1.1-Macronutrients Flashcards
What are proteins?
Large molecules consisting of chains of amino acids made up of carbon, hydrogen, oxygen & nitrogen. (also has R group- this varies in each amino acid)
What are the nutritional functions of protein?
-make up the structure of the body e.g. cartilage, muscles, skin and hair are made of protein.
- required for growth and repair of body cells when they are damaged or old.
-Act as antibodies in the immune system, helping to prevent infection.
-Enzymes are proteins that help reactions occur in the body. They function as a catalysts, increasing the rate of chemical reactions.
-Some hormones are proteins. They are chemical messengers produced in one part of the body to function in a different part of the body.
(water-soluble hormones eg. growth hormones are made from amino acids.)
-Used for energy if other energy sources are running out
How are proteins formed?
Condensation reactions (water is byproduct)
(if 2 amino acds- dipeptide bonds, many amino acids- polypeptide)
What are non-essential amino acids?
Amino acids that the body can make for itself.
What are essential amino acids?
Can’t be synthesised by the body so must be provided in the diet.
What are the essential amino acids?
for adults: Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine,
Tryptophan
Valine
-potentially arginine as its non-essential but can only be synthesised slowly
(Children: histidine)
What is HBV?
High biological value proteins- contains essential amino acids in the necessary amounts
-Found in meat, poultry, eggs, dairy and fish.
What amounts of protein do chicken, fish, eggs and dairy provide?
chicken- 32g per 100g
fish- 20/25g per 100g
eggs- 14g per 100g
dairy- 3/27g per 100g
What is LBV?
-Low biological value proteins.
Contains a limiting amino acid- the amino acid in shortest supply relative to the amounts needed.
-normally plant proteins are LBV
Examples of Plant protein?
Beans, nuts, seeds, quinoa, leafy greens, whole grains
(soya beans & quinoa- HBV, Peas, nuts & seeds- LBV)
What amounts of protein do lentils, chickpeas & beans provide?
lentils- 8/9g per 100g
`chickpeas- 7g per 100g
Beans- 7/10g per 100g
name some examples of limiting amino acids
-Lysine in wheat protein
-Tryptophan in maize protein
-Methionine and Cysteine in beef protein.
What are Novel proteins?
Newer/ rarer forms of protein that have immune-enhancing properties.
Eg. whey and soy
Where can whey and soy (Novel proteins) be found?
whey- in milk, cheese and yoghurt
Soy- soybeans(contains all essential amino acids), miso, soy sauce, tofu
cheese- 19g per 100g
soybeans- 12.35g per 100g
tofu- 8g per 100g
Benefits of novel protein instead animal?
can reduce bad cholesterol & heart disease and cancer
What is protein complementation?
When 2 LBV proteins are eaten together to produce a HBV meal eg. beans on toast- the amino acids of 1 protein compensate for the lack in the others.
What are carbohydrates?
Sugar molecules that provide energy.
3 types-
starch(Complex carbs)
sugar(simple carbs)
fiber (complex carbs)