Effects of Caffeinated and Decaffeinated Coffee

by | Oct 28, 2019 | 2018, Brain Health, Caffeine

Written by Jessica Patella, ND. Study results suggest behavioral activity of coffee beyond its caffeine content, raising issues with the use of decaffeinated coffee as a placebo and highlighting the need for further research into its psychoactive effects.

caffeine - coffeeCoffee is one of the most readily consumed beverages in the world 1. Research has shown the correlation between drinking coffee and better performance on mental tests 2 and reducing the risk of multiple disease, including dementia 3, cardiovascular disease 4, type 2 diabetes 5 and inflammatory diseases such as rheumatoid arthritis, asthma, ulcerative colitis, and Crohn disease, type 1 and type 2 6.  This relationship has often been attributed to the caffeine component of coffee, however a recent study found it could be other components in coffee that result in behavioral effects 1.

Coffee contains more than 1000 different compounds all of which may have the possibility of effecting mood and behavior 1,7.  One of the challenges in understanding whether one of these other components affects behavior is that decaffeinated coffee is often used as the placebo in research studies with coffee1.   Therefore, the recent research included three groups to assess if one of the other compounds might be part of the behavior and cognitive improvements from drinking coffee.  The three groups included a caffeinated coffee group (regular coffee 100mg caffeine), a decaffeinated coffee group (about 5 mg caffeine), and a placebo group (water with 2.5g coffee flavoring).

The study included both young (20-34 years) and older (61-80 years) participants who regularly consumed coffee and tea (2 cups coffee or 3 cups tea daily). All drinks were given in an opaque thermal beaker (220mL) with a black opaque straw and participants were allowed 5 minutes for consuming the beverage 8. A total of 59 participants completed the study (13 young females, 16 young males, 16 old females, 14 old males). Saliva samples were taken before and after consumption to confirm caffeine absorption.  Participants completed various cognitive tasks at baseline and again after 30-minutes post-drink consumption.  The cognitive tasks included word presentation, immediate word recall, picture presentation, simple reaction time, digit vigilance, numeric working memory, verbal fluency and delayed word recall.  The entire group of tasks took approximately 25 minutes to complete. 1

How the participants felt subjectively was also measured at baseline and after drink consumption with the Caffeine Research Visual Analogue Scale which includes: relaxed, alert, jittery, tired, tense, headache, overall mood and mentally fatigued.  An additional test included a computer-based driving simulation to assess driving ability. In total, participants attended three study visits, separated by at least 7 days and they had to abstain from caffeine from noon the day before the study visits but not over 24-hours to minimize withdraw effects. 1

The results were as follows:

  • Regular coffee resulted in decreased reaction time (p=0.02) and increased alertness (p<0.0005) compared to placebo.
  • Regular coffee also resulted in increased digit vigilance accuracy (p=0.01), decreased tiredness (p=0.003) and decreased headache rating (p=0.0049) when compared to decaffeinated coffee.
  • Decaffeinated coffee increased alertness compared to placebo (p=0.0048).
  • Increased jittery ratings followed regular coffee in young females (p=0.046) and older males (p=0.045).
  • Overall mood was significantly higher following regular coffee compared to placebo (p=0.004).

As a point of discussion, the cognitive and mood effects of coffee typically occur 30-120 minutes after consumption 1,8. However, some research suggests that other constituents in coffee may not peak until 4 to 6-hours after consumption 1,9.  In conclusion, behavioral and cognitive effects of coffee were shown to be related to components of coffee beyond just caffeine.  Future research is required to determine the mechanisms and/or components that result in these behavioral and cognitive changes 1.

Source: Haskell-Ramsay, Crystal, Philippa Jackson, Joanne Forster, Fiona Dodd, Samantha Bowerbank, and David Kennedy. “The acute effects of caffeinated black coffee on cognition and mood in healthy young and older adults.” Nutrients 10, no. 10 (2018): 1386.

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Click here to read the full text study.

Posted October 28, 2019.

Jessica Patella, ND, is a naturopathic physician specializing in nutrition and homeopathic medicine and offers a holistic approach to health. She earned her ND from Southwest College of Naturopathic Medicine in Tempe, AZ, and is a member of the North Carolina Association of Naturopathic Physicians. Visit her website at www.awarenesswellness.com.

References:

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