New research suggests a diet that includes pure maple syrup may help to promote liver health.
Researchers from the University of Tokyo, led by Dr. Keiko Abe, fed laboratory rats a diet consisting of 20 per cent pure maple syrup, and compared their liver health to that of rats fed with a 20 per cent syrup mixture, with a similar sugar content.
The study, to be published in the November issue of the science journal Bioscience, Biotechnology and Biochemistry, found after 11 days on the maple sugar diet, the rats had "significantly decreased" amounts of specific liver enzymes, the levels of which are used to test liver damage.
Using nutrigenomics, the study of the effects of foods on gene expression, the researchers also found the maple syrup diet caused genes involved in the production of harmful ammonia in the liver to be less active.
However, as the study so far, has been carried out using only rats, the benefits of consuming maple syrup for humans is not yet understood, said Dr. Melissa Palmer, clinical professor of medicine and director of hepatology at New York University Plainview.
"Further studies need to be done in order to prove these results on humans before we can make any recommendations," said Palmer, a liver health specialist who was not involved in the study.
Palmer said the study confirms the role of lifestyle choices, such as poor diet, stress and lack of exercise, have on liver function.
"If maple syrup did turn out to be beneficial to the human liver, it would be beneficial for patients to choose a sweetener, such as maple syrup, as opposed to pure sugar, an artificial syrup or another type of sweetener," said Palmer.
Palmer said the health benefits of maple syrup for rats are likely a result of its antioxidant and anti-inflammatory properties, which are similar to benefits of phenols found in red wine and blueberries, and in the flavonoids found in grapefruits.
"We've seen this in other types of foods, but the amount you have to take and how beneficial it would be, we don't know yet," said Palmer.
The findings come after a recent study from scientists at the University of Rhode Island suggested maple syrup contains cancer-fighting antioxidant compounds that may also help in the management of Type 2 diabetes.
While the liver study does offer an interesting hypothesis, Dr. Eric Yoshida, chair of the medical advisory committee for the Canadian Liver Foundation, said the high sucrose content of maple syrup poses a greater health risk that could outweigh any potential benefits.
"Sucrose is table sugar . . . and sugar is bad for the liver, simply bad for the liver," said Yoshida, who is also a professor and the head of gastroenterology at the University of British Columbia. "It can cause an accumulation of fat within the liver cell, and later oxidation, which is bad."
The maple syrup used in the study is made up of 66 per cent sucrose, said Yoshida, and other research, including a 2010 study from Princeton University, has linked high fructose corn syrup, a type of sugar, with an increased risk of obesity.
As the study looked only at rats, Yoshida recommended further studies on humans be carried out before touting the health benefits of maple syrup.
"Maple syrup is commercially available, so the researchers could simply look at people who consume a lot of maple syrup and see what the prevalence of liver diseases in that group is compared to the rest of the population," he said. "I think there's a ways to go before they can say maple syrup (promotes liver health)."
As with anything diet-related, Yoshida said moderation is key.
A healthy and functioning liver is important for storing glycogen, regulating blood glucose, producing amino acids, and filtering harmful substances from the blood.
Although often believed to affect alcoholics, there are more than one hundred different forms of liver disease not related to excessive drinking.
According to the Canadian Liver Foundation, the most common form of liver disease in Canada is fatty liver disease.
The study was funded by the Conseil pour le developpement de l'agriculture du Quebec and Agriculture and Agri-Food, on behalf of the Canadian Maple Syrup Industry and the Federation of Quebec Maple Syrup Producers
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