An international study involving the University of Otago (Christchurch) has found that inadequate vitamin C status is significantly linked to increased body weight.
It has raised public health concerns due to the rising prevalence of obesity worldwide.
Lead researcher and Otago Nutrition in Medicine Research Group director Prof Anitra Carr said in a statement the results showed heavier people required a substantially higher recommended daily allowance (RDA) of the essential vitamin to maintain good health, and that much of the world’s population was not covered by the present recommended intakes of vitamin C.
"Our data suggests current vitamin C recommended daily allowances internationally are severely underestimated.
"Current international vitamin C recommended daily allowances for men, women and children are all extrapolated from calculations for a healthy, young, 70kg male, allowing for a 10% deviation — a guideline that’s supposed to cover 97.5% of the population.
"Clearly, with the global increase in body weight, a substantial and growing proportion of the world’s population are no longer covered by these recommended intakes."
New Zealand had a present daily vitamin C recommendation of 45mg per day, as recommended by the World Health Organisation.
However, Prof Carr said this was one of the lowest recommended daily allowances in the world.
She said these new findings estimated an additional 17mg to 22mg of vitamin C was needed daily per 10kg of additional body weight, to reach adequate vitamin C levels as compared to a 70kg individual.
"We feel this new evidence highlights the need for an updated set of vitamin C recommended daily allowances — both here and internationally — to guide future public health recommendations."
The study, co-authored by researchers from the Universities of Copenhagen and Aberdeen, analysed two large international data sets from the United States and Europe, comprising more than 23,000 participants.
It showed only about two-thirds of both cohorts achieved an "adequate" vitamin C plasma concentration by consuming the recommended daily allowance or above, while between one-third and half of the cohorts achieved "adequate" status with an intake of the RDA, plus or minus 10%.
International research suggests obesity may affect the body’s vitamin C dose-concentration relationship as a result of low-grade inflammation, which can increase oxidative stress and a potential increased turnover of vitamin C in the body.
Obesity is also known to increase the risk of type 2 diabetes and non-alcoholic fatty liver disease, both of which are associated with lower vitamin C status.
The study authors suggested additional vitamin C intake could be easily achieved through either diet or supplements.
