Vitamin C deficiency may be more common than we thought, especially in people who are overweight.
Scurvy may not be the museum piece we thought it was.
Recent studies have shown higher rates of vitamin C deficiency in both children and adults, and researchers at Murdoch Children’s Research Institute say symptom awareness needs to be raised and screening of high-risk groups increased.
Of almost 900 children who had their vitamin levels tested over three years at the Royal Children’s Hospital in Melbourne, 31% had a vitamin C deficiency, 5% of whom showed clear clinical symptoms of scurvy.
Nearly 300 children had vitamin C levels of less than 23μmol/L but did not show clear scurvy symptoms, so were instead diagnosed as deficient. The average vitamin C level among the deficient children was only 8μmol/L, with some children testing at less than 5μmol/L.
Researchers urge vigilance in assessing nutrition and symptoms, as well as screening deficiencies in groups at risk of disordered eating, such as children with neurodevelopmental disorders, those with restricted diets (e.g. due to food allergies), and kids described by parents as “fussy eaters”.
Children aged six or older accounted for 68% of deficiencies, with the average age being 9.6 years. Additionally, 65% of deficient children had restricted eating patterns, and 53% had neurodevelopmental disorders.
In another paper released last month the EPIC-Norfolk and NHANES studies of over 20,000 adults found that weight played a role in maintaining vitamin C stocks, with only two-thirds of participants having adequate vitamin C plasma concentration from consuming the recommended daily dose.
Despite a median intake of 79mg/day of vitamin C, which is well above the Australian RDI of 45mg/day, only individuals weighing 83kg or less were estimated to reach an adequate plasma concentration of 50µmol/L.
They concluded that there was a strong inverse association between greater weight and lower concentrations. Every 10kg of weight gain correlated with a 3.5µmol/L decrease in plasma, meaning much of the world’s population is not covered by the current vitamin C RDIs.
Study author and director of the Nutrition in Medicine Research Group says that it’s clear that the global increase in bodyweight has led to a substantial proportion of people who are not covered by the RDIs, which have generally been based around young, healthy 70kg males.
Symptoms of scurvy include fatigue, irritability, joint and bone pain, limping, swollen and/or bleeding gums, folliculitis and skin changes such as petechiae or bruising.
Vitamin C deficiency may present with mild symptoms such as fatigue and irritability, but not as severe or specific as scurvy.
Symptoms of scurvy typically resolve within two weeks of initiating vitamin C supplementation and complete recovery from deficiency is expected after three months.
Even if patients do not present with obvious signs of malnutrition, the researchers at MCRI suggest dietary assessment, vitamin C assays and consideration of an empiric trial of vitamin C supplementation in at-risk patients by clinicians.
