I thought this study was pretty remarkable in that it was a double-blind, randomized controlled trial, and got solid results. Vitamin C supplementation (1000 mg/d) increased physical activity and reduced cold symptoms in young men with adequate-to-low vitamin C status
Nearly 25% of US adults have below adequate vitamin C status (plasma concentrations <28 µmol/L), and 6% of the adult population is classified as deficient (<11 µmol/L). Poor vitamin C status is underdiagnosed as early indications are unremarkable (fatigue, malaise, depression). Such feelings may manifest as a reduced desire to be physically active; moreover, hypovitaminosis C may be associated with increased cold duration and severity. This double-blind, placebo-controlled, randomized study examined the impact of vitamin C (1000 mg daily) on physical activity (PA) and symptoms of upper respiratory tract infections in men during the peak of the cold season. Consenting adults (23.2±3.6 y; 25.1±3.9 kg/m2; 29.5±8.7 μmol/L) completed the Wisconsin Upper Respiratory Symptom Survey-21 daily and the Godin Leisure-Time Exercise Questionnaire weekly. PA was lower in controls (n=14) over the course of the 8-week trial in comparison to the vitamin C group (n=15) (METs: +5.9±3.2 and +18.2±5.9 kcal· kg-1· wk-1; p=0.046). The overall cold symptom severity score was 4-fold higher for controls versus the vitamin C group (2.4±0.7 and 0.6±0.1; p=0.010). The incidence of colds was also higher in controls as compared to the vitamin C group (2.2±0.7 and 0.3±0.1 colds; p=0.008). These data suggest measurable health advantages associated with moderate vitamin C supplementation in a population with adequate-to-low vitamin C status.
Got that? One of the symptoms of low vitamin C status is fatigue. Probably most people suffering fatigue from low vitamin C have no clue as to what’s causing it. (As I documented in my book, lots of common, easily overlooked things can cause fatigue; this makes sense, as without certain essential inputs, whether nutrients or other factors such as sleep and light, the body does not function optimally.)
In the above study, it looks as if physical activity was about 3-fold higher in the C group. As well, they had only about 15% of the number of colds that the control group had. So, if you’re feeling fatigued, vitamin C supplementation as 1000 mg/d, which is completely safe and cheap, would be a very reasonable step to take.
This study adds solid support for vitamin C supplementation.