Thinking about drinking

With the warm weather hopefully just around the corner, we need to remember to keep drinking in order to remain hydrated. As health professionals, is it our duty to reinforce this message in our surgeries, so should we be more precise about the fluid we advocate to drink?

Water makes up 50% to 60% of our body weight and is essential for the continuous maintenance of our bodies. Numerous studies have identified that our bodies can only survive a few days without water.

How much fluid should we be drinking a day?

In moderate climates like Ireland, the general recommendation is that we should drink at least six to eight cups/glasses of water (or other fluids) to prevent dehydration.

However, it is important to remember that individual needs differ due to numerous internal and external factors. These include the age of the individual, their body fat content, physical activity, climate and diet.

What are the general signs of dehydration?

According to a study from, where data was collected via email, 75% of Americans are chronically dehydrated.

So how do we know if we are dehydrated? Thirst is, in fact, a poor indicator of dehydration; by the time you are thirsty you are already dehydrated.

Mild to moderate signs include:

• Flushed face

• Dry/warm skin

• Cannot pass urine or pass reduced amounts of dark/yellow urine

• Dizziness

• Cramps

• Weakness

• Tiredness

• Irritablility

• Headaches

• Dry mouth and tongue.

Signs of moderate to severe dehydration include:

• Low blood pressure

• Fainting

• Convulsions

• Bloated stomach

• Lack of skin elasticity

• Rapid and deep breathing.

How does dehydration affect the oral cavity?

Patients who suffer from xerostomia often complain of cracked lips, a burning sensation of the tongue, changes on the surface of the tongue and oral mucosa.

Clinically, their saliva becomes thicker and less able to lubricate the mouth, thus it is less able to neutralise acids, cleanse the oral cavity and protect the oral mucosa from infections.

Plaque also becomes thicker, which makes maintaining a clean oral cavity that much harder, thus periodontal problems may also accumulate (see

Although the consequences of mild dehydration on the oral cavity are much less severe, the effect of less saliva will ultimately have some effect on both the hard and soft tissues.

Should we be encouraging patients to drink more?

I believe that this should be the case, providing that it does not contradict other healthcare professionals and patients do not take it to extremes and over drink, causing hyponatrimia (a condition where the sodium in the blood may become too dilute) (as reported at

Studies have recognised that by keeping hydrated, memory capacity increases in children, there should be a reduction in kidney stone formation and it should reduce the risk of coronary heart disease and colon cancer (

Oral effects should include maintaining the status quo of the mouth; thus hopefully, along with other preventive advice, ensuring that both hard and soft oral tissues stay healthy.

It is interesting that as part of smoking cessation advice, many professionals give out the four As (avoid, alter, alternatives and activities) followed by the four Ds:

• Take a Deep breath

• Delay

• Do something else

• Drink water!

Discussing drinks

Information we should consider when discussing drinks with our patients includes the following:

• Drink water

It is dentally safe, socially acceptable and widely available. There are three types of bottled water.

• Milk

Plain milk contains natural sugar (lactose). Sugary substances should not be added to milk.

• Limit juice

Fruit juices are good sources of vitamin C. They are recognised as contributing to the five portions per day of fruit and vegetables currently recommended. However, foods that contain fruit and vegetables also contain sugars, whether naturally or added, and therefore have the potential to cause tooth decay. These, therefore, should be limited and fruit juices ideally drunk at mealtimes only as they are also very acidic and can contribute to dental erosion.

• Tea

Drinking tea (without sugar) has been associated with a number of beneficial effects in preventing tooth decay. These include:

1. The tea plant (Camellia sinensis) extracts fluoride from the soil, which then accumulates in its leaves, which means that a cup of brewed tea can be a natural source of fluoride

2. Tannis in tea can inhibit salivary amylase, thereby reducing the cariogenic potential of refined carbohydrates. Tannic acid has been demonstrated in studies to inhibit the growth of S mutans

3. Components of tea, including tannin, catechin, caffeine and tocopherol, have been shown to be effective in increasing the acid resistance of enamel

4. Both green and black tea contain specific flavonoids. These flavonoids have exhibited inhibitatory effects on the growth of cariogenic bacteria including S salivarius and S mutans; flavonoids work by preventing the adherence and growth of the bacteria on the tooth surface. (Information obtained from Tea and Oral Health Fact Sheet at

However, of course, patients should be infomred that drinking tea can stain their teeth.

• Read the labels on drinks

Products that state ‘reduced sugar’ contain at least 25% less sugar than normal full-sugar versions of the drink. These products are not sugar-free. Products that state ‘no added sugar’ are drinks that have no sugar added to them. These drinks are not sugar-free, but contain natural sugars from the fruit ingredient.

• Acidity

Think about the acidity when choosing what to drink, since acidic drinks are a significant cause of dental erosion.

• Keep a drinks diary

Advise your patients to keep a drinks diary so that they can see what they are actually drinking throughout the course of a 24-hour period, and when. It might just surprise them and make your job easier!


Encouraging patients to drink the recommended amounts of water can only be beneficial. Educating them in terms of the risks associated with processed soft drinks will also help to make life easier, for both you and the patient.

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