donderdag 17 augustus 2017

The effect of thyme extract on beta2-receptors and mucociliary clearance.

Thyme is a broncholytic und secretomotoric agent. Thus, our aim was to investigate the influence of a thyme extract on beta (2)-receptors in competition binding experiments and relaxation experiments on rat uteri and trachea. Furthermore, the influence of the extract on respiratory clearance was of interest. Binding experiments were performed using purified rat lung membranes with the beta(2)-receptor ligand [(125)I]-CYP {[(125)I]-(+/-)-Iodocyanopindolol}. The transport of the fluorescence dye rhodamin 123 concerning ciliary action in the tracheal area of a mouse was investigated using a microdialysis technique. The thyme extract reduces only slightly [(125)I]-CYP binding and amplifies the displacement of [(125)I]-CYP by propranolol (non-specific beta-receptor antagonist): the displacement curve in the concentration range representing beta (2)-receptors (nM) is shifted to the left. Thyme extract had relaxing effects on organs possessing beta (2)-receptors (uterus and trachea). The propranolol-induced antagonism to isoprenaline is reverted concentration-dependently by the extract. A duplication of the rate of ciliary clearance by the extract was observed.

IN CONCLUSION:
1) There is evidence for an influence of a thyme extract on beta (2)-receptors by both binding studies and biological effects: As can be derived from the shift of the propranolol displacement curve (nM), ingredients of the thyme extract slightly interact with beta (2)-receptors in rat lung tissue. This effect is indirect since no full range competition curve was reached. 2) An at least indirect interaction with beta (2)-receptors in rat uteri and trachea is revealed by a decreased antagonism of propranolol on the relaxing effect of isoprenaline by the plant extract. 3) An additional mechanism is presumed because at high extract concentrations isoprenaline-induced relaxation is complete, whereas the displacement of propranolol at beta (2)-receptors is only weak. 4) Thyme extract has an indirect (modulatory) effect on the beta (2)-receptor system. 5) Mucociliary clearance is improved in vivo. Its mechanism has still to be elucidated.

Planta Med. 2007 Jun;73(7):629-35. Epub 2007 Jun 12.
Wienkötter N1, Begrow F, Kinzinger U, Schierstedt D, Verspohl EJ.

vrijdag 4 augustus 2017

Natuurlijke vervangers voor statines

Bij te hoge cholesterolwaarden worden meestal statines voorgeschreven. De bijwerkingen van statines zijn echter niet mals, met name voor mensen met een statine-intolerantie. Plantaardige middelen hebben deze bijwerkingen niet of minder. 

Allium ursinum
Statines hebben bewezen preventief werkzaam te zijn bij patiënten die al eens een hartaanval hebben gehad en ook een verhoogd cholesterol hebben. Ze zorgen er dus voor dat er beduidend minder kans is op een volgende (mogelijk dodelijke) aanval. In de primaire preventie – wanneer er nog geen hartaanval is geweest maar er wel sprake is van te hoge cholesterolwaarden – is het echter de vraag of de voordelen van het gebruik van statines opwegen tegen de nadelen. Binnen de wetenschap zijn de meningen hierover verdeeld. Er zijn verschillende onderzoeken met tegengestelde uitkomsten. Toch neemt het aantal mensen dat statines krijgt aanbevolen toe, als gevolg van aanscherping van medische richtlijnen. Voor de groep patiënten die vanwege bijwerkingen, intolerantie of persoonlijke voorkeur geen statines kan of wil gebruiken, zijn verschillende onderzoeken naar plantaardige alternatieven naast elkaar gelegd. Hieruit bleek dat rode gistrijst (Monascus purpureus) van alle onderzochte plantaardige middelen de meest significante verlaging van het cholesterol liet zien. Knoflookpoeder en andere Alliumsoorten kunnen ook een bijdrage leveren aan cholesterolverlaging. Vezels zoals in vlozaad of haverzemelen, producten van artisjokblad en zuurbes (berberis) zijn mogelijk ook bruikbaar.

Een punt van aandacht is dat de inhoud van de vele producten met rode gistrijst die te koop zijn nogal verschillen. Hoe effectief zo'n product is, hangt af van de specifieke gistsoort,het fermentatieproces en de sterkte. De meest werkzame stof in rode gistrijst heet monacolin K. Dit zit 10 tot 20 mg in een dagdosering. Ook andere stoffen dragen bij aan het effect. Monacolin K is zelf een statine. Daarom kunnen erg gevoelige mensen van rode gistrijst dezelfde bijwerkingen krijgen als van statines. Sommige plantencombinaties kunnen voor die gevoelige mensen wel een uitkomst zijn. Hier zou meer onderzoek naar moeten komen.

https://sites.google.com/site/kruidwis/fytotherapie/bloedvaten

woensdag 2 augustus 2017

About bitter herbs

Gentiana lutea
Two different interpretations, each supported by experimental data, can be  found in the pharmacologic literature regarding the mechanism of action of bitters. Both interpretations agree that stimuli originating in the mouth can  reflexly induce gastric secretions. A bitter in the form of an aperitif or stomach bitter, taken in a moderate amount 20-30 min before eating, can stimu-  late gastric and biliary secretions, increasing the acidity of the gastric juice  and aiding digestion (Bellomo, 1939). In one study, 200 mg of gentian root  or 25 mg of wormwood herb significantly increased the production of gastric juice even in healthy subjects. The authors concluded that bitters can increase gastric and biliary secretions in healthy subjects compared with the normal volume of sectretions induced by food stimuli (Glatzel and Hackenberg, 1967).

These findings are contradicted by other studies showing that bitters taken by healthy subjects with a normal appetite do not increase digestive secretions beyond the reflex secretions that normally occur during the cephalic phase of digestion. The secretory mechanism as a whole is already  functioning at an optimum level, and the administration of bitters cannot produce any significant change. In conditions where the reflex secretion of gastric juice is inhibited, however, the administration of bitters can initiate the
necessary reflex, leading to gastric secretion of the same intensity and duration (2-3 h) as normal reflex secretion.

There is a definite psychological component to the efficacy of bitters. This was demonstrated by a study in which bitters markedly improved appetite in patients with gastric achylia, despite the fact that increased gastric acid secretion cannot be induced in these patients (Moller, 1947).

Bitters do not invariably act as appetite stimulants. Animals, for example, tend to prefer sweet-tasting foods and avoid bitter-tasting ones (Nachmann and Cole, 1971). Humans are ambivalent toward bitter-tasting foods and bev-  erages, tending to prize the flavor of artichokes, beer, grapefruit, liquors, etc.  while disliking the sour taste of pickles and heat-preserved citrus juices.  There is a psychological tendency, moreover, to associate a bitter taste with  the bitterness of an unpleasant experience.

Bitter herbs can be ranked according to the intensity of their bitter taste  Bitters that are used medicinally to stimulate appetite and digestive secretions are not merely herbs with a bitter taste; they are herbs that  can produce a pleasant taste sensation in conjunction with their bitter flavor. Another criterion is that medicinal bitters must cause no systemic side
effects when used in the proper concentration. Large amounts of bitters reduce gastric secretions, partly by their direct action on the gastric mucosa,  and cause appetite suppression. Very strong wormwood tea, for example. can spoil the appetite. Other constituents in bitter herbs are important  determinants of taste, and several types of bitter herb are differentiated on that basis.

• Simple bitters such as gentian (Gentiana lutea), bogbean, and centaury (Centaurium minus)

• Aromatic bitters that contain volatile oils, such as angelica root, blessed
thistle, bitter orange peel, and wormwood.

• Astringent bitters that contain tannins, such as cinchona bark and con-
durango bark.

• Acrid bitters such as ginger and galangal.

Besides their action on the digestive glands, bitter principles act reflexly on  the cardiovascular system, causing a decrease in heart rate and cardiac stroke volume. Taking bitters for several weeks can engender an aversion  to certain bitter herbs, accompanied by loss of appetite. The taste of bitter herbs cannot be corrected with raw sugar or other sweeteners. As for adverse effects, bitters occasionally cause headache in susceptible users, and overdoses can induce nausea or vomiting. Because bitters stimulate digestive secretions, they are contraindicated in patients with gastric or duodenal ulcers.

https://sites.google.com/site/kruidwis/inhoudsstoffen/bitterstoffen

Beets: Enhancing Sports Performance and Cognitive Function

Hyped by athletes and sports physiologists, beets (Beta vulgaris, Chenopodiaceae) have emerged as a trendy and promising sports performance supplement ingredient. A growing body of evidence suggests that beetroot, the taproot of the beet plant, has the potential to improve athletic performance and endurance. New research aims to pinpoint its mechanisms of action, and how it may help support body systems and impact blood pressure, heart health, and even cognitive function.

Beetroot contains a variety of health-promoting compounds, including betaines, resveratrol, and quercetin. However, studies of the potential sports performance benefits of beets have focused primarily on nitrates. The nitrates in beets are converted into nitrite, some of which is then transformed into nitric oxide, which plays a role in blood pressure regulation, cardiovascular function, and mitochondrial energy production.

Research supports certain exercise performance benefits of dietary nitrate supplementation, with several studies in recent years showing that supplementation can decrease the oxygen cost of submaximal exercise (exercise conducted at an intensity less than the maximum of which the individual is capable) and increase high-intensity exercise tolerance in recreational athletes.1,2,3 In addition, a 2011 study suggested that nitrate-rich beetroot juice can increase oxygen efficiency in submaximal cycling exercise.4

Exercise Performance
More recently, research is honing in on how and when performance is affected by consumption of beetroot. One 2017 study, led by Oliver Shannon at the Institute for Sport, Physical Activity and Leisure at Leeds Beckett University in the United Kingdom, sought to determine the effects of dietary nitrate supplementation on physiological functioning and exercise performance in trained runners and triathletes during short- and long-distance time trials. The authors measured plasma nitrite, resting blood pressure, and maximal oxygen consumption for eight trained male runners or triathletes. The subjects completed four exercise performance tests, each consisting of a 10-minute warmup followed by either a 1,500-meter or 10,000-meter treadmill time test.5 Three hours prior to each test, the athletes received either 140 mL of concentrated nitrate-rich beetroot juice or 140 mL of nitrate-depleted beetroot juice. Researchers found that nitrate-rich beetroot juice supplementation significantly enhanced performance in the 1,500-meter time trial but not for the 10,000-meter trial.

The findings, the authors wrote, suggest that beetroot juice supplementation may be ergogenic (i.e., performance-enhancing) during shorter-distance time trials at a high work rate, but maybe not during longer-distance time trials at a lower work rate. The authors also noted that the effects of nitrate supplementation are highly variable, and that that these results cannot be easily generalized to other populations or conditions and, as such, further study is warranted.

Much of the earlier research on beetroot has focused on endurance, but one new study from 2017 examined the impact of beetroot on high-intensity or intermittent-type exercise.6 The double-blind, placebo-controlled crossover study, led by Jean Nyakayiru of the Department of Human Movement Sciences at NUTRIM School of Nutrition and Translational Research in Metabolism at Maastricht University Medical Centre in the Netherlands, investigated whether six days of nitrate-rich beetroot juice supplementation would improve exercise performance in trained soccer players. Soccer players were chosen because the sport requires multiple bouts of high-intensity running and a heavy reliance on type II muscle fibers, which are thought to be the muscle group most impacted by nitrates.
The subjects (N = 32), of similar age, height, weight, and playing experience, ingested two 70-mL doses of beetroot juice (140 mL per day) containing 800 mg of nitrate or two 70-mL doses of beetroot juice placebo (with similar taste and appearance but depleted of nitrate) for six days.6 The final dose was ingested three hours prior to the exercise test. Subjects then completed two test days of high-intensity intermittent running performance using the Yo-Yo intermittent recovery level 1 (YoYo IR1) test, a measurement tool that simulates soccer-specific activities in a controlled setting.
Distance covered during the test was the primary measure of performance, although heart rate was measured continuously and blood and saliva samples were taken prior to the test. The authors found that nitrate-rich beetroot juice ingestion improved subject performance by 3.4 ± 1.3% compared to the placebo group, with higher plasma and salivary nitrate concentrations as well.
Interestingly, mean heart rates in the beetroot juice group were also lower than in the placebo group during the test. This may have implications for further study on heart function. The results demonstrate that nitrate supplementation could represent an effective nutritional strategy to improve exercise performance in soccer players, especially toward the end of a match. Further study, however, is needed to see if these same improvements can be translated to athletes at different performance levels.

Cognitive Function
Beetroot juice also may have important benefits beyond athletic performance, extending to healthy aging of the brain and cognitive function. A study published in 2016 examined whether beetroot juice might have a synergistic effect with exercise on neuroplasticity (i.e., the ability of the brain to reorganize by forming new nerve cell connections). Led by Meredith Petrie of Wake Forest University in Winston-Salem, North Carolina, the study looked at the effects of beetroot juice on the functional brain network of 26 older men (with a mean age of 65.4 years) who were randomly assigned to ingest beetroot juice or placebo for six weeks of exercise.7
Using measurements from peak metabolic equivalent capacity and resting state magnetic resonance imaging, the authors found that the community structure consistency of the somatomotor cortex (an area of the brain that controls motor signals to the muscles) was significantly enhanced in the beetroot juice group compared to placebo.7 They also noted significant differences in the secondary connections of the brain between the somatomotor cortex and insular cortex.
The authors concluded that older adults who exercised and consumed beetroot juice demonstrated greater consistency within the motor community and fewer secondary connections with the insular cortex compared with those who exercise without beetroot juice. Because of these results, the researchers wrote that subjects in “the exercise plus beetroot juice group had brain networks that more closely resembled those of younger adults, showing the potential enhanced neuroplasticity conferred by combining exercise and beetroot juice consumption.”

Conclusion
Though these studies shed more light on the benefits of beetroot juice and how dietary nitrates can improve exercise performance and tolerance, many questions remain. In addition to understanding more about when and how much nitrate-rich beetroot juice will have an impact, larger studies with more diverse populations are needed to better understand the exercise advantages and the broader health benefits of dietary nitrates. Furthermore, there is a wide variation in the nitrate content of many vegetables, including beets.8 Nitrate must also be metabolized to nitrite by oral bacteria, so oral hygiene becomes an important factor in the response to nitrate-based supplements, including beetroot juice. More safety data would also be useful to understand the effects of prolonged intake and the advantages or disadvantages of consuming dietary nitrates from beets alone, as opposed to obtaining the nitrates from other vegetable sources. —Karen Raterman

References

  1. Bailey SJ, Winyard P, Vanhatalo A, et al. Dietary nitrate supplementation reduces the O2 cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans. J Applied Physiol. 2009;107(4):1144-1155.
  2. Larsen FJ, Weitzberg E, Lundberg JO, Ekblom B. Effects of dietary nitrate on oxygen cost during exercise. Acta Physiol. 2007;191(1):59-66.
  3. Bailey S.J., Varnham R.L., DiMenna F.J., Breese B.C., Wylie L.J., Jones A.M. Inorganic nitrate supplementation improves muscle oxygenation, O2 uptake kinetics, and exercise tolerance at high but not low pedal rates. J Appl Physiol 2015;118:1396-1405.
  4. Cermak NM, Gibala MJ, van Loon LJC. Nitrate supplementation’s improvement of 10-km time-trial performance in trained cyclists. Int J Sport Nutr Exerc Metab. 2012;22:64-71.
  5. Shannon OM, Barlow MJ, Duckworth L, et al. Dietary nitrate supplementation enhances short but not longer duration running time-trial performance. Eur J Appl Physiol. April 2017;117(4):775-785.
  6. Nyakayiru J, Jonvik KL, Trommelen J, et al. Beetroot juice supplementation improves high-intensity intermittent type exercise performance in trained soccer players. Nutrients. March 2017;9(3):314.
  7. Petrie M, Rejeski WJ, Basu S, et al. Beet root juice: An ergogenic aid for exercise and the aging brain. J Gerontol A Biol Sci Med Sci. 2016. doi: 10.1093/gerona/glw219.
  8. Nuñez de González MT, Osburn WN, et al. A survey of nitrate and nitrite concentrations in conventional and organic-labeled raw vegetables at retail. J Food Sci. May 2015;80(5):C942-949.


dinsdag 1 augustus 2017

Bewegen tegen kanker

Elke sessie redelijke intensieve lichaamsbeweging werkt als een klein chemokuurtje. Fysieke inspanning verandert het lichaam voor kankercellen in een onvriendelijke omgeving. Een dierstudie, die Deense onderzoekers in 2016 publiceerden in Cell Metabolism, vertelt hoe.

Lichaamsbeweging zorgde vooral voor een toename van het aantal Natural Killer-cellen [NK cells]. Natural Killer-cellen zijn de stoottroepen van het immuunsysteem. Als er foute cellen of ziektekiemen in het lichaam circuleren, vallen zij als eerste aan.
"The potential of tumor-infiltrating NK cells is still being unraveled", schrijven de Denen. "NK cells are part of the early innate immune response and can activate other immune cells through secretion of interferon-gamma. Thus, a key action of NK cells is to deliver the initial 'spark' that activates other cell types of the immune system."
Vooral interleukine-6 zou wel eens belangrijk kunnen zijn, vermoeden de Denen. Interleukine-6 komt vrij als spieren intensief zijn aangesproken, en Natural Killer-cellen hebben receptoren voor interleukine-6. En verhip - toen de onderzoekers hun proeven herhaalden, en de actieve muizen inspoten met een antilichaam dat interleukine-6 uitschakelt [Anti-IL6] verdween de kankerremmende werking van beweging.

Maar dat was nog niet het hele verhaal. Toediening van synthetische interleukine-6 had geen kankerremmende werking, ontdekten de Denen in een andere serie proeven. Er was nog iets anders nodig om de Natural Killer-cellen te activeren.
En dat waren de natuurlijke pephormonen adrenaline en het verwante nor-adrenaline, ontdekten de onderzoekers. Blokkeerden ze die hormonen door toediening van de bètablokker propranolol, dan bleef er van de kankerremmende remming van beweging niets over.

Conclusie
Beweging beschermt tegen kanker. Dat geldt zeker voor intensievere bewegingsvormen, waarbij de spieren veel ontstekingsfactoren aanmaken en de bijnieren veel adrenaline afgeven. Hoewel beweging in deze dierstudie niet in staat is om kanker te stoppen, suggereert het Deense onderzoek wel dat beweging het effect van reguliere oncologische behandelingen kan versterken.

Cell Metab. 2016 Mar 8;23(3):554-62.

woensdag 12 juli 2017

La lavande apaise la peur et la douleur de la piqure…

Avant une opération chirurgicale, l’équipe médicale pose « une voie veineuse » avec l’aide d’un cathéter. Cette aiguille munie d’un dispositif d’ouverture/fermeture permettra d’administrer différentes substances dans le circuit veineux, à commencer par l’anesthé-
siant. Cette première intrusion un peu douloureuse dans le corps du patient s’accumule avec le stress de l’opération à venir et génère très souvent une forme d’anxiété. Différents travaux ont déjà démontré l’action de la lavande pour diminuer l’anxiété, mais une étude récente a souhaité évaluer son intérêt dans ce cas précis.

106 patients ont participé. On a proposé à la moitié du groupe d’inhaler 2 gouttes d’une dilution à 1 % d’huile essentielle de lavande durant 5 minutes. L’autre moitié inhalait… de l’eau ! Les scores des différents tests ont été significativement plus bas sur la douleur et l’anxiété pour le groupe lavande. Sur une échelle de 1 à 4, le niveau de satisfaction global était de 1,82 pour le groupe placebo, et de 2,29 pour le groupe lavande.

Le mécanisme de l’effet antidouleur n’est pas encore bien compris par les chercheurs qui avancent l’hypothèse d’une diminution de l’anxiété comme cause principale.
Alors n’attendez pas qu’on vous le propose à l’hôpital, apportez votre flacon de lavande et montrez les résultats de cette étude à l’équipe de soignants !

maandag 19 juni 2017

Inuline zet groei vetmassa stop?

Kinderen - maar misschien ook volwassenen die zwaarder willen worden en toch zo min mogelijk lichaamsvet willen opbouwen - zetten de groei van hun vetmassa stop als ze elke dag 8 gram inuline slikken. Inuline is een prebioticum - een voedingsvezel, die in de darmen fungeert als voedingsbodem voor goedaardige bacteriën.

Studie

Canadese voedingswetenschappers, verbonden aan de universiteit van Calgary, gaven 22 dikke kinderen van 7-12 jaar gedurende 16 weken elke dag een paar gram inulinevezels. De Canadezen gebruikten Synergy-1, een product van het Duitse Beneo. [beneo.com] Beneo betaalde niet mee aan de studie.
Gedurende 2 weken kregen de proefpersonen 4 gram inuline per dag. Daarna verhoogden de onderzoekers de dosis tot 8 gram per dag.
Een controlegroep van 20 dikke kinderen kreeg 3.3 gram maltodextrine per dag. Daarin zit evenveel energie als in 8 gram inuline. De proefpersonen losten zowel de maltodextrine als de inuline op in een glas water, en dronken dat een half uur voor de avondmaaltijd.

Resultaten
De suppletie leidde nauwelijks tot een afname van de hoeveelheid lichaamsvet, maar zette wel de rem op de groei van de vetlagen van de kinderen. Omdat de kinderen verder gewoon door bleven groeien, verminderde de suppletie het vetpercentage met iets meer dan een punt.

Mechanisme
De inulinevezels veranderden de samenstelling van de bacteriepopulatie in de darmen van de kinderen. De suppletie vergrootte de overwegend goedaardige Bifidobacterium-populatie, en dat ging ten koste van onder meer de bacterie Bacteroides vulgatus. Hoe sterker de afname van Bacteroides vulgatus, hoe sterker de afname van de groei van het lichaamsvet.

De onderzoekers vermoeden dat de verschuivingen in de bacteriepopulatie leidden tot een afname van de concentratie van ontstekingsfactoren in het bloed, en dat daardoor het vetpercentage slonk.

Conclusie
"Supplementation with oligofructose-enriched inulin improved obesity outcomes in children with overweight/obesity", vatten de onderzoekers samen. "Importantly, we have shown that oligofructose-enriched inulin induced specific gut bacterial shifts compared to placebo."
"The metabolic and microbial findings from this study provide a foundation for a larger clinical trial in the pediatric population. Prebiotics are inexpensive and non-invasive and therefore a plausible dietary intervention in the overweight and obese pediatric population."

Bron:
Gastroenterology. 2017 Jun 3. pii: S0016-5085(17)35698-6.

Over inuline https://sites.google.com/site/kruidwis/inhoudsstoffen/inhoudsstoffen-inuline