Vitamins (AQA GCSE Food Preparation & Nutrition)
Revision Note
Written by: Ruth Brindle
Reviewed by: Lára Marie McIvor
Fat soluble vitamins
Fat-soluble vitamins dissolve in fat and are present in fatty foods
They are also stored in the bodys fatty tissue and liver
Fat-soluble vitamins include
Vitamin A
Vitamin D
Vitamin E
Vitamin K
Each one has a specific function within the body and is therefore key in maintaining good health
Fat-soluble vitamin | Function | Source | Deficiency of vitamin | Excess of vitamin |
|---|---|---|---|---|
Vitamin A Retinol (from meat products) Betacarotene (from vegetable sources) | Important for vision, immune function, skin health and cell growth | Liver, fish oils, milk, eggs, and colourful fruits and vegetables (such as carrots, spinach, and sweet potatoes) | Night blindness and eventually blindness | Poisonous and potentially harmful for a developing foetus |
Vitamin D | Crucial for bone health by promoting calcium absorption, as well as immune system regulation | Sunlight exposure, fatty fish (like salmon and mackerel), fortified milk, and egg yolks | Rickets Pregnant women, young children and babies and people who have limited exposure to sunlight are most at risk | No obvious issues are associated |
Vitamin E | Acts as an antioxidant, protecting cells from damage, and supports immune function | Nuts, seeds, vegetable oils, green leafy vegetables, and fortified cereals | Rare with no obvious issues | A loss of appetite |
Vitamin K | Essential for blood clotting and bone health | Green leafy vegetables (such as kale and spinach), broccoli, Brussels sprouts, and certain vegetable oils | Blood clotting takes longer leading to easy bruising and bleeding Newborn babies are particularly at risk | No evidence of issues |
Dietary reference values
The recommended intake for fat-soluble vitamins is small for all vitamins and is measured in micrograms (mcg) or milligrams (mg)
They can vary depending on age and sex
Dietary reference values table
Fat-soluble vitamin | Dietary reference value (per day) |
|---|---|
Vitamin A | Up to 10 yrs: 500 mcg 14 yrs: 600 mcg Adult: 700 mcg (m). 600 mcg (f) Over 50's: 700 mcg |
Vitamin D | Over 4 yrs: 10 mcg |
Vitamin E | Males: 4 mg Females: 3 mg |
Vitamin K | Teenagers: 0.045 mg Adult male: 0.075 mg Adult female: 0.065 mg |
Water soluble vitamins
Water-soluble vitamins dissolve in water
They are not stored in the body and so need to be consumed more regularly than fat soluble vitamins
Water-soluble vitamins include
Vitamin C
Vitamin B group, such as:
B1 - Thiamin
B2 - Riboflavin
B3 - Niacin
B9 - Folic acid
B12 - Cobalamin
Each one has a specific function within the body and is therefore key in maintaining good health
Water-soluble vitamin | Function | Source | Deficiency of vitamin | Excess of vitamin |
|---|---|---|---|---|
Vitamin C | Important for the growth and repair of tissues, acts as an antioxidant, aids in the absorption of iron, and supports immune function | Citrus fruits (oranges, lemons), strawberries, bell peppers, broccoli, and Brussels sprouts | Scurvy leading to swollen gums, joint pains and failure to heal wounds | Stomach pain and diarrhoea |
Vitamin B1 - Thiamin | Helps convert nutrients into energy and is crucial for nerve function | Whole grains, pork, sunflower seeds, and legumes | Beri beri, a muscle wasting disease (only seen in countries where there are food shortages) | Rare but can lead to nausea and stomach upset |
Vitamin B2 - Riboflavin | Plays a role in energy production and the metabolism of fats, drugs, and steroids | Milk, eggs, lean meats, green vegetables, and fortified cereals | Can lead to skin problems and poor growth | No known issues |
Vitamin B3 - Niacin | Important for DNA repair, the production of steroid hormones in the adrenal gland, and the metabolism of nutrients | Meat, fish, poultry, fortified bread and cereals, and peanuts | Skin problems such as dermatitis, rashes and diarrhoea | Itching and tingling skin, nausea and vomiting, liver damage |
Vitamin B9 - Folic acid | Crucial for DNA synthesis and repair, cell division, and proper foetal development during pregnancy | Leafy green vegetables, legumes, nuts, and fortified cereals | Can increase risks of developing spina bifida in developing babies | No known issues |
Vitamin B12 - Cobalamin | Essential for red blood cell formation, neurological function, and DNA synthesis | Animal products like meat, fish, dairy, and fortified cereals | Fatigue, weakness, tingling hands or feet | No known issues |
Dietary reference values
The recommended intake for water-soluble vitamins is also small for all vitamins and is measured in micrograms (mcg) or milligrams (mg)
They can vary depending on age and sex
Dietary reference values table
Water-soluble vitamin | Dietary reference value (per day) |
|---|---|
Vitamin C | Up to 10 yrs: 30 mg 14 yrs: 35 mg Adults: 40 mg |
Vitamin B1 - Thiamin | Up to 10 yrs: 0.7 mg 14 yrs: 0.9 mg (m), 0.7 mg (f) Adults: 1 mg (m), 0.8 mg (f) Over 50's: 0.9 mg (m), 0.8 mg (f) |
Vitamin B2 - Riboflavin | 4 yrs: 11 mg 10 yrs: 12 mg 14 yrs: 15 mg (m), 12 mg (f) Adults: 17 mg (m), 13 mg (f) Over 50's: 16 mg (m), 12 mg (f) |
Vitamin B3 - Niacin | 4 yrs: 11 mg 10 yrs: 12 mg 14 yrs: 15 mg (m), 12 mg (f) Adults: 17 mg (m), 13 mg (f) Over 50's: 16 mg (m), 12 mg (f) |
Vitamin B9 - Folic acid | 4 yrs: 100 mcg 10 yrs: 150 mcg Over 14 yrs: 200 mcg |
Vitamin B12 - Cobalamin | Up to 10 yrs: 30 mcg 14 yrs: 35 mcg Adults: 40 mcg |
The effect of cooking on nutritional values
Cooking and preparation techniques can result in a decrease in water-soluble vitamin content
This may lead to a decrease in the nutritional value of food
Things that may result in a decrease in nutritional value could include:
Fruit or vegetables that have been damaged or left to go over-ripe
Storing food in unsuitable conditions
Not eating food when it is fresh
Cutting food (excessively) causes damage and decreases the nutritional value
Soaking food causes vitamins to leach out
Removing skins from fruit and vegetables before eating
Cooking food in water
Using less water can reduce vitamin loss
Placing food into already boiling water and then cooling it as soon as it is cooked can reduce the loss of water soluble vitamins
Image from Freepik
Antioxidant functions of vitamins
Antioxidants are important molecules that help protect cells from damage caused by free radicals
Antioxidants are found in vitamins such as:
Vitamin A - neutralises free radicals
Vitamin C - supports immune function
Vitamin E - protects cell membranes
Each of these vitamins helps to reduce damage and reduce the risk of developing heart disease and certain types of cancer
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