Vitamin C deficiency symptoms

What are the symptoms of vitamin C deficiency?

As described by the NIH, scurvy occurs because the functions of vitamin C in collagen synthesis, carnitine synthesis and elsewhere are impaired. Symptoms are generally described in the following order over time: ^[1]

• Early stage: fatigue (according to the NIH, probably due to impaired carnitine synthesis), malaise, gum inflammation.
• Advanced stage: small bleeding spots in the skin (petechiae), bruising (ecchymoses and purpura), joint pain, delayed wound healing, skin thickening (hyperkeratosis) and curled (corkscrew) hairs.
• Additional findings: depression, swollen and bleeding gums, loosening or loss of teeth; iron-deficiency anemia due to bleeding and reduced absorption of non-heme iron; bone disease in children.
• Untreated course: untreated scurvy is fatal.

Most of these findings also occur for other reasons; for example, bruising and fatigue appear in many conditions. Dietary history and physician assessment are decisive for diagnosis. The NIH describes that scurvy was historically seen in sailors on long sea voyages until the late 18th century and was cured by citrus fruit; ascorbic acid was shown to be the active substance in 1932. ^[1]

How common is deficiency, and when does it develop?

The NIH reports that scurvy is rare in developed countries and that overt deficiency symptoms are seen only when intake falls below about 10 mg/day and continues for weeks. A separate concept is “inadequacy”: intake below the RDA but above 10 mg/day, without overt scurvy. ^[1] According to the NIH, the RDA values (90 mg for adult men, 75 mg for women) are much higher than what is needed to prevent scurvy. ^[1]

In the hospital study by Levine and colleagues, seven healthy volunteers fed a diet containing less than 5 mg of vitamin C per day had their stores depleted over 4–6 months and were then repleted with different doses; the study was designed to show how plasma level behaves in response to dose, not to define deficiency symptoms. ^[4]

Who is at risk?

Groups listed by the NIH: ^[1]

• Smokers and passive smokers. Plasma and leukocyte vitamin C levels are lower in smokers; the reason is reported to be partly increased oxidative stress. For this reason the FNB adds 35 mg to the daily reference. Passive smoking also lowers the level; the FNB could not set a separate requirement for this group.
• People with limited food variety: some older and low-income people who prepare their own meals, people with alcohol or substance misuse, people following “fad” diets, people with mental illness and occasionally children.
• Malabsorption and some chronic diseases: severe intestinal malabsorption, cachexia, some cancer patients; low levels can be seen in end-stage kidney disease patients on chronic hemodialysis.
• Infants fed evaporated or boiled cow’s milk: cow’s milk contains very little vitamin C, and heat destroys the vitamin.

In the EPIC-Norfolk study (a population-based cross-sectional analysis in England), plasma vitamin C <11 µmol/L was defined as deficiency; deficiency was found to be associated with older age, male sex, low physical activity, smoking, socioeconomic deprivation and low educational level. ^[2]

How common is deficiency in a community sample?

The same study examined 22,474 people with a plasma sample who attended the second health check in a cohort of adults aged 40–79 years invited from general practice registers in Norfolk (England). In 315 of these people (1.4%) plasma vitamin C was below 11 µmol/L; 2,410 people (10.7%) were in the 11–28 µmol/L range that the study called “suboptimal”. The authors note that EPIC-Norfolk participants may be healthier than the general English population and that the low frequency of deficiency limits the generalizability of the results; the plasma level is also based on a single measurement. ^[2]

In their introduction, the same authors report that latent scurvy may be overlooked in the general population because symptoms are non-specific, and that in the US 2003–2004 national survey the level was below 11.4 µmol/L in 7.1% of the representative sample. This US figure is not McCall and colleagues’ own finding but is cited from another study; no comparable national plasma vitamin C data for Türkiye are cited. ^[2]

The second question of the study was functional health. Those in the lowest quartile of plasma vitamin C fell into the lowest tertile of the SF-36 physical functioning domain more often than those in the highest quartile (adjusted OR 1.43; 95% CI 1.21–1.70); there was an association in a similar direction in the pain, general health and vitality domains as well. In a cross-sectional design, the direction of the association between low vitamin C and poor functional health cannot be determined: illness may have impaired diet. ^[2]

What does each value mean?

The numbers below answer different questions and cannot be used in place of one another.

How is deficiency identified, and at what level is it considered deficient?

The NIH states that vitamin C status is typically assessed by plasma level; leukocyte level may reflect tissue level more accurately but is difficult to measure and results are not always reliable. ^[1]

There is no single official threshold. The EPIC-Norfolk study defined deficiency as plasma below 11 µmol/L; the authors write that poor self-reported functional health may reflect signs of “latent scurvy”; the cross-sectional design does not show causality. ^[2] The EFSA 2013 opinion, on the other hand, defines an adequate body pool for healthy adults as a fasting plasma ascorbate of about 50 µmol/L; this is not a deficiency threshold but the target level from which the reference intake is derived. ^[3] Placing these two values on the same scale would be misleading: one is a study’s definition of deficiency, the other is the basis of a reference value.

How is the assessment made when deficiency is suspected?

When symptoms and risk factors coexist, the assessment is made by a physician using dietary history, examination and, when necessary, plasma vitamin C measurement. ^[1] The amount and duration to be used in treatment are determined by the physician according to the clinical situation; this page gives no dose on this subject.

This guide does not recommend personal doses.