ABC Radio National

The Science Show





Date/Time 07 Feb 2016 9:40:17pm
The assumption that the human brain is twice as big as it need be to allow for Alzheimer's would be all very well if the disorder was a natural part of aging, but it is not. It is a degenerative disorder resulting from poor modern lifestyle, poor diet, lack of exercise, lack of interests etc.

I read a PubMed paper a while ago about research on Alzheimers that tried to put them on a ketone diet, the assumption being that an excessively high sugar content of their diet had something to do with the disorder. However, poor or non compliance made this change impossible. Then it was discovered that feeding the patients a supplement consisting of short chain fatty acids derived from coconut and palm oil put them into ketosis at the same time as they were consuming their normal high carb diet.

Usually a high carb or normal carb (whatever that is) diet and ketosis are mutually exclusive, but the short length of these fatty acids somehow promotes ketosis in the liver when it had normal reserves of glycogen (stored glucose.) Most fatty acids range around 18 carbons long but these range from 4 to 8 carbons. Ketones are produced from fat during starvation or on a carb restricted diet and most cells of the body adapt to ketones after a couple of days of low carb, including the brain.

However, in this case, the brains of the patients, having a choice of either glucose or ketones, chose ketones with a significant improvement in cognitive function. There is a suggestion that the beta amaloid plaques found in the brains of Alzheimer's interfere with glucose transport, however papers now coming out suggest that Alzheimer's patients are sugar junkies. When there is a very high blood glucose level in the bloodstream, as with diabetes, there is a phenomenal known as non enzymatic glycosation of protein. This is where glucose acts like a glue sticking to surface proteins on epithelial cells lining blood vessels and also trapping plaques of cholesterol in them, thereby raising blood pressure and creating turbulence. The same thing, without the trapping of cholesterol, does happen inside neurons in the brains diabetics but what about of Alzheimer's..

Neurons do not have insulin receptors on them and do not store glucose as glycogen They take glucose in by passive diffusion, meaning that the brain has to regulate blood glucose to suit itself. However when blood sugar becomes deregulated, as with reactive hypoglycaemia, and it shoots up to an abnormal high, glucose pours into the neuron in such toxic concentration that it has to switch on an emergency pathway called the polyol. This converts the glucose first to the alcohol sorbitol then to fructose, which precipitates out at a lower concentration than glucose ie forms crystals. Although the pathway is reversible persistently high blood glucose in the brain could mean the gradual accumulation of these crystals and the interference with normal glucose metabolism, ther
