- Coffee, after water, is the most widely consumed beverage in the United States, and is the principal source of caffeine intake among adults.
- According to the latest National Coffee Drinking Study from the National Coffee Association, approximately 64% of American adults drink coffee each day, and among coffee drinkers, the average coffee consumption in the United States is 3 cups per day.
- Moderate coffee consumption can lower the risk of death and cardiovascular risk.
Any possible health benefits of coffee must be weighed against the potential risks, which are mostly related to its high caffeine content including anxiety, insomnia, jitters, and palpitations. There are reports that high coffee intake (4 or more cups daily) in some post-menopausal women versus a low intake (less than 1 cup daily) was associated with a lower bone density (2-4%) with only a slight for osteoporosis but no increased risk of fracture. In general the medical evidence is reassuring that habitual coffee consumption is associated with no harm. Overall health benefits with drinking up to 3-4 cups per day include: lower risk of heart disease and cardiac related death rates, lower risk of diabetes, and asthma and reports of benefits for those with Parkinson’s and Alzheimer’s.
Lower heart disease risk
Some large population studies suggest that regular coffee drinkers have reduced risks of death from cardiac diseases as well as a lower all-cause mortality rate — that is, a lower chance of dying from any cause! A 2014 meta-analysis (an analysis of thirty-six studies) that included more than one million participants showed a positive association between coffee consumption and lower cardiovascular disease risk including less heart attack, stroke and heart failure risk with 3-5 cups per day. In addition, another large study of about 25,000 coffee drinkers (average age 41 years) reported in Heart, 2015, that 3-5 cups of coffee daily were 41% less likely to have coronary calcium — an indicator of early coronary atherosclerosis or hardening of the arteries. Coronary calcium is an important marker of heart attack risk. Coronary artery disease affects nearly 16 million Americans and is a major cause of death in the United States. However, at more than 28 cups per week some caution especially for younger coffee lovers. Reports of higher cholesterol levels of about 6% related to how coffee is prepared and how many cups are consumed. For people who use a French press or percolator to make their coffee or who prefer espresso or other varieties of unfiltered coffee a small increases in LDL-cholesterol have been reported in very heavy drinkers (5 or more cups) likely related to oils called terpenes (cafestrol) that typically are removed by the paper filter.
Too much coffee?
Based on a Cooper Clinic Study (Mayo Clin Proc. October 2013;88:1066-1074) there may be some reason for caution for those with the most heavy coffee consumption. A positive association between heavy coffee consumption (more than 28 cups per week) and all-cause death rate was found for younger coffee drinkers, less than 55 years. It may be appropriate to recommend that younger people less than 55 years avoid heavy coffee consumption (4 or more cups in a typical day or greater than 28 cups per week).
Caffeine and heart arrhythmia?
Coffee is our largest source for caffeine and a new study suggests coffee may not be as big a concern for a common heart rhythm disorder called atrial fibrillation (AF). Atrial fibrillation, the most common “electrical disturbance” of the heart, affects more than 2.5 million American adults and is projected to increase with the growing population of baby boomers. The condition can have a significant negative impact on an individual’s quality of life, with a five-fold increased risk of stroke. New information about the surprising lack of an AF risk with increased coffee consumption was an important reassuring observation.
- A collection of multiple studies (or meta-analysis) that included more than 228,465 participants is the most recent authoritative study about the effects of increased coffee consumption and atrial fibrillation risk. The study reported by Cheng in the January, 2014 Canadian Journal of Cardiology showed that habitual caffeine consumption actually offers moderate protection against AF. The researchers found that the higher the amount of caffeine consumed and the lower the AF episodes. This new study now builds on 2 prior studies (about 300,000 subjects studied) and dispels the common notion that coffee and caffeine can cause AF.
- In the Women’s Health Study (WHS) a 14-year follow-up of more than 30,000 middle-aged women initially without heart disease or other serious health issues, found that AF was no more common at any level of caffeine intake than it was at the lowest level.
- The Danish Diet, Cancer, and Health Study, a 2005 analysis based on about 48,000 people whose caffeine intake was markedly higher than that of the WHS participants demonstrated that increased caffeine consumption was also not associated with an increased risk of atrial fibrillation. (Frost, L et al. Caffeine and risk of atrial fibrillation or flutter: the Danish Diet, Cancer, and Health Study Am J Clin Nutr 2005;81:578 – 82).
A study of more than 1 million participants followed for as long as 20 years, showed good news on the risk of diabetes. The risk of type 2 diabetes was progressively lower with increased consumption of coffee, regardless of whether non-caffeinated or not. This new report studied a collection of studies (meta-analysis of 28 studies), with more than 1 million participants followed for as long as 20 years, and compared coffee drinker with those with no coffee consumption (caffeinated or no-caffeinated).
- The relative risk for type 2 diabetes with coffee consumption, compared with no or rare consumption, ranged from 8% lower risk of type 2 diabetes for 1 cup per day, 15% lower for 2 cups, and 25% lower for 4 cups. (Diabetes Care (Diabetes Care. 2013; 37:569-586).
It is possible that the reduced risk for diabetes (including lower cardiovascular death, and coronary calcium) with coffee consumption could be related to some of the constituents in coffee such as: polyphenols, which are antioxidants, or a phenolic chemical called chlorogenic acid. Chlorogenic acid has been shown to improve insulin sensitivity and reduce blood sugar absorption.
Coffee consumption can now be added to one of many dietary and lifestyle factors that can contribute to a reduced risk for type 2 diabetes, regardless of whether the coffee is caffeinated or not.
Don’t forget about calories
A point should be made about coffee and calories before leaving a discussion about diabetes. Consider a Starbucks Venti White Chocolate Mocha, for instance, with 580 calories, 22 grams of fat (15 grams of which are saturated) and 75 grams of sugar. A plain cup of brewed coffee, on the other hand, has 0 calories, no fat and zero carbohydrates.
A number of studies have suggested that consuming caffeine can reduce your risk of developing dementia (Alzheimer’s disease) and help with Parkinson’s disease. A 2012 study published in the Journal of Alzheimer’s Disease, found higher blood levels of caffeine (equivalent to 3 cups of coffee) in those older adults with mild memory disorders (a precursor to more severe dementia, including Alzheimer’s disease) were less likely to have progressed to full-blown dementia when studied several years later than those who had consumed little or no caffeine. Another study (Journal of the American Academy of Neurology, 2012) showed that a daily dose of caffeine equivalent to that found in two eight-ounce cups of black coffee could actually decrease the tremor of Parkinson’s disease.
Caffeine stimulates the human central nervous system and temporarily increase brain activity. Moderate caffeine intake can heighten mental alertness and can improve muscle coordination while excessive caffeine intake can cause shakiness. The ability to improve certain cognitive processes, may hint at its protective role brain diseases like Alzheimer’s but the evidence to-date is far from conclusive. Both caffeinated and decaffeinated coffee contain antioxidant and anti-inflammatory compounds, as well as other polyphenols that may directly impact pathways in Alzheimer’s and other degenerative neurological diseases.
In 2013 the Food and Drug Administration (FDA) responded to a trend in which caffeine is being added to a growing number of products. Their investigation focused on the safety of caffeine in food products, particularly its effects on children and adolescents. The FDA explicitly approved adding caffeine for colas in the 1950s when existing rules never anticipated the current proliferation of caffeinated products.
Caffeine is also finding its way into such items instant oatmeal that boasts that one serving has as much caffeine as a cup of coffee, and so-called “wired” waffle and “wired” syrup with added caffeine. Jellybeans, marshmallows, sunflower seeds and even chewing gum are targeted with a dose of caffeine -for its stimulant effect. The Food and Drug Administration (FDA) will investigate the safety of caffeine in food products, particularly its effects on children and adolescents. This comes on the heels of Wrigley’s (a subsidiary of Mars) promotion of a new pack of gum with eight pieces, each containing as much caffeine as half a cup of coffee. One pack of this gum is like having four cups of coffee in your pocket. The FDA has to date not determined the safe amount of daily caffeine for healthy children but the American Academy of Pediatrics discourages the consumption of caffeine and other stimulants by children and adolescents.
Caffeine may be particularly dangerous when added to alcoholic beverages. In 2010 the FDA facilitated the withdrawal from the market of caffeinated alcoholic beverages: primarily malt beverages, in part because of studies indicating that combined ingestion of caffeine and alcohol may lead to hazardous and life-threatening situations. Caffeine can mask some of the sensory cues that people might normally rely on to determine their level of intoxication.
“Energy drinks” with caffeine are being aggressively marketed, including to young people and may have important safety concerns. Energy drink consumption may be associated with serious health problems including serious heart-related events: in the US over a 4-year period from 2007-2011 emergency room visits related to energy drinks more than doubled to more than 20,000 visits annually (Substance abuse Services and Mental Health Admin. January, 2013 The Dawn Report).
A common-sense approach for all of us is to consider drinking no more than 4 cups per day (or less than 28 cups of coffee per week) since there are clearly some benefits of coffee. Those with “cholesterol” or lipid problems may consider brewed and filtered coffee as a preferred coffee preparation instead of French press.
Ding, S et al. Long-Term Coffee Consumption and Risk of Cardiovascular Disease A Systematic Review and a Dose–Response Meta-Analysis of Prospective Cohort Studies. Circulation. 2014;129:643-659.