Vitamin C, also known as L-ascorbic acid, is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Humans, unlike most animals, are unable to synthesize vitamin C endogenously, so it is an essential dietary component. 

Vitamin C is required for the biosynthesis of collagen, L-carnitine, and certain neurotransmitters; vitamin C is also involved in protein metabolism [1,2]. Collagen is an essential component of connective tissue, which plays a vital role in wound healing. Vitamin C is also an important physiological antioxidant [3] and has been shown to regenerate other antioxidants within the body, including alpha-tocopherol (vitamin E) [4]. 

BENEFITS OF VITAMIN C

• Necessary for the growth, development and repair of all body tissues
• Strong antioxidant
• Studies have shown that vitamin C may help lower blood pressure in those both with and without high blood pressure (7)
• Improves Iron absorption
• Boosts immunity by improving the functionality of white blood cells
• Protect memory as you age

Studies suggest that oxidative stress and inflammation near the brain, spine and nerves (altogether known as the central nervous system) can increase the risk of dementia (5). Vitamin C is a strong antioxidant. Low levels of this vitamin have been linked to an impaired ability to think and remember (6, 7). Moreover, several studies have shown that people with dementia may have lower levels of vitamin C in the blood (8, 9).

While deficiency is relatively rare in developed countries due to the availability of fresh produce and the addition of vitamin C to certain foods and supplements, it still affects roughly 7% of adults in the US (10).

* Adequate Intake (AI)

The most common risk factors for vitamin C deficiency are poor diet, alcoholism, anorexia, severe mental illness, smoking and dialysis (12, 13).

SIGNS OF VITAMIN C DEFICIENCY

BRIGHT RED HAIR FOLLICLES

Hair follicles on the surface of the skin contain many tiny blood vessels that supply blood and nutrients to the area.

When the body is deficient in vitamin C, these small blood vessels become fragile and break easily, causing small, bright red spots to appear around the hair follicles.

This is known as perifollicular hemorrhage and a well-documented sign of severe vitamin C deficiency (14, 15).

BRITTLE NAILS

They are more commonly associated with iron deficiency anemia but have also been linked to vitamin C deficiency (16, 17).

Red spots or vertical lines in the nail bed, known as splinter hemorrhage, may also appear during vitamin C deficiency due to weakened blood vessels that rupture easily.

While the visual appearance of fingernails and toenails may help determine the likelihood of vitamin C deficiency, note that it’s not considered diagnostic.

DRY AND DAMAGED SKIN

Vitamin C keeps skin healthy by protecting it from oxidative damage caused by the sun and exposure to pollutants like cigarette smoke or the ozone (18, 19).

It also promotes collagen production, which keeps skin looking plump and youthful (20).

High intakes of v C are associated with better skin quality, while lower intakes are associated with a 10% increased risk of developing dry, wrinkled skin (21, 22, 23).

While dry, damaged skin can be linked to v C deficiency, it can also be caused by many other factors, so this symptom alone is not enough to diagnose a deficiency.

Cardiovascular disease

Evidence from many epidemiological studies suggests that high intakes of fruits and vegetables are associated with a reduced risk of cardiovascular disease [24,25,26]. This association might be partly attributable to the antioxidant content of these foods because oxidative damage, including oxidative modification of low-density lipoproteins, is a major cause of cardiovascular disease [27,28,29]. In addition to its antioxidant properties, v C has been shown to reduce monocyte adherence to the endothelium, improve endothelium-dependent nitric oxide production and vasodilation, and reduce vascular smooth-muscle-cell apoptosis, which prevents plaque instability in atherosclerosis [30,31].

SLOWLY HEALING WOUNDS

Since vitamin C deficiency slows the rate of collagen formation, it causes wounds to heal more slowly (32).

Research has shown that people with chronic, non-healing leg ulcers are significantly more likely to be deficient in vitamin C than those without chronic leg ulcers (33).

In severe cases of vitamin C deficiency, old wounds may even reopen, increasing the risk of infection (34, 35).

Slow wound healing is one of the more advanced signs of deficiency and typically not seen until someone has been deficient for many months (36, 37).

POOR IMMUNITY

Studies show that v C accumulates inside various types of immune cells to help them combat infection and destroy disease-causing pathogens (38, 39).

V C deficiency is associated with poor immunity and a higher risk of infection, including serious illnesses like pneumonia (40, 41, 42).

In fact, many people with scurvy, a disease caused by v C deficiency, eventually die of infection due to their poorly functioning immune systems (43).

Vitamin C Deficiency

Acute v C deficiency leads to scurvy [44]. The timeline for the development of scurvy varies, depending on v C body stores, but signs can appear within 1 month of little or no v C intake (below 10 mg/day) [45]. Initial symptoms can include fatigue (probably the result of impaired carnitine biosynthesis), malaise, and inflammation of the gums [46]. As v C deficiency progresses, collagen synthesis becomes impaired and connective tissues become weakened, causing petechiae, ecchymoses, purpura, joint pain, poor wound healing, hyperkeratosis, and corkscrew hairs [47]. 

Food

Fruits and vegetables are the best sources of vitamin C (see Table 2) [12]. Citrus fruits, tomatoes and tomato juice, and potatoes are major contributors of vitamin C to the American diet [8]. Other good food sources include red and green peppers, kiwifruit, broccoli, strawberries, Brussels sprouts, and cantaloupe (see Table 2) [8,12]. Although vitamin C is not naturally present in grains, it is added to some fortified breakfast cereals. The vitamin C content of food may be reduced by prolonged storage and by cooking because ascorbic acid is water soluble and is destroyed by heat [6,8]. Steaming or microwaving may lessen cooking losses. Fortunately, many of the best food sources of vitamin C, such as fruits and vegetables, are usually consumed raw. Consuming five varied servings of fruits and vegetables a day can provide more than 200 mg of vitamin C.