Vitamin C (Leaving Cert Home Economics): Revision Notes
Vitamin C
Vitamin C, also known as ascorbic acid, is one of the most important water-soluble vitamins needed for maintaining good health. This essential nutrient plays crucial roles in many bodily functions and must be obtained through our diet since the human body cannot produce it naturally.
What is vitamin C?
Vitamin C is a water-soluble vitamin that appears as a white crystalline acid with a distinctive sweet and sour taste. It's also chemically known as ascorbic acid.
Vitamin C is unique because it's extremely unstable and can be easily destroyed during food storage, preparation, and cooking. This makes it important to understand how to preserve it in our foods.
Dietary sources of vitamin C
Getting enough vitamin C through your diet is essential since your body can't make it. Fortunately, many delicious foods are packed with this vital nutrient.
Fruits
Fruits are some of the best sources of vitamin C available. The richest options include:
- Blackcurrants - contain exceptionally high levels
- Kiwi fruits - small but mighty sources
- Citrus fruits - oranges, lemons, limes, and grapefruits
- Strawberries - sweet and vitamin-rich
- Melons - refreshing summer sources
Vegetables
Many vegetables also provide excellent amounts of vitamin C:
- Peppers - particularly red and yellow varieties
- Tomatoes - fresh or in cooking
- Leafy greens - spinach and kale are top choices
- Potatoes - especially when eaten with the skin
Peppers, particularly red and yellow varieties, actually contain more vitamin C than many citrus fruits, making them an excellent choice for boosting your daily intake.
Supplements
Vitamin C supplements are commonly used when dietary intake might be insufficient. These are particularly helpful for people with limited access to fresh fruits and vegetables or those with increased needs due to illness or lifestyle factors.
Functions of vitamin C in the body
Vitamin C performs several critical functions that keep your body healthy and functioning properly.
Collagen formation
One of vitamin C's most important jobs is helping your body create collagen. This protein acts like scaffolding throughout your body, providing structure to:
- Skin and keeping it healthy and strong
- Bones and joints for structural support
- Blood vessels for proper circulation
- Wound healing processes
Without adequate vitamin C, your body struggles to make quality collagen, leading to various health problems including poor wound healing and weakened blood vessels.
Immune system support
Vitamin C is vital for maintaining a robust immune system. It helps your body:
- Fight off infections more effectively
- Recover more quickly from illnesses
- Build resistance against common colds and other ailments
This is why many people increase their vitamin C intake when they feel unwell.
While vitamin C supports immune function, research shows that regular supplementation primarily benefits people under extreme physical stress, such as marathon runners, rather than preventing colds in the general population.
Antioxidant protection
As a powerful antioxidant, vitamin C protects your cells from damage caused by harmful molecules called free radicals. This protective action:
- Reduces oxidative stress throughout the body
- May help prevent chronic diseases
- Supports overall cellular health and longevity
Effects of vitamin C deficiency
When your body doesn't get enough vitamin C, several serious health problems can develop.
Scurvy
Scurvy is the most severe form of vitamin C deficiency. This condition causes:
- Bleeding gums that become swollen and painful
- Joint pain and muscle weakness
- Poor wound healing and easy bruising
- Fatigue and general weakness
Fortunately, scurvy is rare in developed countries today due to better nutrition.
Weakened immune function
Insufficient vitamin C leads to:
- Increased susceptibility to infections
- Slower recovery from illnesses
- More frequent colds and respiratory problems
Skin and tissue problems
Since vitamin C is essential for collagen production, deficiency causes:
- Poor skin health and slow healing
- Weak blood vessels that break easily
- Dental problems and loose teeth
Recommended dietary allowances
Different groups of people need varying amounts of vitamin C to maintain optimal health.
Adults
Most healthy adults require 75-90 mg per day. However, smokers need an additional 35 mg daily because smoking increases oxidative stress, which depletes vitamin C levels more rapidly.
Pregnant women
Expectant mothers need 85 mg per day to support both their own health and their developing baby's growth and development.
Lactating women
Breastfeeding mothers require the highest amount at 120 mg per day since they're providing vitamin C for both themselves and their nursing infant through breast milk.
These recommended amounts are easily achievable through a balanced diet rich in fruits and vegetables. For example, one medium orange provides about 70 mg of vitamin C, nearly meeting an adult's daily requirement.
Properties of vitamin C
Understanding vitamin C's characteristics helps explain why it's easily lost from foods and why proper storage and preparation matter.
Solubility and stability
Vitamin C is water-soluble, meaning it dissolves in water and isn't stored in body fat. This characteristic means:
- Excess amounts are excreted in urine
- Regular daily intake is necessary
- It's easily lost when foods are washed or cooked in water
Unfortunately, vitamin C is also highly unstable and is easily destroyed during:
- Food storage, especially for extended periods
- Cooking processes, particularly boiling
- Exposure to light and air
Sensitivity to destruction
Several factors can destroy vitamin C in foods:
- Heat from cooking processes
- Light exposure during storage
- Alkalis (basic substances)
- Oxidase enzymes naturally present in some foods
- Dehydration processes used in food preservation
This is why fresh, raw fruits and vegetables typically contain more vitamin C than processed or cooked versions.
To preserve vitamin C content in foods, store fruits and vegetables in cool, dark places and consume them as fresh as possible. When cooking, use minimal water and shorter cooking times, or try steaming instead of boiling.
Key Points to Remember:
- Vitamin C is essential for collagen formation, immune function, and antioxidant protection
- Best sources include citrus fruits, berries, peppers, and leafy green vegetables
- It's water-soluble and easily destroyed by heat, light, and air exposure
- Deficiency can lead to scurvy, weakened immunity, and poor wound healing
- Daily requirements vary from 75-120 mg depending on age, pregnancy, and smoking status
- Fresh, raw foods typically contain more vitamin C than processed or cooked versions