More Gout In Tokelauan Migrants
In 1925, the island of Tokelau became New Zealand territory. Tokelauans were granted New Zealand citizenship twenty-three years later. The New Zealand government began to work toward helping Tokelauans to migrate to the mainland in 1963. Three years later, a cyclone devastated Tokelau's crops of breadfruit and coconut and Tokelauans were grateful to take advantage of the government-assisted migration program. By 1971, half of all Tokelauans were living on the mainland.
Between 1971 and 1982, there was a slight reduction in the number of gout cases on Tokelau. Meantime, there was a corresponding increase in gout for Tokelauan migrants to the New Zealand mainland. The mainland Tokelauan men developed gout at a rate nine times that of those who remained in Tokelau, while the rate of gout for mainlander migrant women increased by 2.7.
Gout is caused by excessive levels of uric acid in the blood, which crystallize and form in and around the joints, causing swelling, redness, inflammation, and excruciating pain. Diet is a crucial factor in the development of gout and foods rich in purines lead to an excess of uric acid in the blood. Purines are found in many healthy foods like beans, fish, and wheat germ.
But there are some rather unhealthy dietary culprits which can lead to elevated levels of uric acid in the blood. One such dietary miscreant is refined white sugar. Sucrose increases serum uric acid under controlled conditions and so does fructose, the sugar found in fruit, in comparison with starch. A comparable controlled experiment has never been performed substituting foods rich in purines.
It is notable to mention that Tokelauans tend to a disorder known as hereditary fructose intolerance. The islanders lack an enzyme necessary for metabolizing fructose. If they consume fructose they can become very ill. Some relatives of those with this condition are heterozygous for this mutation which means they have one mutated copy of the gene as well as one normal copy. They can still metabolize fructose but it takes longer than for someone who has two functional copies of the gene. It's also worth mentioning that they also have a much higher incidence of gout.
During the course of the 1971-1982 study, the Tokelauan migrants to New Zealand consumed a much larger amount of sugar than did the Tokelauans who remained on the island. Refined sugars made up 13% of the calories consumed by the mainland Tokelauans as compared with only 8% of the calories consumed by the islanders. One theory is that the inability to metabolize fructose may lead to a corresponding increase in uric acid production when sugar is consumed, which can lead to gout.