Most of us don't drink the recommended daily intake of water, so what damage are we doing to ourselves by chronic dehydration, asks SYLVIA THOMPSON
WATER IS the most fundamental nutrient required for good health yet many of us are not drinking enough of it. In spite of the increased availability of water in dispensers in offices, in bottles from every corner store and from taps in our homes, many people are simply not paying attention to the amount of water they need to drink.
Recent media stories about how we don’t really require six to eight glasses of water a day (two litres) haven’t helped. As most of us realise that we never drink that much water in the day, it’s convenient to lap up these stories and sit back and have another coffee.
Richard Burton, director of the Irish Institute of Nutrition and Health, says that in the past 15 years or so, the consciousness around water has improved.
“People are recognising that drinking more water is a good thing to do and you see people carrying water bottles much more but you can’t treat thirst in the same way as you treat hunger. Many people might not realise that a feeling of being under par can be linked to being dehydrated,” says Burton.
So, how much water do we really need to keep healthy? Does it vary from person to person? Jessica Keane is a nutritional therapist who initially trained as a biochemist.
“It varies massively from person to person and across different age groups and it’s important to consider the types of food you eat and how much water you get from other drinks,” she says.
Mary Flynn from the Food Safety Authority of Ireland says, “It’s an urban myth that people need to drink eight or 10 glasses of water a day on top of normal beverages but I suggest people should always drink first rather than eat. When people are rushing around, they forget to drink water. And, the big thing in relation to obesity is that if people drink water before they eat, they will eat less.”
The European Food Safety Authority (EFSA) recently issued its scientific opinion on how much water we should be drinking. According to EFSA, the average male requires 2.5 litres of water a day while the average female requires about two litres of water a day. Two to three year olds require about 1.3 litres a day, four to eight year olds require about 1.6 litres a day while nine to 13 year olds require about 1.9 litres a day.
In these recommendations, EFSA includes water from drinking water, other beverages and food moisture. The report states that we get about 80 per cent of our water intake from drinking water and other beverages and about 20 per cent from food. Food water content is of course higher in fruit and vegetables (more than 80 per cent) than in hot meals (40-70 per cent) and bakery products (less than 40 per cent). Diets rich in fruit and vegetables therefore provide significant amounts of total water intake while fast food products generally have low water content.
“I usually suggest to clients to drink between 1.5 and two litres of water per day and this includes herbal teas and soups,” says Keane. She says that generally speaking if your urine is clear to light straw coloured, you have sufficient water intake. However, if you are tired, constipated, not feeling well physically, you may need more water.
Factors that influence the amount of water you need include your body composition, your age and physical activity levels. “Babies require more water per kilo of weight than adults although they will get all of their water requirements from breast milk,” explains Keane. Pregnant and lactating mothers also need about 1.1 litres extra of water per day and older people require similar amounts of water to young adults.
Athletes or anyone who trains vigorously and therefore sweats a lot may need to drink up to three litres of water a day to replace lost fluids. The risk of drinking too much water is rare but can occur if consumption of water is higher than the kidney’s ability to excrete which stands at about 0.7 to one litre an hour.
When you consider that our bodies are made up of about 70 per cent of water, rising to 85 per cent in the brain, it’s astonishing that more attention is not given to water. “The body is self-regulating all the time but yes, water is required for the cerebral fluid in the brain, the spinal fluid, the tear ducts, the lining of the lungs, the digestive system, the excretory system and the cardiovascular system,” says Keane. In its report, the EFSA says that water is often disregarded or cursorily treated in national and international recommendations for nutrient intake.
One doctor who believed adequate water was the absolute key to good health is Dr Fereydoon Batmanghelidj, an Iranian doctor who wrote the seminal 1992 book, Your Body’s Many Cries for Water. Batmanghelidj developed his theories of the invaluable role of water while treating fellow prisoners in an Iranian jail during the Iranian revolution of 1979. Following his release from prison, he emigrated to the US and continued his research into water for many years.
Batmanghelidj, who died in 2004, argued that the body has many different thirst signals, the last of which is a dry mouth. He suggested that we have “thirst pain” signals in the same way that we have hunger pain signals. According to Batmanghelidj, these thirst pain signals can be localised pains in the stomach, intestines and even in the joints that we have come to associate with other illnesses.
“Chronic pains of the body that cannot be easily explained as injury or infection should first and foremost be interpreted as signals of chronic water shortage in the area where pain is registered,” he wrote.
“These chronic pains include dyspeptic pain, rheumatoid arthritis pain, anginal pain [heart pain on walking], low back pain, migraine and hangover headaches should be treated with a regular adjustment to daily water intake of no less than two and a half litres,” according to Batmanghelidj.
He also linked high blood pressure, high blood cholesterol and obesity itself to chronic dehydration. However, he cautioned anyone who thought they would find an instant cure from chronic health problems. “Do not over drink, thinking you can undo the damage of many months or years of dehydration by excessive intake of water in a few days. You need to drink a normal amount every day until full hydration of the body is achieved over a longer period of time.”
So, do many people support this theory of water nowadays? Richard Burton says that some students are very taken with the ideas in Batmanghelidj’s book.
“But, we have to remember that like many single-issue solutions to health problems, his theory was developed in extreme circumstances,” says Burton.
The adult male body is 60 per cent water, while the average female body is 50-55 per cent water
60-70 per cent of the dermis layer of the skin is water
We lose one litre of water daily through our urine and faeces
We lose 0.5 litres of water daily through breathing
We lose 0.5 litres of water through the epidermal layer of our skin
We lose 0.5 litres through sweat glands, depending on levels of exercise and/or stress
