Why is vitamin C important and what diseases can you get without it?: A Nutritional Overview

October 26, 2025 •

3 min read

Unlike most mammals, humans cannot synthesize their own vitamin C and must obtain it from their diet, making a consistent intake crucial for health. This makes understanding why is vitamin C important and what diseases can you get without it is therefore essential for preventing serious health complications.

Quick Summary

Vitamin C is a powerful antioxidant essential for immune function, collagen production, and iron absorption. Insufficient intake can cause scurvy, slow wound healing, and compromise overall health.

Key Points

Immune Booster: Vitamin C enhances the function of immune cells like neutrophils and lymphocytes, helping the body fight infections more effectively.
Collagen Synthesis: As a vital cofactor for enzymes, vitamin C is essential for producing collagen, the protein that provides structure to skin, bones, and blood vessels.
Antioxidant Protection: It acts as a powerful antioxidant, neutralizing free radicals that can cause cellular damage and contribute to chronic disease.
Scurvy Prevention: Severe, prolonged vitamin C deficiency causes scurvy, leading to symptoms like bleeding gums, poor wound healing, and extreme fatigue.
Enhanced Iron Absorption: Vitamin C helps the body absorb non-heme iron from plant-based foods, which is crucial for preventing iron-deficiency anemia.
Mental Health Support: Low vitamin C levels have been associated with mood disorders such as depression and cognitive impairment.

The Foundational Roles of Vitamin C

Vitamin C, or ascorbic acid, is a water-soluble vitamin that acts as a vital cofactor in many enzymatic reactions within the human body. Because the body cannot produce it, it must be regularly consumed through diet or supplementation to maintain essential physiological functions.

The Immune System's Ally

Vitamin C is renowned for its role in immune function, supporting both the innate and adaptive immune systems. It enhances immune cell activity, protects them from damage as an antioxidant, and is necessary for the development of T- and B-cells crucial for a targeted immune response.

The Builder of Collagen

A key function of vitamin C is its critical involvement in collagen synthesis, the main structural protein in connective tissues. It's a cofactor for enzymes that stabilize collagen's structure, and without enough vitamin C, the body struggles to form strong collagen, leading to fragile blood vessels, weak bones, and impaired wound healing.

Aiding Iron Absorption

Vitamin C boosts the absorption of non-heme iron from plant-based foods by converting it to a more absorbable form. Low vitamin C intake can contribute to iron-deficiency anemia.

Other Critical Functions

Vitamin C also plays a role in neurotransmitter production and, as an antioxidant, helps protect against oxidative stress linked to chronic diseases.

Diseases and Symptoms of Vitamin C Deficiency

Prolonged inadequate vitamin C intake can deplete body stores, resulting in various symptoms and diseases, most notably scurvy.

Scurvy: The Classic Deficiency Disease

Scurvy is the severe form of vitamin C deficiency. Early signs can include fatigue, weakness, irritability, and loss of appetite. As it worsens, symptoms related to poor connective tissue health appear:

Swollen, bleeding gums leading to potential tooth loss.
Easy bruising and skin spots due to fragile capillaries.
Delayed or poor wound healing.
Joint and muscle pain.
Anemia.

Other Health Complications

Even less severe deficiency can lead to health issues such as increased risk of infections, slower recovery, potential links to depression and cognitive issues, skin and hair problems due to poor collagen, and possibly contribute to weakened blood vessels.

Deficiency vs. Sufficient Intake: A Comparison


Aspect	Vitamin C Deficiency	Sufficient Vitamin C Intake
Immune Health	Increased susceptibility to infections and slower recovery.	Strengthened immune response, improved function of immune cells.
Wound Healing	Delayed and poor wound healing; old scars may reopen.	Efficient and proper healing of cuts, bruises, and other wounds.
Connective Tissue	Weakened collagen leads to fragile capillaries and tissues.	Strong collagen provides structural support for skin, bones, and gums.
Oral Health	Swollen, bleeding gums; potential for tooth loss.	Maintenance of healthy teeth and gums.
Energy Levels	Fatigue, lethargy, and general weakness.	Supports energy metabolism and can reduce fatigue.
Iron Absorption	Decreased absorption of non-heme iron, increasing anemia risk.	Enhanced absorption of iron from plant-based foods.
Mental Health	Potential links to depression and cognitive impairment.	Supports nervous system and cognitive function.

Sources of Vitamin C

Include a variety of vitamin C-rich fruits and vegetables in your diet. Good sources include oranges, strawberries, bell peppers, and broccoli. Some unique sources like Kakadu plums have extremely high levels. Eating some foods raw helps retain vitamin C, as cooking can reduce it.

Fruits: Oranges, strawberries, kiwi fruit, cantaloupe, and papaya are excellent sources.
Vegetables: Red and green bell peppers, broccoli, Brussels sprouts, spinach, and tomatoes are packed with vitamin C.
Unique Sources: Superfoods like Kakadu plums and acerola cherries contain exceptionally high levels of the vitamin.

Conclusion

Vitamin C is crucial for immune function, collagen production, and overall health. Deficiency can lead to serious conditions like scurvy. A diet rich in fruits and vegetables is essential for maintaining sufficient vitamin C levels and protecting against health issues.

For more detailed information, consult the Health Professional Fact Sheet on Vitamin C from the National Institutes of Health.

Frequently Asked Questions

The most severe disease caused by a lack of vitamin C is scurvy, a condition resulting from inadequate intake over a period of months.

Early symptoms of vitamin C deficiency often include non-specific signs such as fatigue, general weakness, irritability, and a loss of appetite.

Vitamin C is essential for the body to produce collagen, a key protein for repairing tissues. Without it, wounds take much longer to heal.

Excellent sources include a wide range of fruits and vegetables such as citrus fruits, strawberries, kiwis, bell peppers, broccoli, and spinach.

Yes, chronic or severe vitamin C deficiency can cause swollen, purple, and bleeding gums, which is a classic symptom of scurvy.

Research suggests a link between low vitamin C levels and an increased risk of depression and cognitive impairment.

Smokers have lower plasma and leukocyte vitamin C levels due to increased oxidative stress, and they need more vitamin C per day than non-smokers.

While supplements can address a deficiency, a balanced diet of fruits and vegetables is the best way to get this nutrient. The bioavailability of ascorbic acid from supplements is comparable to that in food.