cafeine

[KumaR]

Heeft cafeine negatieve effecten?

[Trasher]

bij hoge dosis/hoge gevoeligheid:
slapeloosheid
scheiterij
nieren
afname concentratie

check google 4 more

[XXLtje]

Cafeïne - Wikipedia

Food-Info.net : Gezondheidseffecten van cafeine

[skydirk]

veel koffie of alcohol bevordert ook omzetting van testosteron naar oestrogeen.

[KaLe]

Origineel gepost door skydirk

veel koffie of alcohol bevordert ook omzetting van testosteron naar oestrogeen.

Koffie en oestrogeen?? Heb je daar een artikel van? Eerste keer dat ik dit hoor.

[Kartoffel]

Origineel gepost door skydirk

veel koffie of alcohol bevordert ook omzetting van testosteron naar oestrogeen.

Bron?

[Kartoffel]

Wist je dat als je op de kop gaat staan en dan een appel eet, je al je oestrogeen omzet in testosteron.

[skydirk]

dat weet ik van de bekendste HRT dokter van Belgie die er zich dagelijks mee bezighoudt. alcohol meer dan koffie. en hij zal wel weten waarover hij spreekt want als hij je hormonen voorschrijft, wordt je bloed regelmatig gecontroleerd om dosis aan te passen. en iets wat hij vooral ook nakijkt is de omzetting van testosteron naar oestrogeen.

[sctuning]

Heb je iets van een link?

SC

[skydirk]

hij is de link. ik ben ooit een klein jaartje bij hem op consultatie geweest. ik heb wel het boek thuis dat hij geschreven heeft, waar het volgens mij ook instaat. Dr Hertoghe de bekende anti-agingdokter en endocrinoloog.

[KaLe]

Waarom is dit verder dan niet bekend gemaakt??

[Kartoffel]

Origineel gepost door skydirk

veel koffie of alcohol bevordert ook omzetting van testosteron naar oestrogeen.

Heeft iemand hier misschien wat meer info over?

[XXLtje]

Origineel gepost door Kartoffel

Heeft iemand hier misschien wat meer info over?

Onderzoekers van het Instituut voor Dermatologie en Allergologie aan de Universiteit van het Duitse Jena onderzochten het effect van cafeïne en testosteron op haarfollikels. Ze wilden het effect onderzoeken van substanties op erfelijk haarverlies (androgenetic alopecia) en de mannelijke kaalheid (AGA), waaraan vijftig procent van de mannen lijdt. Daarvoor worden haarfollikels gebruikt, genomen van de bovenzijde van de scalp van hun mannelijke testpersonen. Ze vonden dat applicatie van cafeïne de haargroei stimuleerde, terwijl testosteron de groei duidelijk verhinderde. Het team concludeerde dat cafeïne een belangrijke klinische bijdrage kan leveren aan het bestrijden van AGA. Cafeïne werd al gebruikt in de After Shampoo Liquid van Alpecin Cosmetics en in het Alcina Plantur-concept, dat werking tegen kaalheid claimt omdat cafeïne het testosteronniveau reguleert. In dit onderzoek werd alleen de locale toepassing van cafeïne onderzocht. Of ook het drinken van koffie de haargroei stimuleert, is nog niet bewezen.

Caffeine raises blood pressure, a condition associated with infertility in men and decreased libido in both sexes. Caffeine also places stress on the adrenal glands, which are important to the creation of most hormones. Medical studies show regular caffeine intake decreases testosteron production. It also increases muscle tension, making it hard to relax. This is detrimental since a state of relaxation is very important to a satisfactory sexual experience. Lastly, caffeine is a vasoconstrictor and can impede the penis' ability to fill with blood, resulting in soft or no erections.

alcohol

Alcohol is a depressant and reduces testosteron levels in men. According to a Duke University Medical Center study, regular moderate male drinkers experienced reduced capacity for penile erection, semen production and sperm counts. Consuming even small amounts of alcohol interferes with a man's ability to control premature ejaculation and can result in fewer or no orgasms and decreased orgasm quality.

[Kartoffel]

Thanks XXLtje
Nog meer info over de effecten van cafeine:

Artikel over effect cafeine op vetverbranding:
Cafeïne verbrandt vet op twee manieren

Stukje uit het artikel:
Dat cafeïne de verbranding van vet verhoogt staat inmiddels vast. Maar hoe, daarover is nog weinig bekend. Uit proeven weten we dat cafeine de stofwisseling van cellen verhoogt door het cyclisch nucleotide fosfodiesterase te remmen. Daardoor verandert er in de cel minder van het signaalmolecuul cAMP in het energiemolecuul AMP.




Ander artikel, zelfde pagina:
Cafeïne verbrandt vet op twee manieren

Trainen met spierpijn kan, dankzij cafeine

Cafeine doet wat vitamines, visolie en andere supplementen niet kunnen. Het voorkomt spierpijn tijdens trainingssessies. Dat ontdekten onderzoekers van de University of Georgia.





Weer ander artikel, zelfde pagina:
Cafeïne verbrandt vet op twee manieren

Cafeine maakt resistent voor insuline

Een forse dosis cafeine vermindert de werking van insuline. Dat ontdekten Nijmeegse onderzoekers door onderzoek naar mensen. Voor iemand van honderd kilo waren tussen de vier en de zes koppen koffie genoeg om het effect te bereiken.



Caffeine shown to increase performance in rugby
Caffeine shown to increase performance in rugby

Friday, 15 April 2005
Auckland University of Technology
Scoop

A new study into the effects of caffeine on rugby players suggests it can significantly enhance performance in several ways. The study was performed by Gene Stuart, a research student at the Auckland University of Technology and was supervised by AUT’s Professor Will Hopkins.




Caffeine Might Cut Post-Workout Pain
By Jeanna Bryner, LiveScience Staff Writer

posted: 09 January 2007 04:09 pm ET

Caffeine Might Cut Post-Workout Pain | LiveScience
Caffeine, Health and Bodybuilding
The negative effects of caffeine include its links with raised blood pressure, increased heart rate, arrhythmias, dehydration, anxiety, insomnia, headaches, heartburn, osteoporosis, birth defects, digestive ulcers, miscarriage, infertility, cancer, cardiovascular disease, and more. Please be aware however that these needn't be true, it's just that they are reported.
Reported positive effects of caffeine are relief of fatigue, improve alertness and mental efficiency, creativity and improved athletic performance.

Caffeine Metabolism, Half Life and Toxicity
Caffeine is rapidly absorbed from the digestive system reaching peak concentration in blood 60-90 minutes after ingestion. Caffeine is then metabolised in the liver by the cytochrome P450 enzyme system producing a number of metabolites and some is excreted unchanged in urine. Complete clearance of caffeine from plasma and urine is not until 24-48 hours after ingestion of the last dose. The average half life of caffeine is 4-5 hours but this can vary between 2-10 hours as a result of genetic, physiological and environmental factors (FSPB 2002).
The LD50 (lethal dose for 50% of the population) of oral caffeine is estimated to be 10g, i.e. the equivalent to 50-100 cups of coffee; however this is merely an estimate (Thomas 2003). Toxic effects are abdominal pains, vomiting, seizures and reduced consciousness. Most cases of overdose are due to over consumption of pills and stimulants.

Caffeine as a Stimulant
Methylxanthines exert their effect by blocking certain adenosine receptors in the brain. Adenosine slows down brain activity by a neuronal method not entirely understood, so by blocking its uptake, caffeine acts as a stimulant. Its stimulatory effects propel directly or indirectly onto the heart, lungs, blood vessels, kidneys and muscles causing an improvement in performance and possibly strength.

Caffeine and Athletic Performance
This is the bit we're interested in! Does caffeine help our performance in the gym and ultimately improve our gains? The short answer is yes it does, and this has been confirmed scientifically!
Caffeine has been shown to increase both short term intense exercise performance, 'stop-start' activities (football, rugby, etc), long distance running and help our performance in the gym, so we can train more effectively and ultimately increase size and strength. (EU SCF 2001; Kovacs et al 1998).
The mechanism of how caffeine initiates its ergogenic effect is, however, poorly understood. It is likely that it increases fat burning, thus sparing our carbohydrate stores, which in turn means that the point of lack of ready carbohydrate availability is delayed, so helps performance. This theory also acknowledges the fact that caffeine is slightly fat oxidising, therefore useful in keeping body fat off.
Caffeine may also stimulate neural signals between the brain and neuromuscular junction (how nerves cause muscles to contract) and increase production of metabolites in muscle helping contraction occur.

FSPB Stimulant Drinks Committee (2002). A Review of the Effects of Stimulant Drinks. FSPB
Kovacs EMR, et al (1998). Effect of caffeinated drinks on substrate metabolism, caffeine excretion and performance. J Appl Physio 85: 709-715
Thomas B (2003). Caffeine and Health: A Review. Unilever Bestfoods Ltd





Strong brew: the right dose of caffeine can power you to bigger gains in the gym Muscle & Fitness - Find Articles

Steve O'Reilly, RD, LD, Is CEO of Underdog Nutrition

"Caffeine helps to increase strength because it triggers the release of epinephrine from the adrenal glands, resulting in improved muscle contractions," says O'Reilly. "When this happens, perceived exertion is reduced, allowing athletes to push more weight without making a conscious decision to work harder." While these benefits are not long-lasting, regular use of caffeine before exercise will lead to the long-term benefit of improved strength, which of course is clearly associated with increased muscle mass.

Furthermore, O'Reilly says that caffeine consumption shouldn't affect your muscles' growth rate due to appetite suppression. "Caffeine, especially when taken with ephedrine, suppresses appetite. However, by itself, caffeine's ability to do so seems to be much weaker." O'Reilly notes that if you're taking a thermogenic product, chances are that it contains several other ingredients, some of which are likely more responsible for your decreased appetite than the caffeine itself.

I recommend preworkout caffeine during all phases of a bodybuilding program," O'Reilly says. "It's one of the most thoroughly researched and proven ergogenic supplements available. If you take caffeine 45 minutes before exercise and then work out for 60-90 minutes, your appetite should be somewhat recovered within an hour, post-exercise. If you simply cannot stomach whole food after your workout, just switch your post-workout meal to a protein/carb shake, which will be much easier to get down and may be absorbed more rapidly anyway."

Caffeine lowers perceptual response and increases power output during high-intensity cycling. Journal of Sports Science, 22(7):637-643, 2004.
Effects of caffeine on energy metabolism, heart rate, and methylxanthine metabolism in lean and obese women. American Journal of Physiology, (269):671-678, 1995.