The primary objective of this study is to evaluate the optimal formulation of a natural nutraceutical whose daily consumption at nutritional doses may confer benefits for cardiovascular health. This nutraceutical combines an omega-3 fatty acid (eicosapentaenoic acid, EPA) with hydroxytyrosol (a potent antioxidant found in olives and extra virgin olive oil). The study will allow to compare how and to what extent hydroxytyrosol is absorbed when co-administered the omega-3 fatty acid in capsules across three different formulations.

12 healthy male and female participants will consume various formulations corresponding to three nutraceuticals developed: hydroxytyrosol acetate (HT-Ac), hydroxytyrosol eicosapentanoate (HT-EPA), and hydroxytyrosol extract (Oleacore®) with EPA. One week prior to the intervention, participants will be instructed to refrain from consuming extra virgin olive oil or olives as the primary dietary sources of hydroxytyrosol (wash-out phase). Since three types of nutraceuticals will be evaluated, the study will take place over three separate days, with one week between each intervention.

On each intervention day, following an overnight fast, volunteers will randomly consume one of the nutraceuticals. A polyphenol-free diet will be provided during the 24 hours after the nutraceutical intake.

Blood samples will be collected right before the nutracetical intake at 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10 and 24 hours post-consumption. Urine samples will also be collected in 24-hour collection containers containing 0.5 g of ascorbic acid, at the following intervals: -2 to 0 hours (baseline), 0-3 hours, 3-6 hours, 6-10 hours, and 10-24 hours. All of these samples will be stored at -80ºC until analysis.

Inclusion Criteria:

• Age: 18 to 45 years old
• Body Mass Index (BMI): 18 to 25 kg/m²

Exclusion Criteria:

• Presence of chronic illnesses
• Currently undergoing pharmacological treatment
• Smoking
• Pregnancy
• Following a vegetarian or vegan diet