The US Food and Drug Administration (FDA) announced Monday it plans to modernize its dietary supplement regulations with a focus on areas of unlawful claims, a move that has omega-3 pill producers nervous.

FDA Commissioner Scott Gottlieb announced Monday the administration already sent 12 warning letters and five online advisory letters to companies whose products, many of which are marketed as dietary supplements, are being illegally marketed as unapproved new drugs because the products bear unproven claims to prevent, treat or cure Alzheimer’s disease, as well as a number of other serious diseases and health conditions, including diabetes and cancer.