The dangers in your drinks

Cup of coffee with coffee beans
Cup of coffee with coffee beans
Most people are probably aware of the potential risks associated with drinking excessive amounts of alcohol, which not only affect your own health, but the health of your unborn children and other people who may suffer injury and death as a result of accidents caused by drunk drivers, abusive spouses and so on.

What many individuals do not realise is that other drinks can also affect how you feel and react and therefore also influence your health.


At birth up to 85% of the human body consists of water. As people age and store fat, this percentage decreases. Thus a lean adult would have a body water content of about 70%, but in an obese adult only between 45% and 55% of his or her body weight would consist of water (Mahan et al, 2012).

Water performs many functions in the body such as acting as the vehicle in which important compounds (proteins, carbohydrates, vitamins, minerals and electrolytes) are dissolved and transported. We need water for digestion, absorption and excretion. Excretion occurs via the kidneys as urine, the skin as sweat, and the lungs as water vapour.

We all know that we lose more water when it is hot and when we sweat as a result of a high surrounding temperature or when we do physical activity. Excessive loss of body water (up to 20%) causes dehydration, which if left untreated, can cause death. Individuals lost in the desert without water supplies and marathon runners who do not replenish their liquid intake, collapse with reduced blood volumes and renal failure which can often be fatal (Mahan et al, 2012).

The elderly and the very young are particularly vulnerable to dehydration which is associated with increased morbidity and fatalities. For example, older patients tend not to maintain their normal fluid balance as efficiently as young adults, while infants and babies are exposed to great risk when their fluid balance is disturbed by diseases such as diarrhoea (Van Graan et al, 2012).

How much do we need?

The body can obtain water from a variety of sources, namely about 1.5 litres by drinking liquids (which need not only be water, but can include a wide variety of other beverages), about 700ml from eating foods, particularly fruit and vegetables that have a high water content, and from the cellular oxidation of food (about 200 ml). It is estimated that an adult needs to drink about 2.5 litres of liquid per day.

This is an average figure as recommendations for women are between 2.2 and 2.8 litre/day and 2.5 to 3.7 litre/day for men (Van Graan et al, 2012).  The Food and Nutrition Board have suggested that the water intake of infants should be about 0.7 litre per day at the age of 0 tot 6 months, increasing in accord with age as follows: to 0.8 litre/day (7-12 months), 1.3 litre/day (1-3 years) and 1.7 litre/day (4-8 years) (Van Graan et al, 2012).
High environmental temperatures and strenuous physical activity increase our water requirement considerably. In very hot weather daily water losses may rise to nearly 3.5 litres a day, while prolonged exercise, such as running a marathon, can push up the requirement to 6.6 litres a day (Mahan et al, 2013).

Overdoing our water intake

Most health professionals, including dietitians, encourage the public to "Drink lots of clean, safe water". The latter is one of the new Food-Based Dietary Guidelines that were launched in South Africa last year (Van Graan et al, 2012). As so often occurs when the public are given a recommendation, some people tend to overdo the good advice. This can unfortunately be as harmful as not following such directives.

Members of the public, particularly individuals attempting to lose weight, regularly inform me that they drink up to 10 litres of water a day! This is taking a good thing into the realms of irresponsibility and exposing one’s body to potential danger from electrolyte imbalances.

Electrolytes such as sodium and potassium, and other minerals like magnesium and even calcium, are important to keep the human body functioning optimally. Intracellular (inside the cells) and extracellular (outside the cells in the blood, etc) electrolyte concentrations must be maintained at a delicate balance to permit normal functioning of the body.

When people drink too much water this delicate balance of electrolytes is disturbed and eventually water intoxication as a result of intake exceeding the body’s ability to excrete water, may occur with dangerous consequences. For example, if the intracellular fluid increases excessively, the cells will expand causing swelling which in the case of brain cells is particularly hazardous. The symptoms of water intoxication include headache, nausea, vomiting, muscle twitching, blindness and convlusions, which may be fatal (Mahan et al, 2012).

Endurance athletes who ingest too much water without topping up their electrolytes and overenthusiastic slimmers are probably the most usual examples of water intoxication we encounter in everyday life.

It is evident that while we need to ensure that we and our children drink sufficient liquid (water, bottled water, soda water, milk, tea, coffee, cold drinks, fruit juice, etc), to keep us healthy, it is just as harmful to overdo our water intake, a practice that often occurs when people attempt to lose weight or to pursue a "healthy lifestyle".

Caffeinated beverages which include coffee, tea and all the caffeine-laced "energy" drinks that flood the market nowadays, can also cause problems when used in excess or inappropriately (i.e. by children or pregnant and lactating women or persons who are caffeine-sensitive).

Caffeine is an alkaloid which acts as a nervous system stimulant increasing alertness and temporarily warding off fatigue . When ingested in large quantities, caffeine can cause irritability, anxiety or nervousness, restlessness, tremor, dry mouth, palpitations, insomnia, and rebound fatigue. One of the most detrimental effects of caffeine is that it rapidly causes dependence so that individuals who try to reduce their caffeine intake tend to suffer withdrawal symptoms and cravings.
Caffeine naturally occurs in plants such as tea and coffee bushes, kola nuts, yerba maté and guarana berries. Extracts from the latter two plants are often used in over-the-counter slimming products because of their caffeine content which stimulates the user and gives them a "high".

Authorities recommend that adults should not ingest more than 200mg of caffeine a day, which translates to approximately 4 cups of tea and 2 cups of freshly brewed coffee. Pregnant and breastfeeding women should reduce their intake of caffeine even further. Children should preferably not have any caffeine at all because this stimulant can have a detrimental effect on their developing neurological and cardiovascular systems. Thus the use of caffeine-containing energy drinks by children and teenagers should be carefully avoided.

New soft drink regulation

As of 17 April 2013, an amendment to the South African soft drinks regulations specifies that all caffeinated energy drinks must state on their cans "Not recommended for children under 12 years of age; pregnant or lactating women; persons sensitive to caffeine". In addition, the front of the cans must display the warning "High caffeine content" in letters large enough to be easily visible (Knowler, 2013).

While we can but hope that this sensible regulation will be adhered to by the manufacturers of soft drinks that contain caffeine, the public and parents in particular need to firstly inform their children that caffeine-laced energy drinks are harmful and secondly not allow children to buy such drinks at tuckshops and sporting events.

Many drinks, therefore, have the potential to be harmful if we use them in excess and it is our responsibility to ensure the we and our children do not damage our health when we have a drink!

References: (Knowler W (2013). Energy drinks must carry ‘high caffeine’ label. Pretoria News, Monday 20 May 2013, p.5; Mahan LK et al, 2012. Krause’s Food and the Nutrition Care Process. 13th Edition. Elsevier; Van Graan AE et al (2012). Drink lots of clean, safe water. Personal communication.)

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