The Role of Vitamin C

Vitamin C: Overview and Importance

If vitamins received awards, vitamin C would win for the most popular nutrient taken as a supplement alongside multivitamins. From skin health to immune health to healing you from the inside out.  There is good reason that vitamin C has become well known and for many decades, it remains popular too. 

Does this mean you need to take vitamin C supplements? 

First, let's explore the role of vitamin C...

Role of Vitamin C:

• Antioxidant: Protects cells from damage by free radicals.
• Collagen Production: Essential for the synthesis of collagen, a protein that helps maintain skin, cartilage, tendons, ligaments, and blood vessels.
• Immune Support: Enhances the function of the immune system.
• Iron Absorption: Improves the absorption of non-heme iron from plant-based foods.
• Wound Healing: Plays a crucial role in the repair of tissues.

Top 10 Foods High in Vitamin C (With Amounts per Serving)

1. Guava: ~377 mg per cup (165 g)
2. Red Bell Pepper: ~190 mg per cup (sliced, 150 g)
3. Kiwi: ~167 mg per cup (180 g)
4. Strawberries: ~98 mg per cup (152 g)
5. Oranges: ~95 mg per medium orange (130 g)
6. Papaya: ~88 mg per cup (145 g)
7. Broccoli: ~81 mg per cup (raw, chopped, 91 g)
8. Brussels Sprouts: ~75 mg per cup (raw, 88 g)
9. Pineapple: ~79 mg per cup (chunks, 165 g)
10. Mango: ~60 mg per cup (sliced, 165 g)

Daily Requirements for Vitamin C:

• Adults:
• Men: 90 mg/day
• Women: 75 mg/day
• Smokers: Additional 35 mg/day (environmental exposures and immune health concerns) 
• Upper Limit: 2,000 mg/day for adults

Signs of Vitamin C Deficiency:

• Early Signs: Fatigue, weakness, and irritability.
• Advanced Signs:
• Scurvy: Swollen, bleeding gums, joint pain, poor wound healing, dry skin, and hair, bruising easily.
• Anemia: Due to reduced iron absorption.

How Much is Too Much?

• Excess Vitamin C: Generally considered safe, but amounts above 2,000 mg/day can lead to side effects.

Signs of Too Much Vitamin C:

• Digestive Issues: Diarrhea, nausea, stomach cramps.
• Kidney Stones: In people prone to oxalate stones, high vitamin C can increase the risk.

Note:  If you have an autoimmune condition, consult with your doctor or dietitian about vitamin C supplements and possible discontinuation. 

One-Day Vitamin C Loaded Menu

Breakfast: Vitamin C Smoothie

• Ingredients: 1 orange (~70 mg), 1 kiwi (~84 mg), 1/2 cup strawberries (~49 mg), 1/2 cup pineapple (~39 mg), 1/2 cup spinach (~8 mg), 1/2 cup Greek yogurt.
• Total Vitamin C: ~250 mg

Lunch: Quinoa Salad with Red Bell Pepper and Broccoli

• Ingredients: 1 cup quinoa, 1/2 cup red bell pepper (~95 mg), 1/2 cup broccoli (~41 mg), cherry tomatoes, cucumber, lemon dressing.
• Total Vitamin C: ~150 mg

Snack: Guava Slices and Almonds

• 1 guava (~125 mg)
• Total Vitamin C: ~125 mg

Dinner: Grilled Chicken with Brussels Sprouts and Sweet Potatoes

• Ingredients: Grilled chicken breast, 1 cup roasted Brussels sprouts (~75 mg), 1/2 cup roasted sweet potatoes.
• Total Vitamin C: ~75 mg

Evening Snack: Papaya Chunks

• 1 cup papaya (~88 mg)
• Total Vitamin C: ~88 mg

Daily Total Vitamin C: ~688 mg

This menu provides ample vitamin C from a variety of fruits and vegetables, well above the daily requirement, but safely below the upper limit.

Do We Need Vitamin C Supplements?

As you can see from the list of high sources of vitamin C, for most people, it’s possible to get enough vitamin C from a balanced diet rich in fruits and vegetables. Supplements may be unnecessary if you consume sufficient vitamin C from foods like citrus fruits, strawberries, bell peppers, and broccoli. Not to mention, many of these foods are also high in fiber antioxidants and additional nutrients such as potassium, magnesium, etc. However, certain groups may benefit from supplements:

Who May Need Vitamin C Supplements:

• Smokers: Smoking increases oxidative stress and decreases vitamin C levels.
• People with Limited Diets: Those with restricted diets or limited access to fresh produce may benefit.
• Certain Medical Conditions: Individuals with conditions like malabsorption syndromes or specific gastrointestinal issues may need supplements.
• Pregnant and Breastfeeding Women: They have higher vitamin C requirements.

Vitamin C may also be required in higher dosages for....

1. Chronic Infections

• Examples: Chronic sinusitis, chronic bronchitis, or recurring respiratory infections.
• Why More Vitamin C is Needed: Vitamin C helps combat infections by supporting white blood cell function and enhancing the immune response.

2. Severe Viral Infections

• Examples: Influenza, viral pneumonia, COVID-19.
• Why More Vitamin C is Needed: During severe viral infections, the body’s demand for antioxidants increases. Vitamin C can help reduce oxidative stress and inflammation.

3. Autoimmune Diseases

• Examples: Rheumatoid arthritis, lupus, multiple sclerosis.
• Why More Vitamin C is Needed: Vitamin C may help manage oxidative stress and reduce inflammation, which are common in autoimmune conditions.

4. Wound Healing or Recovery from Surgery

• Examples: Post-surgery recovery, major injuries, or burns.
• Why More Vitamin C is Needed: Vitamin C is vital for collagen production, which is crucial for tissue repair and healing.

5. Immunodeficiency Disorders

• Examples: Common variable immunodeficiency (CVID), IgA deficiency.
• Why More Vitamin C is Needed: People with weakened immune systems may benefit from the immune-boosting effects of vitamin C.

In these conditions, higher vitamin C intake—through diet or supplementation—may be beneficial to support immune function, reduce inflammation, and promote recovery. However, it is important to consult with a healthcare provider before increasing vitamin C intake, especially if considering high-dose supplements.

Who Should Avoid Vitamin C Supplements:

• People with a History of Kidney Stones: High doses can increase the risk of oxalate stones.
• Individuals with Hemochromatosis: Vitamin C enhances iron absorption, which can be harmful in conditions with excessive iron accumulation.

What Happens if You Take High Doses of Vitamin C and Suddenly Stop?

If you regularly take high doses of vitamin C (above 2,000 mg daily) and suddenly stop, the body may initially experience a "rebound scurvy" effect. This occurs because the body adjusts to higher vitamin C levels by increasing its rate of excretion. Abruptly stopping can temporarily reduce vitamin C levels, although this is generally mild and short-lived.

Does the Body Alter Absorption?

The body regulates vitamin C absorption based on intake:

• Lower Doses (≤200 mg): About 70-90% absorption.
• Higher Doses (>1,000 mg): Absorption decreases to less than 50%, with excess excreted in urine.

This regulation helps prevent toxic levels, but excessive supplementation over time can lead to side effects like digestive distress and increase the risk of kidney stones.

 

References:

1. National Institutes of Health (NIH) Office of Dietary Supplements. (n.d.). Vitamin C - Fact Sheet for Health Professionals.
2. Harvard T.H. Chan School of Public Health. (n.d.). The Nutrition Source: Vitamin C.
3. Mayo Clinic. (2023). Vitamin C - Overview.

Karie Cassell RD, LMC
Bestselling Author, Dietitian, Nutrition Coach
[email protected]
www.kariecassell.com

Ph. 780-814-2983