Irish Sea Moss, or Chondrus crispus, is often sold as a health food for “immune support”. Yet, there are no human studies that have been conducted to support this claim. Popular health websites such as WebMD and numerous blogs and supplement companies are making inappropriate and unsubstantiated claims about Irish sea moss. 

Here are the facts:

Sea moss has not been studied in any RTC for effects on the human immune system. WebMD incorrectly cited a study that was conducted on ROUNDWORMS (yes, microorganisms!) as evidence that sea moss is beneficial for human immune support. Obviously humans are much more complex than microorganisms and our immune systems do not function in the same manner, so this claim is baseless and inappropriate. (1)

Sea moss is also touted to be a “good source” of vitamins and minerals. Here’s the problem: the serving size of sea moss is 2 tablespoons, or about 10 grams. In those 2 tablespoons, you are receiving a FRACTION of your daily needs. In fact, according to the FDA, in order to claim a product provides a “good source” of any nutrient or micronutrient, the product must provide 10-19% of the RDI. So in order to suggest that sea moss is a “good source” of calcium, iodine, zinc, iron, potassium or magnesium, a serving would need to provide 10-19% of our daily needs. It’s actually very difficult to even determine the true nutritional value of sea moss because of how little it has actually been studied. According to USDA’s FoodData Central, a serving of sea moss provides 7.2mg of calcium, (nothing listed for iodine), 0.195mg zinc, 0.89mg of iron, 6.3mg of potassium, and 14.4mg of magnesium. (2) None of these would be considered a “good source” per serving.

Sea moss does provide iodine, although the iodine content greatly varies depending on the geographical origin and brand and there is limited literature to support the true iodine value of sea moss. One study suggested that a 4g serving of sea moss provides about 25mcg of iodine, which would be about 17% of the DRI for adults. Since a traditional serving of sea moss is 2.5x more than this, there is some concern about the risk for thyroid dysfunction, specifically in children, when consuming large amounts of sea moss. (3)

Bottom line: Sure, if you enjoy the funky taste and snotty texture of sea moss, feel free to add it to smoothies and recipes. Just understand that it’s not really providing any health benefits and hasn’t shown any benefits for the immune system.

References:

1. https://www.webmd.com/diet/health-benefits-sea-moss#1
2. https://fdc.nal.usda.gov/fdc-app.html#/food-details/168456/nutrients
3. Darias-Rosales, J., Rubio, C., Gutiérrez, Á. J., Paz, S., & Hardisson, A. (2020). Risk assessment of iodine intake from the consumption of red seaweeds (Palmaria palmata and Chondrus crispus). Environmental Science and Pollution Research, 27(36), 45737-45741.