The hulls of sesame seeds contain oxalates. In fact, most of the calcium found in the seed hull comes in the form of calcium oxalate. The sesame seed paste (tahini) found in grocery stores is most often made with seed kernels—the part of the sesame seed that remains after the hull has been removed. These products would generally be safe in moderate amounts on an oxalate-restricted diet. However, products containing the seed hulls might have more oxalates than desired on a low oxalate meal plan. Product labels do not always indicate whether the hulls have been removed or not. For this reason, check the color of the tahini carefully and also inquire as to its taste. Most sesame seed butters made from whole, non-hulled seeds are fairly dark in color and have a much more bitter taste than butters made from hulled sesame kernels.