Is what they claim about sea moss benefits true, or is this a trend that should stay in LA? What is sea moss? While sea moss does have fibre, Toledo points out that every plant-based food has fibre and there are plenty of foods that have way more of it than sea moss. If you look at the label of most sea moss supplements, the fibre content is often less than a gram. That doesn’t mean that sea moss doesn’t contain trace minerals—also called "microminerals" —that the body needs in very small amounts.