Is it true that there is a large difference in calcium content between hulled and unhulled sesame seeds?
Yes, there is a major difference between the calcium content of hulled versus unhulled sesame seeds. When the hulls remain on the seeds, one tablespoon of sesame seeds will contains about 88 milligrams of calcium. When the hulls are removed, this same tablespoon will contain about 5-10 milligrams (about 90-95% less) ...
BUT
... This form of calcium is different than the form found in the kernels, and it is a much less absorbable form of calcium. So even though a person would be likely to get much more calcium from sesame seeds or sesame seed butter (tahini) that contained the hulls, there is a question about how much more calcium would actually be usable.
hmm my conclusion - we don't know yet ... which is actually better - much research needs to be done ... so remember to diversify ...