest in women who get the least vitamin D.

Some experts have suggested going back to cod liver oil as a supplement for children and older adults. So what's not to like about cod liver oil?

In general, cod liver oil is fine, although taking as many as 10 tablespoons a day might trigger hypervitaminosis D, a condition of getting too much vitamin D. When this occurs, symptoms may include:

  • Sensitivity to sunlight causing easy blistering
  • Loose teeth
  • Knots on bones
  • Fractures in bones, that is, osteoporosis

Ironically, getting too much vitamin D can cause some of the same problems as getting too little vitamin D. But unless you have an unusual affinity for cod liver oil, this is highly unlikely to happen.

Selected References:
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  • Gordon CM, DePeter KC, Feldman HA, et al. Prevalence of vitamin D deficiency among healthy adolescents. Arch Pediatr Adolesc Med 2004; 158: 531-7.
  • LeBoff MS, Kohlmeier L, Hurwitz S, et al. Occult vitamin D deficiency in postmenopausal US women with acute hip fracture. JAMA 1999; 281: 1505-11.
  • Linday LA, Dolitsky JN, Shindledecker RD. Nutritional supplements as adjunctive therapy for children with chronic/recurrent sinusitis: pilot research. Int J Pediatr Otorhinolaryngol 2004; 68: 785-93.
  • Oh R. Practical applications of fish oil (omega-3 fatty acids) in primary care. J Am Board Fam Pract 2005; 18: 28-36.
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