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37 Cards in this Set

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What is an adequate diet?

A diet that contains the correct amount of carbs, lipids, proteins, vitamins and minerals to promote:


- optimal body function


- freedom from infection


- disease resistance


- effectiveness of medical treatment


- longevity


- quality of life

What factors do dietary requirements depend on?

age, gender, activity level, pregancy/lactation, disease, genetics

Disease which poor diet is lnked to

cancer, heart disease, hypertension, stroke, caries, perio, poor recovery from trauma

What are the key points of the eat well plate?

- base meals on starchy foods


- eat lots of fruit and veg


- eat more fish


- cut down on sat fat and sugar


- less salt


- be active and be a healthy weight


- drink plenty of water


- don't skip breakfast

What is the need for Dietart reference values?

For every nutrient too much may be toxic, too little may be dificient.


The ideal is in between and can be determined experimentally.


Recommended values are set to ensure people don't suffer deficiencies or toxic effects.




DRVs are estimates of the energy and nutrients needed by different groups of people in the UK. THey were set by COMA in 19990.

How are DRVs estimated?

It is the average requirement to statisfy 50% of the population. This will be too much for a large amount of the population and too little for others. Therefore it is not sufficient and we ne Reference Nutriment Intake values.

What is an RNI?

To satisfy the majority of the population the min and max are set 2 SDs from the mean. This covers from the 5th percentile to the 95th percentile.




The RNI is the value for the 95th percentile.

How can RNIs be used to assess the diet of a population?

The nearer the average intake of a population is to the RNI (95th) the less probable that any individual has a deficient diet.




The nearer to the min RNI the higher the probability that some individuals have a deficient diet.

What do we use energy from diet for?

10% - thermic

30% - physical activity (can vary widely)


60% - basal metabolic rate - maintaining body functions




The only variable one is physical activity so this is the main determinant of requirements




Functions of the digestive tract

Transport of food stuff


Breakdown of food stuff


Absorption


Excretion of waste

General structure of the digestive tract

Long muscular tube


Lining is modified along the way


At various point different organs secrete into it

Parts of the digestive tract and their function

Oral cavity - mechanical breakdown of food, chemical breakdown of starch, lubrication




Oesophagus - muscular tube, transports food across the diaphragm




Stomach - 1.5-2L volume, internal folds for expansion. Acid secretion, antibacterial action, temporary food storage, liquefaction of contents, preliminary enzymatic digestion




Small intestine - nutrient absorption


- duodenum - receives secretions from pancreas and bile from gall bladder


- Jejunum - both


- Ileum - inner surface highly folded to increase SA for nutrient absorption




Large intestine (colon)


- water absorption


- formation of faecal matter


- secretion of mucus

Accessory organs of digestive tract - functions

Pancreas


- 4 sections: head, neck, body, tail


- Secretes enzymes into duodenum (exocrine)


- secretes hormones insulin and glucagon into bloodstream (endocrine)




Liver


- bile production


- detox - drugs, alcohol


- albumin production


- clotting factors


- storage of glycogen




Gall bladder


- stores and secretes bile into duodenum




Omentum


- fatty curtain that hangs from the stomach, cover GI tract




Peritoneum


- membranes of the abdominopelvic cavity


- visceral covers surface of most organs


- parietal lines body wall

In what way does nutrition affect enamel before and after eruption?

Pre-eruption - nutritional effects on enamel are systemic only




Post-eruption - nutritional effects on enamel are topical only

Summary of the different ways nutrition can affect caries risk

Systemic pre-eruption


- nutritional deficiencies or excesses can affect tooth development for better or worse




Increased caries risk:


- dietary components that are fermentable


- dietary components that inhibit remin. process


- dietary deficiencies that compromise salivary gland function




Decrease caries risk


- diet components that inhibit microbial metabolism


- dietary components that promote remin



Dietary factors that affect enamel during development

Mineral ions


- inadequate calcium or phosphate = compromised enamel (rare as enamel development is "protected" by body)


- inadequate fluoride = caries susceptible


- excess fluoride = flurosis




Vitamins


E - disturbs enamel formation (rare)


A - severe = enamel hypoplasia and malformed dentine


D - disturbed calcium and phosphate metabolism = slight enamel hypoplasia - rougher enamel surface


C - disorganisation of ameloblasts and odontoblasts




Protein


Protein Energy Malnutrition (PEM) = enamel hypoplasia

Dietary factors that affect saliva

PEM


- decreased: flow rate, calcium, buffering, protein, IgA and lysozyme




(proteins in saliva that will be reduced)


Arginine


- slow bacterial metabolism in plaque


- converted to urea which is then metabolised by bacteria to ammonia which is basic




Ferritin


- iron sequester





Affect of water intake on saliva

dehydration decreases salivary flow

Which sugars are cariogenic?



ALL


except lactose when in milk because milk has protective properties that negate the cariogenicity




They are particularly bad when mixed with starchy food or as a solid - longer for clearance




Sucrose is the worst because:


- consumed in the greatest amount and frequency


- it can be used by bacteria to produce extra and intra cellular polysaccharides therefore can be stored or used to form the biofilm

How is plaque polysacchride made?

Sucrose + Glucan


- Glucosyltransferase


Glucan(+1) + fructose




Sucrose + fructan


- fructosyltransferase


Fructan(+1) + glucose




The hydrolysis of sucrose releases free energy which can be used to add the glucose or fructose to the glucan or fructan chain.




Fructan is used as an extracellular store of energy

Glucan structure

2 forms:


Dextran - alpha 1-6 glycosidic bonds. branch using 1-4 and 1-3 bonds




Mutan - 1-3 bonds. branches by 1-6 bonds

Cariogenicty of fruit sugars

Whole fruit is considered low cariogenic despite high sugar becasue the sugar is not accessible (trapped in cells), citric acid and chewing stimulates saliva flow




Fruit juices have high cariogenicity because:


- sugar is accessible


- no chewing for salivary stimulation


- lots have added sugar

Cariostatic food

Milk:


- contains sugar but is cariostatic (or even protective)


- calcium and phosphate promotes remin


- non-casein proteins bind enamel suface and protect form acid attack


- casein binds and stabilises calcium phosphate


- milk inhibits S. mutans adhesion to teeth




Cheese


- calcium and phosphate


- protein factors similar to milk


- stimulates saliva but evidence shows it has other effects than this




Tea


tannins - inhibits salivary amylase - limits cariogenicity of starch


tannic acid - inhibits growth of S. mutans


flavonoids - prevent adherence and growth of plaque bacteria at the tooth surface

Sugar substitutes

Bulk sweetners


- not as sweet as sucrose


- calorific


- non-cariogenic




Intense sweeteners


-much sweeter than sucrose


- non-cariogenic


- non-calorific


(- have bull health concerns)







What factors make a drink/food erosive?

-pH


-Titratable acidity - major factor


- presence of chelators


- how it is drunk


- bottle designs


- presence of protective modifiers


- lack of protective salivary pellicle


- salivary flow and buffering capacity


- cohesion of drink to enamel surface

What is the mechanism of acid dissolution of enamel?

Based on an equilibrium between solid enamel and in the ions in solution.




If the concentration of ions in solution drops below the ????? (see bonass lecture) the solid enamel will dissolve.




Acid affects this by removing Phosphate ions from solution (by H+ reacting with them). The equilibrium will try to rectify this change by moving to the left and more phosphate will dissolve.

What is the mechanism of dissolution of enamel by chelating agents?

Similar to acid bu the chelating agent (such as EDTA) binds the calcium ions thereby removing them from the equilibrium

What is the realtionship and titratability

The dissolution constant is a measure of the point of equilibrium. A large Ka = far to the right. Small Ka = far to the left




As pKa is the -log of Ka small pKa = large amount of dissolution therefore strong acid. Large pKa = small dissolution therefore weak acid




Strong acids have a high titratability and strong erosive power.

Why is citric acid particularly erosive?

Both an acid and chelator




As pH goes up it loses ability to acid attack but becomes a strong chelator of Ca (three negative groups to bind it)

Erosive power of phosphoric acid

Phosphoric acid has lower erosive power than citric. An equilibrium is created between the phosphate from the acid and HAP. This actually promotes remin.




Phosphate can act as a chelator at high pH

What is obesity and how is it measured?

Excess adiposity (body fat)


Usually around the middle, most related to morbidity




Measured


Dual Energy Xray adipositometry - expensive


Bioelectirical impedence analysis - expensive


Skinfold thickness - cheap and good







Why are surrogate measurements needed?

Precise measurements are expensive and require training




Surrogates such as:


BMI
Height to weight ratio


Hip to waist ratio


are cheap and easy making them better for studying populations and keeping records.



Definition of obesity using measurements

For adults:


BMI 25-30 - pre-obese/overweight


30+ - obeses


40 + - morbidly obese




Children


BMI fluctuates with age, need a standard growth chart, we use 1990s chart (out of date?)




91st percentile = overweight


98th percentile = obese


(epidemiological 85th and 95th)

What causes obesity?

Diet - high consumption of energy dense food and drink, high consumption of sugar




Physical excess - hours of activity and hours of screen time - strong link




Genetics and endocrine abnormalities <5%




Socioeconomic factors


- areas of deprevation


- higher amongst some minorities

How is obesity linked to oral health?

Caries


-weak or no association with children


- some link between BMI and DMFT




Oral cancer


- not much data


- trend but weak




Perio


- strong link


- diabetes risk factor of perio


- perio worsens with diabetes


- obesity linked to perio in both biabetic and non-diabetic

Link between obesity and perio

Obesity = diabetes = perio - strong link


Obesity <--> perio - strong evidence for bidirectional link




Tridirectional link?


- common factor of inflammatory cytokines


- adipose shown to be exocrine tissue and releases a wide range of mediators

What does the european workshop on perio say about obesity and perio?

- Pts with diabetes must be told of perio risk


- also told perio will make diabetes control harder and pt will be at higher risk of CVD and kidney disease




- pts with type 1 should have thorough exam and preventative care




- Obese pts should be told of possible oral complications and dentists should measure abdominal adiposity reqularly