During this heat wave that Sri Lanka is undergoing, water is one very important part of the daily nutrition intake. However, for something as seemingly simple and essential as drinking water, plenty of myths and misconceptions exist about possible water benefits and harms.Thus, this week’s FYI decided to untangle the myths from the facts regarding water for your information.

MYTH:  Everyone needs to drink eight glasses of water a day.
FACT: Though water is the easiest and most economical fluid to keep you hydrated, the latest Institute of Medicine recommendation is that women should strive for about two litres or eight glasses a day and men should aim for three litres or 12 glasses a day of any fluid, not just water. “No one can figure out where this ‘eight glasses of water’ came from, but I believe it came from the old RDA [recommended daily allowance] for water that matched water requirements to calorie requirements,” notes Georgia Chavent, MS, RD, Director of the Nutrition and Dietetics Programme at the University of New Haven in West Haven, Conn. “The new requirement from the Institute of Medicine is much more generous and includes recommendations for total beverage consumption, not just water.”

MYTH:  Bottled water can cause tooth decay.
FACT: Bottled water in and of itself doesn’t cause the teeth to decay, but it usually doesn’t contain any fluoride, which is added to tap water to help prevent tooth decay. “Fluoride is an important element in the mineralization of bone and teeth,” says Constance Brown-Riggs, RD, CDE, author of The African American Guide To Living Well With Diabetes and a nutritionist and certified diabetes educator in New York City. “With the increased consumption of bottled water, which is not fluoridated, there has been an increase in dental caries [cavities].”

MYTH: Drinking water can help keep your skin moist.
FACT: While it was believed that staying properly hydrated led to youthful, vibrant skin, the reality is that the amount of water you drink probably has very little to do with what your skin looks like. “Unless the individual is severely dehydrated, drinking large quantities of water will not prevent dry skin,” Hess-Fischl says. “Basically, the moisture level of skin is not determined by internal factors. Instead, external factors such as skin cleansing, the environment, the number of oil glands, and the functioning of these oil-producing glands determine how dry the skin is or will become. The water that is consumed internally will not reach the epidermis [the top layer of the skin].”

MYTH: Yellow urine is a sign of dehydration.
FACT: It can be, but not all yellow urine is cause for alarm. “Dark yellow urine may be a sign of dehydration,” says Zuckerbrot. “The kidneys filter waste products and reabsorb water and other useful substances from the blood, so they control the volume and concentration of urine output. Dehydration leads to decreased urine volume, turning your urine dark yellow. Ideally, your urine should be straw yellow in colour.” Other factors, though, such as taking a multivitamin, can also lead to yellow urine.

MYTH: If you’re thirsty, you are already dehydrated.
FACT: If you start to feel thirsty, then you are headed in the wrong direction and should grab a drink of water, but thirst doesn’t necessarily mean you’re dehydrated. “Thirst begins when the concentration of [substances in the] blood has risen by less than two per cent, whereas most experts would define dehydration as beginning when that concentration has risen by at least five per cent,” notes Hess-Fischl.

MYTH: You need sports drinks, not water, to function at a high level in athletics.
FACT: Sports drinks may have fancier advertising campaigns, but water is really all you need to get the fluid necessary to participate in most athletic endeavours. “Adequate fluid, especially water, is most important for athletes of all ages as it is the single most important way the body has to transport nutrients and energy and remove heat during exercise,” says Chavent. “A sports or vitamin beverage may taste better, but is not necessary for hydration and is expensive.” Keep in mind though that people who run marathons or engage in highly strenuous activities may need to supplement their water intake with sports drinks to offset the salt they lose due to heavy sweating over long periods of time. This doesn’t apply to most people who are simply exercising to get fit at the gym, for instance.