Fructose a likely new foe in gout battle
MEDICAL MATTERS:Soft drinks may raise our levels of uric acid, writes MUIRIS HOUSTON
THE LAST time I wrote about gout I signed off with a statement that gout was no longer a disease of the affluent.
However, with a doubling in the number of cases of gout in some developed countries in recent years, it may be time to update that conclusion.
A disease that finds it hard to shake off its 18th century image and association with the excesses of the ruling classes, gout was believed to be brought on by high living and gluttony.
Benjamin Franklin wrote a dialogue in 1780 between himself and “Madam Gout”, pleading to know, “What have I done to merit these cruel sufferings?” Gout replied: “Many things; you have ate and drank too freely, and too much indulged those legs of yours in their indolence.”
According to a recent review published in Nature, “In the past few decades gout has approximately doubled in prevalence in the USA, and is also markedly increasing in prevalence in other countries with established and emerging economies.”
Gout is more common in men, with a prevalence of 5 per cent in men over 65, and is associated with obesity and a high alcohol intake.
But not all types of alcohol are bad in this context: one study found men who drank two glasses of wine per day did not have a higher risk of developing gout, whereas those who drank two glasses of beer had a two and a half times greater risk of having an attack than if they drank no beer at all.
Classified as a form of arthritis, gout typically affects the joint at the base of the big toe.
A severe pain usually comes on without warning, often in the early hours of the morning. The joint becomes so tender that the patient cannot even bear the weight of the lightest of bedsheets. The skin over the big toe joint becomes red and shiny.
What causes this acute inflammation?
Crystals of uric acid are deposited in the space between the affected joints. Uric acid is a natural waste product which usually passes out of the body via the kidneys.
However, if the load of uric acid becomes too great, then it builds up in the bloodstream before being deposited in a joint.
Urate crystals probably collect in the big toes because the feet tend to be cooler than the rest of the body, and the big toes in particular endure a lot of wear and tear which can allow crystals to form.
Proteins called purines are the chemical bricks that make uric acid, which is where the link with food and alcohol comes in.
If you are prone to gout and you load your body with purine-rich foods, then an acute attack is likely. Some of the foods to steer clear of include rich red meats, shellfish and oily fish such as mackerel.
However, now there is emerging evidence that fructose-sweetened soft drinks, as well as contributing to obesity, are also increasing uric acid concentrations in the body.
And with a ballooning in the use of high-fructose corn syrup in processed foods in recent years, some experts say this is a major reason for the increase in numbers of gout cases.
Dr Richard Johnson, professor of medicine at the University of Colorado, says the classic thinking is that the rise in obesity itself may be responsible for the rise in uric acid.
But some epidemiological studies show the rise in uric acid precedes the development of obesity and diabetes.
“Therefore,” he says, “it is likely that there are other reasons uric acid is increasing in our population.
“Our studies suggest that this is driven in part by the intake of sugar and high fructose corn syrup.”
It looks as if we have moved on from gout as a patrician disease, largely confined to those with a regular diet of claret and sweetbreads.
Now it seems it is a globalised food industry that comes to painfully wiggle our big toes in the dead of night.