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This particularly nasty process is going on in your body all the time. The process of glycation (one of the two metabolic processes of aging, along with free radical damage) occurs when reducing sugars (such as glucose, galactose and fructose) bind to protein molecules without the control of an enzyme. This reaction leads to the production of appropriately-titled AGE (Advanced Glycation End-product) molecules. While the process of glycation is reversible, the subsequent production of AGEs is normally irreversible. AGEs produce 50 times more free radicals than proteins that have not been glycated. AGEs can then attach themselves to LDL-cholesterol and increase oxidation, and therefore atherosclerosis; they also cause chronic inflammation.
But perhaps the worst thing about glycation is that it leads to the cross-linking of proteins. Some of the AGEs lock together, and these crosslinks harden tissues that were once elastic and supple. While many proteins are short-lived and quickly replaced by the body, others last much longer, such as basement membrane proteins and the crystallins in the lens of the eye (which last a lifetime). This hardening leads to hypertension, kidney disease, erectile dysfunction, arthritis, cataracts, Alzheimer’s Disease, impaired wound healing, incontinence, and general stiffness of the joints and skin. Collagen, which makes up about a third of the protein in mammals, is particularly affected, as it is long-lasting also.
Obviously reducing glycation as much as possible is going to leave a person much healthier, for much longer, than they otherwise would be. The good news is that there is a strong inverse correlation in mammals between the amount of carnosine present in the blood and the amount of glycation observed. Carnosine also acts as an antioxidant (being especially potent against the very destructive hydroxyl radical), and is not the only protection available from glycation – vitamin C also has anti-glycation and antioxidation properties. A molecule called aminoguanidine has also been found to inhibit glycation and some of its effects, such as kidney disease in diabetics. And aspirin is also a probable inhibitor, with some observed effects on glycation-related disease in regular users of aspirin, who are less likely to develop cataracts.
But while these substances can inhibit glycation, is there any way of reversing it once it has occurred? Alagebrium chloride, developed by Alteon Pharmaceuticals, is currently being trailed as a molecule that breaks existing crosslinks, and has shown considerable success in human trials by improving blood pressure through making arteries more flexible, although at this point its safety has not been completely determined (there is evidence of it altering the structure of liver cells in rats). But if this drug (and others being developed) proves to be safe in the future, there are reports from clinical trials that crosslink-breaking drugs are reversing many of the effects of AGEs – increased flexibility, lower blood pressure, increased bladder capacity, improved kidney function, improved erectile function, and a reduction in joint pain have all been observed.
In the meantime, there is obviously another way to reduce glycation – lowering the amount of sugar in the blood. Meals containing little fat are one way to achieve this, because of the insulin resistance caused by fatty acids, meaning that blood glucose must then increase to supply cells with the same amount of glucose, causing increased glycation. And another way of lowering both glucose and insulin is eating soluble fibre, as is avoiding processed carbohydrates such as white bread, rice and cakes. For while it is likely that there will eventually be drugs available that can reverse the effects of this very damaging process, prevention is always better than cure.
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