Nutrition And Health

What are carbohydrates?

A major macronutrient made mainly of carbon, hydrogen and oxygen

What are the main types of carbohydrates?

Monosaccharides, disaccharides and polysaccharides

What is a monosaccharide?

A single sugar molecule, such as glucose or fructose

What is a disaccharide?

A carbohydrate made from two monosaccharides

What is lactose made from?

Glucose + galactose

What is starch?

A polysaccharide made from many glucose molecules

What is cellulose?

A structural polysaccharide found in plant cell walls

What is the glycaemic index (GI)?

A ranking that measures how quickly carbohydrate-containing foods raise blood glucose levels

What is the usual range of the glycaemic index?

0-100

What are proteins?

Macronutrients made from chains of amino acids

What elements are found in amino acids?

Carbon, hydrogen, oxygen and nitrogen; some also contain sulphur

What are the three main groups attached to an amino acid?

An amino group, a carboxylic acid group and an R group

What is the R group of an amino acid?

The variable group that differs between amino acids and determines their properties

What are the three categories of amino acids?

Essential, non-essential and conditionally essential amino acids

What are essential amino acids?

Amino acids that the body cannot make in sufficient amounts and therefore must obtain from the diet

What are non-essential amino acids?

Amino acids that the body can synthesise

What are conditionally essential amino acids?

Amino acids that may need to be obtained from the diet during certain conditions, such as illness or stress.

Where is most protein in the body found?

Approximately 50% in muscle, 10% in skin, 20% in bone and 20% elsewhere

Why does protein require more energy to digest than carbohydrates or fats?

Protein has a higher thermic effect of food, meaning more energy is used during digestion and metabolism

What happens to proteins in the stomach?

Gastric acid denatures proteins and pepsin begins protein digestion

What does denaturation mean?

The unfolding or alteration of a protein's structure

What enzyme begins protein digestion in the stomach?

Pepsin

What does proteolysis mean?

The breakdown of proteins into smaller peptides and amino acids

What does the pancreas secrete to digest proteins?

Proteases

What are fats?

Lipids that are important sources of energy and have structural and signalling functions

What does hydrophobic mean?

A substance that does not dissolve in water

What are the main components of a fatty acid?

A hydrocarbon chain and a carboxylic acid group (COOH)

What is a saturated fat?

A fatty acid containing no carbon-carbon double bonds

What is an unsaturated fat?

A fatty acid containing one or more carbon-carbon double bonds

What is a monounsaturated fat?

A fat containing one carbon-carbon double bond

What is a polyunsaturated fat?

A fat containing two or more carbon-carbon double bonds

Which enzymes digest fats?

Lipases

Where is lipase produced?

The mouth produces salivary lipase, and the pancreas produces pancreatic lipase

What does pancreatic lipase break fats into?

Monoglycerides and fatty acids

What is emulsification?

The process of breaking large fat droplets into smaller droplets, increasing the surface area for lipase.

What substance emulsifies fats?

Bile

Where is bile produced?

The liver

What are the main functions of fats?

Energy provision, forming cell membranes and acting as precursors for signalling molecules such as eicosanoids.

What are phospholipids?

Lipids that are major components of cell membranes

What are eicosanoids?

Signalling molecules derived from fatty acids that have roles in processes such as inflammation and blood clotting

What is vitamin A also called?

Retinol

What are sources of vitamin A?

Liver, eggs, oily fish, cheese, cod liver oil and carrots

What is an important pregnancy consideration with vitamin A?

• Excessive preformed vitamin A (retinol) can harm the developing fetus,

• High-dose supplements and liver products should be avoided during pregnancy unless advised by a healthcare professional.

What is vitamin C also called?

Ascorbic acid

What disease is caused by severe vitamin C deficiency?

Scurvy

What are some functions of vitamin C?

It is needed for collagen synthesis, neurotransmitter synthesis and carnitine synthesis

What is another important function of vitamin C?

It acts as an antioxidant

How does vitamin C affect iron absorption?

It increases the absorption of non-haem iron

What can vitamin C deficiency cause in the mouth?

Delayed wound healing, dentin abnormalities, bleeding gums and pulpal changes

Why is vitamin C important for collagen?

It is required for normal collagen synthesis and therefore helps maintain connective tissue

What is vitamin B12 also called?

Cobalamin

What are the main dietary sources of vitamin B12?

Animal products such as meat, fish, eggs and dairy products; fortified foods can also provide B12

What is the role of vitamin B12?

It acts as a cofactor for enzymes involved in metabolism and DNA synthesis

Which enzyme requires vitamin B12 as a cofactor?

Methionine synthase

What is the role of methionine synthase?

It helps convert homocysteine to methionine and is involved in methylation reactions

Why is vitamin B12 important for DNA synthesis?

It is involved in folate metabolism, which is necessary for normal DNA synthesis

What is vitamin B12 involved in besides DNA synthesis?

RNA and protein synthesis, red blood cell formation and normal neurological function