If you keep on like this you’ll get diabetes. Or your joints will give up because of your colossal belly. Or you’ll die from a heart attack. You have to get more exercise – but you just can’t bring yourself to do so. According to nutritionists at Arizona State University, you may be able to overcome your resistance by taking a dirt-cheap supplement containing vitamin C.
Hardly any nutritionists are interested in vitamin C these days: pretty much everything is known about it, so why bother? Nothing left to chew on. But large groups of people have a sub-optimal amount of vitamin C in their blood. Some American studies suggest that several tens of percent of the population are at risk of vitamin C deficiency.
Carol Johnston of Arizona State University got together two dozen fat men aged between 18 and 35, all of whom had less than 45 micromols vitamin C in their blood, and gave half of them 1000 mg vitamin C in supplements every day for eight weeks. The other half of the subjects were given a placebo.
Before, during and after the supplementation Johnston got the men to fill out questionnaires about how much exercise they were getting. This way the researcher could calculate how many kcal per kg bodyweight per week the men were burning. Johnston discovered that the supplementation caused calorie expenditure to increase as a result of exercise.
Johnston’s findings are not entirely new. She previously published a study in which she showed that muscle cells burn more fat during moderately intensive exercise the more vitamin C there is in the blood, and in another study she showed that fat people are less aversive to exercise when they take vitamin C.
A shortage of vitamin C also reduces resistance to disease. For this reason Johnston also recorded how often the men caught a cold, and if they did so, how serious it was.
“These data demonstrate a measureable benefit of vitamin C supplementation for reducing cold episodes in young men with low to average vitamin C status”, the researchers conclude. “In addition, the data suggest a modest benefit of vitamin C supplementation for enhancing weekly activity levels in young men.”
“Several large, cross-sectional investigations support a link between vitamin C status and physical activity and corroborate early reports that associated preclinical vitamin C deficiency with fatigue and aversion to exercise. However, there is little causal experimental evidence demonstrating the influence of vitamin C supplementation on daily physical activity. Placebo-controlled intervention studies have documented increased work efficiency during exercise and reduced perception of effort during exercise in vitamin C supplementing untrained adults — characteristics that could possibly inspire physical activity.”
“The role of vitamin C in promoting physical activity may relate to its antioxidant properties since oxidative stress is related to fatigue. Vitamin C also possesses neuroprotective properties and influences the brain’s oxidative fuel supply, processes that may influence a sense of wellbeing.”
“This simple dietary strategy to promote physical activity and physical health merits further research and the consideration of health practitioners.”
Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial.
The early indications of vitamin C deficiency are unremarkable (fatigue, malaise, depression) and may manifest as a reduced desire to be physically active; moreover, hypovitaminosis C may be associated with increased cold duration and severity. This study examined the impact of vitamin C on physical activity and respiratory tract infections during the peak of the cold season. Healthy non-smoking adult men (18-35 years; BMI < 34 kg/m2; plasma vitamin C < 45 µmol/L) received either 1000 mg of vitamin C daily (n = 15) or placebo (n = 13) in a randomized, double-blind, eight-week trial. All participants completed the Wisconsin Upper Respiratory Symptom Survey-21 daily and the Godin Leisure-Time Exercise Questionnaire weekly. In the final two weeks of the trial, the physical activity score rose modestly for the vitamin C group vs. placebo after adjusting for baseline values: +39.6% (95% CI [-4.5,83.7]; p = 0.10). The number of participants reporting cold episodes was 7 and 11 for the vitamin C and placebo groups respectively during the eight-week trial (RR = 0.55; 95% CI [0.33,0.94]; p = 0.04) and cold duration was reduced 59% in the vitamin C versus placebo groups (-3.2 days; 95% CI [-7.0,0.6]; p = 0.06). These data suggest measurable health advantages associated with vitamin C supplementation in a population with adequate-to-low vitamin C status.
PMID: 25010554 [PubMed - in process] PMCID: PMC4113757