Herbal supplements are very common among the 18+, with the most common herbal supplements being green tea, Echinacea and St Johns Wort.
Most people think of herbal supplements the same way as a multivitamin or any other part of their diet. When taking drugs such as paracetamol you don’t worry about what you eat that day, and you certainly don’t think about what supplements you have taken that day.
St Johns Wort
This is a very common herbal supplement, and is taken by a huge number of people for various reasons. However, like many herbs, it has some very unique properties which effect the body in ways you might not know about.
It is not only St Johns Wort to watch out for, other interactions have been noted with many others. These include: green tea (which can prevent the absorption of many compounds) and echinacea (has a very similar effect on the body as St Johns Wort.
Other dietary supplements can also interact with drugs, although usually to a lesser extent than herbals supplements. These interactions are also usually inhibitory (i.e. prevent the absorption) and so will usually reduce the effect of the drug as opposed to emphasis it.
Grapefruit is very interesting in that in has the same effect as St john Wort. In fact, it is incredibly powerful, and just having half a grapefruit with a cup of coffee can cause the caffeine in the coffee to have a noticeable effect the body (in no long term way fortunately). Grapefruit seed extracts are available in supplement form for this reason, but it is important to be aware of their effects.