Eyeworld

EW CORNEA September 2011 39 Research suggests fasting has some impact on tear proteins T he holy Islamic month of Ramadan makes significant nutritional demands on many Muslims, who ab- stain from eating and drinking from dawn to sunset dur- ing that period. Sustained fasting is believed to be a risk factor for certain diseases, including cardiovascular and gas- trointestinal ones, but could it also impact dry eye disease? Researchers recently investi- gated that possibility, and although there are no concrete answers, they found interesting changes in tear protein patterns in a fasting group, which warrants further investiga- tion. "In the present study, we found alterations in the protein content of tear film during one month fasting," reported Reyhaneh Sariri, Ph.D., biochemistry department, Faculty of Science, University of Guilan, Iran. Dr. Sariri's report was published in 2010, volume 53, number 3, in Acta Medica. Analyzing tear proteins Researchers decided to analyze the tear film in fasting participants be- cause certain bodily fluids were shown to be altered under short- term starvation conditions. "Since the biochemistry of some biological fluids (such as blood and urine) has shown slight alterations due to fasting, it is expected that an extended strict fasting may influ- ence tear quality," Dr. Sariri noted. Dr. Sariri and colleagues com- pared the tear protein content of 35 men and 25 women during their Ramadan fasting periods with their tear proteins 1 month previous to fasting. Specifically, a tear protein sample was collected on the 25th day of Ramadan on the 25th day of fasting. "Electrophoresis pattern of tear samples … indicate that some tear proteins are decreased in fasting state," Dr. Sariri reported. "However, total tear proteins showed an in- crease using Lawry protein assay." Meanwhile, a separate high-per- formance liquid chromatography analysis of tear samples found that most proteins were decreased in a fasting state. It appears, therefore, that fasting may induce some type of protein shift in the tear film. But could this shift indicate that fasting is a risk factor for dry eye disease? Researchers could not yet an- swer that question, but they did stress that tear protein makeup is an important factor in dry eye disease. "A significant difference in tear protein patterns between patients suffering from dry eye and healthy volunteers has [been] demonstrated by one-dimensional electrophoretic separation of tear proteins," Dr. Sariri reported. If tear proteins are a central fac- tor to the makeup of dry eye disease and a change in tear film protein oc- curs during fasting, then perhaps there could be some elevated risk for those fasting. However, at this point, any solid link between fasting and dry eye appears to be conjecture. Dr. Sariri is looking to the fu- ture, hopeful that an analysis of tear proteins could better manage dry eye disease patients. "It could be demonstrated that analysis of tear proteins, and the multivariate approach including all peaks in the analysis, can be helpful in dry-eye disease diagnosis or fol- low-up," Dr. Sariri reported. "How- ever, some problems remain before routine clinical use of these meth- ods. Reproducibility must be investi- gated in further studies, and variation of tear protein patterns even in the same subject must be considered." In the meantime, Dr. Sariri is certain about the link between fast- ing and other diseases. "There is no doubt about the influence of fasting on many systemic diseases and even on many eye diseases," Dr. Sariri noted. Although less is known about the impact of fasting on tears, more research is needed because of the im- portance of the tear film for diagnos- tic purposes. "Human tear film is an interest- ing and valuable body fluid in terms of diagnostic purposes," Dr. Sariri noted. "Despite its biochemical simi- larity to blood plasma, it is easily collectable with minimum trauma to the patient. A tiny drop of tear fluid could be used for diagnosis of cer- tain eye diseases and even systemic diseases." Bjorn Johansson, M.D., Linkoping University Hospital, Sweden, said he is not aware of any individuals who have fasted and re- sultantly developed eye problems. "A few people [I know] have gone through fasting for health-re- lated issues, but had no vision re- lated problems," Dr. Johansson said. Still, Dr. Johansson said that fasting does decrease the body's nu- tritional reserves, which could have some impact on health. "When you are fasting, you are taking from the body's energy reserves," he said. EW Editors' note: Dr. Sariri has no financial interests related to this study. Dr. Johansson has no financial interests related to his comments. Contact information Johansson: bjorn.johansson@lio.se Sariri: sariri@guilan.ac.ir by Matt Young EyeWorld Contributing Editor Could fasting cause dry eye?

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