The term sugars covers a wide range of compounds, however, I just want to cover the hexoses (6 sided) normally found in food. All dietary sugars are either dimers (2 joined together) or the polymer starch, the exception being honey in which the double sugar sucrose has been hydrolysed by the bees digestive system into single sugars. Fruit sugar sucrose is fructose glucose, milk sugar lactose is galactose, glucose and starch is a long chain of glucose molecules with side branches sticking out from the main trunk. Glycogen, the form of glucose polymer which acts as a storage medium in animal cells is much the same as plant starch except the side branches are located in a different place and cannot be digested in a human's gastro-intestinal tract. Starch digestion begins in the mouth by the enzyme ptyalin and it is broken down to the double glucose molecule maltose by the time it enters the duodenum.
Okay, now to a VERY IMPORTANT POINT. In the natural world all sugars (except in honey) arrive in the duodenum for digestion as DOUBLE sugars, sucrose, lactose and maltose and cannot be absorbed into the body until cleaved into single sugars by the enzymes sucrase, lactase and maltase which are secreted into the duodenum by the EXocrine pancreas. This is where regulation comes in and is so important in stabilising the blood sugar level, The ENdocrine pancreas, located inside the body and which produces insulin in it's beta cells and glucagon in it's alpha cells, monitors blood sugar and it communicates with the exocrine pancreas via the GIP (gastro inhibitory peptide) axis. The idea is that the exocrine pancreas does not secrete the digestive enzymes into the duodenum until it the endocrine pancreas is ready and the exocrine pancreas monitors the presence and level of sugars in the duodenum telling the endocrine pancreas when to begin making insulin. THUS THERE IS VERY TIGHT CONTROL
Insulin takes about twenty minutes to synthesise. However, in the healthy individual there is a residue of insulin remaining in the cells from the previous release, so that there is a so called biphasic release. This residue is to nip in the bud any premature release of sugar into the bloodstream until de nova synthesis has finished and it is lost with reactive hypoglycaemia, as with migraine, because the pancreas is forced to overreact all the time. This loss of biphasic release is destabilising as I will cover in the next chapter.
Now we come to fibre. Plant fibre is composed of lignin, cellulose, hemicellulose and pectin. Fibre exerts strong osmotic pressure in solution and when present in the digestive tract pulls against the absorption of the monosaccharides resulting from the cleavage of the disaccharrides by the digestive enzymes. The monosaccharrides, glucose and galactose are actively transported in to the bloodstream, whereas, from memory, fructose enters by passive diffusion, So active transport also acts as a regulator.
REFINED SUGARS.
Now I want to leave the subject of digestion and assimilation and talk about the sugars of the concrete jungle. It is harmful to eat monosaccharides as they disturb blood sugar regulation. Processed foods contain the monosaccharides fructose, glucose, dextrose (another name for glucose) and food manufacturers are desperate to shove as much of this stuff into their 'foods' as possible. Sucrose or refined sugar put into a boiling cup of tea or coffee is hydrolysed into the monosaccharides by the heat whilst the caffeine accelerates the rise in blood sugar.
Caffeine poisons the enzyme phosphodiesterase located on the G stimulatory protein of the RAS (rat sarcoma) signalling pathway thereby preventing the pathway from turning off. Let's say that adrenalin binds to the RAS beta receptor outside the cell and activates it. Inside the cell the (C terminus) part of the receptor, now activated, draws the G protein to it and the G protein is diphosphorylated and thus activated. Activated G protein then migrates to adenylate cyclase and activates it and adenylate cyclase then begins to make cyclic AMP or cAMP which in turn activates the rest of the signal transduction pathway.. Within milliseconds or seconds phosphodiesterase on the G protein dephosphorylates the G protein and it migrates back to a position midway between the adenylate cyclase and the RAS beta receptor. Thus by caffeine poisoning phosphodiesterase an adrenalin response remains switched on for some time after adrenalin is withdrawn from the bloodstream. As adrenalin raises blood sugar in a number of ways it is obvious that caffeine is destabilising to blood sugar regulation. RAS pathways are ubiquitous in the body and stimulators include embryonic hormones, hence the suggestion that caffeine can be a promoter of cancer once started and it's cells dedifferientated.
Threobromine is the other blood sugar raiser in Coca Cola and chocolate. It's a xanthine like uric acid, and is essentially caffeine with one less methyl group on it (caffeine has 4). So, boiling coffee, sugar, a lump of chocolate, a swig of Coke and an hour or so the mouth is spewing and the head is thumping, tremors, sweats, no bloody good at all and very destructive.
In part 6 I want to get into the subject of blood sugar regulation INSIDE the body (the GI tract is officially outside the body). This will begin to touch on panic attacks, epilepsy, asthma and schizophrenia..
In veritas Noddy. Paul Hill.