The Evidence for Herbal and Botanical Remedies, Part 2

Coffee consumption leads to increased alertness and can boost mental performance. Based on the literature and US Food and Drug Administration recommendations, four 8-oz cups of coffee (about 400 mg of caffeine) daily is an acceptable average amount of caffeine. More than 500 mg/d is considered excessive use of coffee. ^33,34

Overall mortality . A 2008 study showed that regular coffee was not associated with increased or decreased mortality in both men and women. ³⁵ However, more recent studies show an inverse relationship between mortality and coffee consumption.

Specifically, a 2014 meta-analysis found an inverse relationship between coffee and mortality. ³⁶ A large prospective cohort study from 2015 that included 79,234 women and 76,704 men found that drinking coffee was inversely associated with overall mortality. ³⁷ In this cohort study, an inverse association were observed for deaths from heart disease, respiratory disease, diabetes, and self-harm. ³⁷ While mechanisms were not analyzed, coffee may reduce mortality risk by affecting inflammation, lung function, insulin sensitivity, and depression.

Cardiovascular disease . Coffee consumption may modestly reduce the risk of stroke, according to a prospective cohort study of 83,076 women from the Nurses’ Health Study who were followed for 24 years. ³⁸ Reduced cardiovascular mortality was also found in a large prospective cohort study, as noted in the mortality discussion above. ³⁷ A 2014 meta-analysis concluded that coffee consumption is inversely associated with cardiovascular mortality. Drinking 3 or 4 cups a day appears to be the amount that may decrease one’s risk of death when compared to those who do not drink coffee at all. ³⁶

Liver disease . Friedrich et al performed a study involving 379 patients with end stage liver disease, and found that coffee consumption delayed the progression of disease in patients with both alcoholic liver disease and primary sclerosing cholangitis. ³⁹ Coffee consumption also increased long-term survival after liver transplantation. ³⁹ However, the study found that coffee did not have any effect on patients with chronic viral hepatitis.

In a 2016 meta-analysis, caffeinated coffee consumption reduced hepatic fibrosis of nonalcoholic fatty liver disease, although caffeine consumption did not reduce the prevalence of nonalcoholic fatty liver disease. ⁴⁰ Another meta-analysis, including 16 studies, also found caffeine reduced the risk for hepatic fibrosis and cirrhosis. ⁴¹

Depression. Based on 2 different systematic reviews and meta-analyses from 2016, coffee consumption appears to have a significant protective effect, decreasing the risk of developing depression. ^40,42

Alzheimer’s disease/dementia . Coffee, tea, and caffeine consumption show promise in reducing the risk of cognitive decline and dementia. Individuals who consume one to 2 cups of coffee per day had a decreased incidence of mild cognitive impairment compared to non-drinkers. ⁴³ A 2015 Japanese study also found an inverse association between coffee consumption and dementia among women, nonsmokers, and those who do not drink alcohol. ⁴⁴ Most recently, a 2016 study, the Women’s Health Initiative Memory Study, looked at incident dementia rates in women >65 years of age with high vs low caffeine intake. Women with higher caffeine intake were less likely to develop dementia or any cognitive impairment compared with those consuming <64 mg/day. ⁴⁵