If alpha lipoic acid is equally adept at shuttling glucose into the fat cells as it is into the muscle cells, what advantage can this give in terms of body composition?
The studies I have seen show that ALA increases insulin sensitivity in muscle and not fat cells. Even if it does increase sensitivity in fat cells human adipocytes (fat cells) are not very efficient at converting glucose into fat. In humans most of the converting of glucose into fat occurs in the liver which doesn’t require insulin to work it’s magic. It is preferable to have the glucose moved into muscle cells instead of fat cells because it will more likely be oxidized in muscle than in fat. Fat does use glucose for energy as well but at a much slower rate, which increases the chances that it will be converted to fat. I think it is better to have some glucose moved into fat cells as well as muscle than to have chronically high blood sugar because then the liver cells will get a hold of the extra blood glucose and will almost always convert it to fat if liver glycogen is topped off.
Ken, thanks for the reply. My concern was that ALA increases glut-4 transporters on both the adipocytes and myocytes (cannot show studies at the mo, don’t even know if this is physiologically possible). Given that the muscle cells have a finite capacity for glycogen storage and the adipocytes have a virtually limitless capacity, is ALA a supplement that you would take on a “traditional” bulking diet? Bill made a good point about insulin sensitivity in a recent post, suggesting that it was more a case of a differential in sensitivity between the muscle and fat cells. Comments appreciated.
Bloatbag Stu, I have recently looked at some studies that show ALA improves insulin sensitivity (IS) in fat cells as well as muscle cells as you have mentioned. I can’t find any studies that have compared the two as far as which one improves more. However, I did find a rat study, which demonstrated that ALA did not improve IS in normal lean rats, only in obese type 2 diabetic rats. All of the human studies I have seen show ALA improves IS in type 2 diabetics with no research on normal subjects. If the rat study also applies to humans then ALA’s worth is diminished for people with normal glucose tolerance. If anyone has a reference for human studies that show otherwise I would like to see them posted. The rat study is in " J Appl Physiol 2002 Jan;92(1):50-8." If you want supplements to prevent fat gain on a bulking diet I would suggest CLA and HCA. CLA shunts fat away from fat to muscle and HCA (in theory) can prevent excess carbs from being converted to fat. Free Ex mentioned on the other thread the statement Cy made about Metformin in that it improves IS in muscle more than fat.