Sun, Sep-12-04, 19:28
|
|
Senior Member
Posts: 2,018
|
|
Plan: Atkins
Stats: 320/220/195
BF:
Progress: 80%
Location: Pensacola, FL
|
|
Quote:
|
Originally Posted by fatburner
Fascinating! But I'm still not really clear wether using fatty acids directly in the mitochondria as acetyl Co A is a separate process and energy pathway to ketosis. That is, can you be using FFA's directly in the mitochondria of most cells for energy without a ketone in sight or are ketones a necessary part of energy production from fat. Note that I'm not talking about the mobilization of body fat stores by glucagon into FFA's which can then be available for energy. So the FFA's can be either dietary or bodyfat (or both  ), but are ketones a necessary part of them being utilized for energy, or just one such way. I've never had bodyweight issues, and I've never been in measurable ketosis but I've been on induction carb levels (for optimum health reasons) and very high fat/ moderate protein for over two years. So what's actually happening in my mitochondria. Are ketones necessarily involved. I realize a few kinds of tissue need (some) ketones if glucose is not available - brain for instance. But what about the rest?
Help! I really want to understand this.
Confused |
My understanding is that fat can be metabolized directly in the Mitochondria, without first converting it to Ketones...and that ketones are created only in specific situations (to feed the Brain, when there is inadaquete oxalacetate, when too much fat is being burned too quickly, etc...)
http://www.unisanet.unisa.edu.au/08366/h%26p2fuel.htm
Quote:
|
Fatty acids are mobilised from triglyceride stores and used for ATP production, either directly or via the formation of the water soluble ketone bodies.
|
http://www.unisanet.unisa.edu.au/08366/h%26p2fat.htm
Quote:
An alternative method of utilising the acetyl CoA formed by ß-oxidation is via the synthesis and subsequent oxidation of four-carbon units known collectively as ketone bodies.
Acetyl CoA is converted in the liver into acetoacetate (essentially two acetyl groups covalently linked). Acetoacetate can be further reduced to form ß-hydroxybutyrate. These two compounds are referred to as ketone bodies. Their synthesis occurs in the liver.
They diffuse from the liver into the circulation and are used as fuels by several tissues. Heart muscle and renal cortex, in particular, use acetoacetate in preference to glucose. In contrast, glucose is the major fuel for the brain and erythrocytes in a human on a balanced diet. The brain has the capacity to adapt to the use of acetoacetate during starvation (and in the metabolic disease diabetes mellitus). In starvation of long standing, acetoacetate meets more than 70% of the energy needs of the brain.
This ability of the brain to adapt to the use of acetoacetate is important because fatty acids cannot enter neural tissue. Acetoacetate is regarded as a water soluble and readily transported form of acetyl CoA.
|
|