**Background:** The genus Prunus includes many economically important fruit species, but Prunus lusitanica L. (Portuguese laurel) remains underexploited. Despite being listed as 'least concern' globally, populations in mainland Portugal are classified as 'near threatened' and have declined approximately 40% in the last 15 years. To date, no comprehensive nutritional characterization of its fruits had been performed. This study aimed to evaluate the phyto-nutritional content of P. lusitanica fruits from three locations in northern Portugal over four consecutive years (2016–2019) and assess relationships with meteorological parameters.
**Methods:** Approximately 600 fully ripe fruits (purple color uniformity, early October) were collected annually from the same marked trees at three locations within the UTAD eco-campus botanical garden (Vila Real, Portugal). Whole fruits (pulp and stone) were freeze-dried, ground, and analyzed in triplicate. Nutritional parameters were determined following AOAC methods: dry matter and ash (method 942.05), total protein (method 954.01, Kjeldahl, N × 6.25), total fat (method 920.39, Soxtec), total dietary fiber (AOAC 985.29, enzymatic-gravimetric), and soluble sugars (anthrone method). Eighteen amino acids (9 essential, 9 non-essential) were quantified by HPLC-FLD after acid hydrolysis and AQC derivatization. Eight minerals (Ca, Cu, Fe, K, Mg, Mn, Na, Zn) were determined by FAES (Na, K) and FAAS (others) after HNO₃/H₂O₂ digestion. Meteorological data (monthly accumulated precipitation, maximum/minimum/mean temperature) were obtained from the E-OBS gridded dataset for Vila Real. Statistical analysis used ANOVA with Tukey's test (p < 0.05) and Pearson's correlation heatmaps.
**Key Results:** Energy value ranged from 120.79 to 194.73 kcal/100 g fw across years and locations. Moisture was the primary fraction (55.73–69.96 g/100 g fw). Protein ranged from 2.73 to 6.45 g/100 g fw, fat from 2.33 to 5.93 g/100 g fw, carbohydrates from 19.73 to 35.05 g/100 g fw, dietary fiber from 6.68 to 12.08 g/100 g fw, and soluble sugars from 13.32 to 21.56 g/100 g fw. Total amino acids varied from 2802.00 to 6948.93 mg/100 g fw. The most abundant essential amino acids were arginine (up to 1500.39 mg/100 g fw) and leucine (up to 216.13 mg/100 g fw); among non-essential, tyrosine (up to 1124.83 mg/100 g fw) and glutamic acid + glutamine (up to 1170.26 mg/100 g fw) predominated. In 2019, lysine reached 1323.38 mg/100 g fw, becoming the major essential amino acid. Potassium was the most abundant mineral (3.37–6.03 mg/100 g fw), followed by sodium (2.03–3.94 mg/100 g fw) and iron (0.98–2.35 mg/100 g fw). The year factor had a stronger influence than location on most parameters. Precipitation was significantly negatively correlated with most nutrients except moisture. Temperature showed variable effects: positive correlations with ash, soluble sugars, carbohydrates, and potassium; negative correlations with protein, several essential amino acids (His, Arg, Thr, Val, Lys), calcium, and magnesium.
**Clinical Implications:** P. lusitanica fruits are a rich source of protein, dietary fiber, essential amino acids, and minerals, in many cases surpassing commonly consumed Prunus species. The dietary fiber content (≥6.68 g/100 g fw) exceeds the 3 g/100 g threshold required for a 'source of fiber' claim under EC Regulation 1924/2006. The high protein content (up to 6.45 g/100 g fw) is notable for a fruit. These findings support the potential of P. lusitanica as a functional food ingredient and justify conservation and cultivation efforts. However, the strong influence of climatic variables on nutrient content—particularly the negative impact of precipitation on most nutrients—raises concerns about climate change effects on fruit quality. Further research on phytophysiology, bioactivity, toxicology, and pharmacology is needed before commercial applications can be realized.