Human Nutrition

1. Human Nutrition Chapter 10 Dr. WJ Mueller

2. Nutrient Requirements • Macronutrients • Carbohydrates • Protein • Fats or oils • Micronutrients • Vitamins • Minerals

3. Carbohydrates • Sugars • Monosaccharides (know 2 examples) • Disaccharides (know 2 examples) • Polysaccharides • Starches • Glycogen • Cellulose

4. Proteins • From the book know • How are proteins and amino acids related? • the difference between essential and non-essential amino acids • How many amino acids are necessary for humans • How many are essential

5. OH OH OH C C CH2 H 2 H Fats • The difference between fats and oils • Fats are solid at room temperature • Oils are liquid at room temperature • A fat is a glycerol molecule with three fatty-acid molecules attached to it H2COH-HCOH-H2COH • You do not have to know the structure, but do know that the three long-chain fatty acids attach to the OH molecules to make an oil Glycerol

6. H H C C H H Fatty Acids • They are chains of carbon atoms bonded to hydrogen and oxygen atoms COOH-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3 • Many of you may know that carbon atoms require four bonds • Structurally a fatty acid looks like this:

7. Fatty Acids (cont.) • If the long-chain fatty acids do not have any double bonds between carbon atoms it is said to be saturated, or it has all the hydrogen molecules it can • Previous slide represents a saturated fatty acid

8. Double bond H H C C C C H H H H Fatty Acids (cont.) If the long-chain fatty acid has one double bond along the chain, it is said to be monounsaturated, or lacks 2 hydrogens (remember the four bond rule for carbon atoms) COOH-CH2-CH2-CH2-CH2-CH2-CH=CH-CH2-CH3

9. Fatty Acids (cont.) • If a fatty acid has two double bonds, then it is said to be either polyunsaturated or diunsaturated or lacking four hydrogens H H H C C C C C C C H H H H H H H

10. Fatty Acids (cont.) If the long-chain fatty acid has three double bonds along the chain, it is said to be polyunsaturated, or lacks 6 hydrogens COOH-CH2-CH2-CH=CH-CH2-CH=CH-CH2-CH=CH-CH2-CH3

11. Fatty Acids (cont.) • Oils that have no double bonds tend to be solid at room temperature • Oils with double bonds tend to be liquid at room temperature

12. Fatty Acids (cont.) • Now when you hear the phrase on a margin commercial that it is made of polyunsaturated fats, you will know what they are talking about. • You may have heard that monounsaturated (one double bond) fatty acids are good for you • Oils that are high in monounsaturated fatty acids are include: • Olive Oil • Canola Oil

13. Fatty Acids (cont.) • Another term that is making an appearance lately is “trans-fatty acids” • In organic chemistry one learns that there are two configurations around a double bond. They are cis- and trans- • In nature, there are no trans-fatty acids, only cis-fatty acids

14. Fats (cont.) • To make the perfect butter substitute, people figured out how to hydrogenate unsaturated fatty acids (make it more saturated) • This is done by putting the oil under pressure with hydrogen and a nickel catalyst • What does hydrogenation do? • It breaks double bonds and adds the missing hydrogen atoms to the molecule

15. Fats (cont.) • When you hear the term “partially hydrogenated vegetable oil” you will now know what it means

16. Fatty Acids (cont.) • Cis-fatty acids are when the hydrogens are on the same side of the double bond

17. Fatty Acids (cont.) • Cis-fatty acids are when the hydrogens are on the same side of the double bond (see below) H H H C C C C C C C H H H H H H H H H

18. Fatty Acids (cont.) • Trans-fatty acids are when the two hydrogen atoms are opposite to each other (see below) • This is not the configuration you find in nature H H H H H C C C C C C C H H H H H H

19. Trans-fatty acids (cont.) • The only way that trans-fatty acids are made is by hydrogenation • Some of the double bonds are broken and reformed in the process • When they are reformed, they have a 50-50 chance of being in cis- or trans- formation • Many are saying that trans-fatty acids are bad for you

20. Fat Facts • The cholesterol molecule is closely related to fats • Plants make no cholesterol • Only animals make cholesterol • Even if you never eat any cholesterol, you may be in danger of having high cholesterol (why?)

21. Fats • The current thinking (always subject to change) is that saturated fats are bad for you • Increases LDL cholesterol • Monounsaturated fats tend to be good for you • Decrease LDL and increase HDL (find out what LDL and HDL refers to) • Polyunsaturated fats neither raise or lower cholesterol

22. Fats (cont.) • It is also said that animal fats are bad for you • They are made up of saturated fatty acids • Tropical oils are bad for you (coconut and palm oil) • Also made of saturate fatty acids

23. Cholesterol Story #1 • You are probably familiar with adrenalin, a chemical produced by the body that powers the “flight or fight” mechanism • If someone comes up behind you in a dark alley, your adrenalin may shoot up • Your response might be to run a 100 meters in four seconds flat • Or perhaps pop the oncoming person in the nose

24. Cholesterol Story #1 (cont.) • I remember one time a cow chased my cousin and me out of the pasture • I do not remember how I cleared the fence, but I had no problem doing it • ADRENALIN!

25. Cholesterol Story #2 • When adrenalin is released and then not used, something has to happen to it. It breaks down into other things • One of those other things is cholesterol (LDL)

26. Cholesterol Story #3 • In the early 1980’s a big report came out stating that a big study was done and it showed that fluorescent lights caused heart disease • Everyone jumped! Get rid of those fluorescent lights, it is killing our workers!

27. Cholesterol Story #3 (cont.) • That is like the scientist that did an experiment on jumping spiders • First he measured how high the spider could jump when commanded • Then he pulled off one leg and measured the height he could jump with seven legs on the scientists command • He continued to pull off legs and measured how high the spider could jump when he commanded it to

28. Cholesterol Story #3 (cont.) • Finally the spider had no legs and the spider did not jump when commanded • The conclusion: • Spiders cannot hear without legs!

29. Cholesterol Story #3 (cont.) • The scientists conclusion on the spider seems ludicrous, but is was no more so than everyone changing out the fluorescent lights • Did people working under fluorescent lights have more of a problem with heart disease—Yes • Was it caused by the lights—No

30. Cholesterol Story #3 (cont.) • What was the cause? • People working in offices get stressed • When people get stressed, they produce adrenalin • In an office building are they using that adrenalin to run or punch someone out (maybe the latter!)—No • So it has to break down to cholesterol

31. Cholesterol Story #3 (cont.) • What if you are in a high-stress job? • GET EXERCISE, even if it a brisk walk up and down the hall • Use up some of the built up adrenalin

32. Cholesterol Story #4 • A lady at Utah State University when I was there (about 100 years ago) set up a study on cholesterol. • She paid students to: • Take a cholesterol test every day • Keep track of everything they ate • Keep track of when they slept • What they did and when • What their moods were • Everything about their lives

33. Cholesterol Story #4 (cont.) • The experiment was to find out what raised cholesterol levels • When she analyzed the correlation data, she was very disappointed and to my knowledge did not publish her results

34. Cholesterol Story #4 (cont.) • What did NOT raise cholesterol in students? • Various foods (they did not make a difference) • Types of fats eaten (they did not make a difference)

35. Cholesterol Story #4 (cont.) • What DID raise cholesterol in students? • Breaking up with a girl or boy friend • Having a test the next day • Loosing a loved one • Winning a poker game • Beating someone in a game of chess • Watching a football game on TV

36. Cholesterol Story #4 (cont.) • I think her results were very informative • Stresses (good or bad) increase cholesterol • Now you know the mechanism • What should you do about it? • Get some exercise

37. Fats (cont.) • So what is true? • Science has flip flopped several times on what is good and bad in the past 20 year that I have studied fats on what is and is not good for you

38. My Take-home Lesson • We probably eat too much fat as a society, so instead of worrying about what fat you should and should not eat, reduce your fat intake • Do not stress out over it • Get more exercise

39. My Take-home Lesson (cont.) • There are those individuals who have genetic tendencies toward high cholesterol, and those individuals need to be more careful

40. Fats • May I emphasize that this is not the end of the story. • It will be interesting to follow what is good and bad today may be reversed tomorrow