The use of drugs or medication to maintain or restore health has increased tremendously during the past 20 years.
A 'drug' may be defined broadly as any chemical substance that is not one of the basic nutrients (proteins, carbohydrates, fats, minerals and vitamins) and which, when taken in, changes the body's structure or function. Incidentally, according to this definition, even ordinary table salt could be labelled a drug! For the purpose of this article, however, the term 'drug' will mean a non-food substance that is deliberately introduced into the body in order to produce some physiological or psychological effect. Of course drugs act in a variety of different ways, depending on their particular applications, which may be any of the following:
- relief of symptoms (such as headaches)
- prevention of illness (as in the case of vaccines used against diseases such as polio)
- control of chronic conditions such as high blood pressure
- treatment of certain diseases (for example, antibiotics which are used to treat tuberculosis).
How do drugs work?
What determines how a certain drug acts on a specific problem? Why does one have an effect on the blood vessels and another on the lungs? The answer to these questions has to do with the concept of 'receptor sites' - the idea that a drug has its effect only at specific spots within cells where the drug molecule 'fits'. (A molecule is the smallest unit of a chemical substance such as a drug.) These drug molecules do not act on the whole cell, but only at the receptor sites - and only on those cells with receptor sites that are compatible with the drug molecule. The diagram on the following is a representation of the way in which this compatibility works.
Prescription drugs - handle with care!
Whenever your doctor prescribes a medication, make sure that either he/she or your pharmacist gives you the following information:
- The name of the drug (many drugs go by different names)
- The reason you are taking it
- How the drug should be taken (before or after meals, with water, fruit juice or milk, etc)
- The dosage safety level of the drug (to prevent overdosing if you have to use the drug in an emergency)
- How often you should take the drug
- The length of time you should continue to take it
- Whether taking the drug requires any change in your diet or activities (For example, certain drugs may not be taken with alcohol and others may cause drowsiness or interfere with your coordination.)
- What side effects can you expect? (All drugs cause side effects,ranging from the trivial to the serious.)
After many years of research, health professionals have established that foods and nutrients do interact with drugs to a significant extent. In other words, medication can have an effect on a person's health and conversely, food can influence a drug's effectiveness. The risk that a drug might have an adverse nutritional effect or that drugs and food might be incompatible becomes particularly relevant when:
- the drug is an 'anti-nutrient' (in other words, it acts like a nutrient even though it is not one)
- a drug which has adverse nutritional effects is taken for a long time
- the patient is taking more than one drug at a time
- a patient's diet is either nutritionally inadequate or the patient is already malnourished
- drugs are used excessively (or there is abuse of prescription or over- the-counter drugs)
- food and/or drugs are not being properly absorbed due to disease
- the patient is not given special diet instructions when necessary
- physicians, pharmacists and dietitians are unaware of the risks involved.
The use of medication may influence nutrient intake, absorption, metabolism or excretion; in the same way, foods or their components may affect the absorption, metabolism and excretion of drugs. To paraphrase this, drugs and foods can interact by one of the following mechanisms:
- Drugs plus foods (nutrients) = changed drug effect
- Drugs plus foods (nutrients) = changed nutritional balance
