The number of people with gluten-related illnesses has been increasing and the available treatments include the introduction of a gluten-free diet. In the bakery industry, there are problems with gluten-free products, namely the important characteristics that this component gives to doughs and the low nutritional value they present. A disease that has also increased in recent years is diabetes mellitus, which is characterized by a lack of insulin and the effectiveness of its action (type 1 diabetes) or tissue insensitivity to the hormone (type 2 diabetes). In terms of treatments, there are several approaches: inhibition of digestive enzymes (α-amylase and α-glucosidase) or techniques based on mechanisms of action (stimulation of insulin production and release, insulin transport and decreased glucose absorption). Hyperglycemia is also associated with the production of reactive oxygen species, which leads to cell apoptosis. On the other hand, there was also an association with high levels of cholesterol in the body, which contributed to the development of other types of diseases. In this sense, macroalgae have been studied as a source of natural compounds and used as food supplements, due to their protein, amino acid and mineral content, and the anti-diabetic effect in controlling the glycemic index, oxidative stress and cholesterol have already been demonstrated. Seaweed emerges as a promising source of bioactive nutraceuticals for individuals with coeliac disease, diabetes, and hyperglycemia. The rising prevalence of gluten-related illnesses calls for effective treatments, and seaweed's potential in enhancing the nutritional value of gluten-free products is noteworthy. Additionally, its demonstrated anti-diabetic effects, including glycemic index control, oxidative stress reduction, and cholesterol management, make it a valuable dietary supplement. Further research is needed to explore the specific bioactivities of seaweed compounds and their mechanisms of action. Integrating seaweed-based nutraceuticals into diets could complement traditional treatments, offering potential health benefits to those with coeliac disease and diabetes.