vitamin c deficiency

04/13/23 1Biochemistry For Medics

Vitamin C (ascorbic acid) plays a role in collagen, carnitine, hormone, and amino acid formation.

It is essential for wound healing and facilitates recovery from burns.

Vitamin C is also an antioxidant, supports immune function, and facilitates the absorption of iron.


Scurvy is caused by a dietary deficiency of vitamin C.

The body's pool of vitamin C can be depleted in 1-3 months.

Risk factors include the following:Babies who are fed only cow's milk during the

first year of life are at risk.AlcoholismElderly individuals who eat a tea-and-toast diet Retired people who live alone and those who eat

primarily fast food


Economically disadvantaged persons tend to not purchase foods high in vitamin C (eg, green vegetables, citrus fruits), which results in them being at high risk.

Vitamin C deficiency has been noted in refugees who are dependent on external suppliers for their food and have limited access to fresh fruits and vegetables.


Cigarette smokers require increased intake of vitamin C because of lower vitamin C absorption and increased catabolism.

Pregnant and lactating women and those with thyrotoxicosis require increased intake of vitamin C because of increased utilization.

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People with anorexia nervosa or anorexia from other diseases such as AIDS or cancer are at increased risk of vitamin C deficiency.

People with type 1 diabetes have increased vitamin C requirements, as do those on hemodialysis and peritoneal dialysis.


Because vitamin C is absorbed in the small intestine, people with disease of the small intestine such as Crohn’s, Whipple, and celiac disease are at risk.

Iron overload disorders may lead to renal vitamin C wasting.

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Vitamin C is functionally most relevant for the triple-helix formation of collagen; a vitamin C deficiency results in impaired collagen synthesis.

Proline and lysine hydroxylases are required for the post synthetic modification of procollagen to collagen.

Vitamin C is necessary as a coenzyme for these hydroxylases.


Formation of intercellular cement substances in connective tissues, bones, and dentin is defective, resulting in weakened capillaries with subsequent hemorrhage and defects in bone and related structures.

Hemorrhaging is a hallmark feature of scurvy and can occur in any organ.

Hair follicles are one of the common sites of cutaneous bleeding


Bone tissue formation becomes impaired, which, in children, causes bone lesions and poor bone growth.

Fibrous tissue forms between the diaphysis and the epiphysis, and costochondral junctions enlarge.

Densely calcified fragments of cartilage are embedded in the fibrous tissue.


Subperiosteal hemorrhages, sometimes due to small fractures, may occur in children or adults.


Early symptoms are malaise and lethargy.

After 1-3 months, patients develop shortness of breath and bone pain.

Myalgias may occur because of reduced carnitine production.

Other symptoms include skin changes with roughness, easy bruising and petechiae, gum disease, loosening of teeth, poor wound healing, and emotional changes.


Dry mouth and dry eyes In the late stages, jaundice, generalized

edema, oliguria, neuropathy, fever, and convulsions can be seen.

Vital signs: Hypotension may be observed late in the disease. This may be due to an inability of the resistance vessels to constrict in response to adrenergic stimuli.


Skin: Perifollicular hemorrhages (See figure),purpura, and ecchymoses are seen most commonly on the legs and buttocks where hydrostatic pressure is the greatest.

Poor wound healing and breakdown of old scars may be seen.



Nails: Splinter hemorrhages may occur.

Head and neck: Gum swelling, friability, bleeding, and

infection with loose teeth; mucosal petechiae;


Scleral icterus (late, probably secondary to hemolysis); and pale conjunctiva are seen.

Conjunctival hemorrhage, Bleeding into the periorbital area, eyelids,

and retrobulbar space also can be seen. Alopecia may occur secondary to reduced

disulfide bonding.


Chest and cardiovascular:

Scorbutic rosary (ie, sternum sinks inward) may occur in children.

High-output heart failure due to anemia can be observed.

Bleeding into the myocardium and pericardial space has been reported.


Extremities: Fractures, dislocations, and tenderness of

bones are common in children. Bleeding into muscles and joints may be

seen. Edema may occur late in the disease. Gastrointestinal: Loss of weight

secondary to anorexia is common.


Diagnosis is usually made clinically in a patient who has skin or gingival signs and is at risk of vitamin C deficiency are normal

Laboratory Investigations A plasma or leukocyte vitamin C level can

confirm clinical diagnosis.Scurvy occurs at levels generally less than 0.1 mg/dL.Symptoms occur at levels below 2.5 mg/L, which is

considered deficiency.Levels of 2.5-5 mg/L indicate depletion.Levels can be low in patients who have tuberculosis,

rheumatic fever, or other chronic illnesses; those who smoke cigarettes; and patients on oral contraceptive drugs.


Capillary fragility can be checked by inflating a blood pressure cuff and looking for petechiae on the forearm.

Bleeding time, clotting time and Prothrombin are estimated to rule out other bleeding disorders


An Fe deficiency anemia is generally observed.

Vitamin C enhances the absorption of iron from the small intestine.

This may contribute to the anemia seen with vitamin C deficiency.


Loss of trabeculae results in a ground-glass appearance.

The cortex thins. A line of calcified,

irregular cartilage (white line of Fraenkel) may be visible at the metaphysis.

The epiphysis may be compressed.


In adults, scurvy must be differentiated from

Arthritis, Hemorrhagic disorders, Gingivitis, and Protein-energy malnutrition.


Patients should take ascorbic acid at 100 mg 3-5 times a day until total of 4 g is reached, and then they should decrease intake to 100 mg daily.

Divided doses are given because intestinal absorption is limited to 100 mg at one time.

Parenteral doses are necessary in those with gastrointestinal malabsorption.


Diet Foods high in vitamin C include the

following.Citrus fruits, especially grapefruits and lemonsVegetables, including broccoli, green peppers,

tomatoes, potatoes, and cabbage


The recommended daily allowance for vitamin C varies.

The current recommendation for adults is 120 mg daily, although a dose of 60 mg daily is all that is required to prevent scurvy.

Diets high in vitamin C have been claimed to lower the incidence of certain cancers, particularly esophageal and gastric cancers


Taking >2 g of vitamin C in a single dose may result in-

Abdominal pain, Diarrhea, and nausea. Since vitamin C may be metabolized to oxalate, it is

feared that chronic, high-dose vitamin C supplementation could result in an increased prevalence of kidney stones, thus it is reasonable to advise patients with a past history of kidney stones to not take large doses of vitamin C.

There is also an unproven but possible risk that chronic high doses of vitamin C could promote iron overload in patients taking supplemental iron.


Vitamin C deficiency can occur as part of general under nutrition, but severe deficiency (causing scurvy) is uncommon.

Symptoms include fatigue, depression, and connective tissue defects (eg, gingivitis, petechiae, rash, internal bleeding, impaired wound healing). In infants and children, bone growth may be impaired.

Severe deficiency results in scurvy, a disorder characterized by hemorrhagic manifestations and abnormal osteoid and dentin formation.

Diagnosis is usually clinical. Treatment consists of oral vitamin C.


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