Pneumonia is the leading cause of infection-related deaths in the United States, with potential for severe complications such as respiratory failure and sepsis. (CDC)
The mortality of rate is pneumonia is highest among the elderly (age 70 and over). In 2017, 261 out of 100,000 people died in this age group due to pneumonia. (Our World in Data)
From 2009 to 2014, a team of 13 Japanese scientists, led by Kyoko Kondo of Osaka City University Hospital, sought to find if there’s an association between coffee and green tea intake and pneumonia among the elderly.
The team undertook a matched case–control study of 65 years or older patients who were newly diagnosed with pneumonia by a physician at 24 hospitals in Japan. As a control, patients with the same sex and age who visited the same hospital around the same time for a disease other than pneumonia were selected.
A total of 199 cases and 374 controls were enrolled.
The study found a negative or inverse association between coffee drinking and pneumonia, i.e., the more coffee drinking, the less likelihood of pneumonia.
Compared to those who do not drink coffee, the odds ratio (OR) for pneumonia of those who drink less than one cup of coffee per day was 0.69, OR of those who drink one cup was 0.67, and OR of those who drink two or more cups was 0.50.
No association was found between pneumonia and green tea consumption.
The scientists conclude that their study “suggested” there is “a preventive association between coffee intake over 2 cups per day and pneumonia in the elderly“:
A large prospective cohort study in the United States showed an inverse association between coffee intake and total death, and there were inverse association between coffee intake and chronic respiratory diseases and pneumonia and influenza in deaths by cause3. Other cohort studies have also reported an inverse association between coffee intake and death from respiratory diseases (pneumonia, influenza, chronic obstructive pulmonary disease, and related symptoms)4,14. These findings suggest that coffee may have a preventive influence for chronic and acute respiratory diseases….
In addition to coffee drinking’s positive effects on respiratory functions, coffee also promotes anti-bacterial activity and intestinal flora:
Caffeine contained in coffee has arousal effect, inotropic effect, diuretic effect, and respiratory function improving effect, and theophylline of its metabolites, has bronchodilation, stimulation of respiratory center, and anti-inflammatory effect16. In addition, coffee components such as caffeine, chlorogenic acid, and trigonelline have been reported to have antibacterial activity17,18,19,20,21,22.
There are also some research reports on the association between coffee and intestinal flora. Mills CE and colleagues have tested in vitro that chlorogenic acid, a type of polyphenol abundant in coffee beans23, improves the balance of the gut flora24. In addition, arabinogalactan contained in coffee beans has an effect of growing specific bifidobacteria25, and bifidobacteria grown in the large intestine have a function of activating immune cells26. Because the intestinal flora changes with aging, for example the number of bifidobacteria that work well for the body reduce significantly after the age of sixty27, these coffee components may have a beneficial effect on the gut flora. The role of these components in coffee may have played a role in reducing the risk of pneumonia in the elderly seen in this study.
To read the report of the study, see Scientific Reports volume 11, Article number: 5570 (2021)
Also, a 2018 study by the National Cancer Institute and the National Institutes of Health found that drinking coffee is associated with a lower risk of early death. In fact, drinking up to seven cups every day could cut death rates by 16%. (Independent)