In this study healthy older adults are requested to consume 4 different high-protein nutritional supplements. Each subject will visit the site 4 times and at every visit they will consume 1 of the 4 products after which a series of blood samples will be taken. The blood samples will be analyzed for amino acid bioavailability in the blood up to 4 hours after consumption.

Inclusion Criteria:

• Age 65 years or older
• BMI between 21 and 30 kg/m2

Exclusion Criteria:

• Any condition that may interfere with the definition 'healthy elderly' according to the investigator's judgement.
• Any (history of) gastrointestinal disease that interferes with GI function (e.g. inflammatory bowel disease, gastroparesis, gastrectomy).
• Known allergy to milk and milk products.
• Known galactosaemia.
• Current or recent (within past three months) smoking.
• Known or suspected Diabetes Mellitus.
• Current infection or fever in the last 7 days at the discretion of the physician.
• Use of antibiotics within 3 weeks of study entry.
• Current use of corticosteroids or hormones.
• Current use of antacids or any medication influencing gastric acid production.
• Requirement for any nutritional support.
• Unplanned body weight loss > 5% in the past 3-6 months.
• Adherence to any specific diet (e.g. weight loss, vegetarian).
• Use of protein containing or amino acid containing nutritional supplements within one week of study entry.
• Alcohol or drug abuse.
• Investigator's uncertainty about the willingness or ability of the subject to comply with the protocol requirements.
• Participation in any other study with investigational products concomitantly or within 4 weeks of study entry.