1. Lipids: Not Just Fat
BIOL 103, Chapter 6-2

2. Today’s Topics Lipids Digestion and Absorption Lipids in the Body
Lipids in the Diet
Lipids and Health

3. Lipid Digestion
Digestion of triglycerides (TG), cholesterol, and phospholipids (PL)
Mouth
Chewing + lingual lipase secreted by salivary glands  ___________________________
Stomach
30% Triglycerides + gastric lipase  _______________

4. Lipid Digestion (cont.)
Small Intestine
Emulsified by bile
Rest of the “exposed” TG and DG are digested by pancreatic lipase  _______________________
Phospholipids + pancreatic phospholipase  ___________________________
Cholesterol ester + cholesterol esterase  ___________________________
Bile salts surround MG, FFA, cholesterol, and lysolecthicin forming ___________ (tiny emulsified fat packets made up of phospholipids)

5. Lipid Digestion (cont.)
Micelles carry ______________________ _______________ through the watery environment to microvilli/small intestine
The lipid components are then absorbed into the intestinal cells at the microvilli
Bile salts return to the _______ to be used again
______________________ are directly absorbed into your intestinal cells without the help of micelles.

6. Summary of Lipid Digestion

7. Lipids Absorption
To travel in the bloodstream, lipids are packaged into lipoprotein carriers
How?
In your intestinal cell: ______________________
Cholesterol esters and phospholipids form here also
Then, ________________________ lipoprotein.
Lipoprotein leaves the intestinal cell  _____________  goes to ____________ bloodstream.

8. Summary of Lipid Absorption

9. Lipid Digestion and Absorption (Figure 6.21)

10. Chylomicron Transport
In the blood stream, chylomicrons are large, fatty lipoproteins (90% fat)  circulate in the body while releasing ____________
When reaching capillaries, ______________ “attacks” chylomicrons ______________  FFA and glycerol:
FFA enter ________________ reassembled into TG
OR FFA enter _________________ used for energy
Glycerol  _______________________________
Your liver picks up “left-over” chylomicron and uses them to build ___________________

11. Summary of Chylomicron Pathway

12. Lipids in the Body Very-low-density lipoproteins (VLDL):
Deliver ________________ to cells
Intermediate-density lipoproteins (IDL)
Returns to ________ and is converted to ______
Low-density lipoproteins (LDL)
____________________ to cells, which body uses to synthesize membranes, hormones, etc.
Returns to liver afterwards
High-density lipoproteins (HDL)
____________________ for removal or recycling

13. Lipoprotein Pathway Summary

14. Lipoprotein density
Lipoproteins differ by size, density, and composition of their lipid cores
In general, larger the lipoprotein, the less dense it is.
Size:

15. Problem Set 6, Q#4:
Describe the differences between LDL and HDL and protein composition

16. Lipids in the Diet Recommended intake:
Reduce saturated fat and trans fat
Total fat: ____________________________
Less than 10% of calories from saturated fat

17. Lipids in the Diet Essential FA requirements
Linoleic acid/omega-6 FA should provide about _________________________
Requirements for omega-3 FA is less well-known
Omega-6 and omega-3 FA balance
Ratio of ______ (omega-6 to omega-3 FA)
While omega-3 FA is good for you, consuming too much of the omega-3 FA can suppress immune function and prolong bleeding time
Lip

18. Lipids and Health
Following are examples are diseases associated to high intakes of saturated and trans fat.
Obesity
Determined by excessive accumulation of body fat leading to a body weight in relation to height that is significantly greater than some accepted standard.
High-fat diets promote weight gain
Heart Disease/Cardiovascular Disease
Leading cause of death in US (1 death/minute)
Major risk factors
High blood cholesterol (___________________)
Smoking
High blood pressure

19. Lipids and Health Atherosclerosis Inflammation and atherosclerosis
Slow, progressive hardening and narrowing of arteries
Promoted by ______________________________
Inflammation and atherosclerosis
How? In blood vessel, LDL cholesterol is more likely to be oxidized  attract white blood cells to travel to LDL  certain WBC ingest oxidized LDL, releasing cholesterol  cholesterol builds up  plaque  thickening of arteries (atherosclerosis)
___________________________________ can speed up this process described above

20. AHA diet and lifestyle recommendations:
Reducing heart disease risk (pg )
Go over on your own
Consume an overall healthy diet
Aim for a healthy body weight
Aim for a desirable lipid profile
Aim for normal blood pressure
Aim for normal blood glucose levels
Be physically active
Avoid use of and exposure to tobacco products

21. AHA diet and lifestyle recommendations (cont.):
Reducing heart disease risk (pg )
Balance calorie intake and physical activity to achieve or maintain a healthy body weight
Consume a diet rich in fruits and vegetables
Choose whole-grain, high fiber foods
Consume fish, especially oily fish, at least 2/week
Limit your intake of saturated and trans fat

22. AHA diet and lifestyle recommendations (cont.):
Reducing heart disease risk (pg )
Minimize your intake of beverage foods with added sugars
Choose and prepare foods with little or no salt
If you consume alcohol, do so in moderation
Follow the AHA recommendations when eating outside of the home

23. Metabolic Syndrome ¼ US adults has metabolic syndrome
Has at least ____ of the following symptoms:
Excess abdominal fat
High blood glucose
High serum triglycerides
High blood pressure
Low HDL cholesterol

24. Putting it all together
Healthy People 2020 objectives target:
Reducing deaths from ____________________
____________________________
Reducing the number of adults with _________________________________

25. Cancer Stages of development:
Initiation: _____________ in cell’s genetics  abnormal cell
Promotion: when a chemical (e.g. carcinogen) encourages initiated cells to become __________
Reversible stage
Progression: when promoted cells ____________ _________________ healthy tissues

26. Cancer (cont.) Dietary and lifestyle factors for reducing cancer risk:
Maintain a healthful weight
Adopt a physically active lifestyle
Consume a healthy diet
If you drink alcohol, limit consumption