3-5 Cups a Day: Why Moderate Coffee Is Linked to Benefits

Nutrients published a comprehensive review that collected decades of research on how coffee affects health and well-being. The authors come to a simple but important conclusion: moderate consumption - about 3-5 cups a day - is more often associated with benefits than harm, and this is true for decaffeinated coffee as well. Against this background, the FDA in the United States recently allowed coffee to be labeled as a “health product” if a standard serving contains less than 5 kcal - a rare case for a drink that many people drank “on a whim.”

Background of the study

Coffee is one of the most popular drinks on the planet and a key source of caffeine in the daily diet. Over the past decades, a huge number of studies and, at the same time, contradictory messages have accumulated around it: from “coffee is good for the heart and liver” to “coffee is harmful due to blood pressure, arrhythmia and cancer risks”. This “how to drink it right?” uncertainty became the reason for a new review work in Nutrients, which systematizes large cohorts and fresh clinical data to soberly assess the balance of benefits and possible risks with real, daily consumption.

The authors emphasize that the field has moved beyond narrow questions about caffeine. The focus is on dose ranges (how many cups a day carry the least risk), different types of drink (caffeinated vs. decaffeinated) and everyday additives (sugar, cream) that can change the effect. An important layer is the debunking of old fears: modern data do not confirm an increase in overall cancer risk, do not find a long-term increase in hypertension and do not show an increase in arrhythmia in coffee drinkers, while reasonable restrictions remain for certain groups (pregnancy, people with high anxiety and sleep disorders).

Another reason to reconsider the status quo is the plethora of potential benefit mechanisms beyond “alertness”: improved glucose control, slightly higher daily activity, increased fat oxidation during exercise, bronchodilator effects, and modest reductions in inflammatory markers. In parallel, aspects of well-being that go beyond disease are being discussed: hydration, cognitive clarity, physical performance, and even intestinal recovery after surgery. This broader context allows coffee to be viewed not as a black-and-white risk factor, but as a food habit with measurable dose-response and nuanced use.

Finally, the review outlines the agenda for the coming years: less debate at the opinion level and more randomized trials, Mendelian randomization, and detailed examination of “fine tuning” - from grinding and roasting to time of day and additives in the cup. Such a design will allow us to separate the effect of coffee itself from coffee “companions” and more accurately indicate when the usual “3-5 cups a day” really falls into the “green zone” for health, and when it does not.

What's New and Why Clinicians Need It

The novelty is not that “coffee is not so scary,” but in the scale and integrity of the picture: from general mortality to specific nosologies, from potential mechanisms to everyday details like sugar and cream. For the first time, key cohorts of millions of participants, fresh meta-analyses, and even the FDA’s decision on the “healthy” label are neatly summarized in one text. The result: doctors and nutritionists have a convenient reference point for practical advice – with clear dosages, exceptions, and “when it’s better not to.”

How much is the "sweet spot" in real numbers

The cups → risk of death association is nonlinear, with the lowest relative risk of all-cause mortality around 3.5 cups/day (RR ≈ 0.85). In multiple prospective cohorts in the US, Europe, and Asia, the lowest risk was most often in the range of 3–5 cups/day. This is consistent with the umbrella review of multiple outcomes: the greatest benefit was seen at 3–4 cups/day.

Where exactly is the benefit visible?

The picture is broad but consistent: coffee is associated with a lower risk of: cardiovascular events (both coronary heart disease and stroke), type 2 diabetes (approximately -29%, including decaffeinated coffee), chronic respiratory diseases, cognitive impairment, and Parkinson's disease. Separate blocks are devoted to the liver and kidneys: less fibrosis in NAFLD, lower risk of chronic kidney disease and acute kidney injury in those who drink ≥2 cups/day. Even "non-classical" outcomes such as injuries and falls in the elderly are less common in those who drink coffee.

A short "badge" of benefits from the review:

• Cardiovascular risk is minimal at ~3-5 cups/day (−≈15%).
• Type 2 diabetes: -29% risk; each additional "glass" - another ~-6%. Decaf also has an effect.
• Cognitive impairment: Lowest risk at ~2.5 cups/day.
• Respiratory outcomes: robust inverse associations in multiple large cohorts.
• Cancer: No evidence of carcinogenicity; lower risk of liver and endometrial cancer; WCRF includes coffee in the preventive pattern for colorectal cancer.

What were they afraid of - and in vain

Three "eternal" horror stories - cancer, hypertension and arrhythmia - look different in the current data. Coffee does not increase the overall risk of cancer, and in some localizations, on the contrary, is associated with a decrease in risk. Long-term increase in blood pressure in coffee drinkers is not visible, and in meta-analyses - even minus 7% risk of hypertension (short increases in blood pressure immediately after a cup is a different matter). In terms of arrhythmia, in a large cohort, the risk of hospitalization was lower in coffee drinkers; even an experiment with high doses of caffeine in high-risk patients did not cause arrhythmia.

Important caveats: who should be more careful and when

Pregnancy. Coffee is the main source of caffeine, and a conservative rule of thumb is no more than 200 mg of caffeine per day (≈ 1-2 cups), which is supported by ACOG and EFSA. Observational studies that find a link with low birth weight are highly confounded (smoking, alcohol, "pregnancy signal," memory differences). An RCT on 1,207 women found no difference in birth weight or height between caffeinated and decaf coffee. The authors' conclusion: no significant risks are seen below 200 mg/day, but the upper limit is best respected.

Mental health and sleep. On average, coffee is associated with a lower level of depressive symptoms, but high doses in vulnerable individuals (panic disorder) can be anxiogenic - "excess" of coffee and anxiety symptoms are similar: tachycardia, tremors, insomnia. The picture for sleep is expected: ~-36 minutes of total duration per day in crossover; meta-analysis recommends keeping a distance of 8.8-13 hours between the dose and going to bed.

Molecular "cuisine": why does it work at all

The authors identify five “human-proven” mechanisms: better glucose control, slightly more daily activity (in a crossover RCT - ≈+1000 steps/day on “coffee” days), higher fat oxidation during submaximal exercise, bronchodilation and support for lung function (similar to theophylline), less subclinical inflammation (lower CRP, sTNFRII, proinflammatory chemokines). This adds up to a clear physiology of “pluses”.

Details that really matter at home and in cafes

Not all additives are created equal. Black coffee and "low-sweet" varieties draw associations with health benefits, while sugar has been shown to offset benefits (weight, neurodegenerative outcomes) in some studies. Cream/cream substitutes have not consistently shown such associations. Decaf has similar effects, suggesting it's not all about the caffeine. Ground coffee is also in the "green zone." And finally, the FDA allows a "healthy" label - only if the serving is <5 kcal.

Hydration is not a myth. Despite caffeine's diuretic reputation, coffee is comparable to water in hydration at moderate doses and habitual consumption: no difference was found in total body water, 24-hour urine output, or "hydration index."

Sports and the intestines. According to sports science - from small to moderate ergogenic effects (individual variability is high). After laparoscopic operations on the colon, coffee speeds up the first stool and the first solid food - a trifle, but it is pleasant for hospitals and patients.

What to do in practice (and what to avoid)

• The goal is moderation: aim for 3-5 cups/day (or less if sensitivity is high).
• Sweeten thoughtfully: the less added sugar and saturated fat, the better the chances of a health “plus.”
• In the evening - carefully: keep a gap of 8-13 hours before sleep; monitor your own sensitivity.
• Pregnancy: Keep caffeine to ≤200 mg/day and discuss with your doctor.
• Do you have anxiety/arrhythmia? Start with small doses, monitor your well-being; there is no data on the increase in arrhythmia, but individual reactions do occur.

Where should science go?

Large cohorts have already "said their word," and the results are stable. Next up are randomized trials with strict protocols, Mendelian randomization, and a "microscope" for details: coffee types, roasting/grinding, dairy additives and sugar, time of day, genetics of caffeine metabolism. So far, even RCTs have shown curious behavioral effects like +1,000 steps and stability in safety, but there is still room for precise answers.

Source: Emadi RC, Kamangar F. Coffee's Impact on Health and Well-Being. Nutrients. 2025;17(15):2558. https://doi.org/10.3390/nu17152558