voedings en dieetkunde, weer een andere dag op school...

[sf01]

Hey Marnop. Ik mag je echt. Vind je een top gozer... Maar eerlijk gezegd... ik zie het niet.

Voor mijn idee is er niet zozeer sprake van een superieure houding, maar puur een vragen naar onderbouwing voor stellingen/meningen.
Zoals ik eerder al zei... er wordt zoveel geroepen en eindeloos herhaalt. Ik denk zeker op het gebied van voeding en trainen, wat werkt, hoe en waarom... zijn bronnen alles.
Ik weet het... het is niet relaxt. Je moet dingen erbij gaan zoeken als mensen erop doorvragen. Maar zo haal je wel de klakkeloos herhaalde onzin eruit. Waarmee ik trouwens geenzins wat jij verkondigt daar onder schaar.

Ik ben zelf nu ook maar begonnen met bepaalde stellingen/meningen die ik er op na hou in een document bij elkaar te zetten met de bronverwijzingen erbij. Omdat ik moe werd van het maar telkens weer info op moeten zoeken

Maar in alle eerlijkheid. In dit hele proces, heb ik de afgelopen tijd ook aardig wat meningen/stellingen moeten herzien, bijschaven. En stond ik af en toe met het schaamrood op mijn kaken bij het snoeihard ermee geconfronteerd worden dat ik het fout had.

Laten we gewoon allemaal proberen om de discussies puur te houden. Inhoudelijk, en niet te persoonlijk.

Just my 50 cents

[Falstyr]

Glutamine... vind dat aminozuur persoonlijk ook over the top. Krijgt meer toegedicht dan het werkelijk lijkt te doen. Dit in tegenstelling tot L-leucine. Het aminozuur voor zowel afvallen als zo snel mogelijk anabool te blijven voor spierontwikkeling en andere gezondheidskwaaltjes tegen te gaan.

L-leucine increases [3H]-thymidine incorporation i... [J Cell Biochem. 2008] - PubMed result
http://www.scipub.org/fulltext/AJAV/AJAV4495-100.pdf
L-leucine and a nonmetabolized analogue activate pancreatic islet glutamate dehydrogenase
The effects L-leucine on the synthesis of urea, glutamate and glutamine by isolated rat liver cells.
Mechanism of L-leucyl-L-leucine methyl ester-mediated killing of cytotoxic lymphocytes: dependence on a lysosomal thiol protease, dipeptidyl peptidase I, that is enriched in these cells.

[marnop]

Cliffnotes: The protein RDA was found to be too low.

"...It seems reasonable to conclude that the lowered rate of whole-body and perhaps muscle protein turnover that appears to occur in healthy adult subjects when intakes of indispensable amino acids approximate the current international figures, would probably diminish the individuals capacity to withstand successfully a major stressful stimulus. Again, for those reasons, we view the significant reduction in the rate of body protein turnover in healthy adults, which permits them to more closely approach or even achieve amino acid balance at currently accepted amino acid requirement intakes, as an accommodation. Thus we further conclude that these international requirement intakes are probably not sufficient to maintain a desirable or adapted state."

(Young VR., Marchini JS. Mechanisms and nutritional significance of metabolic responses to altered intakes of protein and amino acids, with reference to nutritional adaptation in humans. Am J Clin Nutr 1990;51:270-89) Emphasis added.

Tarnopolsky and others documented the effects of two diets in a cross-over study on 6 male body builders training 1.5-2 hours/day. Nitrogen balance was determined after a control diet and after consuming the experimental diets for 3 days. A high-protein diet of 1.05 g/kg/day resulted in a slightly positive nitrogen balance in the body builders, while an even higher protein diet of 2.77 g/kg/day resulted in a more positive nitrogen balance (.62 g/day vs. 10.9 g/day) (Tarnopolsky, MacDougall, Atkinson, Blimkie, and Sale, 1986). The researchers concluded that body builders are able to maintain nitrogen balance on a dietary protein intake of less than 1.05 g/kg/day but that higher protein ingestion leads to a more positive balance.

More recently, in a second study headed by Tarnopolsky, strength training males with at least 2 months of weight lifting experience served as the trainees. The average age of the 7 strength training participants was 21.6 years. The workout routine was executed 4 times/week yielding a weekly physical activity duration of 9.7 hours/week. All subjects was involved in three different experiments, each of 13 days. Each experimental period was preceded by an ad libitum washout diet period of at least 8 days. A low-protein group consumed the Canadian RNI of 0.86 g protein/kg/day. A moderate-protein group received 1.4 g/kg/day while a high-protein group ingested 2.4 g/kg/day. Energy was consumed in the amount of approximately 43 kcal/kg/day. Sweat losses of nitrogen were estimated based upon other studies. The low-protein group was shown to be in a negative nitrogen balance of -2.4 g N/day/day. The moderate-protein group had a modest positive balance of 0.7 g N/kg/day. Finally, the high-protein group revealed the highest retention of 3.8 g N/kg/day. Using linear regression analysis, the research team calculated an appropriate protein intake ("requirement" plus 1SD) to be 1.76 g protein/kg/day. They noted a discrepancy between the nitrogen balance method and other techniques they employed, and they recommended that future studies utilize nitrogen balance in conjunction with additional techniques (Tarnopolsky, Atkinson, MacDougall, Chesley, Phillips, and Schwarcz, 1992).


Within four weeks of protein supplementation (3.3 versus 1.3 g kg / day) in subjects resistance training, significantly greater gains were seen in protein synthesis and body mass in the group of subjects with the greater protein intake (Fern et al., 1991).

[sf01]

Top. Kijk hier hebben we wat aan.

Je zou nog steeds aan kunnen dragen dat een onderzoek over 3 dagen wel erg kort is. (eerste onderzoek) en dat de situatie ook echt wel anders is in de eerste jaar trainen dan daarna (tweede onderzoek)
Maar het is zeker een fatsoenlijk onderzoek wat aantoont dat hogere eiwit intake nuttig is.

Moet er natuurlijk wel bij zeggen: De max hier genoemd is 2.77gram per kg. Valt daarmee perfect binnen de 2 tot 3 gram die hier over het algemeen wordt aangeraden.
De 4 of zelfs 5 gram per kg die jij soms aandraagt is dus echt wel extreem veel hoger. Ik kan me goed voorstellen dat dit voor jou zeker nuttig is. Maar voor de gemiddelde persoon hier, zal 2 tot 3 gram meer dan genoeg zijn lijkt me

[marnop]

Hey Marnop. Ik mag je echt. Vind je een top gozer... Maar eerlijk gezegd... ik zie het niet.

Voor mijn idee is er niet zozeer sprake van een superieure houding, maar puur een vragen naar onderbouwing voor stellingen/meningen.
Zoals ik eerder al zei... er wordt zoveel geroepen en eindeloos herhaalt. Ik denk zeker op het gebied van voeding en trainen, wat werkt, hoe en waarom... zijn bronnen alles.
Ik weet het... het is niet relaxt. Je moet dingen erbij gaan zoeken als mensen erop doorvragen. Maar zo haal je wel de klakkeloos herhaalde onzin eruit. Waarmee ik trouwens geenzins wat jij verkondigt daar onder schaar.

Ik ben zelf nu ook maar begonnen met bepaalde stellingen/meningen die ik er op na hou in een document bij elkaar te zetten met de bronverwijzingen erbij. Omdat ik moe werd van het maar telkens weer info op moeten zoeken

Maar in alle eerlijkheid. In dit hele proces, heb ik de afgelopen tijd ook aardig wat meningen/stellingen moeten herzien, bijschaven. En stond ik af en toe met het schaamrood op mijn kaken bij het snoeihard ermee geconfronteerd worden dat ik het fout had.

Laten we gewoon allemaal proberen om de discussies puur te houden. Inhoudelijk, en niet te persoonlijk.

Just my 50 cents

Hey SF,

tja,...
Ik heb je de afgelopen tijd idd dingen zien bijschaven, zoals enkelen bij mij ook gezien hebben. Ik heb ook respect voor je, al zeg ik dat in discussies niet met zoveel woorden.
De eerste tijd dat ik hier kwam stonden bijvoorbeeld Dynobet en ik lijnrecht tegenover elkaar, nu staan we vaak dicht bij elkaar. Dat komt omdat Dynobet vaak op goede wijze iets brengt en onderbouwt, dan ben ik ook geinteresseerd en ga ik lezen wat hij te zeggen heeft en lees ook zijn bronnen. Voor Dynobet heb ik ook verder wel respect, al ga ik soms wat hard tegen hem, als ik wat geirriteerd raak, korte tijd geleden heb ik ook nog gescholden op Dynobet en hij had me toen ook een rode kaart of tijdelijke ban kunnen opleggen, mijn schelden was zeer ongepast, maar hij heeft dat niet gedaan (daarvoor nog dank Dyno).
Maar hij weet dus ook dat ik zijn artikelen wel goed lees en meestal goed vind ook als mijn mening ietsjes anders is/was.

Je weet ik ga een discussie gewoon niet uit de weg en zeker niet als het fatsoenlijk gebeurt.
Jij en ik discussiëren ook en je mag best over en weer wat harder zijn of een steekje geven, geen probleem, maar wij vallen elkaar niet persoonlijk aan.
Deze man echter voelt zich erg superieur en valt ook persoonlijk aan, daar ben ik erg allergisch voor.
Ik laat me ook zeker niet voor leugenaar uitmaken, door niemand.

Als ik in de loop der jaren van alles heb gelezen dan ga ik niet jaren later nog eens diep graven om een bron te zoeken. Hij moet gewoon aannemen dat ik dat gelezen heb, punt. Als iemand het niet eens is ergens mee, dat mag en is prima. Dan mag en kan er gediscussieerd worden.
Als er dan niets uit een duiscussie komt omdat ik de bron niet binnen handbereik heb,..so be it. Dan moet ik opgeven zo simpel is het.
Maar dus zodra iemand zich als superieur gaat gedragen en mij als leugenaar wil neerzetten of als fantast dan raak ik pissed.

[sf01]

@Marnop. duidelijk. En zoals je zelf al aangeeft. Het is soms lastig discussieren als je geen bron kan reproduceren. Ik snap die neiging heel goed. Ik heb ook soms geen zin om terug te zoeken waar ik het heb gelezen. Vandaar dat ik daar een document over aan het maken ben
Misschien ga ik er nog een keer een tread over maken hier. Als ik veel bij elkaar heb.

En het is duidelijk dat je een allergie hebt voor bepaald gedrag. Daardoor zal je bepaalde dingen misschien scherper aanvoelen dan anderen. Maar daarin ligt ook het gevaar dat je dingen kan voelen die er niet zijn/ of niet zo bedoeld zijn.
Daarom blijft het mijns inziens goed... om zelf in ieder geval ten alle tijden zo correct mogelijk te reageren

Wel tof dat je er even op terugkomt en verduidelijkt.

[marnop]

Ik heb het niet verzonnen maar gelezen:


Powerful Benefits of Soy

Written by Gloria Tsang, RD of HealthCastle.com
Published in February 2006

(HealthCastle.com)What has most interested scientists in recent years is the discovery of phytochemicals and the profound benefits of soy on human health. Benefits of soy include promoting heart health and healthy bones, preventing cancer and alleviating menopausal symptoms.
Soy beans contain high amounts of protein, including all essential amino acids (the only such vegetable source). Soy beans are also a rich source of calcium, iron, zinc, phosphorus, magnesium, B-vitamins, omega 3 fatty acids and fiber.
Benefits of Soy: Heart Health

The cholesterol lowering effect of soy milk and its role of heart disease was widely recognized in the mid 90s when the results of a meta-analysis of 38 clinical studies were published. The results demonstrated that a diet with significant soy protein reduces Total Cholesterol, LDL cholesterol (the "Bad" cholesterol) and Triglycerides.
The average consumption in these studies was 47 grams per day of soy protein, which is a considerable amount. One way to include this is to try a soy protein beverage or powder that may add 20 grams preserving. Soy protein was effective even in people who were already following the American Heart Association's 30 percent-fat diet. Soy protein appears to lower triglyceride levels while preserving HDL cholesterol.
Researchers Erdman & Potter in 1993 reported in the American Journal of Clinical Nutrition a 12 percent drop in cholesterol when 20 to 25 grams of soy protein and fiber were included in the diet. Soy beans contain soluble fiber, which is known to interfere with the absorption and metabolism of cholesterol.
As a result of these findings, in 1999, FDA authorized a health claim about the relationship between soy protein and Coronary Heart Disease (CHD) on labelling of foods containing soy protein.
A heart health claim can be found on qualified soy products.

Health Claim:
Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease. One serving of [name of produce] provides [amount]g of soy protein.

A few recent studies released in 2005 found that soy only had a modest effect on cholesterol levels. The American Heart Association no longer recommends soy for heart disease. FDA is currently reviewing its policy on soy health claim. So what should you do? Enjoy your soy foods like before. It may not lower cholesterol to an extent we originally thought, but it certainly does not harm our health!

Benefits of Soy: Healthy Bones

Many soy foods are naturally high in calcium (some fortified with calcium because it is a good source of a particular coagulating agent). In addition, soy also contains magnesium and boron, which are important co-factors of calcium for bone health.
Isoflavones in soy foods may inhibit the breakdown of bones. Daidzein, a type of isoflavone, is actually very similar to the drug ipriflavone, which is used throughout Europe and Asia to treat osteoporosis. One compelling study completed by Erdman in 1993 focused on post-menopausal women who consumed 40 grams of isolated soy protein daily for 6 months. Researchers found that these subjects significantly increased bone mineral density as compared to the controls.
Another study published in the Archives of Internal Medicine in September 2005 also found that intake of soy food was associated with a significantly lower risk of fracture, particularly among early post-menopausal women.
Benefits of Soy: Menopause

In Japan, where soy foods are commonly consumed daily, women are only one-third as likely to report menopausal symptoms as in the United States or Canada. In fact, there is no word in the Japanese language for "hot flashes".
Current studies showed that soy only helps some women alleviate menopausal symptoms. Indeed, soy is more effective in preventing than alleviating hot flashes. Despite these findings, the North American Menopause Society in 2000 recommended that 40 - 80mg of isoflavones daily may help relieve menopausal symptoms.
Benefits of Soy: Cancer

Among all cancers, data on soy and prostate cancer seems to be the most promising; many studies support its role in the prevention and possible treatment of prostate cancer.
While some studies showed soy offers a protective effect against breast cancer, a few studies showed the estrogen-like effects in isoflavones may be harmful for women with breast cancer. American Institute for Cancer Research stresses that data on soy and breast cancer are not conclusive, and more work is needed to be done before any dietary recommendations can be made.
What we know at this point is the phytoestrogens in soy foods are "anti-estrogens". In other words, they may block estrogen from reaching the receptors - therefore potentially protecting women from developing breast cancer. Studies found that pre-menopausal women may benefit from eating soy foods as their natural estrogen levels are high.
However, this may not be true to post-menopausal women. Studies found that soy could become "pro-estrogen" in women with low levels of natural estrogen. In other words, concentrated soy supplements may add estrogen to the body and hence increase breast cancer risk in post-menopausal women. Therefore, post-menopausal women should avoid taking concentrated soy supplements until more is known. Eating soy products, however, is not harmful.

[marnop]

Soy Food Intake and Breast Cancer Survival
Journal of the American Medical Association 2009 (Dec 9); 302 (22): 2437–2443
Soy foods are rich in isoflavones, a major group of phytoestrogens that have been hypothesized to reduce the risk of breast cancer. To evaluate the association of soy food intake after diagnosis of breast cancer with total mortality and cancer recurrence, 5033 surgically treated breast cancer patients were tracked for more than 3 years. Soy food intake, as measured by either soy protein or soy isoflavone intake, was inversely associated with mortality and recurrence. The researchers then concluded that soy food consumption was significantly associated with decreased risk of death and recurrence of breast cancer.


<A href="http://www.chiro.org/nutrition/ABSTRACTS/Childhood_Soy_Intake.shtml">Childhood Soy Intake and Breast Cancer Risk in Asian American Women
Cancer Epidemiology, Biomarkers & Prevention 2009 (Apr); 18 (4): 1050–1059
Soy intake during childhood, adolescence, and adult life was associated with decreased breast cancer risk, with the strongest, most consistent effect for childhood intake. Soy may be a hormonally related, early-life exposure that influences breast cancer incidence.

[sf01]

hmmm. je zou eigenlijk een onderzoek willen waarin 'breed spectrum animo' verhoogd dieet uit willekeurige bronnen, tegenover soja verhoogd dieet vergeleken worden.

Verder zeker een interessant onderzoek.

[marnop]

On another note, researchers have long known that Asian women, who eat large amounts of soy foods, have a relatively low risk of breast cancer. Their risk of breast cancer, however, increases when they move to the United States and begin eating low-soy diets.
Soy foods contain a particular group of flavonoids, called isoflavones, that have very weak estrogenic activity. One of these isoflavones, genistein, has only 1/1000th the hormonal activity of true estrogen. What happens, researchers believe, is that genistein competes directly against estrogen for cell receptors and can block the more powerful estrogen, which is known to increase cancer risk.
Based on animal experiments, a woman who begins eating soy foods as a child might have a lower risk of breast cancer as an adult. Coral A. Lamartiniere, Ph.D., a researcher at the University of Alabama, Birmingham, added either genistein or a placebo to the diets of prepubescent laboratory rats. Later, she exposed all of the rats to a cancer-causing chemical.
The animals given genistein developed almost 50 percent fewer mammary tumors during their lifetimes compared with those given the placebo, according to Lamartiniere's article in Carcinogenesis. They also had slightly longer menstrual cycles, a factor which is also associated with lower breast cancer risk in women. [ 12 ]
Although genistein modulates the effects of estrogen, it may reduce the risk of breast cancers in still other ways. For example, genistein inhibits tyrosine protein kinase, an enzyme that promotes cancer cell proliferation. It also blocks angiogenesis and induces cancer cell death. [ 13 ] Genistein is a potent antioxidant--more powerful than other isoflavones--and, as discussed above, dietary antioxidants are strongly associated with cancer prevention. [ 14 ] In addition, genistein stimulates the body's production of its own antioxidant enzymes, including glutathione peroxidase, catalase and superoxide dismutase (SOD). [ 15 ] What all of this research shows is that common nutrients, in concentrated form, can prevent many types of DNA damage that lead to cancer. [ 16 ] In practical terms, this means women don't have to wait in fear of breast cancer, or hope for the distant promise of high-tech and high-priced gene therapy. Nutritional supplements qualify as a form of natural gene therapy that women can use today to protect the genes they were born with. NSN

[marnop]

hmmm. je zou eigenlijk een onderzoek willen waarin 'breed spectrum animo' verhoogd dieet uit willekeurige bronnen, tegenover soja verhoogd dieet vergeleken worden.

Verder zeker een interessant onderzoek.

Er zijn wel wat onderzekjes naar gedaan.
conclusies waren over het algemeen dat soya eiwit geen tot weinig meerwaarde geeft voor mannen(en bodybuilding), wel voor vrouwen en dan met name mbt borstkanker.
In de vorige post hebben ze het over genistein, daarin zit Tyrosine (een aminozuur) wat een extra preventieve werking zou geven. Nu weet ik niet welke bron meer Tyrosine bevat, ei, melk of soya.


Ik dacht dat het spectrum van amino's in soya groter was dan in de andere eiwitbronnen, maar de bilogische waarde is vele malen lager.
Dynobet had daar een website voor, die had ik ook opgeslagen, maar mijn PC was gecrashed dus die ben ik kwijt.

[sf01]

ja, er zal zeker een toegevoegde waarde zijn voor soja. Maar verhuizen naar de states heeft meer voedings consequenties dan alleen lager in soja

Ik ga toch nog maar eens kijken of ik niet wat Soja wil/ga toevoegen aan mijn dieet
Borstkanker staat ook zeker niet in mijn top 10 van aandoeningen waar ik bang voor ben bij mezelf.
Maar aangezien variatie sowieso goed is. Kan het ongetwijfeld geen kwaad.
De lagere biologische waarde blijft natuurlijk een punt.

[marnop]

Glutamine:

Glutamine supplements have been on the market for well over a decade. There has been great debate and discussion as to the effects of this supplement on human performance. Glutamine has commonly been known to aid athletes in several key forms. First, many believe that glutamine can play a considerable role in supporting a healthy immune function. This is especially true in athletes who may have a tendency to overtrain. This is of great importance as most athletes throughout the year can easily overtrain which often leads to sickness and a significant decrease in performance. Many companies also claim that glutamine aids in the storage and production of glycogen. This can be of key importance to most endurance athletes as well as to a high number of endurance oriented anaerobic athletes. Lastly, glutamine has been known for its anabolic effects of enhancing strength and muscle mass. It is often known around the bodybuilding world as a highly anabolic substance that greatly reduces catabolism and protein degradation. Many theories also advocate that glutamine may play a role in promoting an advantageous environment for heightened levels of growth hormone during intense levels of exercise.

Although the research is somewhat split around the supplementation of glutamine and its positive effects, there are many studies which show conclusive evidence pertaining to the effectiveness of orally ingesting glutamine. In a study performed by Welbourne et al (1), subjects who orally ingested only 2 grams of glutamine increased plasma bicarbonate levels in the body. Increased levels of plasma bicarbonate have been shown to improve one's ability to buffer lactic acid thus increasing performance.

One of the most profound studies (2) performed on glutamine dealt with a very unique muscle regulator known as myostatin which is commonly produced by glucocorticoids. This substance may be one of the key factors that helps determine one's genetic potential for gaining muscle mass and strength. Specifically, moderate to high levels of myostatin may cause glucocorticoid muscle atrophy in healthy humans. In this specific study performed by Salehian et al (2) glutamine was found to prevent glucocorticoid induced muscle atrophy. In other words, this study showed that administration of glutamine provided a potential mechanism for the prevention of muscle atrophy induced by glucocorticoids and myostatin. Also, those who received glutamine had significantly less reductions in body and muscle weights and lower myostatin expression than the placebo group.

In a study by Lacey et al (3) short-term glutamine ingestion had no effect on muscular strength; however, long-term supplementation showed to be a more effective application of glutamine in regards to strength gains. Furthermore other studies have shown that glutamine causes positive effects on performance due to a plethora of physiological events which include increased levels of growth hormone, decreased catabolic effects of skeletal muscle, increased anabolic effects, enhanced protein synthesis, and greater ability to sustain high intensity exercise due to the increased capability of buffering lactic acid.

Glutamine has also been shown to dramatically enhance immune system function for athletes and healthy adults who train at high enough intensities that typically trigger a breakdown in the immune system (4). From the medical literature, glutamine may have a place in the dietary regimen of athletes undergoing intense exercise training and possibly have a role in maintaining optimal health during the competitive season via benefits to the immune system (5).

Glutamine's effect on the immune system may also be witnessed by examining data on hospital patients supplementing glutamine in order to ward off any potential sicknesses associated with surgery or hospital stays. In a very recent study performed by Oquz et al (10) patients undergoing colorectal surgery for cancer were observed over a five year period. Half of the patients received glutamine treatment within their nutrition during their hospital stay and the other half did not. After results were analyzed it appeared as though the group which received glutamine supplementation had less complications after their operation and a shorter hospital stay than those who were not administered the glutamine supplementation.

Many other studies also support glutamines use on immune system function although not directly related to athletes. In a study performed by Fuentes et al (11) glutamine supplementation appears to improve infectious morbidity of hospitalized patients by improving host defenses and other immune system responses. In another study performed by Li et al (12) it appears as though premature infants given intravenous glutamine supplementation spend fewer days in the hospital and also have a decreased rate of hospital related infections.

Although many studies on glutamine supplementation and immune response are not performed directly on athletes, this does not suggest that these findings cannot be of great importance to athletes. In fact exercise in and of itself can be a mild to somewhat intense form of stress and trauma on the body which may heavily tax the immune system. Although not as severe as surgical procedures performed on hospitalized patients, athletes undergoing intense training may find that glutamine does have a positive effect on immune system function.

As previously mentioned there is an increased risk of infections in athletes undertaking prolonged, strenuous exercise. There is also some evidence that cells of the immune system are less capable of producing a defense against infections after such exercise. The level of plasma glutamine, an important fuel for cells of the immune system, is decreased in athletes after endurance exercise. This may be partly responsible for the apparent immuno-suppression which occurs in these individuals. In one of the more conclusive studies done on glutamine by Castell et al (7) oral consumption of glutamine after intense exercise was examined in elite runners and rowers. Most of these athletes were endurance oriented. The results of the study indicate that there was a significant decrease in infections and illness after intense training in those who supplemented with glutamine versus those who did not. Glutamine's role in enhancing immune system function seems to be highly conclusive in this study.

Candow et al (6) assessed the effect of oral glutamine supplementation combined with resistance training in young adults. Strength and muscular skeletal markers were examined before and after the six week study in both the placebo and experimental group. It appears as though there was a slight increase in one repetition squat, force production in the knee extensor, and lean muscle mass. Although these numbers were slightly higher than the placebo group they were not enough to be a "significant" difference. It must be noted that many world class athletes may work years for small increases in performance that may or may not seem "significant" to those in a laboratory setting but may be of utmost importance to the elite athlete. However to the average weightlifter results from this specific study may not warrant supplementation with glutamine.

In regards to the proper and effective dosage of glutamine research is quite varied. Some researches such as Van Gammeren et al (8) have shown success with as low as 2 grams of glutamine per day. While yet other scientists such as Candow et al (6) administered substantially greater levels of glutamine to their subjects with as much as 45 grams of glutamine per day. However, the majority of studies as noted by Hultman et al (9) suggest that 4-10 grams per day will suffice for optimal physiological gains from glutamine supplementation. Yet there are a host of others that would suggest up to 20 grams per day. The most extreme levels of glutamine supplementation can be seen in studies dealing with hospitalized patients. In fact in the study performed by Oquz et al (10) patients received 1g/kg/day which could be anywhere between 50-120 grams per day depending on body weight. It also appears from the previously mentioned studies that glutamine supplementation is far more effective when used long term rather than short term.


Summary and Recommendation

Although further evidence would help support supplementation with glutamine to an even higher degree, there is considerable research to warrant its usage among many high performance athletes. The benefits as previously noted includes: supporting a healthy immune system, less reduction in body and muscle weights, lower myostatin expression, increased levels of growth hormone, decreased catabolic effects of skeletal muscle, increased anabolic effects, increased protein synthesis, and greater ability to sustain high intensity exercise due to the increased capability of buffering lactic acid. All these factors could potentially lead to increases in muscle mass, strength, and power.

The recommended dosage for glutamine is 5-20 grams per day. There are claims that even higher dosages may be more effective but further evidence is needed. However, there have been studies demonstrating that 40 grams a day have no safety or toxicity concerns. Therefore, toxicity is not an issue with glutamine supplementation. Distributing glutamine throughout the day in smaller dosages is also recommended. A common glutamine supplementation protocol is 5 grams in the morning, 5 grams pre-workout, followed by 5 grams post workout, with an optional 2-5 gram dosage before bed. Similar guidelines and dosage amounts are recommended for non-workout days.

According to consumerlab.com and other valid sources some of the best glutamine products on the market include: Dymatize Proline Micronized Glutamine, Effervescent Glutamine, Puritan's Pride L-Glutamine, AST Glutamine, Beverly International Glutamine Select Plus BCAAs, and Precision Engineered Pure L-Glutamine

References

1. Welbourne, T. Increased plasma bicarbonate and growth hormone after an oral glutamine load. Am. J. Clin. Nutr. 61:1058-1061. 1995.
2. Salehian B, Mahabadi V, Bilas J, Taylor WE, Ma K. The effect of glutamine on prevention of glucocorticoid-induced skeletal muscle atrophy is associated with myostatin suppression. Metabolism. 2006 Sep; 55: 1239-47.
3. Lacey, J.M., and D.W. Wilmore. Is glutamine a conditionally essential amino acid? Nutr. Rev. 48:297-309. 1990.
4. Perriello, G., N. Nurjhan, and M. Stumvoll. et al. Regulation of gluconeogenesis by glutamine in normal post-absorptive humans. Am. J. Physiol. 272:E437-E445. 1997.
5. Rowbottom, D.G., D. Keast, and A.R. Morton. The emerging role of glutamine as an indicator of exercise stress and overtraining. Sports Med. 21:80-97. 1996.
6. Candow, D.G., P.D. Chilibeck, D.G. Burke, D.S. Davison, and T. Smith-Palmer. Effect of glutamine supplementation combined with resistance training in young adults. Eur. J. Appl. Physiol. 86:142-149. 2001.
7. Castell LM, Poortmans JR, Newsholme EA. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol Occup Physiol. 1996; 73(5): 488-90.
8. Van Gammeren, D., D. Falk, and J. Antonio. The effects of four weeks of ribose supplementation on body composition and exercise performance in healthy, young, male recreational body builders: A double-blind, placebo-controlled trial. Curr. Ther. Res. 63: 486-495. 2002.
9. Hultman, E., K. Soderlund, J.A. Timmons, G. Cederblad, and P.L. Greenhaff. Muscle creatine loading in men. J. Appl. Physiol. 81:232-237. 1996.
10. Oquz M, Kerem M, Bedirli A, Mentes BB, Sakrak O, Salman B, Bostanci H. L-alanin-L-glutamine supplementation improves the outcome after colorectal surgery for cancer. Colorectal Dis. 9(6): 515-20. 2007.
11. Fuentes-Orozco C, Anaya-Prado R, Gonzalez-Ojeda A, Arenas-Marquez H, Cabrera-Pivaral C, Cervantes-Guevara G, Barrera-Zepeda LM. L-alanyl-L-glutamine supplemented parenteral nutrition improves infectious moribidity in secondary peritonitis. Clin. Nutr. 23(1): 13-21. 2004.
12. Li ZH, Wang DH, Dong M. Effect of parenteral supplementation in premature infants. Chin. Med. J. (English). 120(2): 140-144. 2007.

[marnop]

Glutamine: recent developments in research on the clinical significance of glutamine.

Melis GC, ter Wengel N, Boelens PG, van Leeuwen PA.
Department of Surgery, VU University Medical Center, Amsterdam, The Netherlands.
Abstract

PURPOSE OF REVIEW: The aim of this review is to describe the clinical relevance of supplementation of glutamine from the recent literature. First, new basic research is examined and subsequently recent clinical trials and a metaanalysis are illustrated.
RECENT FINDINGS: Glutamine has a major impact on the functionality of the immune system. It has recently been established that glutamine not only has a protective effect on cells of the immune system, but also on other cells of the body, for instance cardiomyocytes. Evidence is accumulating for an effect of glutamine via glutathione, heat shock proteins as well as taurine. Another area of interest is the way glutamine enhances gut barrier function. More and more research is concentrating on the positive effect of glutamine on the gut-associated lymphoid tissue.
SUMMARY: Based on a recent meta-analysis and up-to-date clinical trials, we may conclude that glutamine has a beneficial effect on infectious complications and reduces hospital stay. In critically ill patients glutamine supplementation may reduce morbidity and mortality. The greatest effect was observed in patients receiving high dose parenteral glutamine. A recent study with high dose enteral glutamine demonstrated a reduced mortality in the glutamine supplemented group. In the future more trials with larger numbers of participants are needed, especially with high dose enteral glutamine in the perioperatively and the intensive care unit setting.

PMID: 15090905 [PubMed - indexed for MEDLINE]

[marnop]

Nu vind ik het even zat, of moet ik me nog meer bewijzen?