Coffee is one of the most studied drinks in nutrition research. This page summarizes what some of the largest studies and reviews have found about coffee drinkers and long-term health, where the findings point the other way, and what official health sources caution. Almost all of this research is observational. It shows associations, and an association doesn't show that coffee caused the result. None of it is about any particular brand.
The Big Picture: An Umbrella Review in The BMJ
An umbrella review in The BMJ pulled together meta-analyses on coffee and many health outcomes (Poole et al., 2017). The authors reported that "coffee consumption was more often associated with benefit than harm for a range of health outcomes," with the largest relative risk reduction for several outcomes at three to four cups a day compared with none. For death from any cause, that comparison gave a relative risk of 0.83. Their conclusion: "Robust randomised controlled trials are needed to understand whether the observed associations are causal."
Coffee and Death From Any Cause
A meta-analysis in the European Journal of Epidemiology pooled 40 studies with 3,852,651 participants (Kim, Je and Giovannucci, 2019). The lowest relative risk of death from any cause was at about 3.5 cups a day (relative risk 0.85), and drinking more was not associated with a further drop. The association held regardless of age, overweight status, alcohol drinking, smoking status and the caffeine content of the coffee.
A UK Biobank analysis of 498,134 adults followed for about 10 years, published in JAMA Internal Medicine, found coffee drinking was inversely associated with death from any cause, including among people drinking 8 or more cups a day. Similar associations were seen for instant, ground and decaffeinated coffee, and the association held regardless of genetic differences in caffeine metabolism (Loftfield et al., 2018, via UK Biobank).
Specific Conditions
Heart disease and cancer
In the BMJ umbrella review, three to four cups a day compared with none was associated with lower cardiovascular mortality (relative risk 0.81), and high compared with low coffee intake was associated with an 18% lower risk of incident cancer (relative risk 0.82) (Poole et al., 2017).
Type 2 diabetes, Parkinson's disease and liver conditions
The same review reported that coffee consumption was consistently associated with a lower risk of type 2 diabetes and of Parkinson's disease, and listed liver conditions among the outcomes with lower risk (Poole et al., 2017).
Dementia
A 2026 JAMA study followed 131,821 people for up to 43 years, during which 11,033 developed dementia (Zhang et al., 2026). The highest quarter of caffeinated coffee intake was associated with a lower dementia rate than the lowest (hazard ratio 0.82, 95% CI 0.76 to 0.89). Decaffeinated coffee was not significantly associated with dementia risk.
The gut microbiome
A 2024 Nature Microbiology study of microbiome data from 54,198 people found coffee drinking was strongly and consistently linked to one gut bacterium, Lawsonibacter asaccharolyticus, and coffee stimulated its growth in lab experiments (Manghi et al., 2024). The study describes a link between coffee and a microbe, not a health outcome.
Where the Findings Point the Other Way
The BMJ umbrella review also found associations with harm. During pregnancy, high compared with low or no coffee intake was associated with low birth weight (odds ratio 1.31) and pregnancy loss (odds ratio 1.46). Coffee drinking was also associated with a higher risk of fracture in women, but not in men (Poole et al., 2017).
MedlinePlus, from the U.S. National Library of Medicine, notes that caffeine increases stomach acid, which can cause an upset stomach or heartburn, may interfere with calcium absorption and raises blood pressure (MedlinePlus).
What About Cold Brew Specifically?
Very little research looks at cold brew on its own. The large studies above asked people about coffee in general. One lab study in Scientific Reports compared cold brew and hot brew made from the same beans: their pH was comparable, and the hot brew had higher total titratable acidity and higher measured antioxidant activity (Rao and Fuller, 2018). That study measured the drinks in a lab. It didn't measure any health outcome in people.
Why Association Isn't Cause
- People who drink coffee differ in other ways. Income, diet, smoking and health status can all travel with coffee habits, and studies can only adjust for what they measure.
- Illness can change habits. People who feel unwell may drink less coffee, which can make coffee look protective.
- Trials are rare. Long-term randomized trials of coffee are hard to run, which is why the BMJ review called for them.
Official Cautions
FDA says up to 400mg a day is an amount not generally associated with negative effects for most healthy adults. The FDA advises people who are pregnant, trying to become pregnant or breastfeeding to talk with their health care provider about caffeine, and says drinks containing caffeine should be avoided for children under 2. MedlinePlus advises people with conditions such as sleep disorders, anxiety, GERD or ulcers, an irregular heart rhythm or high blood pressure, and people taking certain medicines, to check with their health care provider about caffeine (MedlinePlus). More official figures are in How Much Caffeine Is Too Much? What FDA and Research Say.
Frequently Asked Questions
What have large studies found about coffee and health?
A 2017 umbrella review in The BMJ found coffee consumption was more often associated with benefit than harm across many outcomes, with the largest relative risk reduction at three to four cups a day. These are observational associations, and the authors said randomized trials are needed to know whether they are causal.
Is coffee linked to living longer?
A 2019 meta-analysis of 40 studies and 3,852,651 participants found coffee drinking was associated with a lower risk of death from any cause, lowest at about 3.5 cups a day. Association doesn't show cause.
Are there any risks linked to coffee?
The BMJ review found coffee during pregnancy was associated with low birth weight and pregnancy loss, and coffee was associated with fracture risk in women. MedlinePlus notes that caffeine increases stomach acid and raises blood pressure.
Is cold brew different from hot coffee for health?
Large health studies haven't looked at cold brew separately. One 2018 lab study found cold and hot brew had comparable pH, while hot brew had higher titratable acidity and higher antioxidant activity. It didn't measure health outcomes.
This article is general information, not medical advice. Bare Brew is a coffee drink, not a treatment for any condition. Each 12 fl oz can has 320mg of caffeine. It's not recommended for children, people who are pregnant or nursing, or anyone sensitive to caffeine. If you take medication or have a health condition, talk to your doctor about caffeine.
