Health, caffeine and moderation

All questions in this silo, listed with their quick answer. Click for the full entry. — 27 questions.

• Which has more caffeine: Arabica or Robusta?

  Robusta (Coffea canephora) carries roughly twice as much caffeine as Arabica (Coffea arabica): about 2.2-2.7 % of the green bean's weight, versus 1.2-1.5 % for Arabica. Brew for brew and dose for dose

• What are cafestol and kahweol?

  Cafestol and kahweol are two lipid diterpenes naturally present in coffee bean oils. They are the only known dietary compounds that increase LDL cholesterol in a dose-dependent and measurable way. The

• What is caffeine's half-life?

  In a healthy adult, caffeine's half-life — the time the body needs to eliminate half the dose — averages 4 to 6 hours, with a median around 5 h. It varies a lot with genetics (CYP1A2), smoking (×0.5),

• What is chronobiology and what is the best time to drink coffee?

  Chronobiology is the science of circadian biological rhythms. Applied to coffee, it shows that caffeine consumption is most effective and best tolerated when synchronised with natural cortisol troughs

• Does coffee cause heart palpitations?

  Caffeine can mildly raise heart rate and, in sensitive individuals, produce a sensation of palpitations — often without an actual arrhythmia. Recent meta-analyses (JAMA Internal Medicine 2018, Europea

• Is coffee safe during pregnancy?

  Coffee is not banned but should be limited. The European Food Safety Authority (EFSA) and the World Health Organization (WHO) recommend no more than 200 mg of caffeine per day during pregnancy and bre

• Is coffee bad for your stomach?

  Coffee stimulates gastric acid secretion and slightly relaxes the lower oesophageal sphincter: in people prone to reflux or gastritis it can worsen symptoms. For everyone else, moderate intake (< 400

• Why does coffee make some people anxious?

  Coffee can trigger or worsen anxiety through several concurrent mechanisms: caffeine stimulates adrenaline and cortisol release, activates the sympathetic nervous system (stress response), and blocks

• What is the coffee and blood pressure paradox?

  The coffee-blood pressure paradox refers to the fact that caffeine transiently raises blood pressure in non-habitual drinkers (increase of 3 to 15 mmHg systolic within an hour of intake), yet regular

• How does coffee affect cognition?

  Coffee improves several short-term cognitive functions — alertness, reaction time, working memory and concentration — mainly through caffeine's adenosinergic antagonism. These effects are robust at mo

• What's the cutoff time for coffee before sleep?

  A simple rule of thumb: stop caffeinated coffee 6 to 8 hours before bedtime. If you sleep at 11 p.m., that means no more coffee after 3-5 p.m. Polysomnography studies (Drake et al., Journal of Clinica

• Does coffee affect gut microbiota?

  Yes, and the effects are broadly favourable according to recent studies. Coffee — particularly its polyphenols (chlorogenic acids) and soluble fibres — acts as a partial prebiotic by stimulating the g

• Can coffee interact with medications?

  Yes, coffee has several documented and clinically significant drug interactions. The most important concern thyroid medications (levothyroxine — reduced absorption if taken simultaneously), iron suppl

• What's the effect of coffee polyphenols on longevity?

  Coffee polyphenols — mainly chlorogenic acids — are among the most consumed antioxidants in the world in high coffee-drinking countries. Large-scale epidemiological studies suggest that regular coffee

• What's the link between coffee and sports performance?

  The caffeine in coffee is recognised by the World Anti-Doping Agency (WADA) as a legal and effective ergogenic aid. At a dose of 3 to 6 mg per kilogram of body weight — roughly 1 to 2 cups of filter c

• Can coffee help with weight loss?

  Coffee has a real but modest thermogenic effect: caffeine stimulates the sympathetic nervous system, temporarily increases basal metabolic rate by 3 to 11 %, and promotes lipolysis (fat burning). It c

• How many cups of coffee per day is safe?

  For a healthy adult, the European Food Safety Authority (EFSA) sets the daily ceiling at 400 mg of caffeine — roughly 4 to 5 espressos, 3 to 4 standard 200 ml filter cups, or 5 to 6 home brews. During

• What is CYP1A2 and why does it explain caffeine tolerance?

  The CYP1A2 gene encodes a liver enzyme — cytochrome P450 1A2 — that breaks down caffeine in the body. Depending on the inherited genetic variant, this enzyme works faster or slower: 'fast metabolisers

• Does decaf really contain zero caffeine?

  No: decaf coffee always contains a small residual amount of caffeine, typically 1 to 7 mg per cup depending on the process. EU regulation (Regulation 1169/2011 and Directive 1999/4/EC) requires decaf

• Is filter coffee safer than French press for cholesterol?

  Yes, very clearly. Paper filter coffee retains 97 to 99 % of cafestol and kahweol, the two diterpenes responsible for coffee-induced LDL-cholesterol increases. A person switching from 4 cups of French

• How much caffeine is in an espresso?

  A standard 30 ml espresso averages 60 to 80 mg of caffeine, with the USDA reference value around 63 mg. Specialty shots, pulled with a heavier 18-20 g dose, commonly land between 100 and 150 mg. That

• Is coffee addictive?

  Caffeine triggers tolerance and a mild withdrawal syndrome, but it does not meet the strict psychiatric criteria for addiction. The WHO lists 'caffeine withdrawal disorder' in ICD-11 and the American

• Is coffee good for your health?

  Most meta-analyses published since 2015 (BMJ, JAMA Internal Medicine, Harvard T.H. Chan School of Public Health) report that moderate intake — 3 to 5 cups per day, up to 400 mg caffeine — is associate

• How to quit coffee without withdrawal?

  The best-documented method is a progressive taper over 3-4 weeks: cutting caffeine by roughly 25 % each week, or gradually blending decaf into the cup, prevents about 80 % of the withdrawal symptoms (

• Racemic vs natural caffeine: what's the difference?

  Caffeine is an achiral molecule — it has no optical isomers and therefore does not exist in 'R' and 'S' forms like some other biological molecules. Consequently, the term 'racemic caffeine' is chemica

• What is caffeine?

  Caffeine is a naturally occurring alkaloid of the methylxanthine family, produced by coffee, tea, cacao, guarana and kola nut plants. It is the world's most consumed psychoactive substance: it blocks

• Why does coffee keep you awake?

  Caffeine, the active compound in coffee, blocks the brain's adenosine A1 and A2A receptors. Adenosine is the molecule that signals tiredness; by docking onto its receptors without activating them, caf

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