Many studies report coffee as having beneficial effects and a couple of cups of coffee drink only in the morning could have beneficial effects. A meta-analysis indicates that there is at inverse relationship between coffee/caffeine and risk of Parkinson’s disease. A weakness of the forgoing meta-analysis is that the meta-anaylsis focuses on caffeine. Studied indivduals, however, were drinking coffee with is much different than taking caffeine pills. A meta-analysis indicates that moderate coffee intakes is associated with decreased cardiovascular risks. There are, however, increased risks for schizophrenia where there is heavy use of coffee. Where there is heavy use of coffee, coffee most likely is not drunk only in mornings.
Difficulties with coffee can arise given coffee is drunk throughout the day. Coffee inhibits iron absorption in a concentration-dependent fashion. Polyphenols in coffee inhibit iron absorption. A couple of cups of coffee drunk only in the morning would have minimal effects on iron metabolism. Coffee drunk throughout the day could have very adverse effects on iron metabolism.