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When to Take Fish Oil and When to Take Cod Liver Oil

By Ben Kim, D.C.

If you've been a long time subscriber to my natural health newsletter, you know how important two omega-3 fatty acids, DHA and EPA, are to your overall health, particularly to your cardiovascular and nervous systems.

DHA and EPA are so critical to human health that I am convinced that high quality fish oil or cod liver oil should be a regular part of most people's diets.

I have been taking cod liver oil on a daily basis for the past several years to ensure adequate intake of DHA and EPA, as well as to get some vitamin A and D from my diet.

My wife took cod liver oil along with me year-round for the first few years, but in the summer of 2006, she began taking fish oil instead of cod liver oil.

The major difference between cod liver oil and fish oil is that fish oil does not contain vitamins A and D.

My wife and I decided that since she gets a good amount of sunlight in the summer months, to ensure that she doesn't end up with too much vitamin D in her system from sunlight and food sources combined, she should use fish oil to nourish her body with DHA and EPA. And in the fall and winter, when she is unable to get vitamin D production from sunlight, she should use cod liver oil.

I will be sticking with cod liver oil throughout the summer months because areas of my skin burn quite easily when I am out in the sun for long stretches at a time, so I usually stay indoors during the mid-afternoon.

In looking through my patient files from January of 2002 to December of 2005, I found 82 patients whose blood levels of Vitamin D (25 hydroxy D) I had records for. Eighteen of these patients were from Ontario, and the rest were from all over the States. Forty-eight of these patients were taking cod liver oil on a regular basis. And none of them, even those from California and Florida, had toxic blood levels of Vitamin D.

Based on the data that I have to go on as well as research that I have done on Vitamin D toxicity, I believe that most people are just fine taking cod liver oil throughout the year. However, I recommend switching from cod liver oil to fish oil in the following circumstances:

  • During warm summer months, particularly if your skin get lots of sun exposure and/or you eat lots of fish that are naturally rich in vitamin D, such as salmon, mackerel, and sardines.

  • During warm summer months if you are pregnant or nursing.

  • Throughout the year if you live in an area where the weather is warm year-round and your skin is regularly exposed to sunlight.

  • If a blood test shows that your vitamin D level (25 hydroxy D) is greater than 70 ng/mL (175 nmol/L).

If you would like to switch from cod liver oil to fish oil during the warm summer months or even year-round, I recommend fish oil made by Carlson Labs.

Carlson bottles their premium fish oil in a way that ensures maximum freshness and nutritional potency. Their fish oil is regularly tested for potency and purity by an independent, FDA-registered laboratory and found to be free of detectable levels of mercury, cadmium, lead, PCB's and 28 other contaminants.

You can order Carlson Fish Oil directly from Carlson Labs or from our web site using the following link:

Carlson Fish Oil

Order Now

Carlson Fish Oil

1 Large Bottle
(16.8 ounces, 500 ml) of Lemon Flavored Carlson Fish Oil

(plus S&H)


If you prefer a gel capsule form of fish oil, I can recommend:

Carlson Elite Gems (Professional Strength Omega-3 Fatty Acid Supplement)

Nutrient Profile for Carlson Fish Oil:

Supplement Facts
Serving Size 1 Teaspoon
  Amount Per 1 Teaspoon % DV
Vitamin E (as d-Alpha tocopherol) 10
Other Omega-3 Fatty Acids 300
Omega-3 Fatty Acids (from fish oil) 1600
Antioxidant Blend 14
DHA (Docosahexaenoic Acid) 500
EPA (Eicosapentaenoic Acid) 800
* Daily Value (DV) not established

Recommended dose: 1 teaspoon per 50 pounds of body weight per day.

If you prefer cod liver oil for an all-in-one source of DHA, EPA, Vitamin A, and Vitamin D, please feel free to view our page on Carlson Cod Liver Oil.

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Copyright 1997-2007 by Ben Kim

The contents of this website are the opinions of Dr. Ben Kim unless otherwise noted. The information on this website is not intended as personalized medical advice and is not intended to replace the relationship that you have with your primary care provider. Any decisions you make with regard to your daily choices and medical treatments should be made with the help of a qualified health care provider.