Nutrition for MBBS © Christo4 Dwarika (Carbohydrates (Glycogen (Consists…
Nutrition for MBBS © Christo4 Dwarika
Carbohydrates, Proteins, Fats and Oils
10-100 grams daily.
Vitamins and Minerals
Micrograms - milligrams daily.
Food vs Nutrition
Anything that is ingested by an organism that is used to
support growth, provide energy and repair it.
Sum of the processes by which an organism utlises food for sustenance.
carbohydrates, fats and oils, proteins, vitamins and minerals.
is a food and nutrient.
is not a nutrient.
Daily Energy Requirements
PERSONAL ENERGY REQUIREMENT
= BASIC ENERGY REQUIREMENT + EXTRA ENERGY REQUIREMENT
1.3 calories x hours x body weight (kg)
8.5 calories x hours x body weight (kg)
of total energy intake is carbohydrates.
of carbohydrate provides
DNA AND RNA
Roots and Tubers (potato, sweet potato, guam, banana)
Legumes (pulses, nuts)
Grains (rice, wheat, maize)
Disaccharide. Can be hydrolysed by
to form Glucose and Fructose.
Its transporter is
and is thus not transported into most cells.
Does not stimulate insulin release.
Poorly absorbed from the GIT.
Almost entirely cleared by the liver.
Circulating concentration is approximately 0.01 mmol/L in peripheral blood as opposed to 5.5 mmol/L for glucose.
In glycolysis, the enzyme
is inhibited by the presence of ATP. However, the enzyme which breaks down fructose,
is never inhibited. (Refer to slide 7)
Formed from galactose and glucose.
Found in milk.
Results in fermentation in the gut, which leads to
bloating, stomach pains, diarrhoea, wind, bowel sounds, feeling sick, urge to have bowel movement.
Caused by missing lactase in the small intestine.
Consists of 2 glucose units joined by an α1-4 glycosidic bond.
Formed by the partial hydrolysis starch.
Produced by green plants as an energy store. It is a large polymer of glucose subunits joined by glycosidic bonds.
Makes up 15-20% of starch
Consists of 200-20 000 residues
Linear polymer of glucose
Hydrolysed by amylase
End products are glucose and maltose.
Highly branched polymer of glucose.
Has side chains of 30 chains attached via an α1,6 bond every 20-30 glucose units along the chain.
Consists approximately 1700-600000 units of glucose.
Some glucose not used will be stored as glycogen in liver and muscle.
Similar in structure to amylopectin, but more branched.
Extra glucose will be stored as fat.
Equivalent of starch in animals.
The body's glycogen capacity is limited to 350 g. It lasts approximately 10-12 hours when at rest.
Glycogen is important as under normal conditions, glucose is the only fuel used by the brain.
Potency of a food to raise blood glucose compared to potency of glucose.
If fed 50g of glucose (50g carbs), blood glucose = 180 mg/dL. Subject fed 71g of bread (50g carbs) and blood glucose = 126 mg/dL. GI = 100 x 126/180 = 70.
Indicates how much a given serving of a food will raise blood glucose.
GL = GI/100 x grams of carbs in the serving.
Example: GI of watermelon = 72 (high). 120g of watermelon contains 6g of carb. GL = 72/100 x 6 = 4.32 (low)
Essential for functions such as:
growth, repair of worn-out tissues, replacement of used-up blood and resistance against infections.
SOURCES OF PROTEINS:
meat, fish, milk, pulses, nuts and beans are rich sources.
They are the building material of body parts such as:
muscle, brain, blood, skin, hair, nails, bones and body fluids.
FIRST CLASS PROTEINS:
High quality proteins that provide a balanced composition of amino acids such as animal proteins.
ESSENTIAL AMINO ACIDS -
amino acids which are not manufactured by the body, example: arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine.
SECOND CLASS PROTEINS:
low quality proteins that provide an incomplete set if amino acids (such as plant proteins).
energy for every
Fats and Oils
Fats also facilitate the absorption, transport and storage of fat-soluble vitamins A, D, E and K.
of body fat is
Fats provide the building material for some body parts (such as the brain, cell membranes and hormones.
TRANS FATTY ACIDS
Rare in nature, but can can occur in processed foods.
Increase the risk of coronary heart disease by raising levels of LDL cholesterol and lowering levels of HDL cholesterol.
Trans fats from partially hydrogenating oils are more harmful than naturally occurring oils.
includes triglycerides, phospholipids, sterols such as cholesterol.
ESSENTIAL FATTY ACIDS
The 2 essential fatty acids are
α-linolenic acid (omega-3) and linoleic acid (omega-6).
Double bonds can be introduced at α4, α5, α6 and α9 positions in most animals, but not beyond the α9 position.
Plants can introduce double bonds at α12 and α15.
oily fish, flaxseed, dark green leafy vegtables, walnuts and seeds.
of fat provides
Fibres form the bulk of the stool and help in clearing the bowel and preventing constipation and colon cancer.
Fibres slow the absorption of glucose and cholesterol from the GIT, and are thus helpful in diabetes and heart disease.
These are non-digestible, non-absorbable components of food.
Fruits, vegetables, pulses and whole cereals.