Diuretics are frequently taken to correct oedema (water retention) which results from a medical disorder. While they are successful in reducing the excess water level in the body, they also result in the excretion of larger amounts of potassium and magnesium. Patients being treated on a regular basis with thiazide diuretics should therefore increase their intake of foods which are high in potassium such as bananas, orange juice and potatoes.
Alcohol as a drug
Alcohol is regarded as both a drug and a food, since it supplies 29 kilojoules per gram. Because it has mood-altering effects and interferes with the absorption, metabolism and excretion of certain drugs and nutrients, it should possibly be treated with more respect than is usually the case. The reason why the effects of alcohol are felt so swiftly is that it takes a direct route into the system, traveling via the stomach to the small intestine, from where it is quickly absorbed into the blood. A small amount evaporates through the breath and perspiration, but most of it has to be processed by the liver before it isexcreted from the body via the urine.
A regular, excessive alcohol intake decreases the absorption of folic acid, thiamin, vitamin B6, vitamin B12, magnesium, zinc and other trace minerals. High alcohol consumption also tends to go hand in hand with a general decrease in food intake. Alcohol is used as a base in many over-the-counter medications and, ironically, some addicts find all-night chemists a useful secondbest after closing time at the pub!
When combined with the use of other drugs, alcohol can cause serious complications. This is because alcohol itself is a powerful drug and generally speaking, when two or more drugs are taken at the same time they often have a different (and more pronounced) effect than either produces on its own. In addition, if they both act on the same system in the body, their combined effect is often more powerful than might be expected. For example:
- In combination with barbiturates: Both alcohol and phenobarbital (a barbiturate) are depressants. When taken together, even at very low doses, these drugs may increase central nervous system depression and can be fatal.
- In combination with aspirin: Alcohol tends to irritate the stomach lining; when taken in combination with aspirin, which is also an irritant, it can cause internal bleeding.
Other medication: When alcohol is consumed with some antidepressants (ie monoamine-oxidase inhibitors) it may increase blood pressure to a dangerous level. Alcohol combined with antialcohol (Antabuse), antidiabetic and many other medications can lead to abdominal cramps, flushing and vomiting.
Drugs in disguise
Many of us know people who imbibe tea made with loquat leaves for their diabetes, or swear by certain home-brewed herbal mixtures for a multitude of ills. It would certainly be unrealistic to assume that drugs come only in the form of pills or potions created in a laboratory - the early use of the poppy for its narcotic effects is well known - but there are considerable advantages to obtaining one's medication from a pharmacist and not from the garden. These include the fact that the quantity of a compound can be controlled in a pill but not in a leaf, the question of year-round availability and, not least, the convenience.
Some foods are well-known for their adverse drug effects. Liquorice, for example, contains a compound which can cause raised blood pressure if eaten in quantity by people sensitive to this particular substance. Another interesting example (although not of local relevance) is a type of broad bean known as a lava bean' which has a drug-like effect in certain people. Some members of the population in Mediterranean countries have a metabolic defect which causes jaundice, blood in the urine and other symptoms if they eat this variety of bean.
