The 'anti-scurvy' factor of citrus fruit was identified as vitamin C in 1928. One medium orange contains 70 mg of vitamin C.PASCAL POCHARD-CASABIANCA/AFP/Getty Images
Scurvy is often thought of as an archaic disease that affected sailors in the 18th century, when it was common for as many as two-thirds of a ship’s crew to die from it on a long sea voyage.
In 1747, Scottish physician Dr. James Lind demonstrated that supplementing sailors’ diets with citrus fruits cured scurvy. The “anti-scurvy” factor of citrus fruit was identified as vitamin C (ascorbic acid) in 1928.
Despite this knowledge, scurvy still exists. A report published Oct. 7 in the Canadian Medical Association Journal, or CMAJ, described the case of a 65-year-old Canadian woman recently diagnosed with scurvy.
According to the authors, the case highlights the need for doctors to keep scurvy on their radar screens when assessing patients at increased risk for vitamin C deficiency.
Here’s what to know about scurvy, who’s at greater risk and diet strategies to prevent it.
What is scurvy?
Scurvy is caused by a severe vitamin C deficiency. Signs can appear within a month of consuming little (less than 10 mg per day) or no vitamin C.
Initial symptoms include fatigue, lethargy, weakness, irritability and inflammation of the gums.
As vitamin C deficiency progresses, collagen synthesis becomes impaired, causing symptoms such as bruising, poor wound healing, bleeding gums, tooth loss, muscle and bone pain, dry skin, and dry, brittle hair.
Vitamin C plays a critical role in producing collagen, a protein essential for wound healing and maintaining healthy bones, teeth, gums and skin and strong blood vessel walls.
Iron deficiency anemia can also occur because of blood loss and reduced absorption of nonheme found in plant foods. (Vitamin C enhances nonheme iron absorption in the small intestine.)
If undiagnosed and left untreated, scurvy is fatal.
Is scurvy on the rise?
There is no clear evidence that scurvy rates are increasing in Canada, but data suggests vitamin C deficiency may be more prevalent than generally assumed.
A study from McMaster University, published in 2020, examined the medical charts of hospital patients in Hamilton, Ont., over a nine-year period. Vitamin C deficiency was identified in 52 people; 12 were diagnosed with scurvy, and 39 tested positive but did not have symptoms.
A U.S. analysis of more than 19,000 hospitalized pediatric patients, published in July, found the rate of new scurvy cases more than tripled over the five-year period of 2016-2020 to 26.7 cases per 100,000 children, up from 8.2 cases per 100,000 children.
Data from Britain, reported in 2008, found the prevalence of vitamin C deficiency to be as high as 25 per cent in some groups with low socioeconomic status.
Who’s at risk?
Pediatric patients, cigarette smokers (smoking depletes vitamin C in the body), those who have a substance use disorder and people who follow a restrictive eating pattern are at increased risk for vitamin C deficiency.
So are isolated older adults who have little family support and limited mobility, as well as individuals who have a medical condition that reduces vitamin C absorption in the small intestine.
The authors of the CMAJ report recommended that doctors pay particular attention to assessing for food insecurity, an important and pervasive risk factor for vitamin C deficiency.
How much vitamin C?
In Canada and the United States, the recommended dietary allowance or RDA, for vitamin C is based on the amount that’s needed to maintain its biological and antioxidant functions in white blood cells.
The RDA is much higher than the amount needed to prevent vitamin C deficiency. Adults require 75 mg (females) and 90 mg (males) of vitamin C daily; smokers need an additional 35 mg each day.
The RDAs for children are: 15 mg (one to three-year-olds), 25 mg (four to eight-year-olds), 45 mg (nine to 13-year-olds), 75 mg (14-18-year-old males) and 65 mg (14-18-year-old females).
Some experts recommend consuming at least 200 mg vitamin C a day for optimal health.
Foods high in vitamin C
A daily intake of 2.5 cups of fruit and vegetables provides 150 to 200 mg of vitamin C, especially if ones high in the nutrient are consumed.
These include strawberries (85 mg vitamin C per cup), pineapple (80 mg per cup), citrus fruit (70 mg per one medium orange), kiwifruit (65 mg each) and mango (60 mg per cup).
One-half of a raw large yellow, red and green pepper each supply 170 mg, 105 mg and 66 mg of vitamin C. Broccoli (81 mg per cup raw), cauliflower (52 mg cup raw), Brussels sprouts (48 mg per half-cup cooked) and tomato juice (170 mg per cup) are also good sources.
Frozen fruits and vegetables, which have similar nutrient levels to fresh, are more economical options than fresh. Plus, frozen produce has a long shelf-life (eight to 12 months) which helps prevent food waste.
Vitamin C is water soluble and sensitive to heat; a large amount is lost when vegetables are boiled. Steaming and microwaving minimizes vitamin C loss.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on X @LeslieBeckRD