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Diet Balance--> Tissue Balance--> Eicosanoid Balance
     Diet choices influence tissue composition, and in health maintenance and disease prevention, the tissue is the issue. The intensity of omega-6 eicosanoid responses depend on the proportions of omega-6 and omega-3 eicosanoid precursors stored in the 20- and 22-carbon highly unsaturated fatty acids (HUFA) of a responding tissue. The proportion of omega-6 in body HUFA is predicted by an empirical relationship (Biochem. Biophys. Acta 1992; 1180:147-162) for the metabolic competitions among four separate types of essential fatty acid (EFA) in the diet: 1. 18-carbon omega-3 PUFA 2. 18-carbon omega-6 PUFA 3. 20- and 22-carbon omega-3 HUFA 4. 20- and 22-carbon omega-6 HUFA Each of the four types contributes differently to the overall tissue balance. Discussing the four types combined into a single ratio of total dietary omega-6/total dietary omega-3, has no clear meaning, because tissue proportions of omega-6 in total HUFA result from the four separate contributions expressed as a percent of total food energy (en%) shown in the chart below.

 

 

 

     

                                          

en% 18:3n-3   0.85  0.50  0.76 (short3)
en% 18:2n-6  6.82   2.30   5.04 (short6)
en% n-3 HUFA  0.03  0.09  0.54 (long3)
en% n-6 HUFA  0.08  0.08  0.08  (long6)
To see the influence of the different EFA, ENTER different values for the four types and see how different combinations give very different proportions in body tissues. Three typical ethnic diet combinations of essential fatty acid intakes (expressed as percent of energy, en%) are in the columns at the right. Some populations achieve healthy tissue proportions and moderate eicosanoid responses by eating lots of omega-3 HUFA (as do Japanese or Greenlanders), whereas some populations eat lower amounts of the omega-6 18-carbon acid (as do Mediterranean people).   In a 2400 Cal/day diet, 266 mg of fat is 0.10 en%, and a standard 1g fish oil supplement is equivalent to 180mg 22:6 + 120 mg 20:5; about 0.11 en% n-3 HUFA per capsule.
 80%  63%   51%
                                     USA MEDIT JAPAN     

A free interactive computer-aided personal food choice program called KIM-2 Keep It Managed-2nd Version combines all of your daily food choices and predicts the resulting tissue HUFA levels that are biomarkers for essential fatty acid intake as well as surrogate clinical markers related to the probable intensity of an eicosanoid response.