The Pharmacokinetics of Vitamin C

Reduction in Migraine and Headache Frequency and Intensity With Combined Antioxidant Prophylaxis (N-acetylcysteine, Vitamin E, and Vitamin C): A Randomized Sham-Controlled Pilot Study

OBJECTIVE

To investigate the preventive effects of a combined antioxidant drug (N-acetylcysteine, vitamin E, and vitamin C [NEC]) on migraine outcomes. Migraine is characterized by increased oxidative stress and neurogenic inflammation in the brain; therefore, antioxidants may have a migraine preventive effect.

DESIGN

Randomized, double-blind, sham-controlled pilot study.

SETTING

Australian community.

SUBJECTS

Adults reporting 2 to 8 migraines per month for at least a year.

METHODS

After a 1-month baseline period, 35 subjects completed 3 months of treatment with NEC (n = 19) or sham (n = 16) capsules. The primary outcome was the difference in mean number of headaches per month between baseline and final month of the trial for NEC and sham groups; secondary outcomes are listed below.

RESULTS

For NEC there was a significant decrease in mean number of headaches by 3.0 per month (P = 0.004) compared with 1.4 for sham (P = 0.073); there was no significant difference in these changes between the 2 groups (P = 0.052). Average monthly headache (P = 0.041) and migraine frequency (P = 0.018) were significantly less for NEC vs. sham. In NEC subjects, there was a significant decrease in average monthly migraine days (-3.1), moderate/severe headache days (-3.2), migraine duration, headache pain scores, and acute headache medication use.

CONCLUSIONS

This is the first randomized controlled trial to find that combined antioxidant therapy with NEC reduces headaches and migraines in adult migraineurs. Given the limitations of this pilot study, an adequately powered randomized controlled trial is planned to further investigate antioxidant prophylaxis in migraine.

Discrepancies in global vitamin C recommendations: a review of RDA criteria and underlying health perspectives

The concept of a 'recommended dietary allowance' (RDA) and similar terms describing the daily intake of essential nutrients recommended for healthy individuals is widely used by various health authorities around the world. For vitamin C, however, there remain significant discrepancies in the criteria used to establish dietary recommendations and consequently, global recommendations for daily vitamin C intake vary by more than five fold. While it appears that the scientific data underlying the recommendations are more or less the same, the interpretation differs considerably. Moreover, although a number of the assumptions used in e.g. the body pool estimates of the 1960s and 1970s have later been proven wrong and give rise to significant underestimations, these data are still used as the main support of several recommendations. Aspects that modify vitamin C requirements, such as gender, age, pregnancy, lactation, and smoking, have been taken into consideration by many but not all regulatory authorities, and are thus subject of debate. In contrast, body weight, a significant predictor of vitamin C status and requirement, has not been taken into consideration with respect to vitamin C recommendations, even in the face of the looming global obesity pandemic. The present review examines the discrepancies in vitamin C dietary recommendations of international authorities and critically discusses representative examples of criteria and the underlying health perspectives used to derive current recommended intakes of vitamin C. New biological signatures of vitamin C nutriture are also explored with regard to their potential use for future updates of dietary recommendations.

Possible Involvement of Vitamin C in Periodontal Disease-Diabetes Mellitus Association

Ascorbic acid (vitamin C) is an important water-soluble vitamin found in many fruits and vegetables. It has well-documented beneficial effects on the human body and is used as a supplement, alone or in combination with other vitamins and minerals. Over recent years, research has focused on possible new therapeutic actions in chronic conditions including periodontal disease (PD). We conducted a systematic review on clinical trials from four databases (PubMed, Clinical Trials, Cochrane, Web of Science) which measured plasmatic/salivary levels of ascorbic acid in PD–diabetes mellitus (DM) association. Six studies were included in our review, three of them analyzing patients with different grades of PD and DM who received vitamin C as a treatment (500 mg vitamin C/day for 2 months and 450 mg/day for 2 weeks) or as part of their alimentation (guava fruits), in combination with standard therapies and procedures. Decreased levels of vitamin C were observed in PD patients with DM but data about efficacy of vitamin C administration are inconclusive. Given the important bidirectional relationship between PD and DM, there is a strong need for more research to assess the positive effects of ascorbic acid supplementation in individuals suffering from both diseases and also its proper regimen for these patients.

Vitamin C alleviates acute enterocolitis in Campylobacter jejuni infected mice

Human foodborne infections with the zoonotic pathogen Campylobacter jejuni are on the rise and constitute a significant socioeconomic burden worldwide. The health-beneficial, particularly anti-inflammatory effects of vitamin C (ascorbate) are well known. In our preclinical intervention study, we assessed potential anti-pathogenic and immunomodulatory effects of ascorbate in C. jejuni-infected secondary abiotic IL-10-/- mice developing acute campylobacteriosis similar to humans. Starting 4 days prior peroral C. jejuni-infection, mice received synthetic ascorbate via the drinking water until the end of the experiment. At day 6 post-infection, ascorbate-treated mice harbored slightly lower colonic pathogen loads and suffered from less severe C. jejuni-induced enterocolitis as compared to placebo control animals. Ascorbate treatment did not only alleviate macroscopic sequelae of infection, but also dampened apoptotic and inflammatory immune cell responses in the intestines that were accompanied by less pronounced pro-inflammatory cytokine secretion. Remarkably, the anti-inflammatory effects of ascorbate pretreatment in C. jejuni-infected mice were not restricted to the intestinal tract but could also be observed in extra-intestinal compartments including liver, kidneys and lungs. In conclusion, due to the potent anti-inflammatory effects observed in the clinical murine C. jejuni-infection model, ascorbate constitutes a promising novel option for prophylaxis and treatment of acute campylobacteriosis.