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| Not the best way to find out the effects of caffeine on the body |
Do you ever get that gut feeling when drinking coffee?-Coffee and the gastrointestinal system
There is strong evidence that coffee increases gastric acid secretion. Interestingly experiments have shown that it's the other constituents in coffee that contribute to this increase in gastric acid secretion.
This was shown by measuring the dose response of caffeine, regular coffee and decaffeinated coffee for gastric acid secretion in normal subjects. Both regular coffee and decaffeinated coffee gave a similar response in gastric acid secretion which was higher than that of caffeine alone (on a cup equivalent basis) (Cohen and Booth, 1975).
The dose response? what??
Measuring the dose-response enables scientists to observe the change in an effect (in this case:gastric acid secretion) caused by varying the levels of dose of a substance (in this case: dosage of caffeine, regular coffee and decaffeinated) after a certain length of time.
Kidney function
The kidneys play an important role in filtering the blood. The kidneys remove waste products (such as urea) and extra water from the blood which form urine. Any drinker of caffeine beverages is well aware that caffeine tends to stimulate an increased flow of urine.
Caffeine was traditionally used to increase urine output until more potent diuretics became available. The diuretic effects of caffeine appear to be due to an increased rate in blood flow to the kidneys and increased rate of blood filtration. These affects are due to antagonism of circulating adenosine (see previous post) having a regulatory role in the formation of urine (Fredholm 1984).
So will my cup of coffee cause a fluid imbalance?
A dose of 300mg of caffeine (approximately 4-5 cups) can cause acute diuresis- this has been shown by several studies (Oswald and Schnermann., 2011). Caffeine will only cause a significant increases in the volume of urine excretion and a negative fluid imbalance in a large dose. A study in which caffeine was given (6mg/kg) for 11 days showed no effect in daily urine volume (Armstrong et.al 2005).
Time for a breather-Respiratory system
Caffeine is a respiratory stimulant (Braun 1996). However based on the average person's caffeine consumption has little effect on the respiratory system. Larger doses of caffeine has proven to be effective in the treatment of neonatal apnea-the cessation of breathing in newborns.
Upcoming posts
How about I keep it a surprise this time?
Braun S., 1996., Buzz: The Science and Lore of Alcohol and Caffeine., Cary., NC., USA., Oxford University Press
., 252-265. Cohen, S., and Booth, G. H. 1975., Gastric acid secretion and lower-esophageal-sphincter pressure in response to coffee and caffeine., New England Journal of Medicine., 293,897-899.
Fredholm, B. B., 1984.,Cardiovascular and renal actions of methylxanthines., New York:Alan R.Liss
Oswald H and Schnermann J., 2011., Methylxanthines and the Kidney., Handbook of experimental pharmacology., 200., 391-412.
This was shown by measuring the dose response of caffeine, regular coffee and decaffeinated coffee for gastric acid secretion in normal subjects. Both regular coffee and decaffeinated coffee gave a similar response in gastric acid secretion which was higher than that of caffeine alone (on a cup equivalent basis) (Cohen and Booth, 1975).
The dose response? what??
Measuring the dose-response enables scientists to observe the change in an effect (in this case:gastric acid secretion) caused by varying the levels of dose of a substance (in this case: dosage of caffeine, regular coffee and decaffeinated) after a certain length of time.
Kidney function
The kidneys play an important role in filtering the blood. The kidneys remove waste products (such as urea) and extra water from the blood which form urine. Any drinker of caffeine beverages is well aware that caffeine tends to stimulate an increased flow of urine.
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| Anatomy of Kidney |
Caffeine was traditionally used to increase urine output until more potent diuretics became available. The diuretic effects of caffeine appear to be due to an increased rate in blood flow to the kidneys and increased rate of blood filtration. These affects are due to antagonism of circulating adenosine (see previous post) having a regulatory role in the formation of urine (Fredholm 1984).
So will my cup of coffee cause a fluid imbalance?
A dose of 300mg of caffeine (approximately 4-5 cups) can cause acute diuresis- this has been shown by several studies (Oswald and Schnermann., 2011). Caffeine will only cause a significant increases in the volume of urine excretion and a negative fluid imbalance in a large dose. A study in which caffeine was given (6mg/kg) for 11 days showed no effect in daily urine volume (Armstrong et.al 2005).
Time for a breather-Respiratory system
Caffeine is a respiratory stimulant (Braun 1996). However based on the average person's caffeine consumption has little effect on the respiratory system. Larger doses of caffeine has proven to be effective in the treatment of neonatal apnea-the cessation of breathing in newborns.
Upcoming posts
How about I keep it a surprise this time?
References
Armstrong LE, Pumerantz AC, Roti MW, Judelson DA, Watson G,
Dias JC, Sokmen B, Casa DJ, Maresh CM, Lieberman H, Kellogg M. 2005., Fluid,
electrolyte, and renal indices of hydration during 11 days of controlled
caffeine consumption. Int J Nutr Exerc Metab. 15
Braun S., 1996., Buzz: The Science and Lore of Alcohol and Caffeine., Cary., NC., USA., Oxford University Press
., 252-265. Cohen, S., and Booth, G. H. 1975., Gastric acid secretion and lower-esophageal-sphincter pressure in response to coffee and caffeine., New England Journal of Medicine., 293,897-899.
Fredholm, B. B., 1984.,Cardiovascular and renal actions of methylxanthines., New York:Alan R.Liss
Oswald H and Schnermann J., 2011., Methylxanthines and the Kidney., Handbook of experimental pharmacology., 200., 391-412.
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