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L-Arginine is a feasible supplement to heal chronic anal fissure via reducing internal anal sphincter pressure: a randomized clinical trial study.
Khalighi Sikaroudi, M, Sedaghat, M, Shidfar, F, Talebi, S, Hosseini-Baharanchi, FS, Masoodi, M, Farahani, SV
Amino acids. 2023;55(2):193-202
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An anal fissure is a condition resulting from a superficial open wound or tear in the anus mucosa with a sharp pain that can extend from the anal canal to the periphery. The aim of this study was to evaluate the effect of oral L-arginine as a safer method with better performance on clinical symptoms, quality of life, and internal anal sphincter pressure in patients with chronic anal fissure. This study is a randomised, double-blind, placebo-controlled trial with parallel design conducted in the 4-week intervention and the 8-week follow-up. The study recruited 76 adult men and women who were aged between 18 and 65 years of age and were diagnosed with chronic fissures. Participants were assigned to two groups: 3000 mg l-arginine, or a placebo filled with Maltodextrin. Results show that supplementation with l-arginine may relieve clinical symptoms, especially pain and bleeding, and improve the quality of life of patients with chronic anal fissure. In addition, analysis of anal internal sphincter pressures evaluated by manometry and balloon showed the significant reduction of sphincter pressure in these patients. Authors conclude that l-arginine supplementation may relieve clinical symptoms and improve the quality of life, anxiety, and depression in patients with chronic anal fissures.
Abstract
The hypertonicity of internal anal sphincter resting pressure is one of the main causes of chronic anal fissure. Therefore, the aim of this study was to assess the effect of oral administration of L-arginine on the improvement of the anal fissures by relaxing the internal anal sphincter. Seventy-six chronic anal fissure patients (aged 18-65 years) who were referred to Rasoul-e-Akram Hospital, Tehran, Iran from February 2019 to October 2020 participated in this randomized, double-blind, placebo-controlled trial. Participants were allocated into treatment (L-arginine) and placebo groups. They took a 1000 mg capsule three times a day for 1 month, and then we followed them at the end of the first and third months after the intervention. Clinical symptoms, anal sphincter resting pressure, and quality of life (QoL) were completed at baseline and the end of the study. The analysis of data showed a significant decrease in bleeding, fissure size, and pain for each group; however, in the L-arginine group was more than the control group at the end of the study (P values < 0.001). Following that, a significant increase in QoL was seen just in patients treated with L-arginine (P value = 0.006). In addition, the comparison of anal pressures at baseline and, between groups at the end of the study showed a significant reduction in sphincter pressure in patients treated with L-arginine (P value < 0.001, = 0.049; respectively). The oral administration of 3000 mg L-arginine can heal chronic anal fissures by reducing internal anal sphincter pressure with more negligible side effects. However, we recommend long-term study with more extended follow-up.Clinical trial registry: IRCT20190712044182N1 at Iranian clinical trials, date: 2019-08-27.
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Effect of Combined Ingestion of L-Theanine and L-Arginine for Short-Term Psychological Stress in Young Adults: A Randomized Placebo-Controlled Study.
Furushima, D, Sugiyama, I, Nomura, Y, Unno, K, Yamada, H
Journal of nutritional science and vitaminology. 2022;68(6):540-546
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The beneficial effects of green tea and its components are well known. The ingredient L-Theanine is the most abundant water soluble non-proteinous amino acid component in green tea. The second most abundant ingredient is L-Arginine. It also exhibits a high stress-reducing effect. The hypothesis of this study was that the combined ingestion of L-arginine and L-theanine could have beneficial clinical effects for psychological stress compared with ingestion of theanine alone. This study was a randomised placebo-controlled, single-blinded study in healthy young adults. Participants (n=120) were randomly assigned to one of the three groups (1:1:1); L-theanine alone, L-theanine and L-arginine or placebo. Results show that combined ingestion of L-theanine and L-arginine tended to have greater stress reducing effects than ingestion of L-theanine alone. However, the difference was not statistically significant. Authors conclude that their findings are suggestive of synergistic effects of L-theanine and L-arginine against stress in young adults.
Abstract
l-Theanine, the most abundant amino acid component in green tea, has anti-stress effects and refreshes the mental state. A recent study demonstrated that l-arginine, the second most abundant amino acid in green tea, might enhance the anti-stress effects of l-theanine. The aim of this study was to evaluated the effects of combined ingestion of l-theanine and l-arginine on psychological stress in humans. A randomized placebo-controlled trial was conducted including 120 healthy young adults (mean age 22.4 y, 63.3% female). Subjects were randomly assigned to theanine (200 mg l-theanine), combined theanine/arginine (200 mg l-theanine, 50 mg l-arginine), or placebo groups. After consuming a test beverage, we administered a stress-loading test (Uchida-Kraepelin performance test) and performed salivary alpha-amylase activity (sAA) measurements to assess the physiological stress response at 0 min (immediately after), 5 min, and 15 min. The changes in sAA at 15 min after the stress-loading test were -2.75 (11.2) kIU/L in the theanine/arginine group, -0.40 (11.5) kIU/L in the theanine group, and 6.95 (18.6) kIU/L in the placebo group. The values in the theanine/arginine (p=0.007) and theanine (p=0.02) groups differed significantly from those in the placebo group. However, the difference between theanine/arginine and theanine groups, was not statistically significant (p=0.74). From this study, no clear conclusion could be drawn regarding the potentiating effect of theanine and arginine combined ingestion on anti-stress effects in human.
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Mechanisms Underlying the Anti-Depressive Effects of Regular Tea Consumption.
Rothenberg, DO, Zhang, L
Nutrients. 2019;11(6)
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Previous research suggests that tea consumption is linked to a lower risk of depression, but it is not understood why. This meta-analysis and literature review looked at previous human, animal and laboratory studies that might give an indication of the mechanisms by which drinking tea can lead to a reduced depression risk. Tea contains many different active compounds such as L-theanine, various polyphenols and polyphenol metabolites that have effects on the immune system, stress response, brain neurotransmitters such as serotonin and dopamine, and gut bacteria. Different types of tea such as black, green or oolong tea contain different amounts of active compounds. The authors found that these compounds are capable of functioning through multiple pathways simultaneously that together reduce the risk of depression. The authors concluded that daily consumption of moderate amounts of different types of tea may offer significant potential benefit in the risk reduction of depression.
Abstract
This article is a comprehensive review of the literature pertaining to the antidepressant effects and mechanisms of regular tea consumption. Meta-data supplemented with recent observational studies were first analyzed to assess the association between tea consumption and depression risk. The literature reported risk ratios (RR) were 0.69 with 95% confidence intervals of 0.62-0.77. Next, we thoroughly reviewed human trials, mouse models, and in vitro experiments to determine the predominant mechanisms underlying the observed linear relationship between tea consumption and reduced risk of depression. Current theories on the neurobiology of depression were utilized to map tea-mediated mechanisms of antidepressant activity onto an integrated framework of depression pathology. The major nodes within the network framework of depression included hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, inflammation, weakened monoaminergic systems, reduced neurogenesis/neuroplasticity, and poor microbiome diversity affecting the gut-brain axis. We detailed how each node has subsystems within them, including signaling pathways, specific target proteins, or transporters that interface with compounds in tea, mediating their antidepressant effects. A major pathway was found to be the ERK/CREB/BDNF signaling pathway, up-regulated by a number of compounds in tea including teasaponin, L-theanine, EGCG and combinations of tea catechins and their metabolites. Black tea theaflavins and EGCG are potent anti-inflammatory agents via down-regulation of NF-κB signaling. Multiple compounds in tea are effective modulators of dopaminergic activity and the gut-brain axis. Taken together, our findings show that constituents found in all major tea types, predominantly L-theanine, polyphenols and polyphenol metabolites, are capable of functioning through multiple pathways simultaneously to collectively reduce the risk of depression.