This document discusses lipid absorption, transport, and metabolism in the human body. It covers how different types of lipids are absorbed in the small intestine and transported via lipoproteins such as chylomicrons, VLDL, LDL, and HDL to cells throughout the body. It also addresses health implications like heart disease risk and recommendations to improve LDL/HDL ratios through diet and lifestyle factors.

1. Lipid Absorption
• Glycerol, SCFA, MCFA diffuse into
intestinal cells; absorbed directly into
blood stream;
• Monoglycerides and LCFA merge into
micelles; into intestinal cells;
reassemble into TG;
• new TG packed into chylomicrons; into
lymph system; point of entry to
bloodstream at thoracic duct near the
heart; to rest of body;

3. Lipid Transport
• Lipoproteins: clusters of lipids
associated with proteins that serve as
transport vehicles for lipids in the lymph
and blood;
• 4 main types of lipoproteins
– 1. Chylomicrons
– 2. VLDL
– 3. LDL
– 4. HDL

4. Lipoproteins
• 1. Chylomicrons
– transport diet-derived lipids (mostly TG)
from intestine to rest of the body;
– cells from all over the body remove lipids as
the chylomicrons pass by; get smaller;
protein remnants left; go to liver;
• 2. VLDL (Very Low Density Lipoprotein)
– liver site of lipid synthesis; lipid packaged
with proteins shipped to other parts of the
body; cells remove TG; become more
dense;

5. Lipoproteins
• 3. LDL (Low Density Lipoproteins)
– derived from VLDL; circulate throughout body;
content available to cells to build new
membranes, make hormones, or store;
– LDL receptors on liver cells remove LDL from
circulation;
• 4. HDL (High Density Lipoproteins)
– carries cholesterol and other lipids from the
cells back to the liver for recycling or disposal
– mostly protein;

7. Lipid Metabolism
• Storing Fat as Fat
– Fat cells of adipose tissue take up and store
fat;
– LPL on adipose cell surface captures
circulating TG after meals;
• Making Fat from Carb or Protein
– FA can be made from carb or pro
components;
– requires energy
• Making Fat from Fat
– little energy to do this;

8. Health Implications
• LDL (lousy):linked to heart disease
• HDL (happy): protective from heart
disease
• Factors that improve LDL-HDL ratio:
– weight control
– MUFA/PUFA vs. SFA
– Soluble fiber
– Antioxidants
– Physical activity
– Moderate alcohol consumption

9. Heart Disease
• Blood Lipid Profile:
– Total Cholesterol: Desirable: < 200 mg/dl
– (borderline:200-239 and high: >240)
– LDL Cholesterol: Optimal: < 100 mg/dl
– (near optimal: 100-129; borderline high:130-
159
– High: 160-189; Very High: >190)
– HDL Cholesterol: Risk factor: <40 mg/dl
– 40-59: better; >60: protective
– Triglyceride: Desirable: < 150 mg/dl;
– (B: 150-199; high: 200-499; very high: >500)

10. Health Effects of Lipids
• Risks from Saturated Fats
– saturated fats raise LDL cholesterol
– LDL raises the risk of heart disease
• Risks from trans-Fats
– raise LDL cholesterol and lower HDL chol.
• Cardiovascular disease (CVD)
– all diseases of the heart and blood vessels
• Coronary heart disease (CHD)
– arteries around heart are blocked, cause
damage

14. Mediterranean Food Pyramid

15. Fat
• Benefits from Omega-3 Polyunsaturated
Fats/Cancer/Obesity/Fat restriction
• Recommended Intakes of Fat:
– Total Fat 30% of total kcals
– Saturated fat less than 10% of total kcals
– Cholesterol less than 300 mg
• Reduce Total Fat, Saturated Fat, trans-
fat intake from foods
• Reduce Cholesterol Intake

16. Healthy Food Choices
• Balance Omega-3 and Omega-6
Intakes
• Select Lean Meats and Nonfat milks
• Eat Plenty of Vegetables, Fruits, Grains
• Use Fats and Oils Sparingly
• Look for Invisible Fat
• Choose Wisely
• Read Food Labels

17. • J.M. went to see her medical provider to discuss results
of recent lab work: Chol: 250 mg/dl; LDL: 150 mg/dl;
HDL: 65 mg/dl; Trig. 120 mg/dl. Her food recall is:
bkf: 3 eggs, 3 sl. white toast with butter, 16 oz OJ
lun: bologna & cheddar swich, hoho, coke
din: fried chicken thigh, mashed potato, gravy, corn
snack: bowl of ice cream
• 1. Evaluate J.M. lab results--high?low? What are the
recommended levels?
• 2. How is her essential fatty acid intake? What foods
would you recommend she consume?
• 3. Is J.M. consuming any sat. fat? MUF? PUF? Trans?
• 4. List suggested dietary changes for J.M.
• 5. What disease should J.M. be concerned about?
• 6. J.M. is told to increase her fiber intake. Why? How?

18. • 7. Describe 4 types of lipoproteins.
• 8. Look at your food label:
– What type of fat does it contain?
– Is there any cholesterol?
– What fat is listed in the ingredient list?