Effects of Lutein on Learning and Memory in Chronically Stressed Subjects and in an Acute Stressful Situation (TSST - Trier Social Stress Test): A Randomized, Double-blind, Placebo-controlled Trial)

The purpose of this study is to study effects of a four months lutein supplementation (in form of a lutein fortified nutritional beverage) on general learning and memory performance as well as on acute stress-induced changes in learning and memory performance in chronically stressed males and females using 2 different lutein doses in comparison to a placebo.


Eligibility Criteria:
Inclusion Criteria:

* Males and females aged 50 - 70 yrs
* Subjects perceiving themselves as chronically stressed and as verified by the TICS questionnaire with scores \> 18 and \< 48.
* Subject is willing to maintain his or her habitual diet and physical activity patterns throughout the study period
* Subject has a body mass index (BMI) of ≥ 18.50 and ≤ 32.00 kg/m2 at screening.
* Subject is willing to abstain from consuming alcoholic drinks 24 h and from consuming caffeine and caffeine containing products 12 h prior to test days until the end of each visit
* Subject is willing to refrain from heavy physical activity 12 h prior to test days
* Subject finds the taste of the nutritional drink acceptable and is willing to consume 2 drinks per day for the whole study duration
* Subject understands the study procedures and signs the informed consent to participate in the study

Exclusion Criteria:

* Subject has a positive drug screening of amphetamines, barbiturates, benzodiazepines, cannabis, cocaine, methamphetamines, methadone, opiates, phencyclidine or tricyclic antidepressants at screening or at any of the admission days
* Subject has a positive breath alcohol (as a test for alcohol consumption) or breath carbon monoxide (as test for smoking habits and to exclude smokers) at screening or at any of the admission days
* Subject has any health conditions that would prevent from fulfilling the study requirements, put the subject at risk or would confound the interpretation of the study results as judged by the Investigator on the basis of medical history and routine laboratory test results
* Subjects with a history of renal or hepatic disease that is likely to interfere with the metabolism or excretion of the test product
* Subject has donated more than 300 mL of blood during the last three months prior to screening
* Subject has uncontrolled hypertension (systolic blood pressure ≥160 mmHg or diastolic blood pressure ≥100 mm Hg) at screening
* Subject has a history of psychological illness or condition that interferes with the subject's ability to understand the requirements of the study
* Subject has Diabetes Mellitus
* Subject has a history/ presence of cancer during the last two years (excluding non-melanoma skin cancer)
* Excessive caffeine consumption (\>400 mg caffeine/d or ≥4 cups of caffeinated coffee/d), following screening and throughout the study period
* Use of antibiotics or signs of active systemic infections. Treatment visits might be rescheduled
* Subject is on any medication (with the exception of contraception and short-term use of pain treatment e.g. against headache (i.e. 1-2 day use of analgetics such as Paracetamol or ASS) as well as persistent (for at least three months) and well-adjusted medication (e.g. thyroid and blood pressure medication) with no influence on study outcome as judged by the investigator)
* Subject is currently on a regular oral nutrition solution such as Ensure®, Boost® or similar products. Regular is defined as one or more bottles/ cans per day average consumption over the last 10 or more days
* Subjects who are on a significant hypocaloric diet aiming for significant weight loss
* Use of dietary supplements containing any of the following: lutein, ginkgo biloba, St. John's wort, ginseng, gotu kola (Indian pennywort); daily doses of vitamin E (≥30 mg/d) or folic acid (≥400 μg/d); thiamine, riboflavin, and/or pyridoxine (≥2 mg/d); and eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) or a combination of EPA + DHA (≥500 mg/d) within 2 weeks prior to screening
* Subject is a vegetarian
* Subject has had exposure to any non-registered drug product within 30 days prior to the screening visit
* Recent history of (within 12 months of screening visit) or strong potential for alcohol or substance abuse. Alcohol abuse is defined as \> 60g (men)/ 40g (women) pure alcohol per day (1.5 l / 1 l beer resp. 0.75 l / 0.5 l wine)
* Subject has a known allergy or sensitivity to the study product or any ingredients of the study product or meals provided, especially against soy and milk protein
* Subject is pregnant, planning to be pregnant during the study period, lactating, or women of childbearing potential who are unwilling to commit to the use of a medically approved form of contraception throughout the study period. The method of contraception must be recorded in the source documentation
* Subject is unable to perform the tests on the CANTAB system during training as being flagged by the software