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Hydration: How much do you need?

waterWe have been counseled to drink eight, 8-ounce glasses of water a day (8 x 8) for such a long time that the advice has become unwritten law…and slavishly followed at that. This chant started so long ago that most people have no idea of its origin. At the same time, we are cautioned not to count alcohol and coffee as hydration elements. The science behind the recommendation is so scant that little support can be given to the exhortation, yet the possession of a water bottle is ubiquitous. It is possible that this idea is the result of misinterpretation or misreading of a notion proposed by the Food and Nutrition Board of the National Research Council that recommended one milliliter of water for every calorie consumed. The neglected fact is that there is water in our food. That would surely separate liquid intake from total dietary intake.

Dr. Heinz Valtin, a medical professor at Dartmouth, examined this mantra earlier in this century, and learned, “No scientific studies were found in support of 8 x 8.”  After reviewing surveys of food and fluid intake on thousands of adults of both genders, Dr. Valtin stated that, “…such large amounts (of water) are not needed because the surveyed persons were presumably healthy and certainly not overtly ill.”  He added that most other kinds of beverages, including soft drinks and coffee, contribute to one’s daily need for hydration, continuing that a considerable body of evidence supports the premise that the human body is fully capable of maintaining proper water balance.  But all this must be tempered with the qualifier, “in healthy persons.”  He leaves us with, “…large intakes of fluid, equal to and greater than 8 x 8, are advisable for the treatment or prevention of some diseases and certainly are called for under special circumstances, such as vigorous work and exercise, especially in hot climates.”  In the spirit of open-mindedness, Dr. Valtin asks that readers submit their own findings to him.

Including the 20% supplied by foods, the Institute of Medicine recommends a fluid intake of about 91 ounces a day for women and 125 ounces for men.  Do you know how much water is in your food?  Few of us do. The puzzling thing about this recommendation is the lack of sufficient data available on water metabolism in adults, especially those who are sedentary and living in a temperate environment.  Most of us take in more than that suggested level, when we account for comestibles, although the geriatric populace is apt to take in less of both food and liquid water, partly because of insensitivity to a thirst stimulus and partly because of a waning ability to taste foods and beverages as well as they did in their early years.  It appears that older men drink less than their younger counterparts, but excrete more urine.  Differences in women have shown to be insignificant, but contribute to the notion that, “water turnover is highly variable among individuals…”  (Raman et al. 2004)

Admittedly, older adults are at greater risk for dehydration, but water balance in this population had not been faithfully studied until Purdue University picked up the reins in 2005, and compared/contrasted water intake/output and total balance of fluids in an older population (63-81 y.o.) and a younger one (23-46 y.o.), finding that, in fat-free mass, there is little difference.  The study noted, though, that fat-free mass was lower in the elderly and that fat-free hydration was significantly higher.  Considering that the elderly have less muscle to begin with, this is simple to follow.  (Bossingham. 2005)

Many people complain that, if they increase water intake, they will spend more time in the lavatory.  While this is the case with many of us, there is a limiting factor—time.  The period of time over which a specific amount of water is consumed makes a difference in when the urge to evacuate that water will arise.  The faster you drink that glass of water, the sooner you will need to excrete it.  The longer the glass lasts, the more time there will be prior to evacuation.  “A water diuresis occurs when a large volume of water is ingested rapidly.”  (Shafiee. 2005)   Also note that water mixed with a poorly absorbed sugar (not glucose) will retard absorption and delay excretion.

The kidneys can process almost four gallons of water a day.  Too much water will make you sick because sodium stores will become depleted and electrolyte activity will be sorely jeopardized.  Drinking over a period of time can thwart this threat.  You need not measure urine output to figure out how much fluid to replace.  That is something you can eyeball.  Thirst should not be the barometer by which fluid need is determined.  While there is no absolute proof that we all need 8 x 8, have a glass of water even when you are not thirsty, working in the heat, or running a marathon.  To prevent electrolyte displacement, we might consider electrolyte replacement in at least a couple of our glasses.

References

MAIN ABSTRACT
Am J Physiol Regul Integr Comp Physiol. November 2002; vol. 283 no. 5: R993-R1004
“Drink at least eight glasses of water a day.” Really? Is there scientific evidence for “8 × 8”? Heinz Valtin and (With the Technical Assistance of Sheila A. Gorman)

SUPPORTING ABSTRACTS
Am J Physiol Renal Physiol. 2004 Feb; 286(2):F394-401. Epub 2003 Nov 4.
Water turnover in 458 American adults 40-79 yr of age. Raman A, Schoeller DA, Subar AF, Troiano RP, Schatzkin A, Harris T, Bauer D, Bingham SA, Everhart JE, Newman AB, Tylavsky FA.
Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.

Am J Clin Nutr. 2005 Jun; 81(6):1342-50.
Water balance, hydration status, and fat-free mass hydration in younger and older adults. Bossingham MJ, Carnell NS, Campbell WW.
Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907, USA.

Kidney Int. 2005 Feb;67(2):613-21.
Defining conditions that lead to the retention of water: the importance of the arterial sodium concentration. Shafiee MA, Charest AF, Cheema-Dhadli S, Glick DN, Napolova O, Roozbeh J, Semenova E, Sharman A, Halperin ML.

Renal Division, St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada.

Am J Physiol Regul Integr Comp Physiol. 2000 Sep;279(3):R966-73.
Effects of time of day, gender, and menstrual cycle phase on the human response to a water load. Claybaugh JR, Sato AK, Crosswhite LK, Hassell LH.

Department of Clinical Investigation, Tripler Army Medical Center, Tripler Army Medical Center, Hawaii 96859 – 5000. [email protected]

Eur J Clin Nutr. 2010 Feb;64(2):115-23. Epub 2009 Sep 2.
Water as an essential nutrient: the physiological basis of hydration. Jéquier E, Constant F.
Department of Physiology, University of Lausanne, Pully, Switzerland. [email protected]

J Am Soc Nephrol 19: 1041-1043, 2008
Just Add Water
Dan Negoianu and Stanley Goldfarb

Renal, Electrolyte, and Hypertension Division, University of Pennsylvania, Philadelphia, Pennsylvania

*These statements have not been evaluated by the FDA.
These products are not intended to treat, diagnose, cure, or prevent any disease.

Who Needs Electrolytes and Why?

Many people talk about electrolytes but do you have any idea what electrolyte really is? Being among the smallest of chemicals important to a cell’s function, electrolytes are crucial to the manufacturing of energy, the maintenance of membrane stability, the movement of fluids in the body, and a few other jobs, such as contracting a muscle, like the heart.

No Sweat

You know that you’ll taste salt if you lick the back of your hand after jogging or cutting grass on a hot summer day. Sodium is one of sweat’s main ingredients, along with chloride and potassium. All three are carried to the surface of the skin by the water made in sweat glands and the salt stays after the liquid evaporates. The purpose of sweating is regulation of body temperature, which is achieved by the eccrine glands that cover much of the body. An adult can easily sweat two liters an hour (Godek, 2008), up to eight liters a day (Vukasinovic-Vesic, 2015). It’s the evaporation of the water that has the cooling effect. Some animals do not have efficient sweat glands, such as dogs that have to pant to cool down, or hogs that needs to wallow in mud or cool water.

After exercise — or other cause of heavy perspiration — it’s important to restore fluid balance, especially in hot weather when it is easy to get dehydrated. Rehydration occurs only if both water and electrolytes are replaced. The amount of electrolytes lost through sweat varies from person to person. Accurately matching beverage electrolyte intake with loss through sweat is practically impossible. If you are eating at the same time as drinking plain water, this may suffice for rehydration. Otherwise, inclusion of electrolytes is essential.

What Are They and What Do They Do?

In the body, the electrolytes include sodium, potassium, calcium, bicarbonate, magnesium, chloride, and phosphate. Not all are contained — or needed — in an electrolyte replacement beverage. Sodium, the main cation outside the cell, controls total amount of water in the body, regulates blood volume and maintains muscle and nerve function. You need at least 500 mg a day. The suggested upper level is 2300 mg, but most Americans ingest more than 3000. Chloride, also from table salt, is an anion. Found in extracellular fluids, chloride, in the company of sodium, helps to maintain proper fluid balance and pressure of the various fluid compartments.

Potassium is the major cation inside the cell, where its job is to regulate heart beat and blood pressure while balancing the other electrolytes. Because it aids in transmitting nerve impulses, potassium is necessary for muscle contractions, actually the relaxation half of the contraction. Deficiency of potassium is more common than overdose, and may arise from diarrhea or vomiting, with muscle weakness and cramping being symptoms. Intake of potassium is generally much lower than the recommended 4700 mg a day, which is not surprising in light of the deficits in food caused by insulting agricultural practices. Perhaps the most under-appreciated mineral in the nutrient armamentarium is magnesium, not only a constituent of more than three hundred biochemical reactions in the body, but also a role player in the synthesis of both DNA and RNA. As an electrolyte, magnesium supports nerve and muscle function, boosts immunity, monitors heart cadence, stabilizes blood glucose, and promotes healthy bones and teeth. With half the U.S. population deficient, Mg is the orphan nutrient that is able to prevent elevated markers of inflammation (such as CRP), hypertension (It’s called nature’s calcium channel blocker), atherosclerotic vascular disease, migraines, asthma, and colon cancer (Rosanoff, 2012). Supplementation with magnesium is uncertain because absorption is inverse to intake.

Like the others, calcium is involved in muscle contraction and the transmission of nerve messages, but also in blood clotting. Calcium tells sodium to initiate a contraction so that you can pick up a pencil or scratch your nose. In opposition, magnesium tells potassium to let the pencil go or to move your arm back down. Because the heart needs calcium for a strong beat, it will pull the mineral from bone if dietary sufficiency is missing. After calcium, phosphorus — phosphate — is the most abundant mineral in the body. This anion helps to produce energy inside the cell besides being a bone strengthener. It’s a major building block of DNA and the cell membrane. Bicarbonate keeps pH in balance and is important when muscles make lactic acid from work.

Where Can I Get the Electrolytes I Need?

There are scores of electrolyte replacements on the market and entirely too many with sugar or additives. The issue with electrolytes is, in all honesty, that they taste bitter and salty. The fact that sugar is a carbohydrate hinders the processing of a hydration drink because absorption is slowed. That’s what carbohydrates do. Sugar concentrations in many sports drinks are higher than that of body fluid, so will not be readily absorbed. Plain water passes through too fast; carb-laden drinks pass too slowly. Therefore, an electrolyte balanced drink will do the job better and faster. Sodium and potassium, after all, encourage fluid retention and help to reduce urine output.

It is common knowledge that most of us gravitate to sweetness in times of dehydration; saltiness less so. But when you need rehydration, choose the real stuff, BodyBio’s E-lyte and E-lyte Sport, two electrolyte replacements that copy the mineral balance of the body. Elyte may be used as a daily addition to the diet, and is effective to restore homeostasis in times of virus-induced gastrointestinal distress for adults and children, in electrolyte deficit from uncontrolled diabetes and even for restless leg syndrome. When sodium loss is high from exercise, chose Elyte Sport.

References

Coyle EF.
Fluid and fuel intake during exercise.
J Sports Sci. 2004 Jan;22(1):39-55.

Robert W. Kenefick, PhD and Michael N. Sawka, PhD
Hydration at the Work Site
J Am Coll Nutr. October 2007; vol. 26 no. suppl 5: 597S-603S

Meurman JH, Härkönen M, Näveri H, Koskinen J, Torkko H, Rytömaa I, Järvinen V, Turunen R.
Experimental sports drinks with minimal dental erosion effect.
Scand J Dent Res. 1990 Apr;98(2):120-8.

Noble WH, Donovan TE, Geissberger M.
Sports drinks and dental erosion.
J Calif Dent Assoc. 2011 Apr;39(4):233-8.

Sports Med. 2002;32(15):959-71.
Hydration testing of athletes.
Oppliger RA, Bartok C.

Sawka MN, Montain SJ, Latzka WA.
Hydration effects on thermoregulation and performance in the heat.
Comp Biochem Physiol A Mol Integr Physiol. 2001 Apr;128(4):679-90.

Convertino VA, Armstrong LE, Coyle EF, Mack GW, Sawka MN, Senay LC Jr, Sherman WM.
American College of Sports Medicine position stand. Exercise and fluid replacement.
Med Sci Sports Exerc. 1996 Jan;28(1):i-vii.

Rehrer NJ.
Fluid and electrolyte balance in ultra-endurance sport.
Sports Med. 2001;31(10):701-15.

Maughan RJ, Shirreffs SM.
Dehydration and rehydration in competative sport.
Scand J Med Sci Sports. 2010 Oct;20 Suppl 3:40-7

Gal Dubnov-Raza, Yair Lahavb, and Naama W. Constantinic
Non-nutrients in sports nutrition: Fluids, electrolytes, and ergogenic aids
e-SPEN, the European e-Journal of Clinical Nutrition and Metabolism. 6(4); Aug 2011: pp. e217-e222

*These statements have not been evaluated by the FDA.
These products are not intended to treat, diagnose, cure, or prevent any disease.

Athletes And Fuel – Feeling Fuelish?

runnerWhen it comes to fueling an athlete, there had been as many approaches as there are sports to play. Several respected bodies have merged philosophies to incorporate and publicize nutritional recommendations that can be adapted to most athletic pursuits. There is much about diet that is common sense, but the habits cultivated from family traditions just might fly in the face of that. Ethnic or regional cuisines may feature foods that upset the balance of both macro- and micro-nutrient intake. There is no doubt that the physiological needs of serious athletes have to be the first consideration in finding and combining the right fuels.

Optimal nutrition is mandatory if an athlete wants to realize his full potential during an event. Not only performance, but also recovery, is enhanced by food intake. A position paper issued jointly by the American Dietetic Association, the Dietitians of Canada, and the American College of Sports Medicine, states, “Energy and macronutrient needs, especially carbohydrate and protein, must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue,” continuing that, “Adequate food and fluid should be consumed before, during, and after exercise to help maintain blood glucose concentration during exercise, maximize exercise performance, and improve recovery time. Athletes should be well hydrated before exercise and drink enough fluid during and after exercise to balance fluid losses.”  (Rodriguez. 2009)

Your performance will be affected by genetics (over which you have zero control), training (over which you have total control), and diet (ditto). If you fail to consume enough energy, the body will use both fat and lean tissue as fuel. Strength and endurance will then suffer, and the immune system and endocrine glands will pay a stiff price. If you’re trying to lose weight, you still have to pay attention to energy intake. It takes calories to burn calories. This is especially true for women, who may experience amenorrhea and osteoporosis if they aren’t careful.

You can store about 400 to 600 grams of carbohydrates, or 1600 to 2400 calories’ worth. These glycogen stores can be burned in 1 ½ to 2 hours, after which fat is mobilized and you “hit the wall.”  You don’t want to get more than about 60 grams of carbohydrates (CHO) an hour while in a marathon, for example, or you might cramp, but your daily intake could be 5-7 grams per kilogram a day (about 3 grams per pound) for moderate exercise that lasts less than 1 ½ hours. For more intense exercise, like that marathon or a cycling event, that lasts more than a couple hours, you’ll need 8-12 grams of CHO a day per kilogram of body weight. Do this prior to, not during, an event. (Burke. 2011)  You might as well convert your body weight to kilograms now. Divide pounds by 2.2 and you’ll have it.

Eating before an event will enhance performance compared to fasting. Common sense says to eat lesser amounts an hour before an event than you would eat four hours ahead of a strenuous workout. Traditional wisdom says that consuming up to 1 gram of CHO per kg is fine one hour before the start; Consuming 4.5 gm/kg is O.K. four hours before. Take it easy on the fiber and fat, though, or you might experience GI distress. During practice sessions is the time to experiment with different foods to come up with effective refueling strategies that fit you.

Protein intake depends on the type and duration of exercise. 0.8 gm/kg/day is fine for the general public, but you’ll probably need more. An endurance athlete will need 1.2-1.4 gm/kg/day, while a weight lifter needs up to 1.7 gm/kg/day. More than 2.0 mg/kg can tax the kidneys and won’t make much physiological difference. It’s important to get protein right after exercise. There’s a 15 minute to 2-hour window during which muscle balance can be increased and muscle tissue can be repaired. Protein supplements are nothing more than a convenience. Besides, such supplements can become delivery systems for things you neither want nor need, like steroids and other illicit substances.

At the end of your performance you need to refill your buckets. That’s called recovery. Adding protein to your carbohydrate intake at a ratio of 3:1 or 4:1, CHO:Pro, can enhance recovery. (Ivy. 2001)  We know of a few marathoners who eat tuna sandwiches with chocolate milk. You might opt for a bowl of Cheerios and a banana, or a yogurt-fruit smoothie and pretzels. Listen to your body. You might end with steak and potatoes. Lemon meringue pie, and carrot cake, and oatmeal cookies, and…  Dream on….PSST, you can do without the sugar.

*These statements have not been evaluated by the FDA.
These products are not intended to treat, diagnose, cure, or prevent any disease.

Electrolytes and Sugar(s): Stuff You Need To Know

sports-drinkAlthough we are admonished not to mix electrolytes with sugars, we do it anyway. Most of the time it’s isn’t “we”, the consumer; it’s “we”, the marketer. The soda industry wouldn’t sell much product if it weren’t sweet. Plain carbonated lemon juice, cola syrup or turkey gravy just wouldn’t cut it. Even Ragu contains sugar, but thank goodness it isn’t fizzy. Sugar has no place in an electrolyte replacement beverage.

A few electrolyte drinks aimed at professional athletes contain some kind of sugar. The only purpose served by the sweetener is to add palatability. It does absolutely nothing—nada, zilch, zero—for bioavailability and efficacy of the electrolyte minerals. But it sure turns the coach into fly food after a win.

Tests at the University of Nebraska found that fructose increases fecal excretion of minerals, mostly iron and magnesium, but other electrolyte balances are likewise negatively affected (Ivatur, 1986). Sucrose is not without guilt. Well, now, magnesium is an electrolyte, which is supposed to be accompanied by sodium, potassium, chloride and calcium, all of them working to initiate and to inhibit a muscle contraction. In the absence of such contractions you couldn’t pick up the ten dollars your brother owes you. Even more dramatic, your heart might not run on all its cylinders.

Calling sugar a carbohydrate on a food ingredient label is misleading, so labeling guidelines now call it what it is…sugar. Itself, sugar arrests the secretion of stomach acid so that processing of nutrients, including the electrolyte minerals, is stymied. Creating acid in the intestine, however, sugar can lower pH by as much as one or two units, and being logarithmic, represent a tenfold or twentyfold difference in acidity (Rosen, 1965) (Stephan, 1943). Sugar even increases the acidity that tumors find so hospitable to their growth and development (DiPette, 1986).

Many of us are deficient in magnesium, partly because of sugar consumption. Beverage choices are paramount in this affliction (Ballew, 2000), and sports drinks containing sugar elevate insulin as part of the metabolic process, thus increasing the renal excretion of magnesium (Djurhuus, 1995, 2000) and calcium (Hodgkinson, 1965).

Mineral absorption occurs at the juncture of the duodenum and the jejunum. Sugar increases an acidic environment at that point, where it interferes with the alkalinity that minerals enjoy for absorption. The acidity might help the utilization of sugar, but does little for the electrolytes (Daniel, 1986). Major uptake of potassium and sodium occurs at pH of 8.0, with the others close behind. Electrolytes quite possibly are still absorbed at less-than-ideal pH, but why take a chance?

References

Carol Ballew, PhD; Sarah Kuester, MS, RD; Cathleen Gillespie
Beverage Choices Affect Adequacy of Children’s Nutrient Intakes
Arch Pediatr Adolesc Med. 2000;154:1148-1152

J A Blair, M L Lucas, and A J Matty
Acidification in the rat proximal jejunum.
J Physiol. 1975 February; 245(2): 333–350.

Daniel H, Rehner G.
Effect of metabolizable sugars on the mucosal surface pH of rat intestine.
J Nutr. 1986 May;116(5):768-77.

Donald J. DiPette, Kimberly A. Ward-Hartley, and Rakesh K. Jain
Effect of Glucose on Systemic Hemodynamics and Blood Flow Rate in Normal and
Tumor Tissues in Rats

CANCER RESEARCH 46, 6299-6304, December 1986

Dr. M.S. Djurhuus, P. Skøtt, O. Hother-Nielsen, N.A.H. Klitgaard, H. Beck-Nielsen
Insulin Increases Renal Magnesium Excretion: A Possible Cause of Magnesium Depletion in Hyperinsulinaemic States
Diabetic Medicine. Volume 12, Issue 8, pages 664–669, August 1995

S. Djurhuus
Hyperglycaemia enhances renal magnesium excretion in Type 1 diabetic patients
Scan Jou of Clin & Laboratory Investigation. 2000, Vol. 60, No. 5 , Pages 403-410 

Hodgkinson, A and Heaton FW
The effect of food ingestion on the urinary excretion of calcium and magnesium
Clinica Chimica Acta. Volume 11, Issue 4, April 1965, Pages 354-362

Holbrook JT, Smith JC Jr, Reiser S.
Dietary fructose or starch: effects on copper, zinc, iron, manganese, calcium, and magnesium balances in humans.
Am J Clin Nutr. 1989 Jun;49(6):1290-4.

Rao Venkata Krishna Ivatur
Mineral bioutilization as affected by sugars
ETD collection for University of Nebraska – Lincoln.(January 1, 1986). Paper AAI862953

Ivaturi R, Kies C.
Mineral balances in humans as affected by fructose, high fructose corn syrup and sucrose.
Plant Foods Hum Nutr. 1992 Apr;42(2):143-51.

Rosen S, Weisenstein PR.
The effect of sugar solutions on pH of dental plaques from caries-susceptible and caries-free individuals.
J Dent Res. 1965 Sep-Oct;44(5):845-9.

Stephan RM, Miller BF.
A quantitative method for evaluating physical and chemical agents which modify production of acids in bacterial plaques on human teeth.
J Dent Res. 1943;22;45-51.

*These statements have not been evaluated by the FDA.
These products are not intended to treat, diagnose, cure, or prevent any disease.