A lysosome-related organelle contained within the intestinal cells of the nematode C. elegans. Gut granules are acidified, birefringent, autofluorescent, and contain the vacuolar H+-ATPase. They also serve as sites of cellular zinc storage. [ http://www.ncbi.nlm.nih.gov/pubmed/22916203 http://www.ncbi.nlm.nih.gov/pubmed/24204312 ]