TOPIC D1: HUMAN NUTRITION1. Definitions – nutrients, essential nutrients, vitamins and

minerals2. Fat in the diet3. Protein in the diet4. Malnutrition – starvation 5. Malnutrition – obesity6. Appetite control

ESSENTIAL QUESTIONS A balanced diet is essential for (human) life. What are some of the key nutrition-related health threats that

the world faces today? In what ways can we help people to make healthy, sustainable

choices? What do YOU want to learn about human nutrition and health?

GENERAL RESOURCESGLOBAL NUTRITION AND MALNUTRITION The World Food Programme Global hunger map:

http://cdn.wfp.org/hungermap/ The World Food Programme Hunger centre: http://www.wfp.org/hunger

NUTRITION RESOURCES The Harvard Nutrition centre:

http://www.hsph.harvard.edu/nutritionsource/ The US Government Nutrition Resource Centre:

http://www.nutrition.gov The UK Nutrition Foundation:http://www.nutrition.org.uk

1

WHAT DO YOU NEED TO EAT? You should already have learned this in your PE nutrition course, but if you need reminding, take a look at the healthy eating pyramid/plate for the classic recommendations. (Note that different types of plate/ pyramid are produced for different cultures (European, Indian, South Asian, Caribbean etc):http://www.hsph.harvard.edu/nutritionsource/pyramid/

Link to the Macdonald’s nutritional calculator – work out the nutritional content of a MacDonald’s meal….https://www.mcdonalds.com/gb/en-gb/good-to-know/nutrition-calculator.html

UNDERSTANDINGSD.U.1: Essential nutrients cannot be synthesized by the body, therefore they have to be included in the dietDEFINITIONS1. Define nutrient:

2. What is the difference between an essential nutrient and a non-essential nutrient?

3. List the essential amino acids:

4. List essential fatty acids

2

D.1.U.2: Dietary minerals are essential chemical elementsD.1.U.3: Vitamins are chemically diverse carbon compounds that cannot be synthesized by the bodyD.1.A.1: Production of ascorbic acid (Vitamin C) by some mammals, but not others that need a dietary supply

VITAMINS AND MINERALS1. What is the definition of a vitamin? Give 4 examples

2. . What is the definition of a dietary mineral? Give 4 examples

VITAMIN C (Ascorbic acid)Resources: The Linus Pauling Micronutrient Centre: fount of information about

Vitamin C A mystery – why did humans (and other mammals) lose the ability to

synthesise Vitamin C? The WHO definitive guide to Vitamin C

3. What does Vitamin C do in an animal’s body?

4. List foods high in Vitamin C

5. What are the effects of Vitamin C deficiency?

6. What is scurvy? Whom does it affect?

7. What is the recommended daily allowance (RDA) of Vitamin C in adults in: The USA Switzerland Russia

3

The UK Australia

8. According to the US, what is the minimal RDA (required to prevent scurvy) in adults?

9. Is the recommended RDA for Vitamin C the same for all ages and types of people?

10. Which animals cannot synthesise Vitamin C de novo?

11. How have animal studies been used to determine the RDA of Vitamin C in humans?How valid do you think the levels calculated in animals are to humans?Does scurvy affect animals other than humans?

4

TOK: There are positive effects of exposure to sun such as production of vitamin D, as well as health risks associated with exposure to UV rays. How can conflicting knowledge claims be balanced?

VITAMIN D10. What does Vitamin D do in the body?

11. What are the sources of Vitamin D (in the diet and elsewhere)?

12. EVALUATE the risks of Vitamin D deficiency against the risks of sunburn and skin cancer…

5

D.1.U.6: Malnutrition may be caused by a deficiency, imbalance or excess of nutrients in the diet

D.1.U.9: Starvation can lead to breakdown of body tissue (marasmus)

MACRONUTRIENTS

Carbohydrates Proteins FatsSince all macronutrients contain energy, high intake can lead to storage of excess energy as fat, therefore weight gain, possible obesity and coronary heart disease. The ideal is a balance of all

three to ensure sufficient intake of all essential nutrients.Disadvantages

1. Native Inuits traditionally consume a high-far high-protein diet based on whale meat and fish. Why does their diet result in a lower risk of heart disease, stroke and atherosclerosis compared to a western high –fat diet?

Watch Hank’s analysis of High-fructose corn syrup. 2. List 4 ‘PROS and 4 ‘CONS of HFCS1.

2.

3.

4.

6

DIETARY FAT

D.1.U.5: Some fatty acids and some amino acids are essential

Resources: Shining the spotlight on trans fats (from Harvard Pubic Health

department) Learning about the link between fat intake and disease: the good, the

bad, and the downright untrue a 5 minute podcast from the Cochrane Review site, reviewing the

current state of knowledge about heart disease and dietary fat

You need to understand, and be able to define: essential fatty acids The three main sections of a fatty acid: carboxyl, hydrocarbon, and

methyl group Which end of the fatty acid is the omega (ϖ) end?

1. Annotate the fatty acids below to identify these regions specified above:

2. What is the difference between a saturated and an unsaturated fat?

In unsaturated fats, how does the position of the ‘missing hydrogen atoms’ around the double bond affect the chemical properties (and health effects) of the fatty acid?

7

3. Explain the process of hydrogenation. Which types of fat are produced by hydrogenation?

4. Are there any naturally occurring examples of trans fats?

5. List examples of the different types of fat :

Type of fat ExamplesPolyunsaturated: cis

Polyunsaturated: trans

Monounsaturated

Saturated: animal

Saturated: plant

6. Omega-3 and Omega – 6 are naturally occurring cis-polyunsaturated fatty acids. What are the natural sources of these fatty acids?

What are their supposed health benefits?

Are there potential adverse effects of omega -3 and omega-6 fats?

7. Briefly outline the link between a high-fat diet and heart disease

8. Which types of fat carry the highest risk of predisposing to heart disease?

8

PHENYLKETONURIA

D.1.U.5: Some fatty acids and some amino acids are essentialD.1.A.2: Cause and treatment of phenylketonuria

Watch these short interviews with two 18 year-olds (Jack and Claire) for a ‘personal introduction’ to life with PKU: http://www.open.edu/openlearn/body-mind/social-care/phenylketonuria-long-term-conditionResources: Use these links to help you: PKU from Utah Genetics: http://learn.genetics.utah.edu/content/disorders/whataregd/pku/ Learning about PKU from the US Genome Website: http://www.genome.gov/25020037 PKU diagnosis and treatment from the NHS The national PKU alliance:

http://www.npkua.org/index.php

1. Explain the cause and consequences of PKU:

2. Explain how PKU is treated (managed):

9

MALNUTRITIOND.1.U.6: Malnutrition may be caused by a deficiency, imbalance or excess of nutrients in

Watch this 2 minute video from the WFP: http://www.wfp.org/videos/nutrition-2-minutes-0Use the WFP hunger site to help you explore and investigate the differences between hunger and malnutrition: http://www.wfp.org/hunger

1. What is the definition of malnutrition?

PROTEIN MALNUTRITION2. What is the name for the disease associated with general protein malnutrition?

3. What is the origin of this name?

4. What are the key consequences of general protein deficiency malnutrition?

5. Which countries have the highest incidence of protein deficiency malnutrition?

6. Can over-consumption of protein cause protein malnutrition? – explain HOW, and outline the potential consequences of protein over-consumption.

10

STARVATION II: ANOREXIA NERVOSA

D.1.U.9: Starvation can lead to breakdown of body tissueD.1.A5: Breakdown of heart muscle due to anorexia

1. Define anorexia nervosa: When was the disease first identified?

2. Compare the incidence of anorexia nervosa in males and females

3. Outline the adverse health effects of anorexia nervosa

4. Outline SPECIFICALLY the effects of anorexia nervosa on the heart (use this link)

11

OBESITY

D.1.U.8: Overweight individuals are more likely to suffer hypertension and type II diabetes

1. Define obesity:

2. Which countries have the highest obesity rates in the world?

Watch Hank on Obesity:

3. Hank outlines 8 reasons for the obesity epidemic in the US. List the reasons he outlines:

1.2.3.4.5.6.7.8.

4. Hank outlines a 5-step prescription for weight loss. Outline his prescription:

1.

2.

3.

4.

5.

12

5. Outline diseases associated with obesity

13

APPETITE CONTROL

D.1.U.7: Appetite is controlled by a centre in the hypothalamus

Questions are based on the 3 videos on the class Blog on appetite: Appetite is complex: it involves the BRAIN, the STOMACH and INTESTINES, the PANCREAS and ADIPOSE TISSUE and also OUR ENVIRONMENT

Outline the role in appetite control of:

a) The hypothalamus:

b) Ghrelin:

c) PYY366 (and CCK):

d) Leptin (Greek for ‘thin’)

e) Insulin and glucagon:

14

DIETARY FIBRED.2.U7:  Materials not absorbed are egested (Oxford Biology Course Companion page 676). Define egestion. Define dietary fibre. State two examples of dietary fibre. List materials that are egested from the body

Resource: Fibre: Start roughing it – the full story: from Harvard Public Health: http://www.hsph.harvard.edu/nutritionsource/fiber-full-story/

1. What is the definition of dietary fibre?

2. What are the sources of dietary fibre?

3. What is the recommended quantity (in g) of fibre for males and females of your age?

4. What are the health benefits of a high fibre diet?

15

NOW OFF SYLLABUS BUT FUN

DIET, SOCIETY AND HEART DISEASE: A TRIP AROUND THE WORLDResources:The Maasai ‘paradox’: http://sciencenordic.com/maasai-keep-healthy-despite-high-fat-diet http://www.sciencedaily.com/releases/2008/07/080718075357.htm http://www.empiricalzeal.com/2012/09/30/milk-meat-and-blood-how-

diet-drives-natural-selection-in-the-maasai/The Inuit ‘paradox’: http://www.theiflife.com/the-inuit-paradox-high-fat-lower-heart-disease-and-cancer/The Mediterranean diet: http://www.nytimes.com/2013/02/26/health/mediterranean-diet-can-cut-heart-disease-study-finds.html?pagewanted=all&_r=0The unhealthy ‘Western’ diet: Heart disease in Scotland (a world leader!):http://www.hriuk.org/about-heart-disease/Scotland/And just to throw a spanner in the works: this link looks at all sorts of inconsistencies between diet and heart disease in Europe:http://www.dietdoctor.com/stunning-saturated-fat-and-the-european-paradox

Compare and contrast the diets and the health of the different human populations (societies) listed above, with particular attention to their dietary fat intake. Is dietary fat intake (type and quantity) the only (or the key) determinant of risk for heart disease?

16