The effect of common food preservatives on the heart rate of Daphnia magna

Monosodium glutamate (MSG), sodium nitrite, and sodium benzoate are used frequently in the food industry to enhance product flavors and preserve foods, as well as beverages, by preventing bacterial growth. As food additives are being consumed every day worldwide, any side effects of their consumption could have serious implications for human health and should be investigated. The purpose of our study was to examine the effects of MSG, sodium nitrite, and sodium benzoate on the heart rate of Daphnia magna, small freshwater crustaceans with hearts comparable to humans. MSG, sodium nitrite, and sodium benzoate have been linked to several health effects including alteration in heart rate. We hypothesized that MSG and sodium nitrite would increase the heart rate and sodium benzoate would decrease the heart rate of D. magna based on data from previous studies. Our results show that all three of the compounds had some measurable effect on the heart rate of D. magna, with benzoate showing the clearest effect. Sodium nitrite showed slightly increased heart rates as the concentration increased, while in the high concentration of sodium benzoate heart rates were significantly decreased. For MSG the effect was not as clear, and there appeared to be a drop in heart rate at a low concentration. The food industries may use these findings to guide the food additive concentrations in their products as well as to make consumers aware of the possible effects after consumption.