Effects of Alpha-lactalbumin Intake on Metabolic and Cognitive Functions in Elderly

The study involves for all subjects 3 test days (approximately 8 hours each). On this test day the investigators will examine the acute effects of a protein meal. Subjects will receive a mixture of alpha-lactalbumin and/or whey and/or casein, carbohydrates and amino acid stable isotopes to investigate protein and amino acid kinetics (assigned to alpha-lactalbumin or whey or casein group on test day 1, then switch on test day 2 and 3). The subjects will receive these stable isotopes by infusion in their blood and by oral intake (e.g. simultaneously with protein meal). For study purposes, blood will be drawn approx. 25 times during 8 hours on the test day, altogether about 100-120 ml of blood will be drawn on the test day.

Inclusion criteria

subjects with dementia:

• Dementia diagnosis
• Ability to walk, sit down and stand up independently
• Age 55 years or older
• Ability to lie in supine or elevated position for 8 hours
• Willingness and ability to comply with the protocol, including:

Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study visit

Inclusion criteria

healthy subjects:

• Healthy male or female according to the investigator's or appointed staff's judgment
• Ability to walk, sit down and stand up independently
• Age 55 years or older
• Ability to lie in supine or elevated position for 8 hours
• Willingness and ability to comply with the protocol, including:

Adhering to fasting state from 10 pm ± 2h onwards the day prior to each study visit

Exclusion criteria

• Any condition that may interfere with the definition 'healthy subject' according to the investigator's judgment (for healthy control group only)
• Failure to give informed consent or Investigator's uncertainty about the willingness or ability of the subject to comply with the protocol requirements
• Indication of severe cognitive impairment (MOCA score < 17)
• Established diagnosis of Insulin Dependent Diabetes Mellitus
• History of untreated metabolic disease(s) including hepatic or renal disorder
• Presence of acute illness or metabolically unstable chronic illness
• Presence of fever within the last 3 days
• Preplanned surgery of procedures that would interfere with the conduct of the study
• Any other condition according to the PI or study physician that would interfere with proper conduct of the study / safety of the patient
• Current alcohol or drug abuse
• Known allergy to milk or milk products
• Use of long-term oral corticosteroids or short course of oral corticosteroids 4 weeks preceding first test day
• Use of protein or amino acid containing nutritional supplements within 5 days of test day
• (Possible) pregnancy
• BMI of < 18.5 or ≥ 40 kg/m2
• Dietary or lifestyle characteristics: When during the period from enrollment to completion of the study (end of test day) any condition is developed, whether causing the subject to not meet inclusion criteria or to meet exclusion criteria, the subject will be excluded from the study