Fat-Soluble Vitamins
Food Preparation & Nutrition: AQA GCSE, topic 2.2.1
Fat-Soluble Vitamins
Micronutrients are substances that the body needs in small doses, such as vitamins. Vitamins are organic compounds that help us to stay healthy.
Sources of vitamins
- Plants.
- Animals.
Sources of fat-soluble vitamins
- Fatty foods - e.g. beef liver, butter, fatty fish, cheese.
Storing fat-soluble vitamins
- The body stores fat-soluble vitamins it doesn't use up in fat tissue.
- For this reason, the body doesn't have to take in the same quantities of fat-soluble vitamins every day.
- This also means we're in danger of storing an excess of these vitamins.
- This shouldn't be a problem for someone eating a balanced diet. But someone taking multivitamin supplements can risk building up an excess.
Fat-Soluble Vitamins - A and D
We get fat-soluble vitamins from fatty foods, like fatty fish and beef liver.
Vitamin A
- The body needs vitamin A for growth, keeping the immune system healthy, and for good skin and eyesight.
- Vitamin A is an antioxidant.
- We get vitamin A from retinol. Meat, full-fat milk and fatty fish all contain retinol. We can also make retinol from carotene. Carrots and other orange/yellow fruits and vegetables contain carotene.
Excess and too little vitamin A
- Excess vitamin A over a period of time weakens bones.
- Pregnant women are advised to stay clear of foods containing lots of vitamin A (like liver).
- Too little vitamin A can weaken the immune system, cause blindness at night and inflamed skin and stunt growth.
- The daily dose recommended by the NHS is:
- 0.7mg for men.
- 0.6mg for women.
Vitamin D
- We get vitamin D from fish liver oils and fatty fish like tuna and salmon.
- We can also get vitamin D from being in sunlight.
- Vitamin D aids mineral absorption, including calcium absorption. Our bodies need calcium to develop healthy teeth and bones.
Excess and too little vitamin D
- If we take in too much vitamin D, our bodies may absorb too much calcium. Excess calcium can cause damage to our kidneys.
- Bone diseases, such as osteomalacia (soft bones), osteoporosis (brittle bones) and rickets, can arise from the body getting too little vitamin D.
- According to the NHS, the average person should have a daily dose of 0.01mg.
Fat-Soluble Vitamins - E and K
We get fat-soluble vitamins from fatty foods, like fatty fish and beef liver.
Vitamin E
- We get vitamin E from:
- Vegetable oils (e.g. sunflower, corn, and soybean oils).
- Nuts (e.g. peanuts, almonds and hazelnuts).
- Seeds (e.g. sunflower seeds).
- Green leafy vegetables (e.g. swiss chard).
- Vitamin E helps to boost the immune system.
- We also need vitamin E for healthy skin and eyes.
- Vitamin E is an antioxidant, which means it can protect our bodies from free radicals.
Excess and too little vitamin E
- Excess vitamin E can cause someone to feel nauseous, disrupt blood clotting and lead to blurred vision.
- Weak muscles and eyesight problems are both symptoms of having too little vitamin E.
- NHS guidelines for daily doses:
- Men: 4mg.
- Women: 3mg.
Vitamin K
- We get vitamin K from leafy greens, liver, green tea, cheese.
- Like vitamin E, vitamin K supports the immune system. Vitamin K helps us to maintain healthy bones.
- Vitamin K also helps blood clotting and helps us to heal wounds.
Excess and too little vitamin K
- We can't have too much vitamin K.
- Although adults are very unlikely to have too little vitamin K, newborn babies can suffer from uncontrolled bleeding if they have too little vitamin K.
- NHS guidelines for daily dose:
- 0.001mg per kg of body weight.
Test yourself on Fat-Soluble Vitamins
What do we call substances that the body needs in small doses?
Which of the following is NOT an example of a micronutrient?
Which of the following are micronutrients?
What can be caused by consuming too much vitamin A?
Which of the following foods contain retinol?