Wednesday, June 27, 2012

A Clue About Insulin Sensitivity

In 1993, the New England Journal of Medicine Published a study demonstrating that highly unsaturated fatty acids (HUFA; e.g., arachidonate and docosahexaenoate [DHA]) in muscle membrane phospholipids are tightly correlated with insulin sensitivity [38].  Specifically, this means that the more of these HUGAs there are in the muscle membrane, the more insulin sensitive the muscle.  This observation subsequently has been corroborated and extended by multiple other studies.  For example the significant correlation between muscle HUFA and insulin sensitivity was shown to be specific to the phosphatidylcholine phospholipids which predominate on the outer layer of the muscle membrane [39].  This is interesting from the perspective that it implies a role for the background fatty acid composition of the membrane, per se, rather than the protein components inserted into it (like insulin receptors or glucose transporters).  In other words, figuratively speaking, what the 'fabric' of the wall itself is made of is very important for glucose transport - it's not just about the number of switches (i.e. receptors and transporters) inserted in the wall.

How these HUFAs get into muscle membranes is a very complex process involving both diet composition and metabolism of the various essential fats after they are eaten.  

The above is an excerpt from this very engaging book:

In all honesty I do not want to spend a bunch of time sorting out why the HUFAs get into cell membranes ... but I probably will.  

My guess is that where this is going is that inflammation is a contributor to insulin resistance by reducing either the contribution of HUFAs to cell membranes, or because in a high inflammation body (one in which the immune system is "on high alert" chronically) the HUFAs are oxidized too fast and thus lose their ability to serve as transport sites when commanded by the presence of insulin.  Or perhaps, a high insulin environment, in and of itself, damages the HUFAs. OR, as others have speculated, perhaps after some period of time of being stuffed full of sugars by the action of insulin, enough cell damage occurs that the cells develop a means to "defend themselves" from the sugar onslaught.  Or some combination of the above.  

In a way it does not matter.  If you are struggling to regain insulin sensitivity, you must eat a lot of fat, workout consistently, and probably practice fasting from time to time.  You must avoid fructose as much as possible.  And the fat you eat should include saturated fat, polyunsaturates from sources like nuts, and monounsaturates.  Lastly, you should ingest a balanced quantity of omega-3/6 fatty acids.

Eat meat, eggs, vegetables, nuts and seeds, little fruit or starch, no sugar/wheat.

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