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Veroorzaken thee en koffie dehydratie?*

Dit is een belangrijke vraag voor iedereen omdat dehydratie niet gezond is zeker niet voor kankerpatiënten die bijv. een chemokuur ondergaan, de bijwerkingen kunnen dan veel groter worden.

Uit een analyse van ruim 30 studies over koffie, thee, cafeïne en dehydratie kunnen we het volgende concluderen:

Allereerst koffie en bepaalde frisdranken bevatten de meeste cafeïne, thee doorgaans de helft minder.

Normaal gebruik van cafeïne houdende dranken zoals koffie en thee veroorzaakt geen extra uitscheiding. M.a.w. er wordt nauwelijks meer vocht via de urine uitgescheiden dan dat er ingenomen wordt. Er is dus geen sprake van dehydratie.

Voor de meeste gebruikers zijn er meer voordelen van koffie bij normaal gebruik, 2-4 koppen per dag, dan nadelen. Doch voor mensen die gevoelig zijn voor de nadelen zoals kinderen, ouderen, zwangere vrouwen, mensen met hoge bloeddruk, onrustige mensen, bij het gebruik van bepaalde medicijnen en bij kanker kan koffie beter vermeden worden. Thee in allerlei soorten kan dan een beter alternatief zijn.
Do Caffeinated Beverages Cause Dehydration?
This article addresses a thoughtful question that was submitted by one of our website participants. This person asked, “I enjoy a cup of coffee in the morning and a couple of cups of tea during the day. My health care provider told me that because these drinks contain caffeine, they don’t count toward my fluid intake. Is this true?” This is an excellent question. Staying well hydrated is important for all people, but this is especially important for people who are receiving cancer treatments.
The severity of some chemotherapy side effects can be worsened by dehydration. For certain types of chemotherapy, dehydration can increase the toxicity of these therapies. In some cases, dehydration can be life-threatening. Dehydration can contribute to fatigue, headaches, and nausea as well. For all of these reasons, staying well hydrated is vital to good health, both during and after cancer care.
Caffeine and Diuresis
Caffeine has long been considered a diuretic. A diuretic is a substance that causes diuresis, which is a technical term meaning increased excretion of urine by the kidneys. Many people believe that this means caffeinated drinks cause more fluid to be lost from the body than the beverage itself provides, contributing to dehydration. While this belief is common among both the public and medical professionals, research does not support it.
Caffeine Research
Caffeine is one of the most frequently consumed “drugs” worldwide (1,2). It is used for a variety of reasons, but the one with which most of us are familiar is the morning coffee ritual. Indeed, consuming coffee, a good source of caffeine, is proven to enhance alertness and mental function in both regular caffeine consumers and non-consumers (2-4).
Caffeine and Hydration 
In addition to the positive effects of caffeine, such as enhancing alertness, many people worry that there are negative effects of drinking caffeinated beverages, such as contributing to dehydration. Fortunately, the research does not support that drinking moderate amounts of caffeinated beverages cause dehydration (5-10).
Researchers have conducted controlled human studies to examine how caffeine affects hydration under a variety of conditions. Under normal, “everyday” circumstances, caffeine does not cause more fluid to be lost from the body than the caffeinated beverage itself provides (7,8). Caffeine may cause a bit more fluid to be excreted (as urine) in the short term (24 hour period) when compared to plain water, but this effect is mild and is not documented to affect hydration status (7).
When used in people who are exercising regularly, even when exercising in hot, humid conditions, caffeinated beverages appear to provide plenty of fluid for rehydration and do not contribute to dehydration (5,6,9,10). This appears to be true for both non-exercisers and those who exercise regularly.
Caffeine and Health 
When it comes to overall health, it appears that for healthy adults the richest source of caffeine – coffee – provides more benefit than harm when consumed moderately (11,12). In fact, research tells us that coffee is the top source of antioxidants in the American diet (13,14).
The majority of the hundreds of studies on coffee and health find low risk of harm when consuming up to 3-4 cups per day. When consuming more than this, the potential risks quickly begin to outweigh any benefits of this beverage. The key, as with most things, is moderation! Other caffeinated beverages, such as tea, also appear to provide health benefits for healthy adults (15).
Caffeine can have serious downsides in people who are more susceptible to its negative effects, such as the elderly; children and teens; those with high blood pressure, heart disease, and anxiety disorders; and pregnant women. In these cases, caffeine and coffee may need to be avoided altogether. If you are concerned about how caffeine may affect your health, be sure to talk to your doctor about this.
It is important to note that even though caffeine doesn’t appear to contribute to dehydration, it can have other effects on the kidneys. Caffeine can cause increased excretion of sodium (salt) from the body (16). Again, for most healthy adults, this does not appear to cause health problems. However, for certain individuals, such as those who are taking medications that are affected by salt and sodium balance in the body, caffeine may need to be avoided. If you have any questions about how caffeine may affect your medications, talk to your doctor, nurse, or dietitian.
Caffeine and Sleep 
One potential downside to caffeine is the effect its consumption can have on sleep. Research tells us that caffeine can disrupt sleep even when consumed many hours before a person goes to bed (2). Some research suggests there may be a genetic component that explains why certain people experience insomnia if they consume caffeine and others do not (17-19). Other research suggests that in most healthy adults, caffeine will not measurably affect the duration of sleep (20). The bottom line is that some people may experience insomnia with caffeine consumption and others may not. If you have difficulty with insomnia, avoiding caffeine may be one way to help manage this problem.
Caffeine and Cancer Care
One of the single most important things you can do during cancer treatment to help your body heal and recover is to avoid losing weight (21-31). If you think about this a bit, it makes sense.
Weight loss occurs when you are eating fewer calories than your body needs for basic functions, such as breathing, heart rate, and metabolism. This forces your body to use its own tissues for energy. When this happens, when your body is breaking down its own tissue simply to get enough energy for basic functioning, it does not have enough energy for healing and recovery.
If you are experiencing weight loss during cancer treatment, this is one time that caffeinated beverages may do more harm than good. If consumed in moderation, caffeine itself isn’t a major problem for weight loss. However, many caffeinated beverages, such as coffee and tea, do not contain any calories. If you are having trouble keeping your weight up, you cannot afford to fill up on low- and no-calorie beverages.
If you do not need to avoid caffeine for medical reasons, it is fine to have a cup of coffee in the morning if that is what you are accustomed to doing. However, if you are losing weight, you should not consume additional caffeinated, no-calorie beverages throughout the day. Instead, try juice, milk, soy or rice milk, smoothies, shakes, or other drinks that will give you the extra calories you need to prevent or minimize weight loss during cancer treatment.
Fitting Caffeinated Beverages into a Healthy Diet
If you are feeling reasonably well, you are not losing weight, and you are not experiencing symptoms that interfere with your ability to eat normally, having some coffee and tea each day is fine and may even provide health benefits. These beverages do provide fluid and they do count toward your daily fluid intake. They do not cause dehydration when consumed moderately.
The most important point is to keep your intake of caffeine in a reasonable range. As mentioned above, for most people, 3 to 4 cups per day appears to be the highest level of coffee that safely can be consumed without major health consequences. Any more than this and you may begin to experience negative side effects such as jitters, anxiety, heart palpitations, and insomnia.
What is a cup? 
A cup of coffee means 8 ounces. This may come as a surprise to people who enjoy a daily super-sized, mocha latte. Be sure that if you have a very large coffee, you count this as the appropriate number of servings. For example, if your typical cup of coffee is 16 ounces, in reality, this counts as 2 cups.
Tea contains much less caffeine than coffee and may provide some unique health benefits. Both green and black tea appear to have cancer preventive activities in the body (32,33). For this reason, tea is a great choice if you would like to enjoy caffeinated beverages.
A Final Note on Preventing Weight Loss
As I mentioned, it is fine to consume some caffeinated beverages, as long as you are not losing weight. If you are going through treatment and you are losing weight, the most important thing you can do is to eat enough to stop, or at least minimize the weight loss. This means that beverages with no calories, such as coffee and tea, should not be a major part of your diet at this time.
If you are losing weight, ask your doctor or nurse about medical options for better managing your symptoms. Ask for a referral to a dietitian if one is available where you are receiving your cancer treatment.
In addition to this, you can go to the Nutrition section of Caring4Cancer.com at http://www.caring4cancer.com/go/cancer/nutrition. There you can click on links for information on Nutrition and Cancer Treatment, Symptom Support, and Recipes. All of these areas will give you ideas, tips, and hints for better eating during cancer treatment. 
References
1. Bolignano D, Coppolino G, Barillà A, Campo S, Criseo M, Tripodo D, Buemi M. Caffeine and the kidney: what evidence right now? J Ren Nutr. 2007;17(4):225-34. 
2. Roehrs T, Roth T. Caffeine: Sleep and daytime sleepiness. Sleep Med Rev. 2008;12(2):153-62. 
3. Hewlett P, Smith A. Effects of repeated doses of caffeine on performance and alertness: new data and secondary analyses. Hum Psychopharmacol. 2007;22(6):339-50. 
4. Smith AP, Christopher G, Sutherland D. Effects of caffeine in overnight-withdrawn consumers and non-consumers. Nutr Neurosci. 2006;9(1-2):63-71. 
5. Armstrong LE, Casa DJ, Maresh CM, Ganio MS. Caffeine, fluid-electrolyte balance, temperature regulation, and exercise-heat tolerance. Exerc Sport Sci Rev. 2007;35(3):135-40. 
6. Millard-Stafford ML, Cureton KJ, Wingo JE, Trilk J, Warren GL, Buyckx M. Hydration during exercise in warm, humid conditions: effect of a caffeinated sports drink. Int J Sport Nutr Exerc Metab. 2007;17(2):163-77. 
7. Bird ET, Parker BD, Kim HS, Coffield KS. Caffeine ingestion and lower urinary tract symptoms in healthy volunteers. Neurourol Urodyn. 2005;24(7):611-5. 
8. Armstrong LE, Pumerantz AC, Roti MW, Judelson DA, Watson G, Dias JC, Sokmen B, Casa DJ, Maresh CM, Lieberman H, Kellogg M. Fluid, electrolyte, and renal indices of hydration during 11 days of controlled caffeine consumption. Int J Sport Nutr Exerc Metab. 2005;15(3):252-65. 
9. Fiala KA, Casa DJ, Roti MW. Rehydration with a caffeinated beverage during the nonexercise periods of 3 consecutive days of 2-a-day practices. Int J Sport Nutr Exerc Metab. 2004;14(4):419-29. 
10. Armstrong LE. Caffeine, body fluid-electrolyte balance, and exercise performance. Int J Sport Nutr Exerc Metab. 2002;12(2):189-206. 
11. Ranheim T, Halvorsen B. Coffee consumption and human health--beneficial or detrimental?--Mechanisms for effects of coffee consumption on different risk factors for cardiovascular disease and type 2 diabetes mellitus. Mol Nutr Food Res. 2005;49(3):274-84. 
12. La Vecchia C, Tavani A. Coffee and cancer risk: an update. Eur J Cancer Prev. 2007;16(5):385-89. 
13. American Chemical Society Meeting & Exposition, Washington, D.C., Aug. 27-Sept. 1, 2005. News release, American Chemical Society. 
14. Richelle M, Tavazzi I, Offord E. Comparison of the antioxidant activity of commonly consumed polyphenolic beverages (coffee, cocoa, and tea) prepared per cup serving. J Agric Food Chem. 2001;49(7):3438-42. 
15. Gardner EJ, Ruxton CH, Leeds AR. Black tea--helpful or harmful? A review of the evidence. Eur J Clin Nutr. 2007;61(1):3-18. 
16. Shirley DG, Walter SJ, Noormohamed FH. Natriuretic effect of caffeine: assessment of segmental sodium reabsorption in humans. Clin Sci (Lond). 2002;103(5):461-66. 
17. Luciano M, Zhu G, Kirk KM, Gordon SD, Heath AC, Montgomery GW, Martin NG. "No thanks, it keeps me awake": the genetics of coffee-attributed sleep disturbance. Sleep. 2007;30(10):1378-86. 
18. Drake CL, Jefferson C, Roehrs T, Roth T. Stress-related sleep disturbance and polysomnographic response to caffeine. Sleep Med. 2006;7(7):567-72. 
19. Rétey JV, Adam M, Khatami R, Luhmann UF, Jung HH, Berger W, Landolt HP. A genetic variation in the adenosine A2A receptor gene (ADORA2A) contributes to individual sensitivity to caffeine effects on sleep. Clin Pharmacol Ther. 2007;81(5):692-98. 
20. Sanchez-Ortuno M, Moore N, Taillard J, Valtat C, Leger D, Bioulac B, Philip P. Sleep duration and caffeine consumption in a French middle-aged working population. Sleep Med. 2005;6(3):247-51. 
21. Isenring EA, Bauer JD, Capra S. Nutrition support using the American Dietetic Association medical nutrition therapy protocol for radiation oncology patients improves dietary intake compared with standard practice. J Am Diet Assoc. 2007;107(3):404-12. 
22. Ravasco P, Monteiro Grillo I, Camilo M. Cancer wasting and quality of life react to early individualized nutritional counselling! Clin Nutr. 2007;26(1):7-15. 
23. Odelli C, Burgess D, Bateman L, Hughes A, Ackland S, Gillies J, Collins CE. Nutrition support improves patient outcomes, treatment tolerance and admission characteristics in oesophageal cancer. Clin Oncol (R Coll Radiol). 2005;17(8):639-45. 
24. Van Cutsem E, Arends J. The causes and consequences of cancer-associated malnutrition. Eur J Oncol Nurs. 2005;9 Suppl 2:S51-63. 
25. Ravasco P, Monteiro-Grillo I, Marques Vidal P, Camilo ME. Impact of nutrition on outcome: a prospective randomized controlled trial in patients with head and neck cancer undergoing radiotherapy. Head Neck. 2005;27(8):659-68. 
26. Ravasco P, Monteiro-Grillo I, Vidal PM, Camilo ME. Dietary counseling improves patient outcomes: a prospective, randomized, controlled trial in colorectal cancer patients undergoing radiotherapy. J Clin Oncol. 2005;23(7):1431-38. 
27. Bauer J, Capra S, Battistutta D, Davidson W, Ash S; Cancer Cachexia Study Group. Compliance with nutrition prescription improves outcomes in patients with unresectable pancreatic cancer. Clin Nutr. 2005;24(6):998-1004. 
28. Davidson W, Ash S, Capra S, Bauer J; Cancer Cachexia Study Group. Weight stabilisation is associated with improved survival duration and quality of life in unresectable pancreatic cancer. Clin Nutr. 2004;23(2):239-47. 
29. Isenring EA, Capra S, Bauer JD. Nutrition intervention is beneficial in oncology outpatients receiving radiotherapy to the gastrointestinal or head and neck area. Br J Cancer. 2004;91(3):447-52. 
30. Ravasco P, Monteiro-Grillo I, Vidal PM, Camilo ME. Cancer: disease and nutrition are key determinants of patients' quality of life. Support Care Cancer. 2004;12(4):246-52. 
31. Andreyev HJ, Norman AR, Oates J, Cunningham D. Why do patients with weight loss have a worse outcome when undergoing chemotherapy for gastrointestinal malignancies? Eur J Cancer. 1998;34(4):503-09. 
32. Chen D, Milacic V, Chen MS, Wan SB, Lam WH, Huo C, Landis-Piwowar KR, Cui QC, Wali A, Chan TH, Dou QP. Tea polyphenols, their biological effects and potential molecular targets. Histol Histopathol. 2008;23(4):487-96. 
33. Khan N, Afaq F, Mukhtar H. Cancer chemoprevention through dietary antioxidants: progress and promise. Antioxid Redox Signal. 2008;10(3):475-510. 
Publish Date: May 2008 (Mei 2008)

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