Study population recruited on campus
One in seven young adults in Canada is deficient in vitamin C, according to a first-of-its kind study published by U of T researchers on July 13.
The findings, published in the American Journal of Epidemiology, suggest that young adults with a vitamin C (ascorbic acid) deficiency have significantly higher waist circumference, body mass index, inflammation and blood pressure - indicators of chronic disease and obesity - than do people with adequate blood levels of vitamin C.
The study - supported by the Advanced Foods and Materials Network, a national Network of Centres of Excellence - was conducted by University of Toronto researchers Ahmed El-Sohemy and Leah Cahill of the Department of Nutritional Sciences and Paul N. Corey of the Dalla Lana School of Public Health Sciences. Called "Vitamin C Deficiency in a Population of Young Canadian Adults," the study involved 979 Toronto-based participants between the ages of 20 and 29.
"Our research found that 47 per cent of young Canadian adults have deficient or sub-optimal blood levels of vitamin C, which is associated with adverse health effects," said Professor El-Sohemy, senior researcher of the study, the first to examine vitamin C levels and their health effects among young adults. "These results demonstrate the importance of obtaining the recommended dietary allowance of dietary vitamin C for young Canadians."
Summary of the study:
The recommended dietary allowance for vitamin C is 75 milligrams (mg) per day for women and 90 mg/day for men. Since vitamin C is not naturally produced in the body, people must obtain this essential nutrient from their diet. Leah Cahill, a registered dietitian and lead author of the study, suggests that "fruits and vegetables are excellent sources of vitamin C. For example, a yellow pepper contains 341 mg, 3 spears of broccoli contain 87 mg and an orange contains 70 mg of vitamin C."
Vitamin C has a wide range of benefits. It is needed to make several important hormones, to burn fat for energy and to produce collagen which encourages wound healing and promotes healthy bones and gums. Vitamin C also protects cells and their DNA from damage that can cause inflammation and heart disease and it keeps the immune system nourished, strengthening it to battle ailments from the common cold to various types of cancers.
Until now, the health consequences of having inadequate vitamin C levels at a young age were unknown. Previous studies relating insufficient vitamin C to a higher risk of chronic diseases, such as cardiovascular disease and diabetes, have all involved middle-aged or older participants. This is the first study to use blood levels to show the prevalence of vitamin C deficiency in young adults and its possible long-term health detriments.
The study participants - 692 women and 287 men - were recruited from the University of Toronto campus. Using a comprehensive questionnaire, participants were asked to assess their food intake over the previous month. Based on the responses, a total daily vitamin C intake for each person was computed. The researchers measured participants' height, weight, waist circumference and body mass index, and blood tests confirmed their vitamin C, glucose, inflammation, cholesterol and insulin levels.
Findings:
The results of the study showed that one in seven young Canadian adults has a vitamin C deficiency and that one in three has less than optimal levels of vitamin C. The study also associates the deficiency with elevated markers of chronic disease. Specifically:
• 1 in 4 participants did not consume the recommended dietary allowance of vitamin C. These individuals were three times more likely to have a blood concentration deficiency than the participants who met the dietary vitamin C recommendations.
• 47% of all participants had inadequate blood concentrations of vitamin C, with 14% of all participants classified as deficient.
• Despite their young age, the waist circumference, body mass index, inflammation and blood pressure measurements were already significantly higher in participants with vitamin C deficiency than in those with adequate blood concentrations.