Topic
Caffeine & Health
Plain-English summaries of caffeine and coffee health research: how much caffeine is in coffee, safe daily amounts, sleep, blood pressure, digestion, and more — with citations to primary sources.
Articles
42 published
Articles in Caffeine & Health
- 01
Why Do Plants Make Caffeine? The Evolutionary Biology
The evolutionary reasons plants produce caffeine — insect defense, allelopathy, and pollinator manipulation — and why caffeine evolved independently four times.
- 02
Coffee and Parkinson's Disease: What the Research Shows
The evidence linking coffee and caffeine to reduced Parkinson's disease risk — the JAMA 2000 study, A2A receptor mechanism, and why decaf shows no effect.
- 03
Does Coffee Raise Blood Sugar?
Whether coffee raises blood sugar: caffeine's acute effect on insulin sensitivity and glucose, what the research shows for healthy adults and people with
- 04
Coffee and Weight Loss: What the Research Actually Shows
The evidence behind coffee and weight loss — thermogenic effect, fat oxidation, chlorogenic acid research, what the randomised trials show
- 05
Caffeine and Dopamine: Why Coffee Feels Rewarding
How caffeine indirectly boosts dopamine through adenosine receptor interactions, why this makes coffee feel rewarding
- 06
Best Time to Drink Coffee: What the Science Actually Says
When to drink coffee based on caffeine half-life, sleep timing research, adenosine rebound, and pre-workout evidence
- 07
Does Coffee Cause Constipation?
Coffee's paradoxical constipation effect: why the same drink that stimulates bowel movement in most people can cause constipation in others.
- 08
Does Coffee Cause Bloating? Gut Effects Explained
Why coffee can cause bloating: gas from colon stimulation, lactose in milk drinks, sugar alcohols in sweeteners, and gut motility effects
- 09
Coffee and Vyvanse (and Other ADHD Medications)
How coffee interacts with Vyvanse, Adderall, and other ADHD stimulants: overlapping mechanisms, cardiovascular considerations, timing
- 10
Coffee and Iron Absorption: How Much Does It Block?
How coffee blocks iron absorption: the polyphenols responsible, how much iron absorption drops, when it matters
- 11
Coffee Addiction: Are You Actually Addicted?
What coffee 'addiction' really means: physical dependence vs behavioural addiction, how caffeine differs from addictive drugs
- 12
Is Coffee Healthy? What Large Studies Actually Show
Is coffee healthy? What decades of large cohort studies and systematic reviews actually show — the benefits, the risks, and what the evidence supports.
- 13
How Much Caffeine Is Too Much?
Safe daily and single-dose caffeine limits, when caffeine becomes dangerous, how tolerance shifts the threshold, and what the FDA and Health Canada recommend.
- 14
How Caffeine Works: The Adenosine Mechanism
How caffeine actually wakes you up: the adenosine receptor mechanism explained, why tolerance develops, how genetics change your response
- 15
Does Coffee Make You Poop? The Science Behind It
Coffee and the gastrocolic reflex: what controlled studies actually show about coffee's laxative effect, why decaf works too, and who's most sensitive.
- 16
Does Coffee Dehydrate You? What Studies Show
Does coffee dehydrate you? What controlled studies actually show — the myth vs the real, small diuretic effect, and what a typical intake means in practice.
- 17
Does Coffee Break a Fast? Black Coffee and Fasting Rules
Does coffee break a fast? Black coffee vs coffee with milk or sugar, what research shows about caffeine's effect on insulin and autophagy
- 18
Coffee Withdrawal Symptoms: Headaches, Timeline, Relief
What caffeine withdrawal actually feels like, how long it lasts, why headache is the most common symptom, and how to quit or cut back without the crash.
- 19
Coffee on an Empty Stomach: Is It Bad for You?
Coffee on an empty stomach — what actually happens physiologically, why some people feel nauseous and others fine, and what the research shows about cortisol.
- 20
Coffee Before a Workout: Timing, Dose, and Performance
Caffeine as a pre-workout: what the ISSN position stand says about dose, timing, and effect size across endurance, strength, and high-intensity exercise.
- 21
Coffee Antioxidants: What the Research Shows
The antioxidant compounds in coffee — chlorogenic acids, melanoidins, and caffeic acid — what they are, what research shows about their effects.
- 22
Coffee and Pregnancy: Safe Limits and What Research Shows
Coffee during pregnancy: Health Canada's 200 mg daily limit, what studies show about fetal growth, and the evidence behind pregnancy caffeine guidelines.
- 23
Coffee and Liver Health: What Cohort Studies Show
Coffee and liver health: what large cohort studies show about fibrosis, cirrhosis, and hepatocellular carcinoma risk — and whether decaf shows the same effects.
- 24
Is Coffee Bad for Your Kidneys?
Is coffee bad for your kidneys? What large cohort studies actually show about coffee and chronic kidney disease, kidney stones, and hydration.
- 25
Does Coffee Cause Inflammation?
Coffee and inflammation: what large C-reactive protein studies show, why coffee's polyphenols matter, and where the 'inflammatory coffee' myth comes from.
- 26
Coffee and the Gut Microbiome: What Research Shows
What research shows about coffee's effect on gut bacteria — including the discovery of a coffee-linked bacterial species and what habitual drinking does
- 27
Coffee and Gout: Does Caffeine Affect Uric Acid?
Coffee, uric acid, and gout: what the Health Professionals Follow-Up Study and Nurses' Health Study show, why decaf works too, and the acute-flare caveat.
- 28
Coffee and Diabetes: What Studies Show About Risk
Coffee and type 2 diabetes: what large cohort studies show, why decaf shares much of the benefit, and how add-ins can reverse the effect entirely.
- 29
Coffee and Cortisol: When to Drink for Your Hormones
Coffee and cortisol: what controlled research shows about the stress hormone response to caffeine, why tolerance matters, and the best time to drink.
- 30
Coffee and Cholesterol: Cafestol, Diterpenes, and Risk
Coffee and LDL cholesterol: why cafestol and kahweol in unfiltered coffee raise blood lipids, what filter methods remove, and what the meta-analyses show.
- 31
Coffee and ADHD: What the Research Actually Shows
Caffeine, coffee, and ADHD: why the 'paradoxical calming' has a real mechanism, what systematic reviews of caffeine in ADHD show
- 32
Coffee and Acid Reflux: What Actually Causes It
Coffee and acid reflux: what the research shows, why some drinkers react more than others, and what actually reduces symptoms — roast, timing, and acids.
- 33
Caffeine Tolerance: How It Builds and How to Reset It
Why the same coffee stops feeling like it works: adenosine receptor upregulation, which caffeine effects tolerate faster, and how to reset tolerance.
- 34
Caffeine Headache: Why Coffee Both Causes and Cures Them
The two-way relationship between caffeine and headaches: why acute caffeine can relieve headaches, why withdrawal causes them
- 35
Caffeine Half-Life: How Long Caffeine Stays in Your Body
Caffeine half-life, plainly: what it is, why individual metabolism varies so much, how to estimate how much caffeine is still in your system
- 36
The Caffeine Crash: What It Is and Why It Happens
Why energy dips after caffeine wears off: the adenosine rebound mechanism, the blood sugar contribution, and what may help reduce the crash.
- 37
The Caffeine Chemical Structure
What caffeine actually is at the molecular level: a purine alkaloid in the methylxanthine class, its structure, plant biosynthesis
- 38
Black Coffee Benefits: What Large Studies Actually Show
Evidence-based benefits of drinking black coffee: what large cohort studies show about metabolic, cognitive, and cardiovascular effects
- 39
How Much Caffeine Is in Coffee?
How much caffeine is in a cup of coffee? Typical amounts for brewed, espresso, instant, decaf, and cold brew — and what actually changes the number.
- 40
Coffee and Sleep: What Research Shows
How caffeine affects sleep — dose, timing, the six-hour rule, tolerance, and why the same afternoon coffee can leave one person wired and another asleep.
- 41
Coffee and Blood Pressure: What the Research Shows
Does coffee raise blood pressure long term? What the research shows about acute vs sustained effects, individual sensitivity, and who should be cautious.
- 42
Coffee and Anxiety: What the Research Shows
How caffeine affects anxiety — dose thresholds, genetic sensitivity, when a cup crosses the line from stimulating to unsettling, and who is most at risk.