From Pauling's theories to the present, considerable understanding has been acquired of both the physiological role of vitamin C and of the impact of vitamin C supplementation on the health. Although it is well known that a balanced diet which satisfies the daily intake of vitamin C positively affects the immune system and reduces susceptibility to infections, available data do not support the theory that oral vitamin C supplements boost immunity. No current clinical recommendations support the possibility of significantly decreasing the risk of respiratory infections by using high-dose supplements of vitamin C in a wellnourished general population. Only in restricted subgroups (e.g., athletes or the military) and in subjects with a low plasma vitamin C concentration a supplementation may be justified. Furthermore, in categories at high risk of infection (i.e., the obese, diabetics, the elderly, etc.), a vitamin C supplementation can modulate inflammation, with potential positive effects on immune response to infections. The impact of an extra oral intake of vitamin C on the duration of a cold and the prevention or treatment of pneumonia is still questioned, while, based on critical illness studies, vitamin C infusion has recently been hypothesized as a treatment for COVID-19 hospitalized patients. In this review, we focused on the effects of vitamin C on immune function, summarizing the most relevant studies from the prevention and treatment of common respiratory diseases to the use of vitamin C in critical illness conditions, with the aim of clarifying its potential application during an acute SARS-CoV2 infection.

BackgroundFish protein hydrolysates (FPHs) have been reported as a suitable source of proteins for human nutrition because of their balanced amino acid composition and positive effect on gastrointestinal absorption.ObjectiveHere, we investigated the effect of a FPH, Slimpro®, obtained from blue whiting (Micromesistius poutassou) muscle by enzymatic hydrolysis, on body composition and on stimulating cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) secretion.DesignA randomized clinical study was carried out on 120, slightly overweight (25 kg/m2 ≤ BMI<30 kg/m2), male (25%) and female (75%) subjects. FPH was tested in a food supplement at two doses (1.4 and 2.8 g) to establish if a dose–effect relationship exists. Product use was associated with a mild hypocaloric diet (−300 kcal/day). Body composition (body weight; fat mass; extracellular water; and circumference of waist, thighs, and hips) and CCK/GLP-1 blood levels were measured at the beginning of the study and after 45 and 90 days of product use. CCK/GLP-1 levels were measured since they are involved in controlling food intake.ResultsTreated subjects reported an improvement of body weight composition and an increased blood concentration of both CCK and GLP-1. No differences were found between the 1.4 and 2.8 g FPH doses, indicating a plateau effect starting from 1.4 g FPH.ConclusionsBoth 1.4 and 2.8 g of FPH were effective in improving body composition and in increasing CCK and GLP-1 blood levels.

As we age, the aerobic and functional capacities of our major physiological systems progressively decline. In the case of the neuromuscular system, reductions in strength and mobility cause a deterioration in motor performance and in turn a greater tendency to fall (with increased risk of fractures), impaired mobility, disability and loss of independence in the elderly. Given the increase in our life expectancy and the consequent growth in the elderly population, these conditions will have an increasing impact on modern healthcare systems, and their prevention and attenuation needs to be addressed. Several intervention strategies have been used to improve motor performance among the aging. At the cellular level, aging is caused by a progressive decline in mitochondrial function that results in the accumulation of reactive oxygen species (ROS) generated by the addition of a single electron to the oxygen molecule As the level of oxidative stress in skeletal muscle increases with age, the production of some antioxidant enzymes increases adaptively to compensate in part. The aging process is characterized by an imbalance between an increase in the production of reactive oxygen species in the organism and the antioxidant defences as a whole. The goal of this review is to examine the results of existing studies on oxidative stress in aging human skeletal muscles, taking into account different physiological factors (sex, fiber composition, muscle type and function).

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Musculoskeletal disorders in aging and pain are closely connected because of multiple mechanisms leading to loss of mobility and autonomy. Pain is predictive of diability and worsening frailty and the strength of this relationship increases with the severity of pain. This study presents a systematic review of randomized controlled trials, cross sectional studies, and observational studies based on treatment of pain in adults with musculoskeletal disorders using nutritional non-pharmacological (nutrients and antioxidants) interventions. The review found the efficiency of the following topics: (a) accession of the patient to a dietary counselling (e.g., daily recommended amount of protein—equivalent to at least of 1 g of protein per kilogram of body weight); (b) intake of glutamic acid-rich such as soy, egg, and cod and tryptophan-rich foods such as milk and peanuts—or taking quick-acting, free-form supplements; (c) supplementation of vitamin D and magnesium, if lacking; (d) weekly consumption of fish or supplements of omega-3 fatty acids; and (e) availability of botanicals, in particular curcumin and gingerol. These non-pharmacological interventions can help the pain therapist to create a personalized medicine (precision medicine), acting with the maximum efficacy and safety, and also reducing the dosage of analgesic drugs needed.

Dates have a low glycemic index and are a source of antioxidants but, nevertheless, contain more than 70% sugar. This study aims to assess the effects of date consumption (three dates daily) on glycemic profile (HbA1c), body mass index (BMI), quality of life, and lipid profile, including total cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) in terms of safety for type 2 diabetic mellitus (T2DM) subjects. A randomized controlled trial was conducted with a sample of 100 T2DM subjects (39 male and 61 female) randomly assigned in two groups. The first group received three dates daily for 16 weeks, and the control group avoided date consumption. After a 16-week follow-up period, the study results showed an improvement of lipid profile with a statistically significant decrease in total cholesterol of ∆ = −0.209 mmol/L (confidence interval (CI) 95% −0.358, −0.059; p < 0.05) and in LDL of ∆ = −0.171 mmol/L (CI 95% −0.358, 0.016) in the group receiving three dates daily. Intra-group mean differences of BMI were not statistically different in both groups after 16 weeks of date consumption. Even HbA1c did not change, both within and between groups after date consumption (∆ = 0.087%; CI 95% −0.086, 0.261). Between groups, mean difference changes (intervention minus control) showed a statistically significant improvement of quality of life index of ∆ = ± 30.66 points (CI 95% 12.45, 48.23) due to the consequent improvement in mental health. Although the definitive effect of dose/intake response of date consumption on Hb1Ac, lipid profile, and BMI in T2DM subjects is still to be established, the study suggests that dates could potentially have a beneficial effect on lipid profile, especially in reducing total cholesterol and elevating HDL, because of its high polyphenolic content. In addition, a low–moderate consumption of dates did not impact glucose levels because of dates’ low glycemic index.

Beef is a nutrient-rich, high-quality protein containing all the essential amino acids in proportions similar to those found in human skeletal muscle. In order to investigate the efficacy of a beef supplementation strategy on strength and body composition, we recruited 26 young healthy adults to participate in a resistance-training program of eight weeks, based on the use of isotonic machines and free weights at 75% of one repetition maximum. Subjects were randomly divided into two groups, food group and control group, of 12 and 14 subjects respectively. Food group were supplemented after resistance training with a 135 g serving of lean beef (tinned meat), providing 20 g of protein and 1.7 g of fat. No supplementation was provided to control group. Fat mass, fat free mass, lean mass, assessed by bioelectrical impedance analyzer, and muscle strength, assessed by one repetition maximum test, were evaluated in all subjects both at the beginning (week 0) and at the end (week 8) of the study. Pre- and post-training differences were evaluated with paired t-tests while group differences for each outcome parameter was evaluated with independent t-tests. At the end of the study the food group showed a significantly decrease in fat mass (week 0: 15.0 ± 6.7 kg; week 8: 13.1 ± 7.6 kg; Δ: −1.9 ± 2.9 kg; p < 0.05) and a significantly increase in fat free mass (week 0: 52.8 kg ± 9.4; week 8: 55.1 kg ± 10.9; Δ: 2.3 ± 2.5 kg; p < 0.01). No significant differences in lean mass were found in either food group or control group. No significant differences in one repetition maximum tests were found between food group and control group. Tinned meat can be considered a nutrition strategy in addition to other proteins or amino acid supplements, but as with any other supplementation strategy, a proper nutrition plan must be coupled.

Despite the numerous positive effects of physical exercise, some negative physiological changes occur in long-lasting heavy training with transient dysfunction of the immune system, increased inflammation, and oxidative stress. This is the case of elite athletes, who train intensively to compete at the highest levels. However, these athletes can counteract the negative effects of heavy training, reducing acute and chronic inflammations and supporting the immune system, with nutritional and supplementation countermeasures. For this purpose, macronutrient manipulation with an appropriate use of certain supplements can be considered as an intervention to reduce exercise-induced immune changes and inflammatory risk. For example, branched-chain amino acid (BCAA) supplementation may promote such immune responses in skeletal muscle. Furthermore, micronutrients play an important role in immune function; in particular, the antioxidant capacity of several dietary micronutrients (e.g., tocopherols, docosahexaenoate, and flavonoids) is very interesting to support the endogenous antioxidant defense systems of the athletes, counterbalancing the negative effects of oxidative damage due to free radicals. Some of these nutrients have potential anti-inflammatory properties as assessed by the attenuated levels of interleukin-6 (IL-6) and C-reactive protein (CRP). Key Teaching Points: Long-lasting heavy training plan and competition can lead to chronic immune suppression in athletes, increasing infection risk. Chronic exercise increases mobilization of neutrophils, decreases mobilization of lymphocytes, and decreases the absolute and relative numbers of neutrophils at rest. Nutritional deficiencies alter the immuno-system and increase infection risk. Nutrition can influence exercise-induced immune suppression. Elite athletes competing at the highest levels can benefit from nutritional and supplementation support to improve immunity and reduce acute and chronic inflammations.