Algae and Algal Protein in Human Nutrition: A Narrative Review of Health Outcomes from Clinical Studies

As global interest in sustainable nutrition grows, algae have emerged as a promising functional food resource. This review analyzes the nutritional value of edible algae, with a particular focus on protein-rich microalgae, and synthesizes current clinical evidence regarding their health benefits. Algae have been demonstrated to provide a broad spectrum of physiologically active nutrients, encompassing a range of vitamins and minerals as well as polyunsaturated fatty acids, antioxidant molecules and various bioactive compounds including dietary fiber. These nutrients have been linked to improved cardiovascular and metabolic health, enhanced immune function, and anti-inflammatory effects. A particular emphasis is placed on algal proteins as a novel alternative to traditional dietary proteins. Genera such as <i>Spirulina</i> and <i>Chlorella</i> offer high-quality, complete proteins with amino acid profiles and digestibility scores comparable to those of animal and soy proteins, thereby supporting muscle maintenance and overall nutritional status. Recent clinical studies have demonstrated that the ingestion of microalgae can stimulate muscle protein synthesis and improve lipid profiles, blood pressure, and inflammation markers, indicating functional benefits beyond basic nutrition. Algal proteins also contain bioactive peptides with antioxidative properties that may contribute to positive outcomes. This review synthesizes current studies, which demonstrate that algae represent a potent, sustainable protein source capable of enhancing dietary quality and promoting health. The integration of algae-based products into plant-forward diets has the potential to contribute to global nutritional security and long-term public health. However, the available clinical evidence remains heterogeneous and is largely based on small, short-term intervention studies, with substantial variability in algae species, processing methods and dosages. Consequently, while the evidence suggests the possibility of functional effects, the strength of the evidence and its generalizability across populations remains limited.