Irish moss contains every mineral needed for human health, including respectable levels of calcium, iron, and potassium. Irish moss also contains appreciable levels of microminerals such as magnesium, manganese, and copper.  
Although it’s low in fat (about 3%), Irish moss is one of the few non-animal sources of polyunsaturated fatty acids, which promote good brain and cardiovascular health.  
The protein content of Irish moss varies between 12-20% and averages about 15%.  Irish moss protein is considered high quality because it contains every essential amino acid in digestible form. 
Irish moss contains about 300 micrograms iodine per gram, which is more than most other red seaweeds but less than most brown seaweeds.  Finally, Irish moss is a good source of fiber, and its unique polysaccharides benefit intestinal health.