One of the most famous, or infamous, depending on your experiences, classes of prescription pharmaceuticals is the corticosteroids. Aiming to relieve inflammation, these also unfortunately carry many severe side-effects, including those stemming from the fact that they inhibit protein synthesis. Fortunately, one study looking at natural alternatives to medications found a superior alternative in the treatment of post-infectious cough (PPC), a combination of honey......and......coffee! PPC is the name given to a cough that persists for at least three weeks after a cold or other upper respiratory tract infection, and these sometimes stay around for as long as several months. Besides corticosteroids, conventional treatment may also involve codeine, antihistamines, narcotic and bronchodilator drugs, which all carry their own negative side effects.
This study, conducted in Iran, involved 97 participants who had suffered from PPC for more than three weeks. They were divided into three groups: one receiving a jam-like paste consisting of 20.8 grams of honey and 2.9 grams of instant coffee; one receiving 13.3mg of prednisolone, a corticosteroid, and the last group receiving 25mg of guaifenesin (the control). The participants were instructed to dissolve a specific amount of the product they received in warm water, and to drink this every eight hours for one week. Both before and after the week of treatment, the severity of each person's cough was evaluated by a validated visual questionnaire score. While the honey-coffee group saw their cough frequency scores drop from 2.9 to 0.2, the steroid group showed a drop from 3.0 to 2.4, and the control group only showed a drop from 2.8 to 2.7. These differences were deemed to be clinically significant. The authors also stated that even though billions of dollars are spent every year on attempts to control and resolve coughs, the effect of cough medicines are not reliable, and that despite PPC not being responsible for any mortality, it does cause significant disruption to quality of life.
PPC is often caused by persistent inflammation of the upper airways. So, how exactly do coffee and honey work against this? Well, multiple studies have shown anti-inflammatory effects of coffee, such as one where caffeine was found to block caspase-1 and therefore production of interleukin-1beta, which is a common inflammatory cytokine. Caffeine may also relieve asthma by acting as a bronchodilator, as even small amounts have been shown to improve lung function, measured by forced expiratory volume and mid-expiratory flow rates. There seems to be no significant effect of caffeine on nitric oxide levels, which is a chemical that dilates airways and blood vessels. Honey has been found to possess anti-bacterial and anti-inflammatory properties, with the former being relevant to post-infectious coughs where there may be a subclinical infection. It has direct anti-bacterial properties from hydrogen peroxide and constituents derived from the flowers that the bees had taken the nectar from, as well as simply being able to dehydrate bacterial cells due to its high sugar content and acidic pH. Unlike caffeine, honey can increase nitric oxide, which is also anti-inflammatory. The other anti-inflammatory effects of honey come from its prostaglandin-inhibiting abilities, antioxidant effects and its ability to speed up healing, which reduces the "need" for inflammation. So in conclusion, even though it may not make sense that a mixture of coffee and honey is able to stop a cough that often calls for prescription drugs, it has shown efficacy and has plenty of other research to back it up.
*One of these side effects is tendon damage, which is actually a vomiting trigger for me if I think about it or see it.