Tolerability of glutamine supplementation in older adults: a double-blind placebo-controlled randomized clinical trial

In this double-blind placebo-controlled randomized investigation, we assessed the tolerability of glutamine in older adults recruited from three daycare centers. The relevance of studying glutamine supplementation in elderly patients lies in its potential to provide a well-tolerated intervention. Glutamine, a crucial amino acid, plays a vital role in various physiological processes, including immune function and protein synthesis. Understanding its impact on older adults is essential, given the potential implications for their health and well-being. Participants received a daily dose of 12.4 g of oral effervescent glutamine (EGln group) or maltodextrin (placebo group) for 60 days. Fifteen patients from each group completed the study. The mean ages were 77.0±9.1 and 79.0±6.9 years for the EGln and placebo groups, respectively. We evaluated body mass index, aminogram, hemogram, plasma levels of glucose, prealbumin, albumin, urea, creatinine, uric acid, C-reactive protein, vitamin D, calcium, sodium, potassium, and the plasma activities of aspartate aminotransferase and alanine aminotransferase. Notably, we quantified a broad array of inflammatory markers and growth factors providing a holistic understanding of the potential effects of glutamine supplementation. The results demonstrated that oral glutamine did not induce significant changes in any evaluated parameters, and no adverse effects were reported. This finding suggested that the dosage of glutamine used in this study was well-tolerated and safe. This information contributes to the broader understanding of glutamine supplementation, emphasizing its safety and supporting its potential as a viable intervention for maintaining health in aging individuals.

Interleukin-12 as a biomarker of the beneficial effects of food restriction in mice receiving high fat diet or high carbohydrate diet

The impact of food restriction (FR) during 56 days on serum levels of cytokines in mice fed a high-fat diet (HFD) or high-carbohydrate diet (HCD) were evaluated. The amount of food was reduced 50% for HFD-FR and HCD-FR groups compared to mice receiving free access to HFD (HFD group) or HCD (HCD group). We quantified the serum levels of basic fibroblast growth factor, granulocyte-macrophage colony-stimulating factor, inducible protein 10, interferon γ, interleukin 1α (IL-1α), IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17, keratinocyte chemoattractant, macrophage inflammatory protein-1α, monocyte chemotactic protein 1, monokine induced by IFN-γ, and tumor necrosis factor α. Only IL-12 levels were lower (P<0.05), for both HFD-FR (HFD-FR vs HFD) and HCD-FR (HCD-FR vs HCD). Therefore, IL-12 levels could be considered a biological marker of the beneficial effects of FR.

Blood levels of pro-inflammatory and anti-inflammatory cytokines during an oral glucose tolerance test in patients with symptoms suggesting reactive hypoglycemia

We evaluated the impact of postprandial glycemia on blood levels of pro-inflammatory and anti-inflammatory cytokines during an oral glucose tolerance test in non-diabetic patients with symptoms suggesting reactive hypoglycemia. Eleven patients with clinical symptoms suggesting reactive hypoglycemia received an oral glucose solution (75 g) Blood was collected at 0 (baseline), 30, 60, 120 and 180 min after glucose ingestion and the plasma concentrations of interferon-α (IFN-α), interferon-γ (IFN-γ), interleukin-1 receptor antagonist (IL-1RA), interleukin 2 (IL-2), interleukin-2 receptor (IL-2R), interleukin 4 (IL-4), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin-12 (IL-12), interleukin 13 (IL-13), interleukin 15 (IL-15), interleukin 17 (IL-17), IFN-γ inducible protein 10 (IP-10), monocyte chemotactic protein 1 (MCP1), monokine induced by IFN-γ (MIG), macrophage inflammatory protein-1α (MIP-1α), interleukin-1β (IL-1β), colony stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), basic fibroblast growth factor (FGF-basic), eotaxin, tumor necrosis factor α (TNFα), epidermal growth factor (EGF), hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), macrophage inflammatory protein-1α (MIP-1α), and 1β (MIP-1β) were evaluated. Overall, glycemic levels increased, reached its maximum at 30 min (phase 1), returned to baseline levels at 120 min (phase 2), followed by a mild hypoglycemia at 180 min (phase 3). During phase 1, cytokine blood levels were maintained. However, we observed a synchronous fall (P<0.05) in the concentrations of pro-inflammatory (IL-15, IL-17, MCP-1) and anti-inflammatory cytokines (FGF-basic, IL-13, IL-1RA) during phase 2. Furthermore, a simultaneous rise (P<0.05) of pro-inflammatory (IL-2, IL-5, IL-17) and anti-inflammatory cytokines (IL-4, IL-1RA, IL-2R, IL-13, FGF-basic) occurred during phase 3. Thus, mild acute hypoglycemia but not a physiological increase of glycemia was associated with increased blood levels of anti-inflammatory and pro-inflammatory cytokines.