Calcium ascorbate 550mg tablets

Vitamin C is an antioxidant and is essential for immune function and infection resistance. Supplementation is necessary when a sufficient amount of vitamin C is not obtained through the diet. Alternative formulations of vitamin C may enhance its bioavailability and retention over traditional ascorbic acid. This systematic review consolidates the evidence on this and the effects on immunity and infection. A systematic literature search was conducted in October 2024 in Embase and Medline, focused on healthy adults (Population); oral forms of liposomal-encapsulated ascorbic acid, liposomal-encapsulated lipid metabolite ascorbic acid, calcium ascorbate, slow-release ascorbic acid, or lipid metabolite ascorbic acid (Intervention); compared to placebo/others (Comparison); in terms of bioavailability, absorption, vitamin C concentration in plasma, serum, and leukocytes, and impacts on tolerability, immunity, and infection (Outcome); and included randomized or non-randomized controlled trials, single-arm trials, and observational studies (Study design). Thirteen studies were included, several evaluating calcium ascorbate in combination with vitamin C metabolites, including L-threonate, referred to here as Calcium ascorbate EC (Ester C®; n = 7). No safety or tolerability concerns were noted with Calcium ascorbate EC vs. placebo or ascorbic acid. Calcium ascorbate EC showed better tolerability and fewer epigastric adverse events, improved quality of life, and induced favorable oxalate changes vs. ascorbic acid. Four studies reported leukocyte vitamin C concentration, some showing higher concentrations with Calcium ascorbate EC vs. ascorbic acid; seven reported more favorable plasma concentrations with the alternative forms over ascorbic acid or placebo; one reported higher serum vitamin C levels with vitamin C lipid metabolites than with Calcium ascorbate EC, calcium ascorbate, and ascorbic acid. No study reported retention in tissues. One study reported a favorable impact of Calcium ascorbate EC on immune parameters, and one found an association of Calcium ascorbate EC with fewer colds and a shorter duration of severe symptoms vs. placebo. Findings suggest that alternative vitamin C forms can improve leukocyte vitamin C, sometimes without affecting plasma levels. Most studies (77%) had a low risk of bias. In conclusion, the type and delivery modality of vitamin C can impact its bioavailability and functionality. Studies highlight the advantages of Calcium ascorbate EC over traditional ascorbic acid in terms of its tolerability and its potential to increase leukocyte vitamin C concentrations, crucial for immune function and protection against infection. However, further research is required to conclusively establish its effects on immune health.

Abstract licence: CC BY

Sepsis remains the leading cause of death in intensive care units globally, with catecholamine-resistant shock posing a persistent therapeutic challenge. Norepinephrine is the primary vasopressor used to treat hypotension in sepsis, but its efficacy is often limited by multifactorial loss of pressor responsiveness, including adrenergic receptor desensitisation, excess nitric oxide, systemic inflammation, and endothelial injury. Ascorbate (vitamin C) has emerged as a potential adjunct therapy because it supports endothelial function, reduces oxidative stress, activates the immune system and enhances endogenous vasopressor synthesis. Despite restoration of systemic hemodynamics with fluids and vasopressors, the frontal cortex remains particularly vulnerable to microcirculatory ischemia and hypoxia, contributing to sepsis-associated encephalopathy through hypoperfusion, hypoxia, hyperthermia, oxidative stress, neuroinflammation, and mitochondrial dysfunction, ultimately leading to neuronal injury and delirium. Plasma levels of ascorbate are profoundly depleted in sepsis and correlate with disease severity. Cerebral cortical neurons actively concentrate ascorbate at levels up to 250-fold higher than plasma, underscoring its importance in maintaining redox homeostasis and metabolism in the brain. While the conventional intravenous vitamin C formulation, ascorbic acid, has been associated with harm in clinical trials, emerging preclinical and early clinical data suggest that intravenous sodium ascorbate, a pH–neutral formulation of vitamin C, may restore noradrenaline sensitivity and re-establish frontal cortical microvascular perfusion and oxygenation. This review discusses the mechanistic rationale and therapeutic potential of sodium ascorbate in sepsis, including its ability to cross the blood-brain barrier. By stabilising cardiovascular and cerebrovascular function, sodium ascorbate may represent a promising adjunctive therapy to improve the management of sepsis.

Abstract licence: CC BY-NC-ND