Vitamin C recommendations ‘past their sell-by date’
THE recommended daily intake for vitamin C should be doubled, scientists have suggested after insisting current recommendations are informed by an outdated Second World War study.
The World Health Organisation (WHO) advises an intake of 45mg of vitamin C per day, based on a study conducted in 1944 by The Sorby Research Institute. The NHS advises a similar dose: 40mg.
The now-defunct research facility responsible for the guidelines was created to assess the nutrition levels of British citizens when food was scarce.
The vitamin C study was intended to prevent sailors suffering from scurvy. Scientists at the University of Washington have revisited the research and described the methods, which included conducting tests on 20 conscientious objectors, as “shocking”.
Their findings have been published in the American Journal of Clinical Nutrition. Prof Philippe Hujoel, the lead author, said: “The vitamin C experiment is a shocking study. They depleted people’s vitamin C levels long-term and created life-threatening emergencies. It would never fly now.”
The researchers also used modern techniques designed to handle small sample sizes to reassess the research.
Scientists and health professionals have failed until now to comprehensively re-examine the 77-year-old research, according to the university, which said recommended dosages should be upgraded.
Prof Hujoel said the findings suggested the WHO’S recommendation was too low to aid the healing of scar tissue.
He added: “Robust parametric analyses of the trial data reveal that an average daily vitamin C intake of 95 mg is required to prevent weak scar strength for 97.5 per cent of the population.
“Such a vitamin C intake is more than double the daily 45 mg vitamin C intake recommended by the WHO but is consistent with the writing panels for the National Academy of Medicine and (other) countries.” Vitamin C, which is found in citrus fruits and some vegetables, helps to protect cells and maintain healthy skin, bones, blood vessels and cartilage and helps wounds to heal.
Prof Hujoel said: “The failure to re-evaluate the data of a landmark trial with novel statistical methods as they became available may have led to a misleading narrative on the vitamin C needs for the prevention and treatment of collagen-related pathologies.”
The 1944 research was headed by the British-german biologist and Nobelprize winner Sir Hans Adolf Krebs. At the time, researchers conducted an experiment that controlled and monitored vitamin C consumption of 20 volunteers who refused to join the military.
They were each given varying amounts of Vitamin C, which helps the body to produce collagen and given wounds to observe how quickly their scar tissue healed. Those who took part in the trial were given zero, 10 mg or 70mg of vitamin C a day for an average of nine months. Participants who had been deprived were then given a higher dose, with results concluding that 10 mg a day would prevent disease.