Nutrition

Question 1

list the vitamins and their toxicity

Answer 1

Question 2

describe all the vitamins, their principle functions and their deficiency diseases

IGNORE THE TABLE ITS THE ANSWER

Answer 2

Question 3

describe the location, absorption, source, toxicity, deficiency and function of this mineral: fluoride

Answer 3

location
- distributed through ECF
- bound to albumin in blood and tissues

absorption
- rapidly absorbed as it is soluble
- 50% is absorbed after 30 minutes
- excreted through kidneys
- calcium can reduce absorption

function
- not essential
- forms calcium fluorapatite in teeth and bones

deficiency
- increased risk of dental caries

source
- low concentration in food

Question 4

describe the source, toxicity, deficiency and function of this mineral: sodium

Answer 4

source
- dietary sodium in the form of salt
- 2.54g of salt has 1g sodium
- 4g of salt a day is the RNI ideal, but 6g is the achievable one

function
- maintain ECF volume
- maintain acid base balance
- muscle contraction and nerve transmission
- a third of ATP at rest is used to maintain cellular sodium potassium gradient
- 30-40% is stored on the surface of bone

toxicity
- too much salt leads to hypertension, strokes and heart disease
- increases calcium excretion and can affect bone health
- aggravates kidney problems

deficiency
- excess sweating can deplete salt but the body adapts

Question 5

describe the source, toxicity, deficiency and function of this mineral: zinc

Answer 5

function
- synthesis of DNA and RNA - therefore for growth and development
- DNA polymerase is zinc dependent
- antioxidant enzyme superoxidase dismutase needs zinc
- structural role
- expression of genes
- immunity

sources
- oysters, meat, liver, wheatflour

DRV
- 102-109mg a day for males and females

deficiency
- growth retardation, immaturity, neuropyschiatric disturbances, dermatitis, alopecia, diarrhoea, appetite loss
- low serum zinc in pregnancy is associated with low birth weight and pre term delivery

supplementation
- stimulates growth and development
- reduces diarrhoea and respiratory infections in children

Question 6

describe the absorption, forms, source, toxicity, deficiency and function of this mineral: iron

Answer 6

function
- haemoglobin
- ATP production
- oxygen reserve in muscle
- defence against infection via lactoferrin

absorption
- 20-35% of haem iron is absorbed and 1-10% of non haem iron
- spices and tea can reduce iron absorption by 50%
- absorption of haem iron: influenced by amount of haem iron present, enhanced by meat, inhibited by calcium
- absorption of non haem iron: amount of non haem present, iron status and requirements all influence absorption. enhanced by ascorbic acid, meat, fish and seafood. inhibited by phytates, phenolics and calcium

sources
- haem - animal foods like meat and meat products
- non haem - plant foods - cereals, pulses, veg, fruit, egg, dairy

deficiency
- iron deficiency anaemia
- most common nutritional deficiency
- reduced blood cells due to iron deficiency
- ID alone is if it is less than 15-20ug
- IDA is when it is less than 12-13 ug

toxicity
- not an issue in healthy people
- haemochromatosis is an inherited disorder
- supplement overdose: 300mg per kg is lethal, 20 is toxic in children
- supplement overdose in adults:
- 100g is lethal, 45mg a day has adverse effects

Question 7

describe the source, toxicity, deficiency, absorption and function of this mineral: calcium

Answer 7

roles
- bone health
- peak bone mass at 30-35 (when bones are strongest)

sources
- water, milk, cereals, roots, bread, bones from fish, eggs, pulses, broccoli, parsley

DRV
- 700mg a day

absorption
- 10-30% of dietary calcium is absorbed
- reduced absorption when there is vitamin D deficiency, fibre, or large calcium load
- increased absorption when there are lactose and casein peptides from milk
- increased absorption to match needs like during growth, pregnancy, lactation and if there is low calcium load

deficiency
- severe malnutrition, lack of vitamin D, osteoporosis
- tightly regulated so this does not usually happen

toxicity
- unknown

Question 8

describe the forms, source, toxicity, deficiency and function of vitamin: K

Answer 8

form
- 2methyl 1,4 nathoquinone
- menaquinones when formed in the gut bacteria

sources
- green leafy vegetables
- formed by bacteria in gut

funtion
- synthesis of prothrombin in the liver
- synthesis of factors VII, IX and X
- needed for coagulation

deficiency
- unlikely
- some children born with sterile guts and are given vitamin K injection at birth

Question 9

describe the forms, source, toxicity, deficiency and function of vitamin: E

Answer 9

forms
- 8
- 4 tocopherols (alpha, beta delta and gamma)
- 4 tocotrienols (alpha, beta, delta, and gamma)
- most potent is alpha tocopherol
- alpha and gamma tocopherols predominate in a mixed diet

function
- antioxidant, protects cell components from oxidation by free radicals
- regenerated by vitamin C after it has been oxidised
- found in lipid bilayer
- component of plasma lipoproteins that transport cholesterol and polyunsaturated fatty acids

deficiency in infants
- haemolytic anaemia - red blood cells rupture
- thrombocytosis - oedema due to increased platelet count

deficiency in children and adults
- unable to absorb or utilise vitE
- neurological syndrom involving CNS and PNS, deposition of yellow or white pigment in the retina, irregular movement

toxicity
- no adverse effects

sources
- veg oils, fruit and veg, animal products and fortified foods like cereals

DRV
- no DRV because requirement depends on PUFA intake which depends on diet

Question 10

describe the synthesis, source, form, toxicity, deficiency and function of vitamin:

Answer 10

forms
- D2 is dietary - ergocalciferol
- D3 is cholecalciferol
- 7dehydrocholesterol is vitD made in the skin
- active form is 1,25 dihydroxyvitamin D3

synthesis
- 7 dehydrocholesterol made in skin combines with d2 ergocalciferol from food and supplements
- forms d3 - cholecalfiferol
- cholecalciferol is hydroxylated at the 25 position in the liver and is hydroxylated at the 1 position in the kidney
- this forms 1,25 dihydrovitamin D3
- affected by quantity and quality of UV, latitude, amount of sun exposure and amount of skin exposed

function
- promote intestinal calcium absorption
- repair bone
- cell differentiation
- immunity
- promote cell maturation in small intestine
- insulin secretion
- blood pressure regulation

DRV
- 10 ug of VitD a day

food sources
- fatty fish, eggs, liver
- fortified foods like margarine

deficiency
- rickets in children - bowed legs, lack of mineralisation of bones leads to malformation
- hypoplasia of teeth due to lack of enamel calcification
- osteomalacia in adults - softening of bones, pain in pelvis, ribs, shoulder, waddling gate

toxicity
- most toxic of the vitamins
- 7 dehydrocholesterol is broken down by excessive UV, the toxicity therefore comes from excessive oral intake
- leads to hypercalcaemia, which leads to diarrhoea, thirst, anorexia, calcification of soft tissue and urinary stones

Question 11

describe the synthesis, source, toxicity, deficiency and function of vitamin: C

Answer 11

synthesis
- synthesised in plants from d glucose and d galactose
- cannot be synthesised in humans

function
- antioxidant
- regeneration of vitamin E
- collagen synthesis, component of gingival connective tissue
- synthesis of noradrenaline from dopamine
- sysnthesis of carnitine from lysine
- synthesis of bile acid

sources
- leafy veg and legumes lose 50% of vitamin C content after 24 hours from harvest
- labile so it oxidises very quickly
- 27% drinks, 19% fruit juice, 8% soft drinks, 15% potatoes and savoury snacks, 19% fruit

deficiency
- scurvy, connective tissue defects
- poor wound healing
- bleeding, tooth loss
- pain and weakness in legs and ankles
- poor bone and cartilage formation
- bleeding from capillaries

toxicity
- absorption threshold is 2-3g a day
- can cause diarrhoea, calcium oxalate stones in urinary tract, excessive absorption of iron

DRV
- based on amount to prevent scurvy
- 40mg a day
- smokers do 80mg a day
- pregnancy in last trimester increase by 10mg a day
- lactation increase by 30mg

Question 12

describe the forms, source, toxicity, deficiency and function of vitamin: B12

Answer 12

forms
- B12 or cobalamin
- active form consists of porphyrin ring with central cobalt atom

sources
- meat, fish, diary, canned meat, egg white, cheese

deficiency
- iron deficiency and anaemia
- megaloblastic anaemia
- glossitis, apthous stomatitis, atrophy of lingual papilla, burning and redness of the tongue, angular stomatitis, dysphagia, pallor of oral tissues

Question 13

describe the source, toxicity, deficiency and function of vitamin: folate

Answer 13

source
- leafy green vegetables, liver, yeast

function
- coenzyme for dna synthesis
- protein synthesis from serine and glycine
- formation of red blood cells
- closure of neural tube in pregnancy

toxicity
- none

deficiency
- closure of neural tube in pregnancy
- megaloblastic anaemia - abnormal multilobed neutrophil nuclei giant platelets
- orofacial clefts, oral and pharyngeal malignancies

Question 14

describe the source, toxicity, deficiency and function of vitamin: biotin

Answer 14

source
- widely available

deficiency
- rare

function
- lipogenesis, gluconeogenesis
- catabolism of branched chain amino acids

Question 15

describe the source, toxicity, deficiency and function of vitamin: B6

Answer 15

pyridoxine, pyridoxamine, pyridoxal

source
- all foods
- synthesised by colonic bacteria

function
- pyridoxal phosphate is a co factor in many enzymes for protein and amino acid metabolism
- protein synthesis

deficiency
- recurrent oral ulcerations
- halitosis
- gingivitis
- soreness
- discolouration
- cheilitis

toxicity
- sensory neuropathy
- 50-500mg a day
- reversible

Question 16

describe the source, toxicity, deficiency and function of vitamin: pantothenic acid

Answer 16

source
- mushroom, legume, egg, peanut, milk, offal, avocados

deficiency
- no natural

function
- part of CoA in krebs and fat synthesis
- all metabolism

Question 17

describe the source, toxicity, deficiency and function of vitamin: niacin

Answer 17

source
- liver, yeast, legumes, meat, peanuts, cereals
- synthesis of tryptophan

deficiency
- pellagra (dementia, dermatitis, diarrhoea)
- glossitis, stomatitis, rash, angular stomatitis, cheilosis

toxicity
- 3-6g a day
- liver failure and peptic ulcers

function
- needed for NAD, essential for metabolism both catabolic and synthetic

Question 18

describe the source, toxicity, deficiency and function of vitamin: riboflavin

Answer 18

source
- milk, cheese, liver, eggs, offal, leafy green veg

toxicity
- none

deficiency
- rare
- cheilosis lesions, angular stomatitis, fissures on tongue or magenta discolouration

function
- metabolism of fats, ketone bodies, carbohydrates and proteins

Question 19

describe the source, toxicity, deficiency and function of vitamin: thiamin

Answer 19

source
- cereals, meats, legumes, yeasts

toxicity
- more than 3g a day is toxic
- headache, irritability, insomnia, rapid pulse dermatitis, death

deficiency
- wernicke encephalopathy, beri beri, neurodegenerative and metabolic disorders

function
- co enzyme needed for production of ribose
- metabolism of carbs, proteins and fats
- neural transmission

Question 20

describe the function of all B vitamins

Answer 20

maximised function when all B vits work together

function
- release energy from carbs and fats (thiamin, niacin, riboflavins, biotin, pantothenic acid)
- catalyse the formation of RBC (B12, folic acid)
- protein and amino acid metabolism (B6)

Question 21

describe the location, function, deficiency and toxicity symptoms of vitamin: A

Answer 21

two forms
- preformed is found in liver, fatty fish, eggs, dairy
- provitamin A is found in leafy veg, alpha and beta carotenoids

function
- regulates gene expression, rbc production, cell differentiation, tooth and oral epithelial development

deficiency
- low intake can decrease oral epithelial tissue development, impair tooth formation, enamel hypoplasia and presence of periodontitis
- increases susceptibility to infection due to reduced production of mucopolysaccharides, and xerophalmia (increased keratinisation), decreased macrophages and lysozyme activity, antibody function is affected too
- impaired growth and development due to gene expression and cell differentiation impairment, impaired bone growth, infertility in males and low conception rates in females

toxicity
- acute is more than 200mg
- vomiting, headaches, vertigo, uncoordinated muscle movements
- chronic is more than 10mg a day for a month, leads tobone and muscle pain, alopecia

Question 22

describe the main functions of essential minerals

Answer 22

• constituents of bones and teeth (calcium, phosphorus and magnesium)
• formation of soluble salts which help control composition of bodily fluids (sodium, potassium and chlorine)
• essential components of many enzymes and other proteins, necessary for release and utilisation of energy (iron, zinc)

Question 23

describe the features of minerals

Answer 23

inorganic elements. 15-16 essential minerals that cannot be produced in the body

major minerals
- iron
- calcium
- zinc
- magnesium
- sodium
- chloride
- potassium
- phosphorus

Question 24

describe the factors affecting the use of vitamins

Answer 24

• availability
• antivitamins (avidin prevents absorption of biotin, released on cooking)
• provitamins - carotenes converted to vitamin A
• biosynthesis - vitamin K and D
• intestinal disease - coeliac affects B12 absorption
• interactions of nutrients - vit E increased when there is high polyunsaturated fat intake

Question 25

describe the features of vitamins

Answer 25

• essential to humans because we cannot make them (vitD and vitK excluded)
• to prove something is a vitamin, there has to be abnormal metabolic sign and disease when someone is deprived that is cured when there is restoration of the missing compound

fat soluble vitamins
- found with fat in food, absorbed in lymph, stored in liver and fatty tissues
- A
- D
- E
- K

water soluble vitamins
- absorbed directly into blood, high turnover, little storage, more sensitive to heat, harmful in high doses
- C
- B vitamins:
- niacin
- B6
- riboflavin
- pantothenic acid
- thiamin
- folate
- B12
- biotin

Question 26

describe the role of hormones during surgery

Answer 26

overall metabolic effect:
- increased catabolism which mobilises substrates to provide energy sources
- mechanism to retain salt and water and maintain fluid volume and cardiovascular homeostasis

hormonal changes
- ACTH increase
- GH increase
- aldosterone increase
- glucagon increase
- insulin decrease
- T3 decrease

Question 27

discuss control of nutrient metabolism during stress

Answer 27

during stress, the hypothalamic pituitary adrenal axis is activated to regulate many body processes, including energy storage and expenditure

cortisol
- regains glucose homeostasis
- increased blood glucose through gluconeogenesis
- glycogenolysis in liver and muscle tissue by facilitation of the activation of glycogen phosphorylase
- redistributes glucose to areas of the body that need it the most

adrenaline and noradrenaline
- increase fatty acids for ATP production
- trigger intracellular cascade to phosphorylate hormone sensitive lipase to break down TAG of adipose tissue and muscle tissue into glycerol and free fatty acids
- inhibit insulin secretion
- trigger glucagon secretion
- stimulate glycolysis and glycogenolysis

growth hormone
- promote lipolysis and fatty acid oxidation
- reduce liver uptake of glucose and maintain plasma glucose concentration
- promote gluconeogenesis in the liver

Question 28

discuss the energy metabolism adaptations to starvation and positive energy balance

Answer 28

human metabolic processes can adapt to a wide range of fuel supply by altering fuel selection

lack of energy provided by food will lead to negative energy imbalance and vice versa

starvation
- negative energy imbalance
- switch from carbohydrate to fat metabolism
- stores of liver and muscle glycogen are depleted
- increased gluconeogenesis from amino acids and glycerol
- ketogenesis takes over, metabolic needs met by ketone bodies and free fatty acids
- declined metabolism, bone mass, thyroid hormone deficiency, inability to concentrate, reduced physical performance

positive energy imbalance
- increase of fat storage in adipocytes
- plaque can build up in arteries
- hypertension
- total and LDL cholesterol and TAG increases
- insulin resistance develops which leads to development of T2DM

Question 29

discuss the role of hormones in protein synthesis and breakdown

Answer 29

insulin is anabolic and stimulates protein production
growth hormone stimulates protein synthesis and acts through insulin growth factor 1 and 2.
testesterone and adrenergic influences can also lead to protein synthesis

insulin
- increases amino acid uptake
- increases protein synthase enzymes and reduces activity of protein catabolic enzymes

Question 30

discuss the detrimental impact of insulin resistance on fat and carbohydrate metabolism

Answer 30

obesity leads to excess adipose tissue and there is lipid accumulation

Question 31

consider the central role of insulin in regulation of exogenous and endogenous fat metabolism

Answer 31

fat mobilisation is catalysed by enzyme hormone sensitive lipase and this enzyme is inactive when insulin levels are high due to dephosphorylation

stimulates re esterification by provision of glycerol-3-phosphate

increases activity of lipoprotein lipase activity in adipose tissue, which resides on the capillary endothelium of adipose and muscle tissue. this increased activity provides clearance of TAG from chylomicrons and low density lipoproteins

Question 32

consider the central role of insulin and glucagon in regulation of exogenous and endogenous carbohydrate metabolism

Answer 32

insulin
- stimulates glucose uptake by cells
- stimulates glycolyses
- stimulates glycogen synthesis
- inhibits glycogen catabolism

glucagon
- released by alpha cells
- increases glycogen breakdown in the liver
- increases gluconeogenesis in the liver
- increases ketone body synthesis

Question 33

discuss hormonal responses during absorptive and postabsorptive states and their role in regulation of carbohydrates, fat and protein metabolism

Answer 33

hormonal in absorptive state
- increased blood glucose
- increase blood triglycerides
- decreased blood FFA
- decreased betahydroxybutyrate
- increased insulin
- decreased glucagon

hormonal in postabsorptive state
- decreased blood glucose
- decreased blood triglycerides
- increased blood FFA
- increased betahydroxybutyrate
- decreased insulin
- increased glucagon

regulation
- insulin regulates all events in absorptive state
- insulin controls glucose uptake by muscle, suppresses FFA release, FFA release from chylomicrons, liver and muscle glycogen synthesis, protein synthesis

Question 34

discuss the role of endogenous energy substrates in energy metabolism during postabsorptive state

Answer 34

endogenous energy substrates include liver glycogen, adipose tissue, and muscle TAG

the postabsorptive state
- gi tract is empty, energy comes from breakdown of body reserves
- glycogen, tg, and protein synthesis is stopped or very slow
- increased glucose release from liver, lipolysis of TG in adipose tissue is increased

role of lipolysis
- ffa are oxidised to cover the energy demands of muscles
- ffs are used for synthesis of ketone bodies
- glycerol is a substrate for gluconeogenesis

liver glycogen
- first available store of glucose
- blood sugar levels maintained for four hours
- gluconeogenesis is activated in the ilver and glucose is synthesised from lactate, pyruvate, glycerol and amino acids

Question 35

describe the role of sugar transporters in nutrient absorption

Answer 35

glut
- passive transporters
- 12

sglt
- sodium glucose transport family
- active transport
- move glucose from low to high concentration

regulated by dietary carbohydrate availability

Question 36

describe lactose intolerance

Answer 36

loss of lactase enzyme when weaning, meaning lactose is not hydrolysed in digestion. it is metabolised to short chain fatty acids.

diagnosed by hydrogen in the breath due to lactose malabsorption.

Question 37

discuss primary and secondary risk factors for nutritional deficiences, including impaired nutrient digestion, absorption and transport

Answer 37

primary deficiency
- inadequate selection of food
- age, income and education

secondary deficiency
- systemic disorders that can affect digestion, absorption, transport and use of nutrients
- crohsn, CF, bariatric surgery, renal and hepatic disease

Question 38

discuss why nutrition knowledge is important to dentists

Answer 38

nutrition has a key role to play in dental health

can affect dental caries, periodontal disease, gingivitis.

issues within the body due to nutrition and present in the mouth by looking at corners of the mouth, tongue, palate, and teeth

nutrients required for dental health
- calcium
- phosphorus
- vitamin A, C, D
- fluoride

nutrients that are bad for dental health
- carbohydrate
- sweet foods
- sugars
- fruit and carbonated drinks

vitamin D deficiency and oral health
- needed for mineral density
- helps absorb, carry and deposit calcium in the bones supporting teeth
- associated with caries and periodontitis

role of nutrition in oromaxillofacial
- oral disease surgery and injury can affect food and fluid intake which compromises nutritional status

Question 39

discuss dietary reference values for protein, carbohydrate and fat in the UK diet

Answer 39

carbohydrates
- 4kcal per gram
- 47% of total energy intake, 50% of total food intake

fat
- 9kcal per gram
- 33% of total energy intake, 35% of total food intake

protein
- 4 kcal per gram
- 15% of total energy intake, 15% of total food intake

alcohol
- 7 kcal per gram
- included in carbohydrate DRV

Question 40

discuss health implications of free sugar overconsumption

Answer 40

all that is added or found in honey and fruit jucice

adults
- obesity
- caries
- poor diet diversity
- incresed risk of T2DM and CVD

children
- less than 5% is ideal
- sugar should be part of a main meal

Question 41

describe what happens to non starch polysaccharides

Answer 41

they absorb water in the gi tract and provide fuel to bacterial metabolism

they are fermented in the colon to produce short chain fatty acids that are metablised in various parts of the body

SCFA include
- acetic acid - 2c
- propionic acid - 3c
- butyric acid - 4c

Question 42

discuss the fate of macronutrient digestion products in absorptive state

Answer 42

• absorptive state is the time during and right after a meal
• lasts for four to six hours
• end products of nutrient digestion undergo anabolic processes leading to nutrient storage in the form of TAG and glycogen
• most amino acids are used for protein synthesis

fate of glucose
- adipose tissue
- liver contains 400kcal - 100g glycogen
- muscle contains 1600kcal of glycogen - 400g glycogen
- upper limit of glycogen is 1050g

fate of triglycerides
- released from chylomicrons by lipoprotein lipase and ATP synthesis using exogenous and endogenous fat

fate of amino acids
- liver - ATP and protein synthesis
- muscle and all other cells - amino acids form proteins

Question 43

explain the role of the pancreas and liver in digestion

Answer 43

pancreatic amylase and pancreatic proteases are important for the digestion of carbs and proteins.

liver metabolises and detoxifies molecules absorbed from digestion.
liver produces bile acids which are required for fat digestion as it is an emulsifying agent.

Question 44

describe the digestion of carbohydrate, fat and protein and the roles of different enzymes in the digestion of starch, sugars, proteins and fats

Answer 44

digestion is through hydrolysis - major macronutrients are digested in this way. requires alpha amylase.

starch polysaccharides are broken down by salivary and pancreatic amylase to become di and tri saccharides which are broken down by maltase, lactase, sucrase and isomaltase produced from the intestinal surface villi. these become monosaccharides like glucose, galactose and fructose.

• mono and disaccharides are absorbed in small intestine as monosaccharides
• oligosacchardies are digested in large bowel and are absorbed as short chain fatty acids
• polysaccharides if starch are absorbed as glucose, as non starch they are absorbed as short chain fatty acids
• maltase breaks down maltose to two glucose molecules
• sucrase breaks down sucrose into glucose and fructose
• lactase breaks down lactose into glucose and galactose
• starch becomes maltose in the oral cavity which then becomes two glucose molecules

digestion of fats
- emulsification by bile acids forms micelles
- pancreatic lipase hydrolyses TAG and forms 2-monoglycerol
- fats need emulsification to be digested as enzymes are aqueous and fats are hydrophobic
- fatty acids are absorbed at the brush border by diffusion.
- if they are more than 12 carbons long the fatty acids become chylomicrons and enter the lymphatics before entering the blood
- chylomicrobs have TAG and cholesterol esters in their core, and their surface is made up of phospholipids, apoproteins, and unesterified cholesterol

digestion of proteins
- HCl and pepsin in the stomach to break down 20% of proteins into amino acids
- hydrolysed in the lumen of the small intestine into oligopeptides
- relies on pancreatic proteases like trypsin, chymotrypsin and carboxypeptidases
- peptidases and oligopeptidases are intestinal surface enzymes that then break down the peptides into amino acids
- amino acids are absorbed via sodium cotransporters
- peptides longer than 4 amino acids long are not absorbed and must be broken down

Question 45

discuss macronutrients, their classification and functions

Answer 45

carbohydrates
- monosaccharides
- disaccharides
- polysaccharides
- sugars
- dietary fibres are non starch polysaccharides that absorb water in the GI tract, increasing transit time and causing faecal bulking, are fuel for bacteria metabolism
- inulin and oligofructose are prebiotics as they stimulate growth and activity of health stimulating intestinal bacteria. found in chicory roots, jerusalem artichokes and garlic.
- dietary carbs fate: glucose uptake by muscle, liver and muscle glycogen synthesis, disposal of glucose in muscle

proteins
- long chains of amino acids bound by peptide linkages
- must be digested into amino acids or di/tripeptides
- HCl denatures proteins, activates zymogen pepsinogen so it can become pepsin and break down 20% of the proteins.

fats and oils
- fats are solid at room temp oils are liquid
- fats are dietary triglycerides, major form is water insoluble lipids
- main dietary lipids: triglycerides are glycerol+3FA
phospholipids are phosphorus+2FA
sterols are derived from fatty acids, include cholesterol

macronutrient functions
- provide energy in sufficient quantities
- provide range of building blocks
- provide essential nutrients we cannot make ourselves