coffee and decreased mortality, and it may not be just the caffeine

 

A recent study from the National Health and Nutrition Examination Survey (NHANES) database adds more validity to prior studies finding a mortality benefit to drinking coffee, and in a dose-dependent way (see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8715461/pdf/nursrep-11-00083.pdf ). thanks to Paul Ash For bringing this to my attention

 

Details:

-- 23,878 adults, with daily caffeine intake reported in the prospective NHANES study from 1999-2014 

-- NHANES participants had a home-based interview and physical exam, with a 24-h dietary recall done in person, and a second dietary interview in the 2003-2014 cycle

-- caffeine intake was calculated from coffee, tea, soda, energy drinks, chocolate and cocoa-containing products

-- 23% 20-34yo/26% 35-50yo/50% 50+yo, 50% female, 50% white/20% Black/24% Hispanic, 50% had at least some college education, BMI >25 in 70%, 5% smokers, 35% hypertension, 12% diabetes, 10% cancer, 2000 calories/d with 250g carbs/80g protein/75g fat

    -- of these approx numbers, there was a gradient in demographics: high caffeine consumers were older, more often female, more white, higher education, higher income, more smokers, and consumed more calories (including more fat, protein and carbs)

    --6248 people (26.1%) had caffeine intake off >200 mg per day

-- mortality outcomes were from the 2015 public-use Linked Mortality Files

-- main measure: relation between caffeine intake and all-cause mortality, cardiovascular mortality, and cancer mortality

 

Results:

    -- all-cause mortality, 2206 cases; as compared to caffeine intake of less than 100 mg/d:

        -- 100-200 mg/d: adjusted HR 0.78 (0.67-0.91), p<0.05; ie 22% reduction

        -- >200 mg/d:  aHR 0.68 (0.60-0.78), p<0.05; ie 32% reduction

    -- cardiovascular mortality, 394 cases; as compared to caffeine intake of less than 100 mg/d:

        -- 100-200 mg/d: aHR 0.63 (0.45-0.88), p<0.05; ie 37% reduction

        -- >200 mg/d: aHR 0.67 (0.50-0.88), p<0.05; ie 33% reduction

    -- cancer mortality, 525 cases; as compared to caffeine intake of less than 100 mg/d:

        -- 100-200 mg/d: aHR 0.80 (0.59-1.08), strong trend, almost statistically significant 20% reduction

        -- >200 mg/d:  aHR 0.98 (0.76-1.27), not statistically significant

 

Commentary:

    -- 64% of adults in the US drink coffee daily with an average intake of 3.1 cups per day. The overall caffeine consumption is 165 mg of caffeine per person per day

    -- the caffeine content of coffee varies depending on its strength and how it is brewed, for example the average cup of coffee has approximate 91 mg of caffeine per 8 ounces, though the average cup of coffee can contain anywhere from 40 to 150 mg of caffeine.

    -- the main source of caffeine in the US diet is from coffee, accounting for 71% of caffeine intake. However caffeine is also in some teas, soda, energy drinks, chocolate, and cocoa containing products

 

-- this study found that the most profound benefit by caffeine consumption was for cardiovascular mortality, reaching 33-37%.

    --however, in adults aged 20-35 and in those with BMI <18.5, higher caffeine intake was actually associated with increased all-cause mortality

-- a prior blog from the UK Biobank (see http://gmodestmedblogs.blogspot.com/2019/01/coffee-and-decreased-mortality.html ) found that:

    -- compared to non-coffee drinkers, there was overall a dose-dependent association with all-cause mortality: overall the more you drink the better, even for those drinking eight or more cups a day

        -- also a strong statistical trend for benefit in cardiovascular disease deaths and stroke deaths

    -- benefits were found for instant, ground, and decaffeinated coffee, though were stronger for ground coffee; instant and decaffeinated coffee had similar benefits

    -- this study also assessed the genetics of caffeine metabolism, identifying 4 polymorphisms that would lead to differences in caffeine levels after consumption, finding no overall association with mortality events attributed to these polymorphisms; there were, however, some differences depending on the number of genetic alleles present, especially in those consuming at least 6 cups per day

    -- this blog also briefly reviewed data from the Health Professionals and Nurses health studies, the Multiethnic Cohort study, and a large 10-country European study, all finding decreased mortality with coffee consumption

 

-- coffee is associated with transient increases in blood pressure, but also increases in total cholesterol, LDL, and triglycerides. However, more recent studies have found that coffee improves insulin sensitivity, and reduces chronic inflammation and liver enzymes

-- coffee is also associated with many antioxidants, besides the potential role of caffeine itself. For example coffee contains polyphenols,  as well as chlorogenic, ferulic, caffeic, and n-coumaric acids that may well provide clinical benefit. Also, melanoidins in roasted coffee, and trigonelline have been found to be antioxidants. Some of these, such as chlorogenic acid and polyphenols, are geographically-related (see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4665516/#:~:text=Antioxidant%20activity%20of%20coffee%20is,be%20antioxidants%20also%20%5B14%5D. )

    --This all suggests that coffee in its various forms may well be quite protective for all-cause mortality, cardiovascular mortality, and cancer mortality. We do not necessarily know the specific antioxidant or other chemical that might be the most protective one. And it is certainly possible that there is a synergy of multiple antioxidants and chemicals that confer protection: ie, this benefit may not reduce to one specific chemical that could be manufactured as a pill. Unfortunately, our approaches in Western medicine is often reductionist, looking for that single ingredient that seems to be good, and then making a pill of it. this approach, unfortunately, is at odds with nature, since foods for example have a very wide variety of chemicals that may well interact with each other. This became clear, I think, when the antioxidant beta-carotene was studied as a supplement; but 2 studies found an increased risk of lung cancer in those who smoked. It turns out that there are many, many different antioxidant carotenoids. and some of the vegetables that seem to be healthful include several different carotenoids and other antioxidants and other chemicals. Which all means, we should eat well/healthfully, and not assume that a single chemical will be the answer to aging: the "ankh" of ancient Egypt, or the fountain of youth of Ponce De Leon

    -- and the finding in some other studies is that caffeinated drinks may confer some more protection than decaffeinated ones, suggesting caffeine itself may still play a role in addition to other ingredients

-- cancer mortality is more complex, and studies have come to different conclusions, likely because there are so many different cancers, and likely some cancers are more linked to caffeine consumption (and perhaps caffeine my benefit some and harm others??)

 

-- as a further (and welcoming) support for the caffeine benefit are the studies finding benefit from chocolate (especially the really delicious dark chocolate):

    -- improves walking in those with peripheral artery disease: http://gmodestmedblogs.blogspot.com/2014/07/dark-chocolate-helps-with-periph.html

    -- per capita chocolate consumption is higher in Nobel laureates: http://gmodestmedblogs.blogspot.com/2014/07/chocolate-and-cognitive-function-etc.html

    -- decreased CAD, stroke, diabetes and metabolic syndrome: see cad and chocolate bmj 2011 in dropbox, or doi: 10.1136/bmj.d4488

 

Limitations:

-- the actual measures of caffeine intake is likely somewhat inaccurate, given that there were so few assessments of caffeine intake over time. there may well be changes in both the quantity of caffeine over time (perhaps some people stopping or other people starting, confounding the results), as well as potentially changing types of coffee (caffeine content of regular coffee, espresso, cappuccino, decaffeinated, and even mode of coffee preparation as filtered versus not) also change caffeine content

-- all of the studies are observational, so unable to attribute causality:

    -- are there other attributes of coffee-drinkers that are actually lead to better outcomes? do they eat differently and more healthfully? do they jog 5 miles after a cup of coffee?

    -- unfortunately, it is hard to have a rigorous study which can show that caffeine is beneficial, where perhaps 5000 people are enrolled to drink coffee (people of different ages, types and quantities of coffee, etc) and 5000 to not to drink coffee, and follow them for 10 years?? might be difficult to recruit these folks. or pay for the study

-- the higher mortality noted in younger people or those with BMI<18.5 may well be a statistical error, since there were so few people in these groups, and so few of them died in the follow-up period of this study

 

so, further evidence that coffee in its various forms seems to have beneficial health effects. one additional type of benefit (perhaps) is that i am awake enough to write this blog, after my 1.5 cups of morning java (and the small piece of dark chocolate at my deskside). And, we have the unusual finding that a consumable product (coffee) seems to have moved from being vilified in the past to being praised now....

geoff

 

If you would like to be on the regular email list for upcoming blogs, please contact me at gmodest@uphams.org

to get access to all of the blogs (2 options):

1. go to http://gmodestmedblogs.blogspot.com/ to see them in reverse chronological order

2. click on 3 parallel lines top left, if you want to see blogs by category, then click on "labels" and choose a category​

3. or you can just click on the magnifying glass on top right, then  type in a name in the search box and get all the blogs with that name in them

 

or: go to https://www.bucommunitymedicine.org/ , a website from the Community Medicine section at Boston Medical Center.  This site does have a very searchable and accessible list of my blogs (though there have been a few that did not upload over the last year or two). but overall it is much easier to view blogs and displays more at a time.

 

please feel free to circulate this to others. also, if you send me their emails, i can add them to the list