Nutrition Flashcards
Where are vitamins supplied from?
Diet, some can be synthesised (D - sun. B&K -gut bacteria)
What type of compounds are vitamins?
Organic
What type of functions do they have?
Co-enzymes, hormones, cell signalling, antioxidants, regulators of growth & differentiation
What can affect absorption of vitamins?
Properties of the food e.g. low in fat
pre-existing disease e.g. ceiliac - impaired fat absorption and gastritis (low acid- b12)
Drugs may compete for absorption and kill bacteria
What is RDA?
recommended daily allowance - an intake that is adequate to ensure the requirements of all health people are met
Which vitamins are fat soluble and which are water soluble?
Fat soluble: Vitamin A Vitamin D Vitamin E Vitamin K
Water soluble:
B vitamins
Vitamin C
What type of vitamins can be stored?
Fat soluble stored. water soluble not stored
What is the active form of vitamin A?
Retinoids
What pigments give retinoids?
Carotenoid pigments (e.g. B carotene)
What is the function of vitamin A?
binds to proteins (opsin) in the cells of the retina to form visual pigments
Nuclear modulator of gene expression:
Cell proliferation
Differentiation
(especially epithelia)
Development
What are the symptoms of a vitamin A deficiency?
Major cause of blindness in children under 5 in developing countries
impaired resistance to infection - differentiation and function of lymphocytes and neutrophils affected
mild deficiency = night blindness
severe deficiency = metaplasia and keratinisation of the conjuctiva epithelial cells and thickening of the cornea (xerophthalmia)
What process produces vitamin D endogenously?
(D3 -photolysis of 7-dehydrocholesterol)
What are the functions of vitamin D?
Maintenance of plasma Calcium concentration (along with parathyroid hormone and calcitonin)
Steroid hormone activating nuclear receptors and influencing > 50 genes
What is cholecalciferol?
Vitamin D3 which is made by the skin when exposed to sunlight
What is egocalciferol?
also known as vitamin D2 and calciferol, is a type of fat soluble vitamin D found in food and used as a dietary supplement
What is the role of vitamin D in bone metabolism?
- Vit D stimulates intestinal Calcium and phosphate absorption and renal Ca reabsorption - mineralisation of bone is controlled by the availabiliy of Ca and PO4
Osteoblasts have receptors for calcitriol (active metabolite of vitamin D)
Osteoclast activity/number (paradoxically) increased
= Promotes formation and mineralisation of bone
What condition is caused by Vit D deficiency?
Rickets and osteomalacia (the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D)
What is vitamin E?
Lipid soluble antioxidant - very active free radical trapping
What does vitamin E do?
Free radical trapping
Cell signalling (inactivates protein kinase C)
deficiency not normally a problem
What does vitamin K do?
Co-enzyme in postranslational carboxylation of glutamate to γ carboxy glutamate (gla)
Permits binding of proteins to membrane phospholipids
Klotting: vitamin K dependent proteins involved in blood coagulation (thrombin factors VII, IX and X, protein C, S, Z)
What are vitamin K antagonists?
Anticoagulants e.g. warfarin
What can vitamin K deficiency lead to?
Haemorrhagic disease
Name some of the B vitamins
Thiamin (B1), ribofavin (B2), Niacin (B3), B6, Folic acid (B9), B12, pantothenic acid (B5)
What are all B vitamins?
Co-enzymes (co-factors)
What does Thiamin (b1) do?
Co-enzyme in central energy yielding pathways (pyruvate & keto-glutarate dehydrogenase)
Co-enzyme in pentose phosphate pathway (transketolase: NADPH for biosynthesis & ribose for nucleotides)
Co-enzyme in catabolism of leu, isoleu & val
Regulates nerve chloride channels
What does defiency of Thiamin lead to?
Berberi-peripheral neuritis: weakness, stiffness
What does Riboflavin (b2) do?
Electron carriers in a variety of oxidation & reduction reactions central to metabolism (mitochondrial electron transport chain)
B2 remain bound to enzyme
FAD (flavin adenine dinuceotide), FMN (flavin mononucleotide) oxidising coenzymes which accept two H atoms
Deficiency common but rarely a problem - bacterial synthesis, conservation and re-utilisation
What does Niacin (B3) do?
Precursor of co-enzymes NAD (nicotinamide adenine dinucleotide) & NADP (phosphate)
Electron carriers in metabolic redox reactions
Where is B3 synthesised from?
Dietary tryptophan
What deficiency is Niacin B3?
Pellegra - demention, diarrhea and dermatitis
What does vitamin B6 do?
Amino acid metabolism (transamination)
deficiency virtually unkown
What does vitamin B12 and folate (b9) do?
Co enzymes
DNA and myelin synthesis
What does deficiency of vitamin B12 and folate b9 lead to?
Anaemia and neurological damage
What role does vitamin C play?
Specific role in two enzyme classes:
Dopamine β-hydroxylase: synthesis of adrenaline and noradrenaline (Cu + dependent)
Lysine and proline hydrolyases: maturation of connective tissue (collagen)
Iron uptake: keeps iron as Fe2+, chelates it which increases absorbtion
Why may dentists be the first to spot a vitamin deficiency?
Rapid turnover of epithelium makes it sensitive to nutritional deficiencies
Vitamins involved with: wound healing, bleeding, resistance to infection, bone/tooth Ca2+
What facial manefestations of vitamin deficiencies are there?
Malar pigmentation (niacin, B vitamins), nasiolabiial seborrhea (niacin, riboflavin, b6 iron), lack of colour (malnutrition)
Lips - angular fissues (niacin, b6, riboflavin, iron), cheilosis (niacin, b6, riboflavin)
Gingiva - Spongy, bleeding, abnormal redness - vitamin C
Tongue - glossitis (folate, niacin, iron, b6, b12)
pale, atrophic, smooth/slick filiform papillary atrophy (iron, folate)
Magenta colour - riboflavin
What are triacylglycerols used for?
Fuel
What are glycerophospholipids used for?
Membranes
What is cholesterol used for?
Membranes
Bile salts: lipid digestions
steroid hormones: communication
What are triacylglycerols composed of?
3 fatty acids and glycerol joined by ester bonds
fatty acids have variable length and can be saturated or unsaturated (c=c)
efficient form to store energy
What are the sources of lipids?
Diet
make fat from carbohydrates (in liver)
Which type of lipid is a main dietary lipid?
Triacylglycerols
What do bile salts do?
Emulsify lipids into smaller droplets
What do lipases do?
Break down fatty acids from triacylglycerols and then form micelles, absorbed by epithelial cells
These are packaged as chylomicrons in the cells by the RER and golgi complex
What is the fate of chylomicrons?
Packaged back into triacylglycerols
The triacylglycerols in them get digested by lipoprotein lipase (LPL)
The fatty acids are absorbed by cells and the other remnants are absorbed by liver
LPL is produced by adipose, muscle and lactating mammary gland cells which is regulated by insulin
Why are chylomicrons packaged with an outer layer of phospholipids?
Hydrophobic so keeps the water out
What is an apoprotein?
a protein which together with a prosthetic group forms a particular biochemical molecule such as a hormone or enzyme.
What can LPL recognise?
The apoproteins so grab the circulating chylomicrons
What is predominantly the remnants of chylomicrons?
cholesterol and glycerol
Where are fatty acids synthesised mainly?
Liver - reactions in the cytoplasm
What can endodogenous lipids be packaged with to form VLDL (very low density lipoprotein)?
Proteins
What is the fate of VLDL?
The triacylglycerols in it are digested by LPL regulated by insulin
fatty acids absorbed by the cells
vldl remnant remains - mainly cholesterol
same fate as chylomicrons (dietary fat)
What becomes the main energy source during fasting?
fatty acids
Where are long chain fatty acids released from and what is it stimulated by?
Long chain fatty acids released from adipose tissue, stimulated by reduced insulin and increased glucagon
What is the main fatty acid oxidation pathway?
B-oxidation
How do fatty acids enter tissues?
Diffusion
What are the fatty acids activated to using ATP?
fatty acyl coA (INTERMEDIATE)
Where is the fatty acyl coA transported to?
Mitochondrial matrix
What is the fatty acyl coA converted to in mitochondria
Acetyl coA producing NADH AND FAD2H
What does the acetyle coA enter then?
TCA cycle
Why do fatty acids produce a lot of energy?
2 carbons used each time the process happens and chains have many carbons so lot of energy produced continously
What can fatty acyl coA’s be used to produce?
Convert bacj to triacyglycerols for storage
energy - b oxidation ketogenesis
membrane lipids - phospholipids, sphingolipids
Fed state
Packaged chylomicrons produced
lots of glucose coming in - VLDL produced
insulin increased
fatty acids taken to tissues intrinsically and extrinsically
Fasting state
Release of fatty acids
put through b oxidation to produce energy and ketone bodies - more energy
generate glucose in the liver
Where does cholesterol come from?
synthesised or from diet
Why is cholesterol important?
Component of cell membranes
precursor of bile salts
precursor of steroid hormones
precursor of vitamin D
What is cholesterol a major component of?
Blood lipoproteins
How is cholesterol taken up
Mainly by diffusion in gut enterocytes- not good for you
Why does cholesterol entry have to be regulated?
cannot be fully metabolised
but excess can be transported back into gut to be excreted
Where is cholesterol synthesised?
cytosol in liver
What molecule is mainly used to start cholesterol synthesis?
Acetyl coA
Which enzyme is a good drug target for cholesterol reduction?
HMG- coA reductase
statin - lowers cholesterol in blood, comeptitively inhibits the enzyme so this can be designed to look like its substrate - higher affinity for the enzyme
What are the 4 steps for cholesterol synthesis?
Acetyl coA - mevalonate
mevalonate - isoprenes
isoprenes (5c) - squalene (30c)
squalene - cholesterol
What happens to leftover cholesterol?
Converted to bile salts - stored in gallblader, secreted into gut
converted to biliary cholesterol into gut and can be reabsorbed
can be converted to cholesterol esters and packaged into VLDL to go to tissues
Why are bile salts effective as detergents?
Because they carry charge - electrons around them
What affects the recycling of cholesterol to the liver?
interact with bacteria that chemically alter them which deconjugate and dehydroxylate slightly so less able to reabsorb the cholesterol
What are cholesterolr and cholesterol esters transported in?
Lipoproteins (cholesterol helps stabilise them)
how does cholesterol enter the cell?
VLDL remnant left behind
these are converted to IDL (intermediate) and LDL (low)
LDL contain a lot of cholesterol and cholesterol esters
this can be returned to liver to make more VLDL or taken up by other cells needing cholesterol
- e.g. membrane synthesis - e.g steroid hormone synthesis
How are LDL endocytosed?
Recognised by the apoproteins on their surface by the LDL receptors
What happens to excess LDL?
Endocytosed by macrophages (scavenger receptors - recognise some apoproteins)
the ldl causes some of the macrophages to change into foamy cells - cause bumps in the vessels, blood rushes by and causes small thrombus to form, blood clot gets bigger etc which can cause inflammation and contribute to atherosclerosis
Why is maintenance of blood glucose levels essential?
Blood glucose too high = causes release of water from tissues - dehydration and death
Blood glucose too low - lack of fuel to produce ATP
brain depends on glucose as fuel - coma
red blood cells low on ATP, can’t provide oxygen to tissues - death
What happens to insulin and glucagon levels when glucose increases after eating a meal?
Insulin increases and glucagon decreases
Insulin allows uptake of glucose
What does glucagon do?
Increase in glucagon causes release of glucose
decrease in glucagon causes uptake and storage of glucose
Where do the three main sources of glucose come from?
Diet
Glycogen degradation
gluconeogenesis
Which sources of glucose are critical during fasting?
Glycogen degradation
Gluconeogenesis
What is glycogen?
Major storage form of glucose in humans in liver and muscle
What is the structure of glycogen?
Branched chains of glucose joined by alpha 1-4 linkages with branching by alpha 1-6 linkages
one carbon is joined to protein - glycogenin (reducing end)
forms huge polymers
What are the differences in processes in muscle and liver of glycogen?
Muscle - glycogen undergoes glycolysis mainly so that ATP is produced for energy
Liver - glycogen undergoes gluconeogenesis mainly to produce glucose which is released into the blood to raise blood glucose
What does glycogen synthesis require?
Energy in the form of UTP (uridine triphosphate)
What are the steps of glycogen synthesis?
- Glucose is transerred from UDP glucose to glycogenin (enzyme that polymerises first few molecules)
- Glycogen synthase transfers glucose from UDP glucose to growing chain
- This forms a 1-4 linkages
- When 11 residues are reached, 6-8 cleaved off and rejoined by alpha 1-6 linkages by branching enzyme.
Which two enzymes is glycogen degradation carried out by? and what do they do?
Glycogen phosphorylase - removes glucose molecules at end of chains
Debranching enzyme - acts as transferase, removing glucose molecules near branch point
- also cleaves branch point
What hormones regulate glycogen degradation in the liver and what are their effects?
- insulin decreases degradation
- glucagon increases degradation
- adrenaline increases degradation
What stimulates glycogen degradation in the muscles?
Low ATP (high AMP)
Calcium and adrenaline
What process happens when glycogen stores are exhausted?
Gluconeogenesis
How long after a meal does it take for glycogen to start degrading?
3 hours
How long after a meal does it take for gluconeogenesis to start?
30 hours
What is gluconeogenesis?
Process that produces glucose from non-carbohydrate sources
only occurs in liver except in extreme starvation
Why is gluconeogenesis important?
Maintains availability of glucose during fasting/starvation or intense exercise
What are the 4 main enzymes in gluconeogenesis?
Glucose 6 phosphate
fructose 1,6 bisphosphate
phosphoenolpyruvate carboxykinase
pyruvate carboxylase
What are the non-carbohydrate sources of glucose?
Amino acids - mainly alanine but others
Lactate - produce during intense exercise
Glycerol - derived from triacylglycerols
Propionate - from fermentation of fibre
What can lactate, alanine and amino acids be fed in to produce? (gluconeogenesis)
Pyruvate
Amino acids - also in TCA cycle
What can glycerol be used to produce in gluconeogenesis?
Glycerol 3 phosphate
What are the two main regulatory factors in gluconeogenesis?
- Substrate availability (more substrate more gluconeogenesis)
- Activity of key enzymes
How does subtrate availability affect gluconeogenesis?
- when blood glucose low, low insulin stimulates release of:
glycerol from adipose tissue
amino acids from muscle- intense exercise releases lactate from muscle
These increase the non carbohydrate sources for gluconeogenesis
How does enzyme activity affect gluconeogenesis?
Three key regulatory steps:
Pyruvate —-> phosphoenolpyruvate
Fructose 1,6-bisphosphate —->Fructose 6-phosphate
Glucose 6-phosphate —->Glucose
Can be allosteric or at level of gene expression
What is the energy provided by for gluconeogenesis?
Fatty acid oxidation
What are the uses of blood glucose?
muscle storage for later use - glycogen
energy source for muscle and other tissues
storage as fat (triglycerides)
excretion in urine with high blood sugar - diabetes
energy for CNS and brain
liver storage for later use - glycogen
What happens when there is high blood sugar?
Beta cells in the islets of langerhans (pancrease) secrete insulin which stimulates muscles and fat cells to take up glucose from the blood for storage - normal blood glucose achieved
What happens when there is low blood sugar?
The alpha cells in the islets of langerhans in the pancreas secrete glucagon which stimulates the liver to break down glycogen and release glucose into the blood - normal blood glucose achieved
What are is the blood glucose level in normal fasting conditions?
3-5 mmol/l
What are the blood glucose levels in diabetic fasting conditions?
4-7 mmol/l
What are the normal blood glucose levels after a meal?
less than 10 mmol/l 90 min post food
What are the normal blood glucose levels in a diabetic after a meal?
greater than 20 mmol/l
What is Diabetes Mellitus?
Metabolic disorder of carbohydrate metabolism
characteristic - hyperglycemia (increase in blood glucose over prolonged period of time)
What are some of the complications/ co-morbidities of diabetes?
Stroke
Heart disease
hypertension
peripheral vascular disease
Retinopathy
nephropathy - renal damage
peripheral neuropathy - nerve damage
food problems
periodontal disease
What are the symptoms of diabetes?
Blurry vision increased thirst and need to urinate Feeling tired or ill Recurring skin, gum, bladder infections Dry, itchy skin Unexpected weight loss Slow healing cuts & bruises Loss of feeling or tingling feeling in the feet
What are the types of diabetes?
Type I (insulin dependent)
Type II
Gestational diabetes
Impaired glucose tolerance (IGT) and impaired fasting glycaemia (IFG)
What is type 1 diabetes?
Chronic (generally) childhood disease
Affects 18-20 per 100 000 children in UK
Sometimes associated with thyroid disease
Genetic susceptibility shown
Linked to viral infection (e.g. congenital rubella syndrome)
Affects islets of Langerhans
Beta cells are killed by antibodies
Therefore, lack of insulin production
What is type 2 diabetes?
Non-insulin dependent or adult-onset diabetes
can have genetic predisposition - primary beta cells defect - damaged/inadequate insulin
or environmental cause - obesity - peripheral insulin resistance - inadequate glucose uptake
genetics can cause peripheral insulin resistance
hyperglycaemia and free fatty acids leading to type 2 diabetes
What is insulin resistance?
when cells in your muscles, body fat and liver start resisting or ignoring the signal that the hormone insulin is trying to send out—which is to grab glucose out of the bloodstream and put it into our cells
What happens in the liver, muscle and fatty tissue in insulin resistance?
Liver - becomes slow to replenish glycogen as glucose not taken up by cells,so blood glucose increases
muscle - glycogen storage decreases and glucose not taken up by cells so blood glucose decreases
fatty tissue - fat is broken down instead and used as an energy store as cells not taking up glucose
What are the main syptoms of type 2 diabetes? (3 p’s)
Polyuria (frequent urination due to osmotic diuresis)
Polydisia (Increased thirst & increased fluid intake due to polyuria)
Polyphagia (Increased appetite)
Other symptoms:
Dry mouth, itchiniess, increased incidence of thrush, cramps, skin infections
When does gestational diabetes come on?
Onset in late 2nd trimester (20-28 weeks)
2-5 % of all pregnancies
What are the predisposing factors to gestational diabeetes?
age (>35 although can occur in younger mums)
6X more common in South Asian decent
3X more common in African-Caribbean people
obesity
What are the symptoms of gestational diabetes?
No obvious external symptoms
On occasions, classic diabetes symptoms are observed
excessive thirst
frequent urination
increased appetite
Why does gestational diabetes occur?
Hormonal changes cells less responsive to insulin
Increase resistance to insulin
What is the long term effect of gestational diabetes?
Larger babies
Mum at risk of Type 2 diabetes
How are diabetes and pre-diabetes diagnosed?
Fasting plasma glucose (FPG)
Measures blood glucose when the person has not eaten for at least 8h (detect diabetes & pre-diabetes)
Oral glucose tolerance test (OGTT)
Measures glucose after an individual has fasted for at least 8h and 2h after consuming a glucose containing drink (detect diabetes & pre-diabetes)
Random plasma glucose test
Casual plasma glucose test; i.e. measures glucose irrespective of whether the person has eaten or not (diagnose diabetic only)
What is the glycated haemoglobin test?
It measures the amount of glucose attaching to haemoglobin in the blood (irreversible)
Hb1Ac gives an indication of average glucose level for 8-12 weeks
Normal: 3.5-5.5%
Diabetes: ~6.5%
What is the fructosamine test?
Formed from serum proteins such as albumin
(reaction between fructose & amine). When glucose levels in the blood are elevated over a period of time, glucose molecules permanently combine with proteins in the blood in a process called glycation
Used in cases of
blood loss
haemolytic anaemia
sickle cell anaemia
Gives an average results for the last 2-3 weeks
Tends to be basis of over-the-counter tests
A high fructosamine level means that the average blood glucose over the previous 2 to 3 weeks has been elevated. In general, the higher the fructosamine level, the higher the average blood glucose level.
What other factors can cause hyperglycaemia?
Steroids
Antipsychotics
Diuretics
Antihypertensive
What other factors can cause hypoglycaemia?
Alcohol
Hormone deficiencies
Prolonged starvation
What is the management of type 1 diabetes?
Insulin (Essential)
Exercise
Diet (low in fat, cholesterol & simple sugar)
What is the management of type 2 diabetes?
Weight reduction Diet Exercise If above not successful then, Oral hypoglycaemic medications & then insulin
What do oral hypoglycaemic agents do?
Biguanides (Metformin)- Type 2 diabetes & Type 1 with insulin therapy
Inhibits glucose production by the liver (gluconeogenesis)
Useful in patients who are obese
Sulphonylureas ( Tolbutamide, gliclazide, glimepiride)
increase amount of insulin made in pancreas (requires functional islets of Langerhans)
Long lasting effect
Problem: hypoglycaemia in elderly patients or those with kidney problems
Unwanted effects: Appetite stimulants (weight gain) Hypoglycaemia GI upsets (3% of patients) Potentially teratogenic (do not use in pregnancy or planning one)
What are the unwanted effects of oral hypoglycaemic agents?
GI disturbance Lactic acidosis (contraindicated for those with renal, severe pulmonary or cardiac conditions)
What drugs augment the effects of sulfonylureas?
NSAIDs
Alcohol
Antibacterial (Sulphonamides, trimethoprim, chloramphenicol)
Antifungal (Miconazole, fluconazole)
What drugs decrease the effects of sulfonylureas?
Diuretics
Corticosteroids
What dental problems are linked to diabetes?
red swollen gums bleeding on brushing more plaque tooth decay periodontitis ulcers decreased saliva bacteria can enter blood stream - endocarditis longer healing time
What is nutrition?
sum of processes for living organism to
receive and use materials from environment to
promote its own vital activities
What are nutrients?
• substances digested, absorbed, promote
body function
What is an essential nutrient?
substance necessary for life,
cannot be synthesised by body, must be in diet
What is a diet?
foods selected
What is malnutrition?
incorrect amount of one or more nutrients in diet (not just lack)
What is anabolism?
Simple molecules —> complex, requires energy
results in growth
What is catabolism?
Complex molecules —> simple, releases energy
occurs during starvation+illness, energy intake↓
What are the basic roles of carbohydrates, fats, proteins, vitamins and minerals and water?
• Carbohydrate heat and energy • Fats heat and energy incorporated into body tissue • Protein tissue formation and repair broken down to produce energy • Vitamins and Minerals for regulation of body processes incorporated into tissue (minerals) • Water fluid medium essential for metabolism temperature regulation waste product excretion
What is a calorie?
(kCal), unit of heat
What is a joule?
unit of heat/muscular/electrical energy
• measured by oxidation of food
What are the advantages of non-starch polysaccharides?
bulky and take longer to eat
• prolonged feeling of fullness as stay in stomach longer
• prevent constipation, colonic cancer
What is the link of NSP’s to colon cancer?
NSP’s bind and dilute by increase faecal bulk, so deceasing transit time which decreases exposure to the body
What are the disadvantages of non-starch polysaccharides?
• bind to minerals (Ca, Fe) —> deficiencies
• wind from metabolism of NSP in caecum and colon:
methane, CO2
, H2
depending on type of NSP and bacterial flora
• insufficient energy intake:
bulky
take longer to eat
What enzymes are carbohydrates first broken down by?
Salivary amylase –> monosaccharides
What is the glycaemic index?
• rate at which carbohydrate reaches bloodstream as glucose
What happens with a decrease in carbohydrate intake to protein and fat metabolism?
More fat metabolised - ketoacidosis
more protein broken down - depletion of muscle
Give some examples of monounsaturated fats
Olives, nuts avocado
Give some examples of polyunsaturated fats
- omega 3 oily fish, soya bean
* omega 6 sunflower seeds, wheat germ, corn
What are essential fatty acids used for?
- for structure and function of cell membranes
- to regulate cholesterol metabolism
- vegetable and marine oils
Where are fats digested?
Stomach and small intestine
What are the functions of fat?
• energy for tissue activity and body temperature maintenance
• incorporated into body structure
e.g. brain + nervous tissue
• hold position and protection of vital organs
• insulation (subcutaneous heat loss)
• satiety – presence in duodenum delays stomach emptying
• provide fat-soluble vitamins and assist absorption
Which nutrient is the mainconstituent of every living cell?
Protein
What process can turn proteins/peptides into amino acids?
Transamination in the liver
What are the functions of proteins?
• replacement during metabolism and wear and tear
e.g. hair, nails, skin, digestive secretions, bone, dentine, epithelium, antibodies
• new tissue production
e.g. growth, recovery from injury, pregnancy, lactation
• forming enzymes, hormones
• energy source
What is the fat of proteins?
structural proteins, converted into other aas, oxidised for energy
Which vitamins can be made by intestinal bacteria?
• vitamin K and some of B group vitamins
How much of the body is minerals?
3%
What is the function of minerals?
Essential constituents of soft tissues, fluids, skeleton, teeth
• Incorporated into enzymes, proteins and soluble salts
How much of the body is water?
65-70%
What is the function of water?
- fluid medium for almost all body processes
- intra- and extra-cellular fluids
- body secretions, excretions
- sufficient urine flow, prevention of constipation
- joint lubrication
- temperature control (lung and skin evaporation)
How is water lost from the body?
lost: urine, faeces, sweat (lose salt), exhaling,
vomiting, diarrhoea, haemorrhage,
exudate from burns
What is water intake balanced by?
thirst, kidney regulation
What happens if there’s too much water?
kidneys can`t keep up excretion
blood diluted, lower salt concentrations
water moves from blood to cells and organs
brain swells and prevents vital functions
What is energy required for in the body?
growth and maintenance of body tissues
• maintenance of body temperature
• voluntary and involuntary muscle movement
What are the calories and energy given from 1g of carbohydrate, protein, fat and alcohol?
• 1g carbo 16kJ (4kCal), most efficient source
• 1g fat 37kJ (9kCal)
• 1g protein 17kJ (4kCal), takes time to turn into energy, needs
energy
• 1g alcohol 29kJ (7kCal)
What is your basal metabolism?
amount of energy required for basic life
processes e.g. heartbeat, respiration, cellular activity
What is a healthy balanced diet?
• Lots of fruit and vegetables (40%)
• Starchy staple foods (wholemeal bread, wholegrain cereals; 40%,
incl B vits and fibre)
• Protein rich foods (lean meat, fish, eggs, lentils)
• Some dairy foods (pref. lower fat variety)
What are the food standards agency guidelines for a healthy diet?
Base meals on starchy foods
• 5 (7) portions of different fruit and vegetables per day
• 2 portions of fish per week (incl. 1 portion oily fish)
• Cut down on saturated fat and sugar
• Eat less salt (no more than 6g day)
• Get active and try to be a healthy weight
• Drink plenty of water
• Limit alcohol intake
What are the key findings from the WCRF report?
Things that decrease risk of cancer: Physical activity (colorectum, breast, endometrium) • Wholegrain, foods containing dietary fibre (colorectum) • Non-starchy vegetables (mouth, pharynx, larynx) • Fruit (as above, lung)
Things that increase risk of cancer: Body fatness (11 cancers) • Adult weight gain (breast) • Processed foods high in fat, starches, sugars (through weight gain and obesity) • Red meat (colorectum) • Processed meat (stomach, colorectum) • Alcoholic drinks (7 cancers)
What are the key lifestyle recommendations for the prevention of cancer?
Be a healthy weight and avoid weight gain in adult life - greater fatness causes many cancers and overweight in childhood often leads into adulthood
Be physically active - protects against weight gain/obesity and several cancers
Limit consumption of ‘fast foods’ and
other processed foods high in fat,
starches or sugars - cause of weight gain, Glycaemic load is a cause of endometrial cancer
Limit consumption of sugar-sweetened
drinks - weight fain/obesity
Eat a diet rich in wholegrains, vegetables,
fruits and beans/pulses/legumes - whole grains protect against colorectal cancer, non starchy veg and fruit protect against aerodigestive cancers, decreases likelihood of obesity
Limit consumption of red and
processed meat - causes colorectal cancer, processed meat can cause stomach cancer
Limit alcohol - causes many cancer
Do not use supplements for cancer prevention - High-dose beta-carotene supplements are a cause of lung cancer in current and former smokers.
For mothers; breastfeed your baby, if you can -Breastfeeding protects the mother against breast cancer
Having been breastfed helps protects children against excessive
weight gain, overweight and obesity
How can policy be used to improve adherence to lifestyle recommendations?
Nourishing framework:
NOURIS:
- nutrition label standards
- offer healthy foods
- use economic tools to address food affordability
- restrict food advertising and other promotions
- Improve nutritional quality of whole food supply
- set incentives and rules to create a healthy retail and food service environment
H - harness food supply chain and actions across sectors to ensure coherence with health
I - inform people about food and nutrition through public awareness
N- Nutrition advice and counselling in health care settings
- G - give nutrition education and kills
New policy framework:
- healthy enhancing environments
- systems change
- behaviour change communication (check powerpoint for picture)
obstacles:
social. economic, built environment, food environment
What is the relationship between lifestyle and cancer?
Food, nutrition, obesity and physical activity all affect DNA repair, proliferation, hormonal regulation, differentiation, inflammation and immunity, apoptosis, cell cycle, carcinogen metabolism which all can lead to cancer
What are the causes of cancer?
Mututations - passed onto subsequent cells which accumulate
loss of genes
risk increases with age
chemical carcinogens
radiation
viruses
hromones
diet
gender
metabolic state
smoking/alcohol
15% inherited, 85% environmental
What was the approach fine-tuned since the 2007 report?
Greater focus on cohort studies
More pooled analyses of cohort studies
Greater opportunities to analyse by cancer subtype
More stratified analyses (eg smoking status)
More evidence about dietary patterns
Greater use of non-linear analysis; permits
identification of thresholds of association
What is the most convincing lifestyle factor that increases the risk of a lot of different types of cancers?
Adult body fatness
What were the limitations of the WCRF report?
Poorly characterised exposures
Inconsistencies in definition of disease
endpoint
Residual confounding
Evidence comes mainly from Europe and US
Lack of understanding of nutrition impact on
biological mechanisms
What are the lifestyle risk factors for cancer of the mouth, pharynx or larynx?
– Smoking
– Drinking alcohol
– Being overweight/obese
limited evidence for non-starchy veg, healthy dietary patterns and coffee decreasing risk
- only alcohol, smoking, and body fatness have strong evidence for increasing risk
What are the other risk factors for cancers of the mouth, pharynx and larynx?
• Other risk factors:
– Age – risk increases as you get older
– Gender – mouth and throat cancer is three times more common in men than
in women (may in part be related to higher rates of smoking in men)
– Infection with human papilloma virus (HPV) increases the risk of mouth and
throat cancer
– Exposure to asbestos may increase the risk of laryngeal cancer
What are some examples of implemented policies that have helped to change lifestyle behaviour? (health enhancing, systems change and behaviour change communication)
Health-enhancing environments
• Restriction of alcohol consumption in public places
(Costa Rica)
• Sugar sweetened beverage tax (Mexico)
• Tax incentives to promote physical activity (Finland)
Systems change
• Co-ordinated multisectorial approach (Tanzania)
Behaviour change communication
• Breastfeeding media campaign (Bangladesh)
• Livelighter campaign (Australia)
What is an eating disorder?
Complex mental illness
Behaviours are often a way of coping with an underlying issue
can affect anybody
What are the predisposing factors to an eating disorder?
No specific cause / multifactorial
Can be predisposed: high achievers/goal oriented families previous bullying/teasing relating to appearance broken families peer/family/social pressures genetic (esp. in Anorexia) hormonal/neurotransmitters hobbies/sports physical/sexual abuse
What is the clinical presentation and medical management of orthorexia?
Not clinically recognised as a separate eating disorder
Obsession with eating ‘pure’ or ‘clean’ foods
Feelings of extreme guilt if eat something unhealthy
Judging others
Behaviour is used to:
cope with negative thoughts or feelings
feel in control
Fatigue Poor immune responses Malnutrition: angular chelitis recurrent apthous ulceration Management: therapies to tackle underlying mental health disorder (e.g. CBT, counselling)
What is the clinical presentation and medical management of anorexia nervosa?
Body image disorder
Sufferers often believe they are fat, even when they are severely underweight
Disproportionate concerns about weight gain (e.g. from OCP)
Rapid weight loss
Secretive behaviours and social withdrawal
hair loss, muscle wastage, fine downy hair, weak bones
consequences: Faltering growth Delayed puberty amennorrhea infertility Dehydration kidney failure Cardiac heart failure/death
management: Multidisciplinary and long term Psychoeducation about anorexia Mental health family therapy for children CBT/Group therapy Monitoring physical health ‘no blame’ approach weight gain key for recovery meal planning and vitamin supplements Pharmacological interventions TCA/SSRI Counselling for family Inpatient care Not force-fed unless lack mental capacity
Dental considerations: Halitosis - ‘pear-drops’ (ketosis) Dry mouth – TCAs Drug dosages Reduced immune response periodontal disease angular chelitis (malnutrition) Medical emergencies vasovagal syncope (faint) cardiac arrest
What is the clinical presentation and medical management of bulimia nervosa?
Serious mental illness Cyclical binge-eating and purging behaviours self-induced vomiting obsessive exercising use of laxatives/enemas/diuretics Binges are often distressing: sufferers are not in control eat until painfully full Often have a history of anorexia or obesity
bloating, inflammation of gut, back of throat, acid burns on knuckles
Normal/slightly overweight Laxative abuse Lazy colon/increased risk of colon cancer Dehydration/electrolyte imbalance Vomiting Barrett’s oesophagus Diabulimia (hyperglycaemia) Cardiac arrhythmias heart failure/death
management: Multidisciplinary and long term Educate re. harmful effects of purging Mental health family therapy for children CBT Monitoring physical health inc. risk factors ‘no blame’ approach meal planning and vitamin supplements Support for family
dental considerations: Regular dental reviews needed (NICE, 2017) Orofacial features: parotid enlargement acne oral ulceration Medical emergencies: vasovagal syncope cardiac event Dental features Erosion vomit pH ~3.8 palatal surfaces of incisors perimylolysis (molars) Caries
Dental management Specialist shared care Prevention education 2800ppm/5000ppm fluoride toothpaste fluoride varnish 4 x per year fissure sealants mouthwash after vomiting no brushing for > 1 hour CPP-ACP (tooth mousse) Saliva substitutes
Monitor: Smith and Knight/BEWE Study models/clinical photos Restore ideally once stable minimally invasive adhesive restorations (direct/indirect) Multidisciplinary input Oral med - ulceration Radiology - sialography
What is the clinical presentation and medical management of binge eating disorder?
Binges similar to bulimia, but without purging
Buying lots of food and hoarding it
Secretive eating – rapidly and until over-full
Social withdrawal
More common in adults
May have had another ED previously or go on to develop one
Weight gain Bad skin Bloating and constipation Stomach rupture Longer term: obesity type II diabetes sleep apnoea heart disease
BED medical management:
Mental health
CBT/group CBT
outpatient care unless self harm/suicide risk
Monitoring physical health inc. risk factors
daily food intake plan – avoid dieting
weight monitoring
dental considerations Caries Weight dental chair max. 127kg GA airway risks Medical emergencies hypoglycaemia MI cardiac arrest
What is the clinical presentation and medical management of Obesity?
BMI 30 and above
Not classified as an eating disorder, though there may be some overlapping features
Can be many reasons why a person is obese
may or may not be related to underlying mental health
Clinical features and dental considerations similar to BED
Management tailored to the underlying cause:
exercise on prescription
healthy living classes
CBT/Counselling
What are some of the factors that decide choice of food?
age, gender, mood
cost, availability, preference, advertising, income, environment, transport, social status, location, culture, religion
What happens to the energy and nutrient requirement of an adults diet?
Nutrient requirements stay the same but energy requirements fall - less calories needed
What are the nutrient and food recommendations?
Fat total intake ~35% dietary energy- Reduced fat spreads and low-fat dairy
Saturated Fat total intake <11% dietary energy
Replace sat. fats and oils with those low in sat., rich in polyunsaturates
Complex Carbohydrates increase by 50%
Increase consumption of fruit, vegetables, bread, potatoes
What are the alcohol guidelines?
Men and women less or equal to 14 unites a week, spread out over more than 3 days
none in pregnancy
What are the salt recommendations?
6g, 2.4g sodium (Na x2.5= salt)
What happens when cholesterol oxidises?
Forms atheromas, narrowing the arteries
What is the reference and suggested range for total, LDL and HDL cholesterol?
Total 3.5-7.8 <5.2 LDL cholesterol 2.3-6.1 <4.0 HDL cholesterol 0.8-1.7 >1.15
What are the guidelines for a healthy diet on a budget?
- plan >1 day ahead, shopping list; buy in quantities you will use; supermarket brands
- try small amounts of new foods
- buy fruit and veg regularly (markets) and store carefully
- include generous helpings of starchy foods per meal (cheap, filling, healthy) • buy the leanest meat you can afford (mix with veg/pulses to casseroles to go further); tinned/frozen fish and meat cheaper
- careful cooking re: fuel use e.g. water in kettle, toaster cf grill, multiple dishes in oven, lids on saucepans, share (+shopping)
- beware processed foods (contents and cost)
Why may the nutrient requirements of older people be more difficult to achieve?
Poor appetite
in pain
have a disability
What are the causes of older mal/undernourishment?
Extreme age • increasing frailty increases the risk
Social isolation and loneliness
• ~14%+ live alone; social contact aids well-being
Loss of appetite
• food enjoyment depends on visual appearance, taste, smell
• smoking, poor OH, drugs
• salivary secretion - taste, chewing and swallowing (salivary gland dysfunction: Sjögren`s syndrome; xerostomia [drugs]; chemotherapy: mucositis, candidiasis)
Mental disturbances
• e.g. dementia – forget, lack of motivation
Physical disability
Dental problems
• 200-300kcal less intake due to poor-fitting dentures
• due to discomfort
• results in soft, bland diet; indigestion
Dysphagia: swallowing difficult or painful
• MS, MND, CV attack/stroke, radiotherapy, surgery, confusion
• IV fluids, fluid thickeners, gastrostomy feeding
• speech-, occupational-, physio-therapists, dietitian
Foods difficult to chew or swallow:
hard (toast, crackers, raw vegetables); chewy (meat); sticky (mashed potato); crumbly (fruit cake)
Constipation/bowel problems: due to reduced gut motility and inactivity (fibre and fluids
How can you prevent older mal/undernourishment?
Dehydration
• 6-8 glasses, account for spills
• headache, constipation (disorders of GIT), UTIs, confusion
Home care assistants
• buy and prepare
Meals on wheels
• portability, loss of nutrients, punctuality
Lunch clubs
• ideal, less nutrient deterioration, social contact
Institutions
• puréed food unappetising, taste similar if taste and smell
• sip feeds (Fortisip)
• Percutaneous Endoscopic Gastrostomy (PEG) feeding
What did the national diet and nutritional survey look at?
Food consumption, nutrient intakes and nutritional status 1.5yrs+ living in private UK households
interviews, diet-diary, main food provider (purchase, prepare), nurse visits, blood, urine • different data, but can compare previously • continuous, cross-sectional data • blood indices of nutritional status and 24hr urinary sodium in children and older adults (from ‘11/’12) • new in ’15/’16 – free sugars and fibre (as AOAC=total dietary fibre=NSPs and cellulose, etc. following SACN 2015 carbs report)
What did the national diet and nutrition survey find?
- Adults was 19-64yrs & 65+ (now 65-74 and 75+ ‘older old’ i.e. 3 grps) • High quality, nationally representative data • Overall diet and nutrient intakes similar to previous assessments
- Takeaways/eating out Fridays and Saturdays* • High meat and vegetable intake on Sundays* *but still some bias on weekends days even though sample days changed • Vegetarian, smoking, obesity, blood pressure, alcohol
• 31, 32 and 19% (3 age grps) meet 5-a-day target • Oily fish: below and no change over time • Processed meat: mean consumption reduced (and women meeting <70g/dy recommendation) • Saturated fat: above recommendations and no change over time • Mean total fat: met recommendation <35% total food energy, except in older old • Free Sugars signif reduced: in men cf yrs 1 and 2, tho’ above recommendations; BUT is 11.1, 11.2 and 11.3% in all 3 adult age groups • Fibre: 15-20g/dy (below recommendation 30g/dy) • Vitamins and minerals: less than RNI, esp. iron. • Salt: above
What developmental defects of teeth are associated with nutrition?
deficiencies - calcium, vitamin A and D (hypoplastic enamel), manlnutrition
excesses - fluoride, tetracycline - if given during enamel formation stage to pregnant women, causes enamel staining
What is the percentage reduction in caries with fluoride?
15-50% reduction in caries
excess fluorosis, GIT upset, respiratory arrest and death
What can patients with vit D resistant rickets present with in their teeth?
Large pulp chambers Large/promininent pulp horns Enamel hypoplasia Clefts and tubular defects in dentine may present with spontaneous dental abscesses
What are the risk factors for a vitamin D deficiency?
high BMI, low fish consumption, low educational level, and limited skin exposure
What is the evidence for the role of calcium and phosphates in dental development?
There was a significant decrease in prevalence of enamel hypoplasia in children (1929-1943) following introduction of:
Cheap milk
Cod liver oil for pregnant women and young children
Bread fortified with calcium
Patients with disorders of calcium and phosphate metabolism (x-linked hypophosphatasia, hypoparathyroidism) show significant increases in enamel defects (hypoplasias)
What was the evidence for the role of vitamin D in dental development?
Historically, May Mellanby (early 1900s) found that dogs fed on diets deficient in vit D had:
Delayed dental development
Deficient (hypoplastic) enamel
What was the evidence for the role of vitamin A in dental development?
Severe changes in ameloblasts occurs in rats fed with diet deficient in vitamin A – with resultant defective enamel and dentine formation
No evidence for the role of vit A in human tooth formation
What is the evidence for the role of malnutrition in dental development?
Nigerian study (1973) found the following dental defects in malnourished children (severe lack of protein)
Enamel hypoplasia (linear grooves) involving primary incisors
Generalised enamel hypoplasias in 20% of children
Delayed dental eruption
What are some extrinsic dietary causes of erosion?
Acidic drinks (most fruit-flavoured or carbonated drinks)
Acidic food (citrus fruits, yoghurts)
Vit C tablets
Pickled foods + vinegar
> 2 citrus fruits daily
Vegetarians/vegans
4 carbonated drinks daily: 252% increased risk
What is the link between food consistency and periodontla health?
In (some) animals there is evidence that a fibrous diet will help reduce incidence of plaque-related gingivitis and periodontal disease
no evidence in humans but eating fibrous foods may help to maintain the supporting tissues of the periodontium, and increased salivary flow from eating fibrous foods may have some beneficial effects on oral health generally
What do children who are PEG fed readily develop?
excessive calculus deposits on all tooth surfaces
What is vitamin C deficiency related to?
poor peridontal health
Disturbed collagen formation
Bleeding and swollen gums, loose teeth
First seen in sailors (now seen in people with very deficient diets: homeless, fussy teenagers!)
What is the most deficient nutrient in adults?
Folic acid and periodontal health
Primarily concerned with DNA synthesis and cell turnover
Probably plays a role in periodontal health by maintaining epithelial integrity and attachment
Folate mouthwashes and supplements have been shown to reduce pregnancy-related gingivitis
Name some foods rich in folate?
leafy greens, asparagus, broccoli, oranges, avocado, seeds and nuts, brussel sprouts, cauliflower, bell peppers
What are the oral mucosa manifestations of vitamin B12, C, K, folic acid, iron and protein deficiencies?
Vitamin B12 (glossitis, fissured tongue, burning mouth, erosive or ulcerative lesions) Vitamin C (haemorrhage and swelling) Vitamin K (gingival bleeding) Folic acid (ulcers, burning mouth, depapillation of tongue) Iron (ulcers, glossitis, burning mouth) Protein deficiency/kwashiokor (oedema of tongue, atrophy of papillae, circumoral hypopigmentation)
What is orofacial granulomatosis and what are some agents that trigger it?
Probable delayed hypersensitivity reaction
agents identified - benzoates E210-219, cocoa, cinnamon, carvone (found in essental oils - caraway, spearmint, dill)
What are the clinical signs of orofacial granulomatosis?
Diffuse facial swelling Lip enlargement + vertical fissuring Angular cheilitis Oedema of buccal mucosa Mucosal tags Aphthous-like ulceration
How can you investigate and confrim orofacial granulomatosis?
Biopsy – non-caseating granulomata
Bloods
Patch-testing
How do you manage orofacial granulomatosis?
Exclusion diet
Symptomatic relief (difflam, gengigel)
Immunosupresants
Steroids (mouthwash, systemic)
What are the problems with diet diaries?
They forget to return their diet sheet or lose it
They change their eating habits (subconsciously or consciously)
They may be observing a religious festival or be on a special diet at the time of the diet diary
They write what they think you would like to see
They forget details
There may be literacy or language difficulties
What is the 3 step approach from a diet diary analysis?
Identify and target at-risk patients (high caries experience or erosion) Ask them (or guardian) to keep a written record of everything they eat and drink for 3 days (including one weekend day) Ask them to return it for you to appraise and give feedback
What is the cochrane evidence for dietary analysis?
2012
interventions to change diet in a dental care environment
Review aimed to determine whether efforts by dentists and other dental staff members are successful in changing patients’ diets
5 studies identified – 2 concerned with diet advice given concerning general health (one was about alcohol and one was about fruit and vegetable consumption). In both these studies there was a change to healthier behaviour following the advice.
Most of the studies concerning sugar consumption are of relatively weak quality.
The evidence for dietary advice aiming to change sugar consumption is poor. Further studies in this area should be considered
What are the dietary recommendations in dental practice in relation to dental erosion?
discourage frequency and amount of acid drinks and foods consumed
discourage adding acidic drinks to infant feeding bottles
promote chilling of drinks, use at one go and limit to mealtimes any soft drinks consumed
discourage use of acidic sweets especially inbetween meals
promote drinking water, also nutritious drinks e.g. milk, also promote fresh fruits as part of a healthy diet
promote use of neutralising food e.g. cheese after having an acidic food or drink
use of a straw
refrain from toothbrushing straight after an acid attack
What are the steps after the diet diary has been returned to you?
step 1 - thank the person for returning the diet sheet and show a genuine interest, tell them you would like some time to look at it before their next visit and give them feedback
gain a general idea of whether the sheet has been completed thoroughly or not, could ask some follow up questions at their next visit e.g. do they take sugar in their tea
step 3 - find some positive/ good about their diet history to feedback
step 4 - identify all the cariogenic/erosive food or drinks that are taken outside of a mealtime, count up episodes
step 5 - hidden sugars, cereals ketchup flavoured crisps, fruit yoghurt, dried fruit
step 6 - ideally provide individualised written and verbal feedback so that the patient can take something away with to help them remember your advice
step 7 - feedback about caries:
say something nice
explain that frequency of sugar attacks need to be reduced to prevent decay
offer safe altenratives
advice against drinks for infants in a bottle
recommend general healthy eating guidelines ( 5 a day)
reinforce toothbrushing with F toothpast twice a day
step 8 - reinforcement - repeat the exercise at a recall visit
What are some ‘safe’ snacks and drinks?
Water/milk/tea with no sugar (or sweetners for older patients)
Fresh fruit/veg
Cheese/meat
Bread/breadstick
(Plain crisps)
Nuts (for older patients, with no nut allergy!)
What are the general principles for dietary analysis?
Keep it simple (avoid too much information at once)
Don’t be judgemental
Be positive and encouraging
Give practical alternatives
Accept that there may be medical reasons that override your diet advice for dental health
Reinforce your advice
