The metabolic syndrome is the cause of a worldwide epidemic consisting of: Obesity, poor tolerance to glucose, hyperinsulinemia, hyperuricemia (high serum uric acid,) hypertriglyceridemia, and hypertension, which are all risk factors for cardiovascular disease. The metabolic syndrome is seen in 27% of the population of the United States and the diagnosis of metabolic syndrome triples the person’s cardiovascular risk.
The last 25 years have shown a marked increase in fructose intake in the United States, frequently consumed as table sugar and high fructose corn syrup (HFCS). Table sugar contains 50% fructose and corn syrup contains 55% fructose. Soft drinks and fruit juices also commonly contain fructose.
The metabolic syndrome correlates with elevated serum uric acid levels and increased fructose intakes. The intake of fructose causes high blood levels of uric acid. However, glucose does not raise blood uric acid. High uric acid in the blood reduces the availability of nitric oxide in the body, which is necessary for normal circulation.
Insulin requires the presence of nitric oxide for glucose absorption. The authors propose to show that the above factors are the reason that fructose intake with hyperuricemia is an important cause of metabolic syndrome.
Four studies were done by the authors as follows:
1. Pair feeding studies. These studies showed that fructose caused the features of the metabolic syndrome and dextrose did not.
2. Fructose fed rats received xanthine oxidase inhibitors or medications to help uric acid elimination by the urine. The xanthine oxidase inhibitor and the medication to increase uric acid elimination were shown to prevent symptoms of metabolic syndrome. The xanthine oxidase blocker used was allopurinal.
3. The rats receiving 60% sucrose and the rats receiving 60% fructose did not vary in their dietary intake and weight gain. Only the fructose fed rats developed metabolic syndromes and sucrose does not result in an increase in uric acid. In humans, fructose can cause an increase in uric acid within 30 to 60 minutes.
4. Uric acid was shown to reduce the ability of blood vessels to dilate. The blood vessels did not dilate properly in response to acetylcholine. This was because nitric oxide was reduced by uric acid.
CONCLUSION: The results of the author’s studies show that fructose is the likely cause of the metabolic syndrome with obesity. The mechanism may be the fructose induced elevation of uric acid, which blocks insulin activity and alters circulatory activity. Lowering the uric acid with xanthine oxidase inhibitors reduces the severity of the metabolic syndrome, including obesity, hypertriglyceridemia, and diabetes.
NOTE: Flavonoids, black tea, astragulus, cocoa polyphenols, and white mulberry twigs have been been shown to have xanthine oxidase inhibitor activity.
Murugaiyah, V., et al, wrote an article about the ability of a plant, Phyllanths niruri (Stone Breaker,) to reduce uric acid blood levels (PMID: 16953466.)
To read the author’s abstract of the article click on the link to the author’s title of the article above.