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

NCT02082418 | Completed

• 1 other identifier: 2014-0065
• Study Type: interventional
• Target: 59
• Locations: 1 country
• Sites: 1

Brief Summary

Aging modifies the metabolic pathway of the neurotransmitter serotonin by reducing the synthesis rate and increasing the breakdown rate of serotonin, possibly related to the observed enhanced sensitivity of the serotonergic pathway. Since serotonin plays a prominent role in neuropsychological functions such as anxiety, mood and memory, the enhanced sensitivity of the serotonergic pathway in aging can probably explain the fact that elderly are more vulnerable to develop cognitive deficits and depressive symptoms. Serotonin synthesis in brain is regulated by its precursor tryptophan (TRP). Because tryptophan is an essential amino acid, modifying the availability of tryptophan through dietary intake, can directly influence central serotonin metabolism and consequently affective and cognitive processes. The aim of this study is to test the hypothesis that an acute intake of whey protein with high levels of TRP such as alpha-lactalbumin can stabilize the metabolism of serotonin and subsequently enhance metabolic and cognitive functions in healthy older adults. The acute effects of this dietary protein will be investigated in subjects with mild cognitive impairment (MCI), or dementia, compared to control subjects in order to examine whether healthy older subject with MCI benefit more from the intake of alpha-lactalbumin and/or whey. The investigators will investigate if this meal can optimize serotonin metabolism by elevating plasma TRP levels and plasma TRP appearance and enhance splanchnic TRP extraction. In addition, the effects on mood and cognitive functions will be examined.

Conditions

Mild Cognitive Impairment

Keywords

Mild cognitive impairment; Protein digestion; Tryptophan digestion; Cognitive function; Mood; Muscle function; Alpha-lactalbumin

Outcome Measures

Primary Outcomes (1)

• Net whole-body protein synthesis

  Change in whole-body protein synthesis rate after intake of meal

  0, 15, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210 min post-meal

Secondary Outcomes (12)

• Citrulline rate of appearance

  Postabsorptive state during 2 hours

• Skeletal and respiratory muscle strength

  1 day

• Cognitive function and mood

  Postabsorptive state during 3 hours and change after feeding

• Protein digestion after feeding

  0, 15, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210 min post-meal

• Arginine turnover rate

  Postabsorptive state during 3 hours

Study Arms (3)

Healthy

EXPERIMENTAL

healthy control subjects

Dietary Supplement: Alpha-lactalbumin; Dietary Supplement: Whey; Dietary Supplement: Casein

MCI

EXPERIMENTAL

mild cognitive impariments

Dietary Supplement: Alpha-lactalbumin; Dietary Supplement: Whey; Dietary Supplement: Casein

Dementia

EXPERIMENTAL

established diagnosis of dementia

Dietary Supplement: Alpha-lactalbumin; Dietary Supplement: Whey; Dietary Supplement: Casein

Interventions

Alpha-lactalbumin DIETARY_SUPPLEMENT

Subjects will ingest the liquid meal containing alpha-lactalbumin and carbohydrates (0.6 g/kg FFM protein + 0.3 g/kg FFM carbohydrates).

Dementia; Healthy; MCI

Whey DIETARY_SUPPLEMENT

commercially available whey protein

Dementia; Healthy; MCI

Casein DIETARY_SUPPLEMENT

commercially available casein protein

Dementia; Healthy; MCI

Eligibility Criteria

• Age: 55 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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
• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Texas A&M University: lead

Study Sites (1)

Texas A&M University

College Station, Texas, 77843, United States

Location

Related Publications (2)

• Yu AK, Deutz NEP, Perez CN, DeWandel S, Ruebush LE, Engelen MPKJ. The acute effects of alpha-lactalbumin intake on tryptophan metabolites and mood in older adults with Mild Cognitive Impairment. Nutr Neurosci. 2025 Sep 14:1-15. doi: 10.1080/1028415X.2025.2554359. Online ahead of print.

  PMID: 40946231 DERIVED

• Deutz LN, Wierzchowska-McNew RA, Deutz NE, Engelen MP. Reduced plasma glycine concentration in healthy and chronically diseased older adults: a marker of visceral adiposity? Am J Clin Nutr. 2024 Jun;119(6):1455-1464. doi: 10.1016/j.ajcnut.2024.04.008. Epub 2024 Apr 12.

  PMID: 38616018 DERIVED

MeSH Terms

Conditions

Cognitive Dysfunction

Interventions

Lactalbumin; Whey; Caseins

Condition Hierarchy (Ancestors)

Cognition Disorders; Neurocognitive Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Albumins; Proteins; Amino Acids, Peptides, and Proteins; Whey Proteins; Milk Proteins; Animal Proteins, Dietary; Dietary Proteins; Milk; Beverages; Diet, Food, and Nutrition; Physiological Phenomena; Dairy Products; Food; Food and Beverages; Phosphoproteins

Study Officials

• Marielle P Engelen, PhD

  Texas A&M University

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: PhD

Study Record Dates

• First Submitted: March 6, 2014
• First Posted: March 10, 2014
• Study Start: April 2, 2014
• Primary Completion: December 1, 2016
• Study Completion: December 1, 2016
• Last Updated: September 30, 2025

Record last verified: 2025-09

Locations

US (1)