Insufficient intake of dietary fibers in Western societies is considered a major contributing factor in the high incidence rates of diabetes. The dietary fiber pectin has been suggested to be beneficial for management of both Diabetes Type 1 and Type 2, but mechanisms and effects of pectin on insulin producing pancreatic beta-cells are unknown. Our study aimed to determine the effects of lemon pectins with different degree of methyl-esterification (DM) on beta-cells under oxidative (streptozotocin) and inflammatory (cytokine) stress and to elucidate the underlying rescuing mechanisms, including effects on galectin-3. We found that specific pectins had rescuing effects on toxin and cytokine induced stress on beta-cells but effects depended on the pectin concentration and DM value. Protection was more pronounced with low DM5 pectin and was enhanced with higher pectin-concentrations. Our findings show that specific pectins might prevent diabetes by making insulin producing beta-cells less susceptible for stress.