Essential Fatty Acid Metabolism

Diagram of EFA Metabolism

It may be necessary to choose the browser option "Fit Image To Window" to display this large and detailed jpg properly. The diagram shows some of the factors involved in how omega 3 and omega 6 oils are converted into body-useable nutrients and hormones. It ignores some factors such as how certain vitamins and minerals are also crucial for the reactions to occur. Using a decent multivitamin and ensuring sufficient magnesium intake will address this.

The conversion process is driven through the delta 5 and 6 desaturase reactions, which are indicated by the vertical boxes. Arrows with plus or minus signs show which factors catalyze (increase) and which decrease the reactions.

The point of the Zone Diet and other diets which limit starches and sugars and provide adequate fat and protein is to increase the production of "good" prostaglandins, PGE3, especially, and also PGE1, and decrease that of the bad prostaglandin, PGE2. PGE2 production should not be stopped completely. It does perform some useful functions in the body, like causing blood to clot when one is cut. Too much, though, can increase the chance of clots in the blood vessels, increase inflammatory reactions, and lead to weight gain and lethargy, and these are not good.

The first step in achieving an optimum balance is to increase the Delta 6 desaturase reaction. This allows both types of EFAs to start the conversion process. High levels of insulin slow the reaction and this is caused by not eating enough protein in relation to carbs. High levels of glucogen have the opposite effect. They speed up the reaction. At a 70% ratio or greater of protein to carbs (70g of protein are consumed for each 100g of carb) more glucogen than insulin is produced and this is what is desired.

Trans fatty acids (XFA) directly inhibit the Delta 6 reaction, so they should be avoided. High amounts of saturated fats (SaFA) indirectly slow the Delta 6 reaction by increasing insulin levels. High amounts of raw omega 3's, like flax oil, can also inhibit the reaction, so are avoided. This is less of a factor when the protein to carb ratio is higher, so doing something like eating plenty of cottage cheese or other quality protein with the flax oil can prevent the inhibition.

The next step is to decrease the Delta 5 desaturase reaction. This stops the omega 6 chain from producing as much arichidonic acid (AA) which produces the "bad" PGE2. However, it should not be stopped completely, again, since some PGE2 is necessary, and so that raw omega 3's can be converted into EPA. This is again done by using the correct dietary ratios of protein to carb. Glucogen inhibits the reaction while insulin increases it. EPA taken directly by eating fish or EPA capsules also decreases the Delta 5 reaction. DHA has virtually the same effect as EPA since there is no major enzyme reaction required to convert between the two.

If the Delta 5 reaction is not slowed down, AA can easily be produced by any omega 6's in the diet. When this occurs, more PGE2 and less PGE1 is formed. If GLA supplements are used and there is no inhibition of the Delta 5 reaction by diet or sufficient amounts of EPA, more AA is eventually produced, which is not good. PGE2 also has the undesireable trait of inhibiting the Delta 6 reaction.