WATER: THE MOST IMPORTANT NUTRIENT How water intake improves health By Stavros A. Kavouras, PhD, FACSM, FECSS
"Kids that drink more water in school perform better in cognitive tasks." United States alone, there are more than 29 million patients with diabetes and 85 million with pre-diabetes. How is diabetes related to water intake and hydration? Recent studies indicate that dehydration and low water intake lead to higher levels of anti-diuretic hormone. A higher level of this hormone is associated with development of diabetes, heart disease, and death. High water intake is thought to be associated with better mood and cognitive function. Kids that drink more water in school perform better in cognitive tasks.
Water is the most abundant molecule in the human body accounting for 50-60% of its weight. Nevertheless, water is the most overlooked and under-studied element in Nutrition Science. Did you know that water is not included in the U.S. Department of Agriculture’s “My Plate” nutrition graphic (choosemyplate.gov)? Water was also not present in neither the 2005 nor the 1992 food guide pyramid. For this reason, water is considered the “Forgotten Nutrient.” Water intake and hydration are mainly regulated by thirst and the kidneys. When we run low on water, we get thirsty and we drink. When we drink too much, we go to the bathroom more often to eliminate the extra water. What is important to understand is that we do not get thirsty until we are dehydrated. Then, water intake quickly turns off our body's thirst signal, well before body water is replenished. As a result, many people do not know that they are chronically under-hydrated because they are not thirsty. After all, thirst is a survival instinct, but it is not necessarily a reliable way to gauge optimal hydration for health. A 2015 study, based on the U.S. National Health and Nutrition Examination Survey, reported that more than 50% of children are under-hydrated. One-in-four do not drink any water, and three-in-four children drink at least one serving of a sugary beverage. What is worrisome is that low water intake is associated with a variety of health outcomes. Specifically, studies have shown that low water intake is linked to the development of kidney stones, urinary tract infections, and chronic kidney disease. Probably more important are the findings in the area of water intake and diabetes. In the Western world, diabetes is one of the first causes of cardiovascular diseases, the number one factor for all-cause mortality. In the 12
A simple and practical way to assess if you are drinking enough water is your urine color and number of visits to the bathroom. Light or clear urine color and more than 6-7 visits to the bathroom per day are both good indicators of appropriate hydration.
Stavros A. Kavouras, PhD, FACSM, FECSS, is an associate professor at the University of Arkansas’ Hydration Science Lab. Follow him on Twitter: @DrHydration.
COLLECTIVE IMPACT EFFORTS ARE NEEDED TO CREATE CONDITIONS THAT FAVOR DRINKING WATER EFFECTS By Jodi D. Stookey, PhD
Drinking water can significantly improve public health with support from collective impact efforts. Collective impact efforts are important, perhaps even necessary, for creating conditions that favor drinking water effects. Depending on background conditions, drinking water can have negative, null, or beneficial effects on health. In the case of weight management, for example, drinking water has had 83 null effects on body weight outcomes, out of 115 effects, reported by randomized controlled trials . Background conditions in these trials did not enable drinking water to lower energy intake and/or increase fat oxidation. Conditions in New York City schools, on the other hand, allowed for installation of