Poor vitamin C status is associated with increased depression symptoms following acute illness in older people

Background: Vitamin C has important physical and mental health benefits and plasma concentrations reflect recent intakes. Inflammation associated with any acute illness can lead to poor appetite and low food intake in older people. The aims of this report were to assess the prevalence and clinical significance of vitamin C deficiency among hospitalized acutely-ill older patients. Methods: Three hundred and twenty two patients (152 [47 %] female), aged 65 yrs. and over who took part in a randomized, double blind, placebo-controlled trial had their nutritional status assessed from anthropometric, hematological and biochemical data at baseline, and after 6 weeks and 6 months. Vitamin C was measured using a fluorimetric technique and logistic regression analysis was performed to determine the influence of a number of clinical indicators, including tissue inflammation measured using C-reactive protein on vitamin C concentrations. Clinical outcome measures including symptoms of depression were also compared between patients with vitamin C deficiency and those with normal levels. Results: At baseline, 116 (36 %) patients had a vitamin C concentration below 11 μmol/L indicating biochemical depletion. The figures at 6 weeks and 6 months were 28 (22 %) and 44 (28 %) patients, respectively. Older age, male gender, smoking, increased dependency and tissue inflammation were associated with lower vitamin C concentrations. Patients with vitamin C biochemical depletion had significantly increased symptoms of depression compared with those with higher concentrations at baseline (p = 0.035) and at 6 weeks (p = 0.028). Conclusions: A high proportion of older patients had sub-optimal vitamin C status and this was associated with increased symptoms of depression.