Today, we live in a competitive world that has led to a stressful lifestyle. Although mild stress increases work efficiency, long-term stress may lead to anxiety, fatigue, confusion, in addition to systemic inflammation and oxidative stress.
Chronic inflammation and oxidative stress accelerate aging. The profound effect of which can be seen in cognitive functions, especially memory and attention. Middle-aged individuals, particularly those susceptible to stress, may have steeper cognitive decline with advancing age.
Therefore, anti-inflammatory supplements are being developed to counter cognitive decline with improved brain function in middle-aged individuals.
ProBeptigen® (PB or previously known as CMI-168), a hydrolyzed chicken extract, is one such nutritional supplement researched for over 10 years. It is known for its anti-inflammatory properties and is specially developed for cognitive-enhancing effect.
Back in 2013, a pilot study was carried out by Azhar et al. on middle-aged healthy adults to see the effects of PB on cognition. The result showed an enhanced learning and memory in the subjects supplemented with PB for 6 weeks compared to the placebo group.
This promising outcome motivated the researchers to carry out a larger clinical trial recently which showed that subjects on PB supplementation of 670 mg per day had a significant improvement in spatial working memory (p = 0.045), short-term verbal memory (p = 0.015) and long-term verbal memory (p = 0.023), as well as the long-term gist memory (p = 0.014) compared to the placebo group at the end of 8 weeks of supplementation as well as during the 2-week follow-up after discontinuation of supplement. The subjects in both the clinical trials were between the ages 35 and 65.
In this clinical study, Wu et al. also measured several blood markers and brain electrical signals. And the most prominent result was the anti-inflammatory effect of PB in which a progressive decline in the inflammatory marker, high-sensitivity C-reactive protein (hs-CRP), was seen throughout the 8-week-supplementation (p = 0.042) and remained low in the two-week follow up as well, in contrast to the placebo group where the values remained the same as baseline throughout the study.
PB enhanced cognitive functions possibly by its anti-inflammatory and antioxidative effects, elevation in dopamine levels, and reduction of damage to mitochondrial DNA in the brain.
The anti-inflammatory effect of PB in humans by reduction of blood hs-CRP in the above clinical study is noteworthy. However, the cognitive-enhancing effect may have been a result of supplementation of specific amino acids and peptides found in PB, which warrants further investigation.
It is widely known that working memory capacity deteriorates with advancing age; the cognitive-enhancing effect of PB then becomes quite alluring for middle-aged and older adults. As the working memory declines with age, older adults mostly rely on gist-based memory. The superior beneficial effect of PB on gist memory is all the more appealing for PB to be used as a nutritional supplement for middle-aged individuals and elderly.
The daily supplementation of ProBeptigen® 670 mg for 2 months has been proposed to enhance cognition, especially short- and long-term verbal memory, spatial working memory, and gist memory in middle-aged healthy adults with perceived stress.
Additional information on different types of memory
Short term memory refers to the short term information required for a verbal or visual task (e.g. remembering a phone number, blending sounds into words when reading, remembering objects, colours, location, direction) (3).
Verbal memory primarily indicates acquisition or registration of memory for spoken materials (4).
Gist memory is memory for essential meaning, the “substance” of information irrespective of exact words, numbers, or pictures. Hence, gist is a symbolic, mental representation of the stimulus that captures meaning (5).
Spatial memory is one of the most important cognitive functions in daily life. It supports retrieval of the locations of objects and places in the environment (e.g. distinguish roads, places, or simply recognize an object in a certain environment) (6).
Working memory involves processing of small amount of information that is held in mind and can be used in the execution of cognitive tasks (e.g. remembering the question and all options while deciding on the correct answer, reverse sequences of objects/numbers) (7).
References:
- Wu D, Yang CC, Chen KY, Lin YC, Wu PJ, Hsieh PH, Nakao Y, Ow MYL, Hsieh YC, Hu CJ. Hydrolyzed Chicken Extract (ProBeptigen®) on Cognitive Function in Healthy Middle-Aged People: A Randomized Double-Blind Trial. Nutrients. 2020 May 10;12(5):1362
- Azhar ZM, Zubaidah JO, Norjan KO, Zhuang CY, Tsang F. A pilot placebo-controlled, double-blind, and randomized study on the cognition-enhancing benefits of a proprietary chicken meat ingredient in healthy subjects. Nutr J. 2013 Aug 15;12:121
- Cowan N. What are the differences between long-term, short-term, and working memory?. Prog Brain Res. 2008;169:323-338. doi:10.1016/S0079-6123(07)00020-9
- Tatsumi I.F., Watanabe M. (2009) Verbal Memory. In: Binder M.D., Hirokawa N., Windhorst U. (eds) Encyclopedia of Neuroscience. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-29678-2_6266
- Reyna VF. A new intuitionism: Meaning, memory, and development in Fuzzy-Trace Theory. Judgm Decis Mak. 2012;7(3):332-359
- Shrager Y, Bayley PJ, Bontempi B, Hopkins RO, Squire LR. Spatial memory and the human hippocampus. Proc Natl Acad Sci U S A. 2007;104(8):2961-2966
- Cowan N. Working Memory Underpins Cognitive Development, Learning, and Education. Educ Psychol Rev. 2014;26(2):197-223