The impact of a minimally processed seaweed meal on the appearance of amino acids in the peripheral circulation in healthy adults: A pilot dietary intervention

BACKGROUND AND AIMS: Seaweed is a nutrient-dense, sustainable food source with the potential to support global protein needs. However, its complex structure may limit protein bioavailability. Although seaweed is traditionally consumed with minimal processing and may provide amino acids without extensive processing, the quantity needed for meaningful protein intake raises safety, tolerance, and acceptability concerns that remain unexamined in humans. This study aimed to evaluate the impact of a minimally processed seaweed meal (SWM) on postprandial plasma amino acids, micronutrient bioavailability, safety, gastrointestinal tolerance, and sensory acceptability. METHODS: In a single-blinded, randomized crossover trial, 20 healthy adults consumed SWM or a control meal (CON). Blood samples and questionnaires were collected over 4 h and urine samples over 24 h. RESULTS: Pooled plasma essential amino acids showed no statistically significant difference between meals (P > 0.6); however, the pilot sample size may have limited the ability to detect meaningful differences. Compared to CON, SWM reduced postprandial asparagine, glutamine, alanine, proline, and tyrosine. Glucose, insulin and triglyceride responses were similar between meals. Increases in serum iodine (P = 0.02), urinary iodine (P < 0.001), and urinary arsenic (P = 0.007) were observed following the SWM. Gastrointestinal symptoms, including distension and belching, were greater after SWM (treatment-time interaction P = 0.03 and < 0.001, respectively). Sensory evaluations indicated lower preference scores for the SWM compared to the CON for appearance and odour (both P = 0.03). CONCLUSION: SWM and CON had similar EAA bioavailability. SWM was associated with greater gastrointestinal symptoms and lower satiety scores. For minimally processed seaweed-based foods to substantially contribute to protein requirements, optimisation for protein bioavailability and gastrointestinal comfort is required. CLINICAL TRIAL REGISTRY: This trial was registered at https://www.anzctr.org.au/as ACTRN12624000335594.