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  and has been shown to regenerate other antioxidants within the body, including alpha-tocopherol (vitamin E) .
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).
|0–6 months||40 mg*||40 mg*|
|7–12 months||50 mg*||50 mg*|
|1–3 years||15 mg||15 mg|
|4–8 years||25 mg||25 mg|
|9–13 years||45 mg||45 mg|
|14–18 years||75 mg||65 mg||80 mg||115 mg|
|19+ years||90 mg||75 mg||85 mg||120 mg|
|Smokers||Individuals who smoke require 35 mg/day
more vitamin C than nonsmokers.
* Adequate Intake (AI)
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.
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
It also promotes collagen production, which keeps skin looking plump and youthful (20).
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.
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 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 . 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) . Initial symptoms can include fatigue (probably the result of impaired carnitine biosynthesis), malaise, and inflammation of the gums . 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 .
Fruits and vegetables are the best sources of vitamin C (see Table 2) . Citrus fruits, tomatoes and tomato juice, and potatoes are major contributors of vitamin C to the American diet . 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.
VITAMIN C FOOD SOURCES
|Food||Milligrams (mg) per serving||Percent (%) DV*|
|Red pepper, sweet, raw, ½ cup||95||158|
|Orange juice, ¾ cup||93||155|
|Orange, 1 medium||70||117|
|Grapefruit juice, ¾ cup||70||117|
|Kiwifruit, 1 medium||64||107|
|Green pepper, sweet, raw, ½ cup||60||100|
|Broccoli, cooked, ½ cup||51||85|
|Strawberries, fresh, sliced, ½ cup||49||82|
|Brussels sprouts, cooked, ½ cup||48||80|
|Grapefruit, ½ medium||39||65|
|Broccoli, raw, ½ cup||39||65|
|Tomato juice, ¾ cup||33||55|
|Cantaloupe, ½ cup||29||48|
|Cabbage, cooked, ½ cup||28||47|
|Cauliflower, raw, ½ cup||26||43|
|Potato, baked, 1 medium||17||28|
|Tomato, raw, 1 medium||17||28|
|Spinach, cooked, ½ cup||9||15|
|Green peas, frozen, cooked, ½ cup||8||13|
*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of products within the context of a total diet. The DV for vitamin C used for the values in Table 2 is 60 mg for adults and children age 4 years and older . This DV, however, is changing to 90 mg as the updated Nutrition and Supplement Facts labels are implemented . The updated labels and DVs must appear on food products and dietary supplements beginning in January 2020, but they can be used now . FDA requires current food labels to list vitamin C content, but this requirement will be dropped with the updated labels. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.
The U.S. Department of Agriculture’s (USDA’s) National Nutrient Database lists the nutrient content of many foods and provides a comprehensive list of foods containing vitamin C arranged by nutrient content and by food name.