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Preventing the common cold with a vitamin C supplement: A double-blind, placebo-controlled survey

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  • Independent Researcher

Abstract

One hundred sixty-eight volunteers were randomized to receive a placebo or a vitamin C supplement, two tablets daily, over a 60-day period between November and February. They used a five-point scale to assess their health and recorded any common cold infections and symptoms in a daily diary. Compared with the placebo group, the active-treatment group had significantly fewer colds (37 vs 50, P<.05), fewer days challenged virally (85 vs 178), and a significantly shorter duration of severe symptoms (1.8 vs 3.1 days, P<.03). Consequently, volunteers in the active group were less likely to get a cold and recovered faster if infected. Few side effects occurred with the active treatment, and volunteers reported greatly increased satisfaction with the study supplement compared with any previous form of vitamin C. This well-tolerated vitamin C supplement may prevent the common cold and shorten the duration of symptoms. Volunteers were generally impressed by the protection afforded them during the winter months and the general acceptability of the study medication.
... This review includes results from fourteen articles [12,16,[27][28][29][30][31][32][33][34][35][36][37][38] reporting on a total of thirteen unique RCTs (two articles [16,38] report results from the same RCT) ( Table 2). All studies included healthy populations; most included young or middle-aged adults and the mean age of the participants included in the different studies ranged from 24 to 48 years (Table 2). ...
... Two studies assessed only males [27,31]. Out of the thirteen unique studies, seven used Calcium ascorbate EC [27,28,30,[32][33][34]38], one used lipid-metabolite ascorbic acid (PureWay C ® ) [35], two used sustained or slow-release ascorbic acid [29,31], and three used liposomal-encapsulated ascorbic acid [12,36,37] as an intervention. Studies compared Calcium ascorbate EC with ascorbic acid and placebo [27,28,30,[32][33][34]38], and one study compared it with lipid metabolite, ascorbic acid, and calcium ascorbate [35]. ...
... Out of the thirteen unique studies, seven used Calcium ascorbate EC [27,28,30,[32][33][34]38], one used lipid-metabolite ascorbic acid (PureWay C ® ) [35], two used sustained or slow-release ascorbic acid [29,31], and three used liposomal-encapsulated ascorbic acid [12,36,37] as an intervention. Studies compared Calcium ascorbate EC with ascorbic acid and placebo [27,28,30,[32][33][34]38], and one study compared it with lipid metabolite, ascorbic acid, and calcium ascorbate [35]. Intervention studies on liposomal-encapsulated forms had non-liposomal vitamin C as the comparator [12,36,37]. ...
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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.
... Various forms of vitamin C are used in supplement formulations (i.e., calcium ascorbate (CA), liposomal encapsulated ascorbic acid (AA), liposomal encapsulated lipid metabolite AA, slow-release AA, lipid metabolite AA) with companies making claims these forms are superior to AA in absorptive ability, bioavailability, retention in leukocytes, and tolerability. Most comparative trials assess the efficacy of CA against AA [1][2][3][4][5][6][7][8]; however, several trials have shown higher retention, greater absorption, and tolerance in liposomal encapsulated vitamin C [8][9][10][11][12][13], but equivocal findings with sustained release vitamin C in plasma vitamin C concentration compared to AA [14][15][16]. ...
... Acute doses at 1000 mg of calcium ascorbate (CA), compared to AA, have been shown to enhance vitamin C retention in leukocytes as long as 24 h following ingestion [1,2]. In addition, Van and colleagues [5] found reduced frequency and severity of cold-like symptoms in those supplementing 1000 mg CA for 60 days, which could be attributed to leukocyte function. Neutrophils are a heavily abundant leukocyte type. ...
... One reason for the inconsistent findings may be related to the bioavailability of different forms of vitamin C studied. Vitamin C trials comparing the PK profiles and immune effects of CA vs. AA or other forms of vitamin C have shown favorable responses to CA in plasma and leukocyte vitamin C retention and increased bioavailability in leukocytes in acute supplemental protocols [1][2][3][4][5][6]. Vitamin C is present in high concentrations in leukocytes. ...
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Background: Previous trials have displayed augmented intracellular vitamin C concentrations in the leukocytes at 24 h after acute supplementation with 1000 mg calcium ascorbate (CA), compared to ascorbic acid (AA). Objective: The primary objective was to evaluate comparative leukocyte vitamin C accumulation kinetics over 32 h following acute 250 mg or 500 mg doses from the two sources. Secondary objectives were to evaluate neutrophil phagocytic function and lymphocyte differentiation between the two sources of vitamin C. Methods: Ninety-three healthy females (250 mg, n = 27; 500 mg, n = 24) and males (250 mg, n = 19; 500 mg, n = 23) were assigned to ingest a single dose of CA or AA providing 250 mg or 500 mg of vitamin C in two separate double-blind, randomized crossover trials. Results: There were no significant differences in the primary or secondary outcomes between the two treatments in the 250 mg low-dose study. Conversely, there was evidence that ingestion of 500 mg of CA increased DHA in plasma, increased neutrophil functionality during the first 8 h of the PK study, promoted increased natural killer cells, and altered weight-adjusted PK profiles, suggesting greater volume distribution and clearance from the blood. Conclusions: These findings indicate that 500 mg of CA may promote some immune benefits compared to 500 mg of AA ingestion.
... Витамин С уменьшает выраженность обострения инфекций дыхательных путей, восстанавливая дисфункциональный эпителиальный барьер легких: снижение заболеваемости простудой и уменьшение продолжительности простудных заболеваний при регулярном приеме витамина С отмечено в ряде клинических исследований [69][70][71]. ...
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Acute respiratory viral infections are widespread diseases, poorly controlled infections and are characterized by moderately pronounced constant growth. The use of vitamin-mineral complexes (nutraceuticals) for nonspecific prevention and treatment of acute respiratory viral infections is experiencing a “second youth” thanks to new data accumulated during the novel coronavirus infection (COVID-19) pandemic. As part of the review, we examined the possible impact of deficiency of the microelements selenium and zinc, vitamins A, E and C on various aspects of the course of ARVI: nonspecific prevention, treatment and rehabilitation. We searched for relevant sources in the PubMed and Scopus information databases, including the time period up to 04.07.2024. The presence in the arsenal of a practicing physician of 2 forms of the vitamin-mineral complex Selzinc® at the outpatient stage of medical care will increase the effectiveness of nonspecific prevention of ARVI in the pre-epidemic period, especially in “frequently ill adults with ARVI,” as well as the treatment of ARVI as adjuvant therapy and subsequent rehabilitation.
... In addition, ascorbic acid is vital for developing healthy bones, teeth, gums, ligaments, and blood vessels [2]. Vitamin C is used in the prevention and treatment of a broad spectrum of conditions [19], including diabetes [20,21], atherosclerosis [22], the common cold [23], cataracts [24], glaucoma [25], macular degeneration [26], strokes [27], heart disease [28,29], COVID-19 [30], and cancer [31,32]. ...
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The content of vitamin C in fruit juices can be lowered by alterations in storage and temperature. This study compared storage circumstances (temperature, duration, and packaging type) to determine which variable had the biggest influence on changes in the vitamin C content of juices (grapefruit, mandarin, peach, apple, pear, plum). Fruit juices held in glass (plastic) containers at 4 °C saw vitamin C losses in the range of 0.0–10.9% (2.4–17.4%) in 24 h, 1.4–22.6% (5.2–25.3%) in 48 h, and 2.8–37.0% (6.0–39.0%) in three days. By raising the storage temperature to 23 °C, vitamin C losses in glass (plastic) containers were found to be 1.4–19.1% (5.2–22.2%), 2.8–20.9% (5.9–25.9%), and 4.5–43.5% (6.0–38.7%) of the value after 24 h, 48 h, and three days, respectively. When decreasing the temperature to −18 °C in fruit juices stored in glass (plastic) containers, there were losses of vitamin C in 24 h in the range of 1.5–19.6% (3.0–20.0%), in 48 h, 4.5–26.1% (4.5–26.1%), and in three days, 6.0–43.1% (5.8–43.5%) of the value. The effect of temperature on vitamin C concentration has been proven. Fruit juice’s vitamin C is more stable when kept in glass containers as opposed to plastic ones, which have a limited shelf life.
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