New Research: Vitamin C Reduces the Frequency and Severity of Colds
August 13, 2014
Vitamin C reduces the frequency and severity of colds and improves physical activity in men with suboptimal vitamin C status
Although severe vitamin C deficiency resulting in scurvy is a rare occurrence in modern society, as many as 22% of U.S. adults are believed to have inadequate vitamin C status, with as many as 6% classified as vitamin C deficient. Insufficiencies are often undiagnosed because early symptoms of poor vitamin C status are not obvious and may include fatigue, malaise, depression and irritability. Inadequate vitamin C levels have also been associated with increased duration and severity of colds during the peak of cold season.
In a new study published in the journal Nutrients, researchers examined the impact of vitamin C status on physical activity and upper respiratory tract infections during the winter months.
The participants in this double-blind randomized trial included healthy, nonsmoking college men, with a marginal plasma vitamin C level, who were not training for or competing in sports. The men were randomized into one of two groups that received either 1000 mg of vitamin C/day or a placebo. Participants were given a booklet at the beginning of the study that contained the Wisconsin Upper Respiratory Symptom Survey-21, the Godin Leisure-Time Exercise Questionnaire, and a short food frequency measure. Over the course of the eight week study, the men completed the symptom survey daily, and the exercise and food frequency measures weekly.
During weeks 6-8 of the study, the physical activity score for the vitamin C supplemented group rose moderately compared to the placebo group. The number of cold episodes reported during the study was lower in the vitamin C group (7) compared to the placebo group (11), as was the reported duration of colds (reduced 59% versus placebo).
Although this study was limited by a relatively small sample size, the results suggest that there may be measurable health advantages associated with vitamin C supplementation in men with adequate-to-low vitamin C status. Since this study was conducted during winter months and included only men with similar vitamin C status, more research is needed to determine whether these results can be extended to other populations and seasons.
Carol S. Johnston, Gillean M. Barkyoumb, and Sara S. Schumacher. Vitamin C Supplementation Slightly Improves Physical Activity Levels and Reduces Cold Incidence in Men with Marginal Vitamin C Status: A Randomized Controlled Trial. Nutrients 2014, 6, 2572-2583; doi:10.3390/nu6072572.
Higher vitamin D levels increase survival rate in postoperative adults with colorectal cancer
August 06, 2014
At a Glance
A new research article published online suggests that having a higher plasma level of vitamin D is associated with a better chance of surviving colorectal cancer.
Read more about this research below.
Low vitamin D levels are known to be associated with poor health outcomes or increased risk in many diseases including cardiovascular disease, diabetes, and some cancers.
In a new study published in the Journal of Oncology, researchers investigated whether the plasma level of vitamin D after a diagnosis of colorectal cancer (CRC) has a significant impact on survival outcome. The Scottish research team analyzed data from 1,598 adults who had undergone surgery for stage I-III colorectal cancer. Blood samples were taken after surgery and evaluated for vitamin D and for a specific Vitamin D gene receptor.
When compared to the patients with the lowest one-third of vitamin D levels, the patients whose vitamin D levels were in the top one-third of subjects had a significantly lower (32%) risk of dying of CRC and a 30% lower risk of dying from any cause during the 5 year follow-up period. In patients with stage II CRC, those in the top one-third of vitamin D levels experienced a 56% reduction in mortality.
The researchers found interactions between vitamin D levels and specific type of vitamin D gene receptor, indicating a causal relationship between vitamin D and survival.
This study shows that in patients with stage I-III colorectal cancer, higher post-surgery vitamin D levels are associated with a better outcome and a lower risk of mortality. Since this was an observational study, carefully designed clinical trials are still needed to confirm whether vitamin D supplementation would provide survival benefits for patients with colorectal cancer.
Zgaga L Plasma Vitamin D Concentration Influences Survival Outcome After a Diagnosis of Colorectal Cancer. J Clin Oncol. 2014 Jul 7. pii: JCO.2013.54.5947. [Epub ahead of print]