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Components of the Human Diet Option A: Human Nutrition & Health Stephen Taylor Image: Banana - Isolated http://www.flickr.com/photos/53507547@N06/5129712590 Found on flickrcc.net
Assessment Statements Obj. A1.1 Define nutrient. 1 List the types of nutrients that are essential in the human diet, including A1.2 1 amino acids, fatty acids, minerals, vitamins and water. State that non-essential amino acids can be synthesised in the body from A1.3 1 other nutrients. A1.4 Outline the consequences of protein deficiency malnutrition. 3 Explain the cause and consequences of phenylketonuria (PKU) and how A1.5 3 early diagnosis and a special diet can reduce the consequences. Outline the variation in the molecular structure of fatty acids, including A1.6 saturated fatty acids, cis and trans fatty acids, monounsaturated and 2 polyunsaturated fatty acids. Evaluate the health consequences of diets rich in different types of fatty A1.7 3 acid.Command terms: http://i-biology.net/ibdpbio/command-terms/ Assessment statements from: Online IB Biology Subject Guide
Assessment Statements Obj. Distinguish between minerals and vitamins in terms of their chemical A1.8 2 nature. Outline two of the methods that have been used to determine the A1.9 2 recommended daily intake of vitamin C. Discuss the amount of vitamin C that an adult should consume per day, including the level needed to prevent scurvy, claims that higher intakes A1.10 3 give protection against upper respiratory tract infections and the danger of rebound malnutrition. A1.11 List the sources of vitamin D in human diets. 1 Discuss how the risk of vitamin D deficiency from insufficient exposure to A1.12 sunlight can be balanced against the risk of contracting malignant 3 melanoma. Explain the benefits of artificial dietary supplementation as a means of A1.13 3 preventing malnutrition, using iodine as an example. A1.14 Outline the importance of dietary fibre as a component of a balanced diet. 2Command terms: http://i-biology.net/ibdpbio/command-terms/ Assessment statements from: Online IB Biology Subject Guide
Nutrients are chemical substances found inComponents of the Human Diet food that are used in the body Nutrition Information: Food energy: from carbohydrates, proteins, fats. Units: food calories (kcal) or kilojoules (1kcal = 4.18kJ) 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 blood Dietary 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.http://www.wolframalpha.com/input/?i=big+mac+nutrition
Nutrient: a chemical substance found in foods that used in the body.Essential Nutrients Non-essential NutrientsCannot be replaced or Can be replaced or synthesisedsynthesised by the body, so must by the body, so are not necessarybe taken in the diet. in the diet.• Water • Carbohydrates/ sugars (energy could• Minerals come from proteins or fats)• Some vitamins • Other minerals and some vitamins• Some unsaturated fatty acids • Saturated fatty acids• Some amino acids • Some amino acids.Dietary fibre is also necessary, though as it is Dietary fibre is also necessary, though as it isnot absorbed it is technically not a nutrient. not absorbed it is technically not a nutrient. Image: La Boqueria http://www.flickr.com/photos/9147703@N03/2803305840 Found on flickrcc.net
Protein-deficiency malnutritionKwashiorkor: “The disease of the first childwhen the second is born.”Link: NCBI PubMed HealthCaused by a lack of essential amino acids as a result of extremelylow protein intake (such as when breastfeeding ceases for onechild and the diet switches to low-protein sources of energy). http://www.youtube.com/watch?v=P-POKztF9nsEssential amino acids are therefore not available to make newproteins - enzymes, pumps, antibodies – that are necessary fornormal cell function, growth and immunity.Edema (severe swelling) results as fluids gather in tissues andcannot be returned to the blood effectively. Growth is severelystunted and mental development can be impaired.Risk factors: • Extreme poverty, overpopulation, large family sizes • Drought, war, poor infrastructure http://en.wikipedia.org/wiki/Kwashiorkor
Phenylketonuria (PKU) Inherited, progressive, degenerative.Genetics Review1. Is this disorder autosomal or sex-linked? •2. What is a mis-sense base-substitution mutation? •3. What is the chance of a child having PKU if both parents are asymptomatic carriers? • http://en.wikipedia.org/wiki/Phenylketonuria
Phenylketonuria (PKU) Inherited, progressive, degenerative.Genetics Review1. Is this disorder autosomal or sex-linked? • Autosomal (chromosome 12)1. What is a mis-sense base-substitution mutation? • One base in the allele has been replaced by another, resulting in one different amino acid being used in protein synthesis.1. What is the chance of a child having PKU if both parents are asymptomatic carriers? • 1 in 4 http://en.wikipedia.org/wiki/Phenylketonuria
Phenylketonuria (PKU) Inherited, progressive, degenerative. Cause Autosomal recessive, disease-causing allele: mis-sense base-substitution mutation on the gene for the enzyme phenylalanine hydroxylase. Result Phenylalanine (Phe) cannot be metabolised into tyrosine. Phe builds up in the brain, and competes with other amino-acids related to transport. Effect Mental development is retarded. Detection Heel-prick (Guthrie test) of newborns to test concentration of Phe and Phe:Tyr ratio.http://en.wikipedia.org/wiki/Phenylketonuria
Phenylketonuria (PKU) Inherited, progressive, degenerative. Detection Heel-prick (Guthrie test) of newborns to test concentration of Phe and Phe:Tyr ratio.http://youtu.be/2ODyeOBrkao Treatment Strict low-Phe diet: no dairy, meat, breastmilk, nuts or aspartame (artificial sweetener). Lots of medication.http://en.wikipedia.org/wiki/Neonatal_heel_prick 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. http://youtu.be/CEiOYSYhnhY
Fatty Acids CH3(CH2)nCOOH • High-density energy storage • Usually solid at room temp • Usually oils at room temp • Animal products, palm and • Usually plant sources, e.g. coconut oil olive oil • High contribution to • Lower contribution to CHD coronary heart disease (CHD)Image: Ã–l 2http://www.flickr.com/photos/67499195@N00/2071538655Found on flickrcc.net
Fatty Acids CH3(CH2)nCOOHHigh-density (efficient) energy storageMetabolism of fatty acids in cell respiration skips glycolysis.Coenzyme A* cuts off carbon atoms from the fatty acid in the linkreaction 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. It’s all connected!
Fatty AcidsImportant components of the plasma membrane http://en.wikipedia.org/wiki/Cell_membrane
Fatty Acids CH3(CH2)nCOOHHave other diverse functions. Triglycerides are efficient energy stores. g fatty acids l saturated y c e mono-unsaturated r o poly-unsaturated l “Good Cholesterol”: High Density Lipoproteins Lipid Hormones • Transport triglycerides out of the blood • Steroid hormones, such as and so reduce the risk of CHD. testosterone and cortisol, are made using lipids. “Bad Cholesterol”: Low Density Lipoproteins • Hormones are chemical • Raise blood triglyceride levels and blood messengers. pressure, increasing risk of CHD. http://en.wikipedia.org/wiki/Triglyceride
Saturated, mono-unsaturated or poly-unsaturated?Describe these fatty acids If they’re unsaturated, what’s their omega-number? Are the unsaturated fatty acids cis- or trans-fats? O H H H H H H H H H H H C C C C C C C C C C C C H HO H H H H H H H H H H H O H H H H H H H H H H C C C C C C C C C C C C H HO H H H H H H H H H H H H H H H H H H H H H O H C C C C C C C C C C C C H H H H H H H H H OH
Saturated, mono-unsaturated or poly-unsaturated?Describe these fatty acids If they’re unsaturated, what’s their omega-number? Are the unsaturated fatty acids cis- or trans-fats? O H H H H H H H C C C C C C C C C C C C H HO H H H H H H H H H H H O H H H H H H H H C C C C C C C C C C C C H HO H H H H H H H H H H H H H H H H H H H H H O H C C C C C C C C C C C C H H H H H H H H OH
Should we ban trans fats? Nutrition Information: California bans trans fats http://youtu.be/WHcg_zoo1oc Doctors demand ban on man-made trans fats: http://www.guardian.co.uk/society/2010/jan/18/trans-fats-ban-health-faculty Watch out for trans fats on your food labels (or search your favourite foods on Wolfram|Alpha).http://www.wolframalpha.com/input/?i=big+mac+nutrition
Vitamins & Minerals Minerals are elemental ions found in food. http://tinyurl.com/35d6qyq Vitamins are complex organic compounds (contain C, H and O). Some can be made by the body, but others are essential in the diet. http://en.wikipedia.org/wiki/Vitamin_C
Image: Banana - Isolated http://www.flickr.com/photos/53507547@N06/5129712590 Found on flickrcc.net@IBiologyStephen Please consider a donation to charity via Biology4Good. Click here for more information about Biology4Good charity donations. This is a Creative Commons presentation. It may be linked and embedded but not sold or re-hosted.