Option D 1 Human nutrition Essential idea A

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Option D. 1 Human nutrition Essential idea: A balanced diet is essential to human

Option D. 1 Human nutrition Essential idea: A balanced diet is essential to human health

D. 1 Human nutrition Nature of science: Falsification of theories with one theory being

D. 1 Human nutrition Nature of science: Falsification of theories with one theory being superseded by another—scurvy was thought to be specific to humans, because attempts to induce the symptoms in laboratory rats and mice were entirely unsuccessful. (1. 9) Understandings: • Essential nutrients cannot by synthesized by the body, therefore they have to be included in the diet • Dietary minerals are essential chemical elements • Vitamins are chemically diverse carbon compounds that cannot by synthesized by the body • Some fatty acids and some amino acids are essential • Lack of essential amino acids affects the production of proteins • Malnutrition may be caused by a deficiency, imbalance or excess of nutrients in the diet • Appetite is controlled by a centre in the hypothalamus • Overweight individuals are more likely to suffer hypertension and type II diabetes • Starvation can lead to breakdown of body tissue

D. 1 Human nutrition Application and skills: • Application: Production of ascorbic acid by

D. 1 Human nutrition Application and skills: • Application: Production of ascorbic acid by some mammals, but not others that need a dietary supply • Application: Cause and treatment of phenylketonuria (PKU) • Application: Lack of Vitamin D or calcium can affect bone mineralization and cause rickets or osteomalacia • Application: Breakdown of heart muscle due to anorexia • Application: Cholesterol in blood as an indicator of the risk of coronary heart disease • Skill: Determination of the energy content of food by combustion • Skill: Use of databases of nutritional content of foods and software to calculate intakes of essential nutrient's for a daily diet

What is nutrition? • Nutrition is the act of taking food in (ingestion), breaking

What is nutrition? • Nutrition is the act of taking food in (ingestion), breaking it apart (digestion), and cellular uptake (absorption) • Our food provides the nutrients and minerals that we are incapable of synthesizing on our own. • Nutrients: chemical substance found in foods and used in the human body • Minerals: inorganic substances that living things need for a variety of purposes

Essential Nutrients vs Non-Essential Nutrients • Nutrients are used in a variety of ways

Essential Nutrients vs Non-Essential Nutrients • Nutrients are used in a variety of ways by the body, including providing energy and biosynthesis • Some nutrients can be made by cells, but many cannot • Those nutrients that cannot be made by our bodies are called essential nutrients • Other nutrients are non-essential, either because another nutrient can be used for the same purpose or because they can be made in the body from another nutrient

Essential Nutrients vs Non-Essential Nutrients • Glucose, starch, and other carbohydrates are non-essential because

Essential Nutrients vs Non-Essential Nutrients • Glucose, starch, and other carbohydrates are non-essential because they are used in respiration to provide energy and lipids can be used instead. In fact amino acids can be fed into both glycolysis and the Krebs cycle • Some essential nutrients are conditionally essential. In adults, vitamin K is produced by the metabolism of symbiotic bacteria in the intestine. Infants do not have colonies of such bacteria at birth, they are often given supplementary injections of vitamin K • Essential nutrients include: essential amino acids, essential fatty acids, minerals, and most vitamins

Minerals • Minerals are inorganic substances which are needed in small amounts by humans

Minerals • Minerals are inorganic substances which are needed in small amounts by humans (milligrams or micrograms per day rather than grams) • They can be distinguished from vitamins by their chemical nature • Minerals are chemical elements, usually in ionic form • Examples of minerals include calcium, iron, sodium, magnesium, iodine, and chloride. • Minerals are fairly long-lived, so a large quantity is not necessary, but the supply must be constant to replace those that are used by the body

Minerals • Minerals can be used for biosynthesis (building bones, hemoglobin etc. ) and

Minerals • Minerals can be used for biosynthesis (building bones, hemoglobin etc. ) and for sending chemical messages (synaptic transmission, action potentials etc. ) • Deficiencies cause disease. The consequences of deficiency diseases can be serious. An example is the mineral iodine. It is needed by the thyroid gland for synthesis of the hormone thyroxin. This hormone stimulates metabolic rate • If a pregnant woman has this deficiency, her baby may be born with permanent brain damage. If an adult has this deficiency, they may develop a goiter

Mineral Deficiency: Goiter

Mineral Deficiency: Goiter

Mineral Deficiency: Goiter

Mineral Deficiency: Goiter

Vitamins • Vitamins from the words “vital amine” because the first vitamins discovered contained

Vitamins • Vitamins from the words “vital amine” because the first vitamins discovered contained an amino group • Vitamins are essential organic (carbon compounds) molecules with diverse functions that cannot be synthesized by the body • Vitamins, like minerals, are only needed in small amounts, due to their long-lived nature. They must be obtained from the diet

Vitamins • Some of their functions include co-factors for enzymes, anti-oxidants, and hormones •

Vitamins • Some of their functions include co-factors for enzymes, anti-oxidants, and hormones • Vitamins can be classified as either water soluble or fat soluble. Water soluble vitamins have to be constantly consumed any excess is lost in urine. Fat soluble vitamins can be stored • Some people who are deficient in vitamin intake will consume multivitamins • It’s unclear whether massive doses of vitamins provides any health benefits or are even safe

Vitamin Deficiency: Vitamin C • Vitamin C is needed for the synthesis of collagen

Vitamin Deficiency: Vitamin C • Vitamin C is needed for the synthesis of collagen fibers that form part of many tissues including skin and blood vessel walls • In most plants and animals, vitamin C (ascorbic acid) is non-essential. Teleost fish (e. g. cod, salmon, herring) and many primates cannot synthesize this vitamin. This is the result of a mutation of a gene that codes for the last enzyme in the final reaction of this pathway • In humans, some other primates, and guinea pigs, it is needed to avoid a disorder known as scurvy • Scurvy is characterized by anemia, debility, exhaustion, ulceration of the teeth and gums, and in some cases, death • It is because of scurvy that we have the term “limey”

Vitamin Deficiency: Vitamin D • Vitamin D is also an important component of human

Vitamin Deficiency: Vitamin D • Vitamin D is also an important component of human diets • Sources: oily fish, eggs, liver, and artificially fortified milk • Vitamin D helps with the absorption of calcium in the intestines which is then used for bone formation • In children, vitamin D deficiency can cause rickets, a disease that leads to irregular bone growth along growth plates • In adults, vitamin D deficiency (which has same symptoms as calcium deficiency) can lead to osteomalacia, or soft bones • Osteomalacia is inadequate bone mineralization due to calcium salts not being deposited or being reabsorbed, so bones become softened

Vitamin D • Does not fit the definition of a vitamin very well, as

Vitamin D • Does not fit the definition of a vitamin very well, as it can be synthesized in the skin • Vitamin D can be synthesized by cells in the skin when exposed to UVB radiation from the sun (290 -310 nm) • UV light has some harmful consequences, including mutations that lead to skin cancer. Melanin intercepts and absorbs light • The intensity of UV is too low in winter in high latitudes for much vitamin D to be synthesized, but the liver can store enough during the summer to avoid a deficiency in winter

Essential Fatty Acids • Humans can make most of the fatty acids that are

Essential Fatty Acids • Humans can make most of the fatty acids that are needed for survival • However, omega-3 and omega-6 fatty acids, which are unsaturated, cannot be made • Omega-3 and omega-6 refers to the position of a double bond in relation to the end of the molecule. Development of the brain and eye involve particularly large quantities • For those who don’t like oily fish like salmon, sunflower seeds are a good source of these essential fatty acids • Flaxseeds, chia seeds, hemp seeds, and walnuts are also a good source

Essential Amino Acids • Essential amino acids are needed for protein synthesis • There

Essential Amino Acids • Essential amino acids are needed for protein synthesis • There are several (8, 9 in infants) amino acids that humans cannot synthesize • There is no way to store amino acids therefore all essential amino acids must be included in the diet • Some cultures rely on a specific type of agricultural crop, such as corn, which may be deficient in several amino acids • In these populations, a higher rate of amino acid deficiencies are seen • Protein deficiency malnutrition (cannot make enough proteins) causes a lack of blood plasma proteins, which results in fluid retention in tissues which causes swelling (edema) and may be often seen in the abdomen • Through the use of biotechnology, scientists are genetically modifying certain crops to produce the essential nutrients needed for proper nutrition

Phenylketonuria (PKU) • Some individuals lack the ability to convert the amino acid phenylalanine

Phenylketonuria (PKU) • Some individuals lack the ability to convert the amino acid phenylalanine to the amino acid tyrosine • This is an autosomal recessive disorder (genetic) • This leads to a build up of phenylalanine in the blood and tissues, which can lead to mental retardation, seizures, and a variety of other problems • There is no cure, but in developed countries where infants are tested soon after birth, a diet that limits certain proteins (high amounts of phenylalanine like meat, fish, nuts, cheese, peas and beans) can be established and the individual can live a normal life • Children are normal prior to birth because the mother’s metabolism has kept phenylalanine and tyrosine at normal levels • Newborn genetic screen can pick up this disorder at about 24 hours after birth

Appetite • Appetite is the desire to eat • A person’s appetite is controlled

Appetite • Appetite is the desire to eat • A person’s appetite is controlled by the hypothalamus in the brain • The feeling of being satiated is a complex system of negative feedback loops between the nervous, digestive, and endocrine system • The small intestine secretes the hormone PYY 3 -36 when it contains food • The pancreas secretes insulin when the blood glucose concentration is high • Adipose tissue secretes the hormone leptin when amounts of stored fat increase • If the appetite control center receives these hormones, it reduces the desire to eat • This helps us to avoid health problems due to overeating, including excessive blood glucose levels, and obesity

Appetite • There a variety of hormones and other signals the brain uses to

Appetite • There a variety of hormones and other signals the brain uses to detect hunger and fullness • There also physical cues, such as when the stomach expands, it sends a message to the brain that it’s full and to stop eating

Eating and Nutritional Disorders • There are many issues that play a role in

Eating and Nutritional Disorders • There are many issues that play a role in eating and nutritional disorders • In some cases, the brain’s appetite control center is not properly functioning, and the individual may lose weight if they have no appetite, or become obese if they cannot be satiated • Some disorders are a result of social, cultural, and economic factors

Malnutrition • A lack of quantity or quality of food can lead to nutrition

Malnutrition • A lack of quantity or quality of food can lead to nutrition problems, collectively called malnutrition, which can be classified as a deficiency, imbalance, or excess of nutrients • Deficiencies can occur not just with nutrients but with calories as well • When the body is deprived of energy in the form of calories, it will begin to break down glycogen stored in the liver, then lipids, and finally proteins • Typically skeletal muscle is the protein that gets broken down for energy, and leads to thinner, less efficient muscles

Malnutrition: Anorexia • Anorexia means reduced appetite • It is a psychiatric illness with

Malnutrition: Anorexia • Anorexia means reduced appetite • It is a psychiatric illness with complex causes. Involves starvation and loss of body mass • Anorexia is an eating disorder in which the individual may have an ideal body image for themselves and will not eat in order to obtain this mental image • When an individual restricts essential nutrients, they can damage their bodies, including the muscle and valves of the heart • The amounts of carbs and fat consumed are too small to satisfy the body’s energy requirements, so proteins and other chemicals in the body are broken down. There is a wasting of muscles. Hair becomes thinner and can drop out. Skin becomes dry and bruises easily. Blood pressure is reduced, with slow heart rate and poor circulation. Infertility with no ovulation. Heart muscle deteriorates • If untreated, anorexia can result in death

Anorexia

Anorexia

Starvation • Caloric deficiency leads to starvation

Starvation • Caloric deficiency leads to starvation

Nutritional Excess • When individuals consume more nutrients or calories than needed for metabolic

Nutritional Excess • When individuals consume more nutrients or calories than needed for metabolic processes, obesity can occur • There a variety of factors that have lead to the increase in obesity rates world-wide. These include: • Migration to urban centers • Less time and energy prepping and making food • The consumption of high-calorie, low nutrition pre-packaged foods

Obesity: Hypertension • There are many complications that arise from obesity • Obesity is

Obesity: Hypertension • There are many complications that arise from obesity • Obesity is defined as having a BMI (Body Mass Index) of 30 or greater • Obese individuals have a greater chance to develop hypertension or high blood pressure • This occurs because as the size of the body increases, more blood is needed to carry the necessary oxygen, and this increases the pressure on the artery walls

Obesity: Type II diabetes • In addition to the risk of hypertension, there is

Obesity: Type II diabetes • In addition to the risk of hypertension, there is a positive correlation between obesity and the development of type II diabetes • Type II diabetes is when the body develops a resistance to the hormone insulin as well as a decrease in the production on insulin • This leads to high blood glucose levels • Unless carefully managed, diabetes can cause other health problems to develop: atherosclerosis (narrowing of arteries by fatty deposits), hypertension and coronary heart disease (narrowing of the coronary arteries with the associated risk of heart attacks)

Correlation between high levels of cholesterol in blood plasma and an increased risk of

Correlation between high levels of cholesterol in blood plasma and an increased risk of coronary heart disease (CHD) • Cholesterol in blood is an indicator of the risk of coronary heart disease Positive correlation • Cholesterol is a normal component of plasma membranes in human cells and is synthesized by the liver in hepatocytes • It turns out that cholesterol is transported in lipoproteins, which are small droplets coated in phospholipid • LDL is the so-called “bad cholesterol” because it carries cholesterol from the liver to body tissues. • High density lipoprotein (HDL) is “good cholesterol” as it collects cholesterol from body tissues and carries it back to the liver for removal from the blood

 • As a result, dietary cholesterol intake appears to have a very small

• As a result, dietary cholesterol intake appears to have a very small effect on blood cholesterol levels and therefore little effect on CHD • Genetic factors are more important than dietary intake • 5% of population has a dominant gene for hypercholesterolemia • Drugs (statins) can be more effective at reducing blood cholesterol levels than reductions in dietary intake • Positive correlation between dietary intake of saturated fats and intake of cholesterol, so it is possible that saturated fats, not cholesterol, cause the increased risk of CHD in people with high cholesterol intakes. (Saturated fats are solid at room temperature)

Nutritional Imbalances • In some parts of the world, single food crop staples can

Nutritional Imbalances • In some parts of the world, single food crop staples can leave members of the population in a state of nutritional imbalance • This is because the staple crop is missing one or more essential nutrients for human health • To fight this, scientists have genetically modified certain types of food • Golden rice, which features the addition of beta carotene, helps alleviate Vitamin A deficiency, which can lead to blindness and death

Calorimetry- determination of the energy content of food by combustion • The simple calorimeter

Calorimetry- determination of the energy content of food by combustion • The simple calorimeter is based on the knowledge of the specific heat capacity of water • It takes 4. 186 J of heat energy to raise the temperature of 1 gram of water by 1 degree Celsius • Q = mass of water x specific heat capacity x change in temperature • Q= m x C x ΔT • The apparatus consists of thermometer to detect the change in temperature and a vessel containing a known mass of water (1 ml of water = 1 gram) • The sample to be tested is ignited and placed below the container with water and the change in temperature is noted • Specific heat = 1 cal/g/o. C or 4. 186 J/g/o. C

Calorimeter

Calorimeter

Problem • Using the experimental results below, estimate the energy content of the nut

Problem • Using the experimental results below, estimate the energy content of the nut per gram. • Sample data: • Mass of nut = 0. 60 grams • Volume of water = 25 m. L • Initial water temperature = 20 o. C • Final water temperature = 65 o. C • Q= 25 m. L x 4. 186 J/g/o. C x 45= 4709. 25 J/1000= 4. 70 k. J/0. 6 g= 7. 85 k. J/g • Q = 25 m. L x 1 cal/g/o. C x 45 = 1, 125 little calories/1000 = 1. 125 kcal • 1. 125 Kcal/ 0. 6 grams = 1. 875 kcal/gram of nuts

Problem • Using the experimental results below, estimate the energy content of the food

Problem • Using the experimental results below, estimate the energy content of the food per gram in k. Joules and calories • Sample data: • Mass of food= 0. 89 grams • Volume of water = 50 m. L • Initial water temperature = 10 o. C • Final water temperature = 80 o. C • Q= 50 m. L x 4. 186 J/g/o. C x 70= 14651 J/1000= 14. 651 k. J/0. 89 g= 16. 46 k. J/g • Q = 50 m. L x 1 cal/g/o. C x 70 = 3500 little calories/1000 = 3. 5 kcal/0. 89 g= 3. 93 kcal/g

Problem • Using the experimental results below, estimate the energy content of the food

Problem • Using the experimental results below, estimate the energy content of the food per gram in k. Joules and calories • Sample data: • Mass of food= 1. 5 g • Volume of water = 75 m. L • Initial water temperature = 10 o. C • Final water temperature = 75 o. C • Q= 75 m. L x 4. 186 J/g/o. C x 65= 20406. 75 J/1000= 20. 40675 k. J/1. 5 g= 13. 60 k. J/g • Q = 75 m. L x 1 cal/g/o. C x 65 = 4875 little calories/1000 = 4. 875 kcal/1. 5 g= 3. 25 kcal/g

Monitoring personal dietary intake • It is possible to use databases of nutritional content

Monitoring personal dietary intake • It is possible to use databases of nutritional content of foods and software to calculate intakes of essential nutrients from a daily diet • “Super Tracker” available from the US Department of Agriculture (USDA) and is free • https: //www. supertracker. usda. gov • Assignment- Print out an image of a day of eating that you analyzed with this website! • 25 points

Super Tracker screenshot example

Super Tracker screenshot example

Definitions 1. Nutrition: the act of taking food in (ingestion) breaking it apart (digestion)

Definitions 1. Nutrition: the act of taking food in (ingestion) breaking it apart (digestion) and cellular uptake (absorption) 2. Nutrient: chemical substances found in foods and used in the human body 3. Mineral: inorganic substance which are needed in small amounts in humans (mg) that living things need for a variety of purposes. Chemical elements usually in ionic form 4. Vitamin: chemically diverse carbon compounds needed in small amounts that cannot be synthesized by the body 5. Malnutrition: a deficiency, imbalance or excess of specific nutrients in the diet 6. Obesity: excessive storage of fat in adipose tissue, due to prolonged intake of more energy in the diet than is used in cell respiration 7. Anorexia: condition in which an individual does not eat enough food to sustain the body even thought it is available. Voluntary starvation 8. Starvation: prolonged shortage of food. Once glycogen and fat reserves are used up, body tissues have to be broken down and used in respiration

Definitions 8. Phenylketonuria: an autosomal recessive genetic condition in which the level of phenylalanine

Definitions 8. Phenylketonuria: an autosomal recessive genetic condition in which the level of phenylalanine (amino acid) in the blood becomes too high due to the lack of a functional phenylalanine hydroxylase due to a mutation of the gene coding for the enzyme. 9. Rickets: a disease that leads to irregular bone growth along growth plates due to a deficiency of Vitamin D 10. Coronary heart disease: narrowing of the blood vessels that lead to cardiac muscle. Risk factor for heart attack 11. Osteomalacia: inadequate bone mineralization due to calcium salts not being deposited or being reabsorbed, so bones become softened. Vitamin D deficiency implicated

Distinguish between essential and nonessential nutrients • Non-essential nutrients can be made by cells

Distinguish between essential and nonessential nutrients • Non-essential nutrients can be made by cells or because another nutrient can be used for the same purpose • Example: glucose • Nutrients that cannot be made by our bodies are called essential nutrients • Essential amino acids, essential fatty acids, minerals, and most vitamins

Consequences of a deficiency in the diet of an essential amino acid • If

Consequences of a deficiency in the diet of an essential amino acid • If you are missing one of the 8 (9) essential amino acids, amino acid deficiency results in protein deficiency malnutrition • Amino acids cannot be stored and must be included in the diet

Outline 2 conditions that might cause the breakdown of heart muscle tissue • Anorexia:

Outline 2 conditions that might cause the breakdown of heart muscle tissue • Anorexia: restriction of essential nutrients can lead to damage of the body including the muscle and valves of the heart • Fats and carbohydrate intake too limited to satisfy body’s energy requirements, so proteins and other chemicals in the body are broken down • Starvation: prolonged shortage of food leads to body tissues break down

Outline 2 conditions caused by being overweight • Hypertension: high blood pressure • As

Outline 2 conditions caused by being overweight • Hypertension: high blood pressure • As size of the body increases, more blood is needed to carry the necessary oxygen, and this increases the pressure on the artery walls • Increased capillary network to move blood through • Can lead to strokes and heart attacks • Type II Diabetes: body develops a resistance to the hormone insulin as well as a decrease in the production of insulin • This leads to high blood glucose levels • Can lead to atherosclerosis and chronic heart disease

Outline the mechanism that can prevent the body from becoming overweight • Appetite control

Outline the mechanism that can prevent the body from becoming overweight • Appetite control is the negative feedback mechanism that the body uses to prevent it from becoming overweight • Control center is in the hypothalamus of the brain • Negative feedback loops between the nervous, digestive, and endocrine systems • Hormones secreted: PYY from intestines when it contains food; insulin from pancreas when blood glucose level is high; leptin from fat cells (adipose) when the amounts of stored fat increase • Target: hypothalamus. Effect: reduces desire to eat • Brain also uses other signals such as physical cues, such as when the stomach expands and sends message to brain that it is full and to stop eating.

Explain how the content of energy and essential nutrients in a diet can be

Explain how the content of energy and essential nutrients in a diet can be assessed • Energy content of food = calories • Determined using a calorimeter which is based on the knowledge of the specific capacity of water and the combustion of food • In this method, a known quantity of water of known initial temperature, is heated by the combustion of a known quantity of food and the temperature difference measured. • Q = Mass of water x specific heat of capacity x change in temperature • Nutrients: monitoring personal dietary intake ex: super tracker. Data base.

Outline the cause and treatment of PKU • PKU: autosomal recessive condition due to

Outline the cause and treatment of PKU • PKU: autosomal recessive condition due to the lack of the enzyme that breaks down the amino acid phenylalanine to the amino acid tyrosine or due to the presence of defective enzyme. • As a result, phenylalanine accumulates in blood and tissues which can lead to mental retardation, seizures, and a variety of other problems. • Treatment: Screening at birth for the disorder. Switching infant to a low phenylalanine/ low protein diet.

Evaluate the research that has shown a correlation between high levels of cholesterol in

Evaluate the research that has shown a correlation between high levels of cholesterol in blood plasma and an increased risk of coronary heart disease 1. Positive correlation with the blood plasma cholesterol level and increased risk of CHD. 2. This correlation may not be causative. 3. Cholesterol is made by liver. It is used to synthesize bile, steroid hormones, plasma membranes. 4. Reducing dietary cholesterol does not reduce blood cholesterol levels greatly. 5. Genetic factors are more important than dietary intake.

All cholesterol is not created equal • Turns out that cholesterol being carried by

All cholesterol is not created equal • Turns out that cholesterol being carried by Low Density Lipoproteins (LDL cholesterol) is correlated with CHD risk while High Density Lipoproteins (HDL cholesterol) is correlated with reduced risk. • Drugs (statins) can reduce blood cholesterol and risk of CHD. • Positive correlation between dietary intake of saturated fats and intake of cholesterol, so it is possible that it is the saturated fats, not the cholesterol, that causes the increased risk.

Explain how the lack of vitamin D or calcium can affect bone mineralization and

Explain how the lack of vitamin D or calcium can affect bone mineralization and cause rickets or osteomalacia • Vitamin D helps with the absorption of calcium in the intestines which is then used in bone formation. • Without Vitamin D, calcium is either not absorbed or is resorbed from bones so that bones become softened. So mineralization due to calcium salts is deficient.

 • Vitamin D helps with the absorption of calcium in the intestines which

• Vitamin D helps with the absorption of calcium in the intestines which is then used in bone formation • Without Vitamin D, calcium is either not absorbed or is resorbed from bones so that bones become softened • So mineralization due to calcium salts is deficient