ADVANCED NUTRITION: INTRO TO LIPIDS

Lipids

compounds that dissolve in organic solvents:

-- Energy (storage - 9 kcal/gm)

-- Essential FA’s 18:2 ω6 linoleic acid

18:3 ω3 α-linolenic acid)

-- Fat-soluble vitamin carriers (A,D,E,K)

-- Insulation (subcutaneous)

-- Organ protection (visceral)

-- Satiety (taste?)

-- Membrane structure & fluidity

(PL, cholesterol)

-- Signal transduction

-- Regulation of gene expression

Fatty Acids

endogenous activators of PPARs

- Pharmaceuticals also target PPARs

- Fibrates target PPARα for lowering cholesterol

- TZDs target PPARγ for blood sugar reduction

TRIACYLGLYCEROL (TG)

a neutral lipid (uncharged)

1. 9 kcal/gm

2. anhydrous

Phospholipids

Amphipathic molecules with a phosphate and glycerol backbone

Cholesterol

Precursor of bile acids and Vitamin D → Regulating membrane fluidity and amphiphatic

Lower

Double bonds lower or higher Melting Point

higher

Single bonds lower or higher Melting Point

Free cholesterol

Active form of cholesterol

Cholesterol Ester

Stroage form of cholesterol

oxysterols

Oxidized sterol metabolites of cholesterol

Naturally occurring fats

Double bonds are in cis configuration with H’s are on same side of C=C bond

Trans Fatty Acids

produced by hydrogenation of oils (processed foods)

small amounts in dairy naturally occurring

∆ nomenclature

Carbons counted from carboxyl end

ω nomenclature

Carbons counted from methyl end

Essential Fatty Acids (EFA)

(must be obtained from the diet)

• 18:2 ω 6 (linoleic acid)

• 18:3 ω 3 (α-linolenic acid)

Olive, Cananola, Peanut Oils, Nuts and butter, avocado

Monounsaturated fats examples

Safflower, sunflower, corn, soybean, cottonseed oils, nuts

Omega-6 PUFAs, mainly LA (18:2n-6), arachidonic (20:4) examples

Mostly cold water fish: salmon, anchovies, tuna, herring

Omega-3 PUFAs, including ALA (18:3n-3), EPA (20:5), DHA (22:6) examples

• Limit intake of solid fats

• Less than 10% SFA (> age 2)

• No Trans fat

• As little cholesterol as possible

• Remember to maintain total caloric intake

to maintain ideal body weight

Dietary recommendations for lipid intake

Palm oil

50% SFA, 40% MUFA, 10% PUFA

Palm kernel oil

similar to Coconut oil (high in medium chain SFA)