Lipids - Health Issues & Lipids Chapter 4

Vocabulary flashcards covering key lipids concepts, types, metabolism, transport, dietary guidelines, and health implications from the course notes.

Lipids

A diverse group of fats, oils, and related compounds that are insoluble in water; provide energy (9 kcal/g), supply essential fatty acids, aid absorption of fat‑soluble vitamins, improve palatability, promote satiety, and support cell structure and protection.

Essential fatty acids (EFAs)

Fatty acids the body cannot synthesize in sufficient amounts and must be obtained from the diet; include linoleic acid (n‑6) and alpha‑linolenic acid (n‑3).

Linoleic acid (n‑6)

An essential omega‑6 fatty acid; precursor to arachidonic acid and important for skin integrity, cholesterol regulation, growth, and immune function.

Alpha‑linolenic acid (ALA) (n‑3)

An essential omega‑3 fatty acid; precursor to EPA and DHA; important for heart health and brain development.

Omega‑3 fatty acids

Polyunsaturated fats with the first double bond at the third carbon from the methyl end; includes ALA, EPA, and DHA; beneficial for cardiovascular health.

Omega‑6 fatty acids

Polyunsaturated fats with the first double bond at the sixth carbon from the methyl end; includes linoleic acid; essential and involved in inflammation and skin integrity.

Arachidonic acid (AA)

Omega‑6 fatty acid that can be made from linoleic acid; a precursor in the synthesis of eicosanoids.

Eicosapentaenoic acid (EPA)

Long‑chain omega‑3 fatty acid derived from ALA; contributes to anti‑inflammatory eicosanoids and cardiovascular health.

Docosahexaenoic acid (DHA)

Long‑chain omega‑3 fatty acid important for brain and neural development; mainly from fish and algae sources.

Saturated fat

Fatty acids with no double bonds; usually solid at room temperature; high in animal fats and certain tropical oils (e.g., coconut, palm kernel).

Monounsaturated fatty acids (MUFA)

Fatty acids with one double bond; examples include olive oil and canola oil; linked to favorable lipid profiles when replacing saturated fat.

Polyunsaturated fatty acids (PUFA)

Fatty acids with two or more double bonds; include omega‑3 and omega‑6 fatty acids; essential fats and fish oils.

Trans fatty acids

Fats with trans double bonds formed during hydrogenation; raise LDL, lower HDL, and increase risk of heart disease and diabetes; often labeled in foods.

Cis fatty acids

Natural configuration where hydrogens are on the same side of the double bond; most dietary fats are cis.

Triglycerides

The main form of dietary and stored fat; glycerol backbone with three fatty acids; energy dense (9 kcal/g).

Monoglyceride

Glycerol with one fatty acid attached; intermediate in fat digestion.

Diglyceride

Glycerol with two fatty acids attached; intermediate in fat digestion.

Lipoproteins

Lipid‑protein particles that transport fats in the bloodstream; include chylomicrons, VLDL, IDL, LDL, and HDL.

Chylomicrons

Lipoproteins formed in intestinal cells to transport dietary triglycerides via the lymphatic system to the bloodstream.

Very low‑density lipoprotein (VLDL)

Lipoprotein that carries endogenous triglycerides from liver to tissues; can become LDL as triglycerides are removed.

Low‑density lipoprotein (LDL)

Lipoprotein that transports cholesterol to tissues; high levels linked to atherosclerosis; 'bad' cholesterol.

High‑density lipoprotein (HDL)

Lipoprotein that returns cholesterol from tissues to liver for excretion; protective against heart disease; 'good' cholesterol.

Cholesterol

A sterol, not a fat or triglyceride; essential for hormone synthesis, bile acids, brain and nerve tissue, and cell membranes; found in animal products and synthesized by the liver.

Phospholipids

Lipids with a phosphate group; major component of cell membranes and lipoproteins; lecithin is a key phospholipid.

Lecithin

A major phospholipid that acts as an emulsifier in lipoproteins and cell membranes.

Bile acids

Cholesterol‑derived acids produced by the liver that emulsify fats to aid digestion and absorption.

Hydrogenation

Industrial process adding hydrogen to unsaturated fats to make them more saturated; creates trans fats and improves shelf life.

Cis vs. Trans fatty acids

Cis fats have hydrogens on the same side of a double bond; trans fats have hydrogens on opposite sides due to hydrogenation and raise cardiovascular risk.

Visible fat

Fat that can be seen in foods (e.g., butter, margarine, oil, bacon).

Hidden fat

Fat present in foods not obviously fatty (e.g., milk, eggs, cheese, nuts, bakery items).

Acceptable Macronutrient Distribution Range (AMDR) for fat

20–35% of total daily calories from fat.

AMDR balance with carbohydrate

Recommendation to balance fat (20–35%) with carbohydrate (45–65%) to meet energy and nutrient needs.

Essential Fatty Acid Deficiency (EFAD) symptoms

Dry, scaly skin; liver abnormalities; poor wound healing; growth failure in infants; impaired hearing and vision.

Dietary Reference Intakes for LA (AI)

LA AI: 17 g/day for men 19–50; 12 g/day for women 19–50; 14 g/day men 51+; 11 g/day women 51+.

Dietary Reference Intakes for ALA (AI)

ALA AI: 1.6 g/day for men; 1.1 g/day for women.

EPA and DHA formation from ALA

EPA and DHA can be synthesized from ALA, but conversion is slow; best sources are fatty fish.

Fish intake recommendations during pregnancy

Pregnant and lactating women are encouraged to eat 1–2 portions of fatty fish per week to support DHA/EPA intake.

Fish oil supplements

Promoted with medical supervision; may prolong bleeding time; use with caution in those on anticoagulants; algae sources for vegans; two servings of fish weekly recommended.

Coconut oil and other highly saturated oils

Coconut oil is highly saturated (~88%); palm kernel oil also high in saturated fat.

Short‑chain fatty acids

Fatty acids with 4–7 carbons; remain liquid at room temperature and are absorbed directly into the portal blood.

Medium‑chain fatty acids (MCFA/MCTs)

Fatty acids with 8–12 carbons; absorbed directly and often used in intestinal diseases.

Micellar bile‑lipid complex

Initial lipid absorption complex formed when bile salts emulsify fats in the small intestine.

Enterohepatic circulation

Recycling of bile acids from the intestine back to the liver.

Atherosclerosis

Buildup of lipids and fibrous material in arterial walls, increasing risk of heart attack and stroke.

Arteriosclerosis

Hardening of the arteries.

Olestra

A non‑absorbable fat replacer that can interfere with absorption of fat‑soluble vitamins.

Fat replacers (Simplesse, Carrageenan, Salatrim)

Ingredients used to replace fat in foods to reduce kcal without losing texture; effects vary on digestion and absorption.