In the Lab, Maple Syrup Helps Zap Superbugs

Maple syrup is more than just a prime pancake topper. It also helps kill bacterial pathogens, according to a recent paper in the journal Applied and Environmental Microbiology.

Nathalie Tufenkji and colleagues at Canada’s McGill University found that concentrated maple syrup made such microbial nasties as E. coli and Proteus mirabilis, a common cause of urinary tract infections, far more susceptible than usual to eradication with antibiotics.

In Tufenkji’s study, maple syrup both increased the permeability of the bacterial outer membrane–such that more killer antibiotic gets inside the bacterial cell –and inhibited the activity of the bacterial efflux pumps–those tiny transport proteins that bacteria ordinarily use to toss internalized antibiotics out. This double whammy means that disease-causing bacteria can be effectively destroyed with markedly lower doses of antibiotics.

While it’s not known yet whether the maple syrup effect works in humans–all the experiments done to date were performed in petri dishes–the medical implications are hopeful. Most importantly, lowering the dosage of antibiotics required for treating an infection also lowers the chance of generating antibiotic-resistant superbugs, an increasingly serious problem for the health care industry.

Superbugs are strains of bacteria that are unfazed by multiple types of antibiotics, and are therefore difficult or downright impossible to kill.  Examples include multidrug-resistant tuberculosis, now a health threat worldwide, and MRSA– (methicillin-resistant Staphylococcus aureus)bane of nursing homes and hospitals. These days, according to the U.S. Centers for Disease Control and Prevention, over two million people are infected with superbugs each year, and at least 23,000 people die.

Scientists agree that the recent influx of superbugs is largely our own fault, brought on by overuse and misuse of antibiotics. Bacteria will normally develop resistance to drugs–but how rapidly resistance develops and how widespread it becomes are promoted by drug overuse. Antibiotics fed to livestock–a total of 29 million pounds in 2009, according to the U.S. Food and Drug Administration–end up, largely intact, in the environment, where they boost resistance in bacteria in soil and water. And they will continue to rise (See As Appetite for Meat Grows, Farm Antibiotics Use Will Soar.)

Misuse of drugs by doctors and patients also plays a role. Antibiotics are not effective against viruses. They won’t cure colds or flu, for example, but people who insist on taking them anyway risk converting normal body bacteria to resistant varieties. Worse, resistance can be passed from bacterium to bacterium. Once a resistant trait pops up, it can spread faster than a fashion fad.

One approach to fending off superbugs is to develop new and more effective antibiotics–though researchers admit that it’s not easy keeping ahead of a mushrooming population of resistant bugs. Another is to use less antibiotic, and that only when needed.

Tufenkji’s concentrated maple syrup method just may–eventually–help us to cut back on our antibiotic use. Until more research comes down the pike, however, there’s no way of knowing how or even if this effect will translate to human beings.

In the meantime, nutritionists warn, it’s best to go easy on the maple syrup, scrumptious though it is. While it does contain some healthful minerals and cancer-combatting antioxidants, it’s about 67 percent sugar, and most of that is sucrose, the stuff of refined white sugar. Half a cup of maple syrup adds up to 420 calories. Which means, calorie for calorie, it’s a lousy source of nutrients compared to fresh fruits and vegetables.

On the other hand, maple syrup also contains about 300 different flavor components, which give it its uniquely delicious taste. There’s nothing better on waffles, pancakes, and French toast at the occasional, indulgent Sunday brunch.

For more on the history and the process of making maple syrup, see Tim Herd’s Maple Sugar: From Sap to Syrup.