On a global scale 780 million people are without access to safe drinking water and 2.6 billion are without access to basic sanitation 1.4 million children, or 4 per minute, die due to preventable waterborne illnesses such as diarrhea every year.
Having clean water to wash hands reduces risk of diarrhoea, infectious diseases and parasites is not a secret.
Furthermore, dehydration reduces the body’s ability to regulate body temperature, impairs cognition, reduces maximal anaerobic and aerobic capacity, and results in poor digestion and absorption of food should not be a surprise either.
But that lack of water increases risk of heart disease may be a surprise.
Dr. Jacqueline Chan Adjunct Asst Research Professor at Loma Linda University and Executive Director at Water Charity has studied the effects of drinking water on the human body.
5 glasses of water a day
From a study published in 2002, after 29,000 men and women had been studies since 1976, Dr. Chan has shown that drinking 5 or more glasses of water a day reduces the risk of heart disease.
– We showed that there was an inverse association between people who drank water and risk of fatal heart disease. The more water consumed, the lower the risk of death by heart disease, says Dr. Chan.
The effect is more prominent in men than women.
– For men, if they drank 5 or more glasses of water spread throughout the day, their risk of a fatal heart attack was 60% lower than men who drank 2 or less glasses of water throughout the day. Women showed a 40% reduction in risk, says Dr. Chan.
This occurred in people who had no history of heart disease, stroke or diabetes.
– In both cases, there was a significant dose response relationship, meaning the more water consumed, the greater the benefit. We could not determine the cut off point for benefits as there were not enough people who drank higher amounts, says Dr. Chan.
She also found indication that for those who had had a history of heart disease, stroke or diabetes, the risk of fatal stroke was reduced by more than 50%.
The effect is not seen when drinking fluids other than water and in some cases (women) results in an increased risk of heart disease.
– There was a significant two and a half fold increase in risk of fatal heart attacks in women who drank 5 or more glasses on fluids other than water, compared to those who drank 2 or less, says Dr. Chan.
Analyses were done to determine whether or not the effects were truly due to water, or to maybe the healthier lifestyles of those who drank more water.
– We adjusted for all the factors related to risk of heart disease and stroke that were available from the gathered data, including not smoking, not drinking, exercise, socio-economic status, obviously age, blood pressure, total energy intake, BMI, and dietary factors such as eating nuts, whole grain bread, vegetarian diet, and the associations remained significant. We could conclude from that that the benefits of water, and detriment of fluids other than water that were found in the study were likely due to the fluids, and not to some other lifestyle factor of the subjects, says Dr. Chan
In 2002-2007, data from another 96,000 people across the US and Canada was collected. Currently the relationships in this larger population are being examined to see if the results still stand.
– It is important to do this, as there are no other published studies looking at this relationship, and it is important that results can be replicated in other populations, says Dr. Chan.