Coffee and Caffeine

  • Food & Drink
  • Updated June 17, 2016

Caffeine, a natural component of coffee and tea, is the most commonly consumed psychoactive substance in the world. It has well-documented effects on mental alertness. Caffeine, and possibly coffee, might promote long-term brain health, but the evidence is inconclusive. It is particularly unclear whether an elderly individual who increases coffee consumption later in life will benefit or be harmed.


Several meta-analyses and systematic reviews exist, though no clinical trials have studied the effects of caffeine on brain health or dementia prevention [1][2]. Our search identified:

• Multiple meta-analyses and systematic reviews of observational studies
• 0 randomized controlled trials on whether caffeine or coffee can reduce risk of dementia
• Multiple observational studies
• Multiple preclinical studies [3]

Potential Benefit

Evidence suggests that caffeine has cognitive benefits, including alertness and attention [4-6]. Human studies on whether long-term use of coffee or caffeine can reduce risk of cognitive decline or Alzheimer's disease are inconclusive. Meta-analyses and systematic reviews of observational studies report that drinking coffee can either provide a long-term benefit to brain health or have no effect [1][2][7][8][9]. These observational studies have a number of issues that result in inconsistencies. For instance, it is unknown whether people who drink coffee share other aspects of health and lifestyle that might be responsible for better brain health. In addition, coffee and caffeine consumption are rarely measured in the same way between studies.

Even if long-term coffee intake does promote brain health, it is unclear whether elderly people might reduce their risk of Alzheimer's if they start drinking coffee later in life. In one study, cognitively normal elderly people who increased their consumption of caffeine were at a greater risk of developing mild cognitive impairment (MCI) [10]. The acute cognitive benefits from coffee may also decrease with age, eventually causing cognitive deficits [11]. However, in another study, individuals with MCI were less likely to progress to dementia if they had higher caffeine levels in their blood [12].

APOE4 Carriers:

The results to-date on caffeine and APOE4 status are inconsistent [9]. For more information on what the APOE4 gene allele means for your health, read our APOE4 information page.

For Dementia Patients

Few studies have examined whether coffee or caffeine is beneficial to patients with dementia. One study reported that caffeine consumption in elderly patients with dementia improved some physical symptoms and apathy, but it interrupted sleep when consumed after 6 pm [13]. Another study reported that individuals with mild cognitive impairment (MCI) were much less likely to progress to dementia if they had higher caffeine levels in their blood [12]. These studies, however, did not directly assess whether caffeine promotes brain health in individuals with MCI or dementia. In addition, people with dementia often suffer sleeping problems and are sometimes taken off caffeine for this reason. If caffeine impairs sleep, it could also impair cognitive function or even accelerate cognitive decline.


Moderate coffee and caffeine intake (200–300 mg/day or 1–3 cups of coffee) is generally considered safe [14]. At high doses, however, it may cause anxiety [4][5][6]. Caffeine may decrease performance in some elderly individuals [11]. People with a history of cardiovascular or high blood pressure problems should consult their physician or healthcare provider about consuming caffeine. Caffeine can also interact in dangerous ways with some medications and reduce the effects of others. The U.K. Food Standards Agency recommends pregnant women not consume more than 200 mg of caffeine per day.

NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.

How to Use

Coffee is the primary source of dietary caffeine and most human observational research on caffeine's benefits are based on coffee. Generally, one cup of coffee contains 95–200 mg caffeine while one cup of tea contains about 14–70 mg [15]. The caffeine content of sodas and energy drinks can range from 25–60 mg and higher per 12 oz. can, although the sugar content of such beverages may promote obesity and diabetes, which are risk factors for dementia. Additionally, caffeine is available as a dietary supplement in pill form, often in doses of 100–200 mg. For protection against cognitive decline and dementia, there is no evidence for or against caffeine supplements or energy drinks, though adverse health effects have been reported for some energy drinks.

Learn More

Additional information on caffeine doses in common drinks can be found at the Mayo Clinic.

More information on the health effects of coffee can be found at the Institute for Scientific Information on Coffee.

The Center for Science in the Public Interest provides information on caffeine levels in different foods and drinks.

Check for drug-drug and drug-supplement interactions on Drugs.com.


  1. Beydoun MA, Beydoun HA, Gamaldo AA et al. (2014) Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis. BMC Public Health 14, 643
  2. Wu L, Sun D, He Y (2016) Coffee intake and the incident risk of cognitive disorders: A dose-response meta-analysis of nine prospective cohort studies. Clinical nutrition.
  3. Carman AJ, Dacks PA, Lane RF et al. (2014) Current evidence for the use of coffee and caffeine to prevent age-related cognitive decline and Alzheimer's disease. J Nutr Health Aging 18, 383-392
  4. Baker LB, Nuccio RP, Jeukendrup AE (2014) Acute effects of dietary constituents on motor skill and cognitive performance in athletes. Nutrition reviews 72, 790-802.
  5. Einother SJ, Giesbrecht T (2013) Caffeine as an attention enhancer: reviewing existing assumptions. Psychopharmacology 225, 251-274.
  6. Cappelletti S, Piacentino D, Sani G et al. (2015) Caffeine: cognitive and physical performance enhancer or psychoactive drug? Current neuropharmacology 13, 71-88.
  7. Kim YS, Kwak SM, Myung SK (2015) Caffeine intake from coffee or tea and cognitive disorders: a meta-analysis of observational studies. Neuroepidemiology 44, 51-63.
  8. Xu W, Tan L, Wang HF et al. (2015) Meta-analysis of modifiable risk factors for Alzheimer's disease. Journal of neurology, neurosurgery, and psychiatry 86, 1299-1306.
  9. Panza F, Solfrizzi V, Barulli MR et al. (2015) Coffee, tea, and caffeine consumption and prevention of late-life cognitive decline and dementia: a systematic review. J Nutr Health Aging 19, 313-328.
  10. Solfrizzi V, Panza F, Imbimbo BP et al. (2015) Coffee Consumption Habits and the Risk of Mild Cognitive Impairment: The Italian Longitudinal Study on Aging. Journal of Alzheimer's disease : JAD 47, 889-899.
  11. Walters ER, Lesk VE (2016) The Effect of Prior Caffeine Consumption on Neuropsychological Test Performance: A Placebo-Controlled Study. Dementia and geriatric cognitive disorders 41, 146-151
  12. Cao C, Loewenstein DA, Lin X et al. (2012) High Blood caffeine levels in MCI linked to lack of progression to dementia. Journal of Alzheimer's disease : JAD 30, 559-572.
  13. Kromhout MA, Jongerling J, Achterberg WP (2014) Relation between caffeine and behavioral symptoms in elderly patients with dementia: an observational study. J Nutr Health Aging 18, 407-410
  14. Crippa A, Discacciati A, Larsson SC et al. (2014) Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis. American journal of epidemiology 180, 763-775.
  15. Caffeine content for coffee, tea, soda and more [Internet]. Mayo Clinic. [cited 2016Sep20].