Effects of -Cystine and -Theanine Supplementation on the Common Cold: A Randomized, Double-Blind, and Placebo-Controlled Trial

Kurihara, Saburo; Hiraoka, Takenori; Akutsu, Masahisa; Sukegawa, Eiji; Bannai, Makoto; Shibahara, Seiji

doi:10.4061/2010/307475

Cited by 13 publications

(14 citation statements)

References 27 publications

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“…In another randomized double blind and placebo controlled study conducted, 176 male individuals were given placebo or L-cysteine and L-Theanine mixture capsules (490 mg) 2 times a day for 35 days. At the end, the common cold incidence in the group given L-cysteine and L-Theanine mixture capsules was seen lower compared to the placebo group and the sickness period was the same for both groups (Kurihara et al, 2010). In a study conducted on the mice, L-cysteine and L- Theanine incited the production of antibodies specific to antigen after antigen stimulation.…”

Section: 7l-theanine and Common Coldmentioning

confidence: 95%

L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety

Türközü

Şanlıer

2015

Critical Reviews in Food Science and Nutrition

153

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Tea has been a very popular beverage around the world for centuries. The reason that it is delicious, enabling hydration, showing warming and relaxing effect can be mentioned why it is consumed so much in addition to its prominent health effects. Although the catechins and caffeine are the primary bioactive components that are related with the health effects of the tea, the health effects of theanine amino acid, which is a nonproteinic amino acid special to tea, has become prominent in recent years. It has been known that the theanine amino acid in tea has positive effects especially on relaxing, cognitive performance, emotional status, sleep quality, cancer, cardiovascular diseases, obesity, and common cold. The results of acute and chronic toxicity tests conducted on the safety of theanine express that L-theanine is reliable in general even if it is consumed too much with diet. However, it has not revealed a clear evidence-based result yet regarding theanine metabolism, health effects, and its safety. Within this frame, chemical structure of theanine, its biosynthesis, dietary sources, metabolism, health effects, and safety are discussed in present study.

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Section: 7l-theanine and Common Coldmentioning

confidence: 95%

L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety

Türközü

Şanlıer

2015

Critical Reviews in Food Science and Nutrition

153

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“…With regard to the daily dosage and duration of cystine and theanine treatment, the daily dosage used in the present study was the same as in other studies, but the duration of treatment varied from 10 to 35 days between studies 3 , 27 – 30 . In the present study, these amino acids were administered for 4 days prior to surgery, over a total of 10 days; the duration of this presurgical treatment was shorter than that in other studies.…”

Section: Discussionmentioning

confidence: 82%

“…Five other studies on the effects of cystine and theanine administration in humans have been reported 3 , 27 – 30 . The first was a study of malnourished elderly patients in whom significantly increased antibody levels after influenza vaccinations were observed with administration of cystine and theanine 27 .…”

Section: Discussionmentioning

confidence: 99%

“…The third was a study of runners participating in a long‐distance relay race ( Eki‐den ) where increases in granulocytes and decreases in lymphocytes after intense endurance exercise were reduced by cystine and theanine 28 . The fourth found a significantly reduced incidence of the common cold in adults who received cystine and theanine 29 . The fifth reported that continuous administration of cystine and theanine over 2 weeks of training suppressed reductions in natural killer (NK) cell activity in bodybuilders 30 .…”

Section: Discussionmentioning

confidence: 99%

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Perioperative Oral Administration of Cystine and Theanine Enhances Recovery After Distal Gastrectomy

Miyachi

Tsuchiya

Oyama

et al. 2012

J Parenter Enteral Nutr

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Appropriate regulation of inflammation during the perioperative period is important for achieving a stable postoperative course and early recovery and for reducing the malignancy relapse rate. For these reasons, an immune-modulating diet that includes anti-inflammatory substances such as ω-3 fatty acids has been used widely in clinical settings. The amino acids cystine and theanine are both involved in the synthesis of glutathione (GSH), a strong antioxidant, and there have been several reports that oral cystine and theanine enhance immunoreactions. This study was a pilot study to assess the effect of perioperatively administering oral cystine and theanine in gastric surgery patients and suggested that oral administration of these amino acids may reduce inflammation and promote recovery after gastric surgery. IntroductionPreventing organ dysfunction and immune suppression by inhibiting excess inflammation is considered an important aspect of perioperative surgical management, and several studies have indicated that immunonutrition is effective for this purpose.1,2 Administering the amino acids cystine and theanine has been shown to significantly suppress increases in C-reactive protein (CRP) levels and neutrophil counts and decreases in the number of lymphocytes after excessive exercise, resulting in a reduction in excessive inflammation and immune dysfunction; similar effects are expected to result from immunonutrition. 3 Cystine is a sulfur-containing amino acid that consists of 2 cysteine molecules joined by a disulfide bond. 4 Transporters on cell membranes (including those of neutrophils, macrophages, and dendritic cells) mediate the uptake of cystine into cells, and then thioredoxin rapidly 798P ENXXX10.1177/0148607112458798Journal of Parenteral and Enteral Nutrition / Vol. AbstractBackground: It has been reported that cystine and theanine, amino acids related to glutathione synthesis, have immunomodulatory effects, such as suppressing inflammation after strenuous exercise. In this study, we examined the effects of oral administration of cystine and theanine during the perioperative period as a pilot study. Methods: Forty-three cases of distal gastrectomy for cancer conducted in our department were assigned to the cystine and theanine group (CT group) or to the placebo control group (P group), and a randomized, singleblind, parallel-group study was then performed. Cystine (700 mg) and theanine (280 mg) or a placebo was administered to participants for 10 continuous days (4 days before to 5 days after surgery). Changes in pre-and postoperative interleukin (IL)-6, C-reactive protein (CRP), albumin, white blood cell (WBC) count, neutrophil count, total lymphocyte count, resting energy expenditure (REE), and body temperature were compared and examined. Results: Ten patients were excluded, leaving 33 patients in the study. The CT group had significantly lower IL-6 values (postoperative day [POD] 4), CRP levels (POD 7), neutrophil counts (POD 4), and body temperatures (POD 5) than the P group (P < .05). In addi...

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“…The body's defence against foreign molecules relies on the homeostatic regulation of innate and adaptive immune systems [71]. Conventional methods of treatment for common illnesses usually involve a regimen of antibiotics, antivirals, immunosuppressant's and dietary intervention that may support or enhance immune function [72]. A number of recent studies have suggested that L-THE administration can improve the body's immune system.…”

Section: Immune Systemmentioning

confidence: 99%

l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion

et al. 2016

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Tea has been consumed for thousands of years and is an integral part of people's daily routine, as an everyday drink and a therapeutic aid for health promotion. Consumption of tea has been linked to a sense of relaxation commonly associated with the content of the non-proteinogenic amino acid theanine, which is found within the tea leaves. The aim of this review article is to outline the current methods for synthesis, extraction and purification of theanine, as well as to examine its potential benefits related to human health. These include improvements in cognitive and immune function, cancer prevention, reduced cardiovascular risk and its potential usefulness as a functional food product.The relative concentration of L-THE in the Camellia sinensis plant varies between the plant's structures, over maturation and through the growth period. Recent studies have indicated that L-THE is distributed across the entirety of the plant with concentrations ranging between 1.2 and 6.2 mg/g fresh weight, with higher concentrations being expressed in the roots (6.2-13.7 mg/g). The biosynthesis of L-THE is proposed to occur in the roots of the plant and it is then transported towards the leaves [11]. The shading treatment and nitrogen fertilisation have been shown to influence the L-THE levels and the total free amino acid content in the Camellia sinensis plant [12]. Although most often related to GT, L-THE is present at similar levels in other types of teas made from the plant, including black, white and oolong teas [13]. Chemical, Physical and Flavour PropertiesL-THE is a water soluble non-proteinous amino acid [14] containing a glutamine backbone within the core of L-THE as well as existing as an ethylamide derivate of glutamate [15]. It is stable in acidic conditions but yields glutamic acid and ethylamine during base hydrolysis [8,16]. L-THE is insoluble in organic solvents such as chloroform and methanol, which facilitates the easy separation of L-THE from caffeine, catechins and other lipophilic tea constituents [8]. Aqueous L-THE solutions (1% (w/v)) stabilised at pH 5-6, were found to be stable (>1 year) under normal environmental conditions [8,16,17] and have a boiling point higher than that of water (range 214-216˝C) [8]. Furthermore, its systematic nomenclature is described as (2S)-2-amino-5-(ethylamino)-5-oxopentanoic acid (C 7 H 14 N 2 O 3 , M.W. = 174.2 g/mol) [18]. and L-glutamic acid-gamma-ethylamide have also been used to denote L-THE and it is also available under the proprietary name Suntheanine ® [5,19]. Similar to other amino acids in nature, theanine is a chiral species and occurs predominantly as the L-(S) enantiomer (Figure 1), whereas a synthetically derived theanine is typically a racemic mix of L-and D-enantiomers. As such, the use of synthetically derived theanine may not necessarily exhibit the same physiological effects as theanine found "naturally" occurring in foods [8].

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Effects of -Cystine and -Theanine Supplementation on the Common Cold: A Randomized, Double-Blind, and Placebo-Controlled Trial

Cited by 13 publications

References 27 publications

L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety

L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety

Perioperative Oral Administration of Cystine and Theanine Enhances Recovery After Distal Gastrectomy

l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion

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