The Role of Oil Consumption in

Metabolic Diseases

Lipids

• Category of compounds that includes

– Triglycerides

– Sterols

– Phospholipids

• Contain carbon, oxygen, and hydrogen

• Hydrophobic

Lipids

• Basic functions in the body

– Store and provide energy – Fats provide 9 kcal per gram

– Provide insulation

– Help manufacture steroids and bile salts

– Play a role in transporting fat-soluble nutrients in the blood

– Used to manufacture major sex hormones

– Key to the structure of cell membranes

Type of Lipids

• Saturated fat

–Animal oil like meat, milk, butter (long chain fatty acid)

–Vegetable oil like coconut and palm kernel oil (short and medium chain fatty acid)

• Polyunsaturated fat

–Plan source like safflower, corn, cottonseed, sunflower oil and soybean oil (Omega 6)

–Cod liver oil (Omega 3)

• Monounsaturated fat

–Plant and animal product like olive oil, canola oil, avocado and peanut oil (omega 9)

Melting Point and Fatty Acid Composition of Some Fats and Oils

Fatty Acids Vary in Length

• Short-chain fatty acids

– Two to four carbons

– Weak attraction

– Liquid at room temperature

• Medium-chain fatty acids

– Six to 10/12 carbons

Fatty Acids Vary in Length

• Long-chain fatty acids

– 14 or more carbons

– Most common type of fatty acid in foods

– Strong attraction

– Solid at room temperature

Coconut oil

• Coconut oil contains antioxidants such as vitamin E, provitamin A, polyphenols and phytosterols.

• Because coconut oil has a lot of medium-chain fatty acids it can be useful for malabsorption conditions.

• May have some antibacterial, antiviral and antifungal properties.

• May help support the immune system. • Maintains coagulation factors and therefore does not

increase heart disease risk. • Reduces cholesterol and triglyceride levels. • Best result (i.e. reducing heart disease risk) is obtained

when combined with safflower, corn, or olive oil.

What happens if…

• You replace vegetable oils (soy, corn, canola, olive) with coconut oil?

– Vegetables oils contain more of the healthful fats (polyunsaturated and monounsaturated) that prevent heart disease and they have essential fatty acids.

– Replacing all healthful fats with coconut oil is not prudent since coconut oil does not provide any essential fatty acids.

– Will receive benefits from the other healthful components in coconut oil (phytosterols etc).

– American Heart Association recommends that only 7% of total daily calories come from saturated fat.

Coconut Oil in Cooking

• Coconut oil is used in cooking because it: – Has a higher burning point.

– Doesn’t go bad as quickly as some other fats.

– Adds a nutty, vanilla-like flavor to foods.

– Is solid at room temperature and can be used in cooking and baking.

– Is used by certain cultures as the main cooking oil.

Photo by Amy Selleck, Flickr

Coconut oil

• Can use virgin coconut oil prudently.

• Does not seem to increase heart disease risk.

• Is safe to use in small amounts.

• Can add flavor to cultural foods.

Fatty Acids Differ in Double-Bond Location

• The location of the first double bond in unsaturated fatty acids effect the omega-3 fatty acid and omega-6 fatty acid

• Omega-3 fatty acid – First double bond is between the third and fourth

carbon from the omega end

– Example: Alpha-linolenic acid • One of the two essential fatty acids

Fatty Acids Vary in Saturation

• Unsaturated

– Some carbons on fatty acid form a double bond with each other instead of binding to hydrogen

– Monounsaturated fatty acids (MUFA)

• Has one double bond

– Polyunsaturated fatty acid (PUFA)

• Has two or more double bonds

– Liquid at room temperature

– Lower melting point

Fatty Acids Vary in Saturation

• Saturated

– All the carbons on the fatty acid are bound to hydrogen

– Solid at room temperature

– Higher melting point

Fatty Acids Differ in Double-Bond Location

• Omega-6 fatty acid

– First double bond is between the sixth and seventh carbon from the omega end

– Example: Linoleic acid

• One of the two essential fatty acids

Fatty Acids and Rancidity

• Rancidity: spoiling of fats through oxidation – More double bonds therefore more susceptible to

oxidation and rancidity

PUFA > MUFA > Saturated fatty acids

• Enhancing stability of fatty acids by reducing rancidity – Adding antioxidants

– Limiting food exposure to oxygen, heat, and light

– Hydrogenation

• Fatty acids – Carbon and hydrogen chain, carboxylic acid, methyl group

– Basic structural units of triglycerides and phospholipids

– Differ in chain length, degree of saturation, shape

• Saturated fatty acids: no double bonds

• Monounsaturated fatty acids: one double bond

• Polyunsaturated fatty acids: two or more double bonds

– Essential fatty acids

• Lenoleic

• Alpha-linolenic acid

– Food manufactures hydrogenate or add antioxidants to fatty acids to reduce susceptibility to rancidity

Portion of Figure 5.7

Triglycerides • Three fatty acids connected to a glycerol

backbone

Caution: High levels in the blood are a risk factor

for heart disease

Triglycerides

• Most common lipid in both foods and the body

• Make up about 95% of lipids found in foods

• Functions – Add texture

– Makes meats tender

– Preserves freshness

– Stores as adipose tissue for energy

Beberapa jenis lemak • Triglycerides

– Found in the body – Stored in the adipose tissue – Major source of energy

• Phospholipids – An important part of cell membrane structure – Lecithin

• Important to cell membrane

• Used as a food emulsifier

• Sterols – Do not contain fatty acids – Do not provide energy

Proses cerna dan metabolisme

• Most fats are digested in the small intestine with the help of bile acids and pancreatic lipase

• Short- and medium-chain fatty acids are absorbed directly into the bloodstream

• Longer chain fatty acids and other remnants of fat digestion – Packaged in chylomicron lipoprotein carriers – Travel in lymph before entering the bloodstream

• Lipoproteins are globularshaped transport carriers – Outer shell high in protein and phospholipids – Inner core carries insoluble fat, cholesterol, and other

lipids through lymph and bloodstream

Uses of Fat and Cholesterol

• Source of energy

• Form body structures

• Regulate metabolism

• Enhance absorption of fat-soluble vitamins

• Provide insulation to help regulate body temperature

• Cushion major organs

Fat Is Used as Energy

• Fat

– Provides concentrated source of kilocalories

• 9 kilocalories per gram

– Readily available when the body needs energy

– Body’s main source of energy throughout the day

Fat Is Used as Energy

• Fat

– Body has an unlimited ability to store excess energy as fat in adipocytes

• Fat cells have the capacity to enlarge as much as 1,000 times their original size

• Body has the ability to produce additional fat cells

Fat Is Used as Energy and Helps Absorb Lipid Compounds

• Preferred source of energy for the heart, liver, and muscles

• Cannot sustain life alone

• Needs glucose – Only glycerol can be used for gluconeogenesis

• Several essential nutrients require dietary fat for absorption

• 20 grams per day are needed to stimulate chylomicrons that transport fat-soluble vitamins

Fat Helps Insulate and Protect

• Fat in subcutaneous tissue

– Insulates body

– Maintains body temperature

• Fat protects bones and vital organs from trauma

– Too much fat eliminates the protective benefit

Essential Fatty Acids, Eicosanoids, and Cell Membrane

• Linoleic acid can be elongated and converted to arachidonic acid

• Alpha-linolenic acid

– Converts to eicosapentaenoic acid (EPA)

• EPA elongates to docosahexaenoic acid (DHA)

– Needed for healthy cell membranes

Essential Fatty Acids, Eicosanoids, and Cell Membrane

• EPA and arachidonic acid are used to manufacture eicosanoids

• Eicosanoids are hormonelike substances

– Prostaglandins, thromboxanes, and leukotrienes

– Regulate the immune system, blood clotting, inflammation, and blood pressure

Cholesterol Is Used to Make Bile, Hormones, and Vitamin D

• Cholesterol

– A structural part of the cell membrane

– A precursor to vitamin D

– A precursor to bile acid

– Precursor for sex hormones such as estrogen and testosterone

Kegunaan Lemak

• Fat – An energy-dense source of fuel – Cushions and protects bones, organs, and nerves – Helps maintain body temperature – Provides essential fatty acids – Is needed for the absorption of fat-soluble vitamins and

carotenoids

• Essential fatty acids are precursors to EPA and DHA which manufacture – Prostaglandins – Thromboxanes – Leukotrienes

• Regulate the immune system • Regulate blood clotting • Regulate inflammation • Regulate blood pressure

Fungsi kolesterol

• Essential functions of cholesterol

– Is part of cell membrane

– Is needed to make

• Vitamin D

• Bile acid

• Sex hormones

Trans dan saturated fats

• Intake of trans fats and saturated fats correlate with increased risk of – Cardiovascular disease

– Stroke

– Cancer

• Substituting or replacing trans fats and saturated fats with MUFA and PUFA can lower risk

Dietary Cholesterol Is Not Essential

• The liver synthesizes cholesterol needed by the body

– Liver synthesizes ~900 mg/d

– Liver decrease synthesis based on dietary intake

• To reduce the risk of cardiovascular disease, dietary cholesterol should be limited to < 300 mg/d

Kebutuhan Lemak

• Dietary lipids are an important part of a healthy diet, especially essential fatty acids

• Saturated fat, trans fats, and cholesterol intake should be limited

• Dietary fat intake per day – Should range from 20 to 35% of total kilocalories – 5–10% of kilocalories from linoleic acid – 0.6–1.2% of kilocalories from alpha linolenic acid – Limit saturated fat intake to < 10% of total fat intake – Limit trans fat intake to < 1% of total fat intake – Limit cholesterol intake to < 300 mg

Sumber lemak

• Lean meat and poultry, fish, low-fat or nonfat dairy products and limited amounts of nuts and cheese – Best sources of essential fatty acids – Limit intake of saturated and trans fats

• Commercially prepared baked goods and snack items – Are high in kilocalories – Are high in saturated and trans fats – Should be consumed rarely

• Use vegetable oils in the place of butter

Trans Fats

• Trans fat may actually be worse for heart health than saturated fats

– Raise LDL cholesterol

– Lower HDL cholesterol

• FDA requires trans fat to be listed on food labels

• The food industry is working to find replacements for trans fats in foods

Food Sources of Cholesterol and Plant Sterols

• Cholesterol comes mainly from animal products • The cholesterol produced in plant cell walls and

oils is so minimal they are considered cholesterol free

• Phytosterols and stanols – Lower LDL levels by competing with cholesterol for

absorption – Are found in soybean oil, many fruits, vegetables,

legumes, sesame seeds, nuts, cereals, and other plant foods

– Food manufacturers are fortifying foods with them to help lower cholesterol

Trans fat dan Kolesterol

• Trans fats are made by heating oil and adding hydrogen gas to saturate the carbons of the fatty acids

• Trans fats raise LDL cholesterol and lower HDL cholesterol

• Trans fats are found in many commercially prepared foods and must be listed on the food label

• Other oils are being tested to replace trans fats in foods

• Cholesterol is found mostly in animal products • Phytosterols are found in vegetable oils, nuts, legumes,

whole grains, fruits, and vegetables

Lowering Blood Cholesterol Levels

• Consume less saturated and trans fats • Consume less cholesterol • Make smart, informed food choices

– Avoid or consume processed food in moderation – Eat at least two servings of fish per week – Consume more plant foods – Consume antioxidants and phytochemicals – Garlic may help lower cholesterol – Flavonoids may help prevent LDLs from oxidizing

• Exercise • Alcohol, in moderate amounts, can reduce the risk of heart

disease

Putting It All Together

• For optimal long-term health a diet should include a proper balance of all nutrients including fat

• There are different types of lipids, some essential and others not required from foods

• Goal – Consume mostly unsaturated fats – Limit amount of saturated and trans fats

• A plant-based diet plentiful in whole grains, fruits, and vegetables, with some low-fat dairy and lean meats, poultry, fish, and vegetable oil will be high in fiber and lower in saturated fats, trans fats, and dietary cholesterol