Coffee and all-cause mortality

• Studies have found an association between drinking coffee (around 4 cups/day) and reduced all-cause mortality (16%) and cardiovascular disease (21%).
• However, these nutritional epidemiology studies have limitations, such as relying on self-reported data and not controlling for confounding factors like variations in coffee preparation.

Coffee and cardiovascular disease

• Multiple studies found the strongest reduction in cardiovascular disease risk at 3-4 cups of coffee per day.
• Benefits seem to diminish by 10 cups per day.

Caffeine and athletic performance

• Caffeine doses of 3-6mg per kg of body weight can measurably improve endurance and peak power output, especially in trained athletes.
• However, improvements are relatively minor for non-elite athletes and may require consuming large amounts of coffee.

Coffee, sleep, and anxiety

• Despite potential health benefits, coffee consumption can interfere with sleep quality and duration, negating positive effects.
• Individuals' responses to caffeine vary based on genetics (slow vs. fast metabolizers).
• Experimenting with reducing/eliminating caffeine may improve sleep for some.
• Caffeine's half-life is ~5 hours, taking up to 12 hours to fully clear the system.

Filtered vs. unfiltered coffee

• A large Norwegian study found filtered coffee associated with lower all-cause mortality and heart disease risk compared to unfiltered, possibly due to kahweol and cafestol oils.
• However, an Italian study on espresso drinkers found similar benefits, suggesting other factors like overall diet and smoking habits may play a role.

Coffee and gut health

• Coffee is a source of beneficial polyphenols (like chlorogenic acids) and fiber (~2g per cup), which may positively impact gut microbiome.
• Polyphenol content is highest in fresh, light roast coffee and decreases with staling and darker roasts.

Coffee and GERD (acid reflux)

• While coffee is less acidic than stomach acid, it can exacerbate pre-existing GERD by triggering the condition in the esophagus.
• Cold brew is less acidic than hot coffee but also lower in beneficial antioxidants and overall chemical diversity.

Coffee and cognitive function

• Studies suggest coffee consumption is associated with lower incidence of mental decline, impairment, and neurological diseases like Alzheimer's and Parkinson's in older adults.

Coffee and cancer

• Despite concerns about acrylamide (a potential carcinogen found in small quantities in coffee), no evidence directly links dietary acrylamide to increased cancer risk.
• Some studies even suggest coffee consumption may reduce the risk of certain cancers, like liver and kidney.
• Mycotoxins (mold/fungi toxins) have been found in low levels in raw coffee, but roasting significantly reduces them to non-concerning levels, especially in specialty coffee.