Earlier today, I received a phone call from a customer wanting to know the ideal ratio of omega-6 to omega-3 in our diet. Not being terribly well versed in nutrition, I certainly didn't know the answer. But where to turn to for this information?

The library has two outstanding encyclopedias on nutrition, (The Encyclopedia of Nutrition and Good Health by Robert Ronzio and Nutrition and Well-Being A to Z, Delores C.S. James, editor in chief,) and both offered valuable information on the role omega 6 and omega 3 play in our diet, but unfortunately, they didn't list a recommended ratio.

I next turned to the library's Consumer Health Complete database, (available both at the library and from offsite!) The first result from a search for "omega 6 omega 3 ratio" brought me to an article in the August 2006 issue of American Chiropractor titled "Omega-6 Mobile -- only diesel vehicles should eat n-6's." Mentioned within the article was the following, "The biochemistry of human body needs to consume at least 4:1 ratio of n-6 to n-3 fatty acids. When the consumption exceeds the 4:1 ratio, the human vehicle begins to show pro-inflammatory conditions." So, it appeared I had found an authoritative source. But is one authoritative source sufficient when it comes to health or medical information? I decided to continue my research.

I next turned to PubMed, a service of the U.S. National Library of Medicine that provides free access to MEDLINE, its database of indexed citations and abstracts to medical, nursing, dental, veterinary, health care, and preclinical sciences journal articles. There I learned in the October 2002 issue or Biomedicine and Pharmacotherapy that ratios ranging from 2:1 up to 5:1 had beneficial impacts depending on the disease in question. For example, "in the secondary prevention of cardiovascular disease, a ratio of 4/1 was associated with a 70% decrease in total mortality." And, "a ratio of 2.5/1 reduced rectal cell proliferation in patients with colorectal cancer."

At this point, I shared the results of my research with the library customer, and she was pleased! Nevertheless, I decided to see what the Wikipedia had to say. As many of you hopefully know, Wikipedia is an enticing option for online researchers, but the information found there isn't always trustworthy. In an entry on omega-3 fatty acids, I learned that "the ideal ratio of omega-6:omega-3 [ranged] from 3:1 to 5:1." But what was the source of this information? Fortunately, in this case, the information was backed up by a citation to an article in World Review of Nutrition and Dietetics, specifically "Omega-6/omega-3 Essential Fatty Acid Ratio: The Scientific Evidence" by AP Simopoulos.

At last, this reference question was complete.

Sources:
Seaman, David (2006). "Omega-6 Mobile -- only diesel vehicles should eat n-6's." American Chiropractor, 28(9), 66-68.

Simopoulos AP (2002). "The importance of the ratio of omega-6/omega-3 essential fatty acids."
Biomedicine and Pharmacotherapy, 56(8), 365-79.

Simopoulos AP, Cleland LG (eds) (2003). "Omega-6/omega-3 Essential Fatty Acid Ratio: The Scientific Evidence." World Review of Nutrition and Dietetics, 92, 1-22.