Components of the Human Diet

Components of the Human DietOption A Human Nutrition amp Health

Stephen TaylorImage Banana - Isolated

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Assessment Statements Obj

A11 Define nutrient 1

A12 List the types of nutrients that are essential in the human diet including amino acids fatty acids minerals vitamins and water 1

A13 State that non-essential amino acids can be synthesised in the body from other nutrients 1

A14 Outline the consequences of protein deficiency malnutrition 3

A15 Explain the cause and consequences of phenylketonuria (PKU) and how early diagnosis and a special diet can reduce the consequences 3

A16Outline the variation in the molecular structure of fatty acids including saturated fatty acids cis and trans fatty acids monounsaturated and polyunsaturated fatty acids

2

A17 Evaluate the health consequences of diets rich in different types of fatty acid 3

Assessment statements from Online IB Biology Subject GuideCommand terms httpi-biologynetibdpbiocommand-terms

Assessment Statements Obj

A18 Distinguish between minerals and vitamins in terms of their chemical nature 2

A19 Outline two of the methods that have been used to determine the recommended daily intake of vitamin C 2

A110Discuss the amount of vitamin C that an adult should consume per day including the level needed to prevent scurvy claims that higher intakes give protection against upper respiratory tract infections and the danger of rebound malnutrition

3

A111 List the sources of vitamin D in human diets 1

A112Discuss how the risk of vitamin D deficiency from insufficient exposure to sunlight can be balanced against the risk of contracting malignant melanoma

3

A113 Explain the benefits of artificial dietary supplementation as a means of preventing malnutrition using iodine as an example 3

A114 Outline the importance of dietary fibre as a component of a balanced diet 2

Assessment statements from Online IB Biology Subject GuideCommand terms httpi-biologynetibdpbiocommand-terms

httpwwwwolframalphacominputi=big+mac+nutrition

Components of the Human Diet Nutrients are chemical substances found in food that are used in the body

daily needs vary by individual based on gender age size and activity

Fats (lipids) can be saturated or unsaturated Trans fats are particularly unhealthy

Sodium (salt) keep it low Carbohydrates are polymers of sugars (an energy source) Sugars are absorbed easily into the bloodDietary fibre (cellulose) cannot be digested (healthy)

Proteins are polymers and sources of amino acids They are used to build new proteins in cells

Vitamins are organic compounds that are essential in small amounts in the diet

Minerals are mineral ions (elements) that are also essential

Food energy from carbohydrates proteins fats Units food calories (kcal) or kilojoules (1kcal = 418kJ)

Nutrition Information

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Nutrient a chemical substance found in foods that used in the body

Essential NutrientsCannot be replaced or synthesised by the body so must be taken in the diet bull Waterbull Mineralsbull Some vitaminsbull Some unsaturated fatty acidsbull Some amino acids

Dietary fibre is also necessary though as it is not absorbed it is technically not a nutrient

Non-essential NutrientsCan be replaced or synthesised by the body so are not necessary in the diet bull Carbohydrates sugars (energy could

come from proteins or fats)bull Other minerals and some vitaminsbull Saturated fatty acidsbull Some amino acids

Dietary fibre is also necessary though as it is not absorbed it is technically not a nutrient

phenylalanine hydroxylase

Protein-deficiency malnutritionKwashiorkor ldquoThe disease of the first child when the second is bornrdquo

httpwwwyoutubecomwatchv=P-POKztF9ns

Link NCBI PubMed Health

Caused by a lack of essential amino acids as a result of extremely low protein intake (such as when breastfeeding ceases for one child and the diet switches to low-protein sources of energy)

Essential amino acids are therefore not available to make new proteins - enzymes pumps antibodies ndash that are necessary for normal cell function growth and immunity

Edema (severe swelling) results as fluids gather in tissues and cannot be returned to the blood effectively Growth is severely stunted and mental development can be impaired

Risk factors bull Extreme poverty overpopulation large family sizesbull Drought war poor infrastructure

httpenwikipediaorgwikiKwashiorkor

Phenylketonuria (PKU)Inherited progressive degenerative

Genetics Review

1 Is this disorder autosomal or sex-linkedbull

2 What is a mis-sense base-substitution mutation bull

3 What is the chance of a child having PKU if both parents are asymptomatic carriers

bull

httpenwikipediaorgwikiPhenylketonuria

Phenylketonuria (PKU)Inherited progressive degenerative

Genetics Review

1 Is this disorder autosomal or sex-linkedbull Autosomal (chromosome 12)

2 What is a mis-sense base-substitution mutation bull One base in the allele has been replaced by

another resulting in one different amino acid being used in protein synthesis

3 What is the chance of a child having PKU if both parents are asymptomatic carriers

bull 1 in 4

httpenwikipediaorgwikiPhenylketonuria

Phenylketonuria (PKU)Inherited progressive degenerative

Cause Autosomal recessive disease-causing allele

mis-sense base-substitution mutation on the gene for the enzyme phenylalanine hydroxylase

ResultPhenylalanine (Phe) cannot be metabolised into

tyrosine Phe builds up in the brain and competes with other amino-acids related to transport

EffectMental development is retarded

DetectionHeel-prick (Guthrie test) of newborns to test

concentration of Phe and PheTyr ratio

httpenwikipediaorgwikiPhenylketonuria

httpenwikipediaorgwikiNeonatal_heel_prick

Phenylketonuria (PKU)Inherited progressive degenerative

DetectionHeel-prick (Guthrie test) of newborns to test

concentration of Phe and PheTyr ratio

TreatmentStrict low-Phe diet no dairy meat breastmilk nuts

or aspartame (artificial sweetener)Lots of medication

httpyoutube2ODyeOBrkao

There is no cure for PKU

Genetic counseling would be sought by prospective parents who suffer from or are suspected carriers of the disease-causing PKU allele

httpyoutubeCEiOYSYhnhY

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CH3(CH2)nCOOHFatty Acids

bull High-density energy storagebull Usually solid at room tempbull Animal products palm and

coconut oil bull High contribution to

coronary heart disease (CHD)

bull Usually oils at room tempbull Usually plant sources eg

olive oilbull Lower contribution to CHD

CH3(CH2)nCOOHFatty AcidsHigh-density (efficient) energy storage

Metabolism of fatty acids in cell respiration skips glycolysis Coenzyme A cuts off carbon atoms from the fatty acid in the link reaction and carries them to the Krebs cycle

Therefore longer chains are a greater store of potential energy

Coenzymes assist enzymes and are made using vitamins Itrsquos all connected

Fatty AcidsImportant components of the plasma membrane

httpenwikipediaorgwikiCell_membrane

Fatty AcidsHave other diverse functions

httpenwikipediaorgwikiTriglyceride

ldquoGood Cholesterolrdquo High Density Lipoproteinsbull Transport triglycerides out of the blood

and so reduce the risk of CHD

ldquoBad Cholesterolrdquo Low Density Lipoproteinsbull Raise blood triglyceride levels and blood

pressure increasing risk of CHD

glycerol

fatty acids

CH3(CH2)nCOOH

Triglycerides are efficient energy stores

saturated

mono-unsaturated

poly-unsaturated

Lipid Hormonesbull Steroid hormones such as

testosterone and cortisol are made using lipids

bull Hormones are chemical messengers

C C C C C C C C C C C C

HO

O H H H H H H H H H H H

H H H H H H H H H H H

H

Describe these fatty acidsSaturated mono-unsaturated or poly-unsaturatedIf theyrsquore unsaturated whatrsquos their omega-numberAre the unsaturated fatty acids cis- or trans-fats

C C C C C C C C C C C C

HO

O H H H H H H H H H H

H H H H H H H H H H

H

C C C C C C C C C C C

H H H H H H H H H H

H H H

H

H H H H H H

H C

OH

O

C C C C C C C C C C C C

HO

O H H H H H H H

H H H H H H H H H H H

H

Describe these fatty acidsSaturated mono-unsaturated or poly-unsaturatedIf theyrsquore unsaturated whatrsquos their omega-numberAre the unsaturated fatty acids cis- or trans-fats

C C C C C C C C C C C C

HO

O H H H H H H H H

H H H H H H H H H H

H

C C C C C C C C C C C

H H H H H H H H H H

H H H

H

H H H H H

H C

OH

O

httpwwwwolframalphacominputi=big+mac+nutrition

Should we ban trans fats Nutrition Information

California bans trans fatshttpyoutubeWHcg_zoo1oc

Doctors demand ban on man-made trans fats httpwwwguardiancouksociety2010jan18trans-fats-ban-health-faculty

Watch out for trans fats on your food labels (or search your favourite foods on Wolfram|Alpha)

httptinyurlcom35d6qyq

Vita

min

s amp

Min

eral

s Minerals are elemental ions found in food

Vitamins are complex organic compounds (contain C H and O) Some can be made by the body but others are essential in the diet

httpenwikipediaorgwikiVitamin_C

httpwhqlibdocwhointpublications20049241546123pdf

httphigheredmcgraw-hillcomsites0072507470student_view0chapter25animation__b_vitaminshtml

httpwwwyoutubecomwatchv=onSPZ0aBUKM

Understanding Vitamin D

httpwwwyoutubecomwatchv=dcw1m31zuTE

httpwwwmjacomaupublicissues175_05_030901grovergroverhtml

httpwhqlibdocwhointpublications20049241546123_chap7pdf

httpwhqlibdocwhointpublications20049241546123_chap7pdf

httpwwwtedcomtalksmichael_specter_the_danger_of_science_denialhtml

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IBiologyStephen

Image Banana - Isolated httpwwwflickrcomphotos53507547N065129712590

Found on flickrccnet