the fat facts final

8/9/2019 The Fat Facts Final

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The

FAT FACTS

By :

A.H.Mohamed Rushdi

Department of Food Science & TechnologyUniversity of Peradeniya

2010


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INTRODUCTIONWhat is fat?

Fat is a nutrient. It is crucial for normal body function and without it

we could not live. Not only does fat supply us with energy, it also

makes it possible for other nutrients to do their jobs.

Fats, which consist of a wide group of compounds, are usually soluble

in organic solvents and insoluble in water. The term 'fat' refers to

triacylglycerols (TAG), phospholipids and cholesteryl esters. Dietary

fat consists predominantly (90-98%) of mixtures of TAG. TAG consists

of three fatty acids linked to a glycerol backbone. Fatty acids are

made up of three elements: Carbon, Hydrogen, and Oxygen

At room

temperature

fats may be

present in

either liquid orsolid form; this

depends on

their structure

and

composition.

Oils - Any fat which exists in liquid form at roomtemperature. Oils are also any substances that do not mixwith water and have a greasy feel.

Fats - All types. However, fats are commonly referred to asthose which are solid at room temperature.

Lipids - All types of fats, regardless of whether they are liquidor solid.

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Where are they found?Fats widely occur in the adipose tissue of animals and in the seeds,

nuts, and fruits of plants.

They can be found in several natural sources, both from plant andanimal, as well as in many products made out of them such as these

MeatsBeef, Pork, Chicken, Ham, Fish Meat products - Hot dog, Burger, Sausage, Pizza Oils Canola, Corn, Olive, Sun flower, Soy bean, Coconut Nuts/ Seeds- Peanuts, Almonds, Cashew, Flaxseed, Walnuts Dairy products Cheese, Milk, Ice cream , Butter, Ghee Sweets/ Baked goods- Candy, Chocolate, Cake, Pastry, Fries Fats added during cooking or at the table

Margarine, Lard, Shortenings

Dressings

Different types of Fat / Fatty AcidsDietary fats are classified by their structure. There

are two chief categories of fat or

fatty acids - saturated and

unsaturated. Within these

categories, there are at least 40

different types of fatty acids.

Broadly speaking, unsaturated

fatty acids are 'good' fatty acids

and saturated fatty acids are

'bad' fatty acids

There are four major dietary fats

in the foods we eat:

Saturated Fats Monounsaturated Fats Polyunsaturated Fats Trans Fats

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The four types have different chemical structures and physical

properties.

The bad fats, saturated and Trans fats, tend to be more solid at room

temperature (like a stick of butter), while monounsaturated andpolyunsaturated fats tend to be more liquid (like liquid vegetable oil).

Fats can also have different effects on the cholesterol levels in your

body.

SATURATED FATTY ACIDS

What are Saturated Fats?Saturated fats have a chemical makeup in

which the carbon atoms are saturated with

hydrogen atoms. Saturated fats are typically

solid at room temperature.

C : Carbon Single bond

H : Hydrogen Double bond

How do Saturated Fats affect my health?Eating foods that contain

saturated fats increase the LDL

(bad Cholesterol), a bigger

amount, and increases HDL (Good

Cholesterol), a smaller amount,

finally result in a net increase in

the Total Cholesterol in yourblood. High levels of blood

cholesterol increase your risk of

heart disease and stroke. Be

aware, too, that many foods high in saturated fats are also high in

cholesterol which raises your blood cholesterol even higher.

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MONOUNSATURATED FATTY ACIDS (MUFA)

What are MUFAs?From a chemical standpoint,

monounsaturated fats are simply fats that

have one double-bonded (unsaturated)

carbon in the molecule. Monounsaturated

fats are typically liquid at room temperature

but start to turn solid when chilled. Olive oil

is an example of a type of oil that contains

monounsaturated fats.

C : Carbon Single bondH : Hydrogen Double bond

Oleic acid is the main monounsaturated fat in our diets andthis is sometimes called Omega-9 Fatty Acid.

How do MUFAs affect my health?

Eating foods that contain MUFAs decrease

the LDL (bad Cholesterol), and decreasesHDL (Good Cholesterol), a smaller amount,

finally resulting a net decrease in the Total

Cholesterol in your blood. Therefore MUFAs can

lower your risk of heart disease and stroke.

They are also typically high in vitamin E, Also a diet

which is relatively high in MUFAs may offer

improved glycaemic control for diabetics

POLY UNSATURATED FATTY ACIDS (PUFA)

What are PUFAs?From a chemical standpoint, polyunsaturated fats are simply fats that

have more than one double-bonded (unsaturated) carbon in the

molecule. Polyunsaturated fats are typically liquid at room

temperature and when chilled.

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How do PUFAs my health?

Eating foods that contain PUFAs decrease the

LDL (bad Cholesterol), and increases HDL (Good

Cholesterol), finally resulting a net decrease inthe Total Cholesterol in your blood.

Therefore PUFAs can help reduce the

cholesterol levels in your blood and lower your

risk of heart disease.

They also include essential fats that your body

needs but cant produce itself such as

omega-6 and omega-3.

So these are the better one of all fat trypes.

ESSENTIAL FATS (EFA)

What are Essential Fats (EFA)These Essential fatty acids are a part of the poly Unsaturated fats,

and they are categorized as like this because of

the special health benefits they have.

The body requires about twenty fatty acids in

order to live and operate. It can make all but two

of these: linolenic and linoleic. These two are

called "essential fatty acids" because they are

essential for life and health. However, the

human body cannot make these substances;

they can be supplied only by food or

supplements. EFAs occur mostly in seafood

and plant foods, with only trace amounts

found in meat.

The two most important essential fatty acids are linolenic acid (an

omega 3 fatty acid) and linoleic acid (an omega 6 fatty acid). The

omega number describes where the important carbon atom is

located on the fat molecule. 05
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1) Omega 3 (Linolenic Acid)

The family of omega -3 Fatty Acids includes 3 fatty acids

which are vital for Human health.

a) DHA- (Docosahexanoic acid) -found in brain and retina of the

eye. And it is very important in

brain development, as well as

other aspects of fetal

development.

b) EPA- Eicosapentaenoic acidc) ALA- Alpha-linolenicc acid

2) Omega 6 (Linoleic Acid)Omega 6 acids are mainly found in seeds of plants, nuts,

vegetable oils and whole grain cereals. Especially in Soya

bean oil, canola oil. Sun flower oils are some omega 6 rich

oils

How do EFAs affect my health?Because they have the ability to

Lower the risk of breast and colon cancer Improve learning and attention span in

school-children

Improve cognitive function in the elderly Elevate mood, resulting in less depression Lower the risk of cardiovascular disease Promote healthy skin Improve vision, especially night vision

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WHY MY BODY NEEDS FAT ?

Fats Provide Energy - Fats are themost efficient source of food

energy. Each gram of fat provides

nine calories of energy for the

body, compared with four calories

per gram of carbohydrates and

proteins.

Fats build healthy cells -Fats are

a vital part of the membrane thatsurrounds each cell of the body.

Fats build brains -Fat provides the structural components notonly of cell membranes in the brain, but also of myelin, the fatty

insulating sheath that surrounds each nerve fiber, enabling it to

carry messages faster.

Fats help the body use vitamins -Vitamins A, D, E, and K arefat-soluble vitamins, meaning that the fat in foods helps theintestines absorb these vitamins into the body.

Fat provides healthier skin - Fats gives the skin a roundedappeal, as well as the layer of fat just beneath the skin (called

subcutaneous fat) acts as the body's own insulation to help

regulate body temperature

Fat forms a protective cushion for organs- Many of thevital organs, especially the kidneys, heart, and intestines are

cushioned by fat that helps protect them from injury and hold

them in place.

Fats are pleasurable - Besides being a nutritious energysource, fat adds to the appealing taste, texture and appearance

of food. Fats carry flavor.

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FUNCTIONS OF FATS IN PREGNANCY AND INFANCY

During the last trimester of pregnancy

childs brain doubles in size. As ourhuman brain is made out of 60% fats, it is

vital that mum should get high quality

essential fats into her diet, during this

period to maintain this rapid brain

growth.

Getting good fats in the diet is also important after the baby is born.

So the Breast milk needs to be high in fats to continue this growth.

This can be fulfilled by taking DHA a fatty

acid from omega 3 family. If mum dont get

the omega fats from brain, the fetus will

take it from her brain resulting in problems

with focusing, concentration and memory

in Mum after the childs birth.

Meanwhile, Babies cannot produce DHA

and they are depended on mum to get

those requirements. Therefore this leads

to a situation of loosing of her DHA supply.

Therefore taking proper omega 3

supplements by mum helps to supply the

DHA needed for child as well as maintainher own supplies.

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FOOD SOURCES OF FATSSATURATED FATS

Saturated fats are commonly found in various products listed below

Meats Products -Fatty Beef, Lamb, Pork, Poultry with Skin,Lard

Dairy Product- Full Fat, Milk, Cheese, Butter, Cream Baked Products - Pastries, Pizza, Burger, Biscuits Deep-Fried Foods - Potato Chips, Short eats Oils - Coconut oil, Palm Oil, Palm Kernel oils

Saturated fat should be limited to 10% of caloriesMONO UNSATURATED FATS (MUFA)

Significant amounts of MUFAs are found in following food types

Fruits-Avocado, Olive fruit

Oils-Olive oil, Canola oil Nuts-Hazel nuts, Cashews, Almonds Peanuts, Margarine Spreads- Canola or Olive Based

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POLY UNSATURATED FATS (MUFA)

Significant amounts of MUFAs are found in following food types

Marine Source - Fish (oily fish) Sea food - Vegetable oils - Soybean oil, Corn oil, Sunflower oil,

Safflower oil,

NutsWalnuts, brazil Nuts, Seeds

ESSENTIAL FATS (EFA)

Omega-3 fatty acids - Found in both plant foods (Canola and SoyOils) &marine foods (Oily Fish such as

Atlantic Salmon, Mackerel, Southern

Blue Fin Tuna, Trevally and Sardines)

Omega-6fatty acids - Found primarily in nuts, seeds & plant oils(Corn, Soy , Safflower)

MUFAs & PUFAs, both tend to lower blood cholesterol when they

replace saturated fats in the diet. PUFAs have a slightly greater

impact than MUFAs.But unsaturated fats (mono/poly) have a lot of

calories, so you still need to limit them. 10


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CHOLESTEROL

What is cholesterol?

Cholesterol is a type of fat that is

part of all animal cells. It contains

no calories, so the body cannot

derive any energy from it. But it is

essential for many of the bodys

metabolic processes. However,

theres no need to eat foods high

in cholesterol. The body is verygood at making its own

cholesterol You can live quite well, even better, with eating little or

no cholesterol. In fact, too much cholesterol in your diet can lead to

heart disease.

Why Cholesterol is essential?

Cholesterol is produced by the liver and also made by most cells inthe body. It is carried around in the blood by little couriers called

lipoproteins. We need blood cholesterol because the body uses it to:

Build the structure of cell membranes Make hormones like oestrogen, testosterone and adrenal

hormones

Help your metabolism work efficiently; (for example,cholesterol is essential for your body to produce vitamin D )

Produce bile acids, which help the body digest fat and absorbimportant nutrients.

Types of CholesterolThere are two types of blood cholesterol:

1. Low Density Lipoprotein (LDL) Cholesterol- LDL is considered the

bad cholesterol because it contributes to the

narrowing and silting up of the arteries, which can

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2. High Density Lipoprotein (HDL) Cholesterol- HDL cholesterol isconsidered to be the good cholesterol because it

actually carries cholesterol from the blood back to

the liver, reducing the risk of cardiovascular disease.

Effects of high cholesterol levelsThe liver is the main processing centre for

cholesterol and dietary fat. When we eat animal fats,

the liver transports the fat, together with cholesterol

in the form of lipoproteins, into our bloodstream.

Too much cholesterol circulating within LDL in our

bloodstream leads to fatty deposits that develop inthe arteries.

This causes the vessels to narrow and they can

eventually become blocked. This can lead to heart

disease and stroke.

What to avoid?The Basic thing is,

Any diet that raises cholesterol and LDLs and/or lowers HDL is bad.Any diet that lowers cholesterol and/or raises HDL is good.

All foods from animals contain some cholesterol. Foods from plants

do not contain cholesterol. The cholesterol in your diet comes mainly

from eggs and from animal products that are rich in fat.

Therefore foods containing Trans Fats and Saturated fats should be

replaced with food containing Mono unsaturated Fats and Polyunsaturated fats. So you should try to avoid:

Fatty Meats Full Fat Dairy Products Processed Meats Like Sausages Snack Foods Like Chips Most Takeaway Foods, Especially Deep Fried Foods Cakes, Biscuits and Pastries.

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TRANS FATTY ACIDS (TFAs)

What are Trans Fats?Double bonds in unsaturated fatty acids can exist on two

configurations; the cis or the trans. When the hydrogen atoms are on

opposite sides of the carbon chain (see diagram below), the double

bond is in the trans configuration and the fat is known as a trans-

fatty acid.

C : Carbon Single bond

H : Hydrogen Double bond

Trans fats (or trans fatty acids) are created in an industrial process

that adds hydrogen to liquid vegetable oils to make them more solid.

Another name for transfats is partially hydrogenated oils." Look for

them on the ingredient list on food packages.

How do TFAs affect my health?Eating foods that contain trans fatsdecrease the LDL (bad Cholesterol),

and decreases HDL (Good

Cholesterol), finally resulting a net

decrease in the Total Cholesterol in

your blood. . So are potentially even

more damaging. Therefore Trans

fatty acids increase the risk of heartdisease strike.

Its also associated with a higher risk

of developing type 2 diabetes.

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How it comes to our Food?Trans fats are rare in nature. TFAs in our diet come from two sources;

From ruminant animalsRuminant animals, such as cows and sheep, contain bacteria

in their rumen (part of the gastrointestinal tract), which

naturally convert cis double bonds to trans double bonds.

This means that approximately 4-7% of the fats from the

meat and milk of ruminant animals are trans fatty acids.

During the process of partial hydrogenation.This is done by food industry to increase the melting point of

fats. In this process, common unsaturated fatty acids areconverted to their trans equivalents. Partially hydrogenated

fats typically contain anywhere between 5% and 30% TFAs.

Fully hydrogenated oils do not contain Trans fatty acids and

are not believed to have a negative effect on health.

Which foods contain TFAs?

Especially Trans fats can be found in fried foods and baked goods.

Fried foods - Potato chips, French Fries Baked Goods - Pastries, Biscuits, Pizza Dough, Cookies,

Crackers, Doughnuts

Margarines & Shortenings

You can also spot trans fats by reading ingredient lists and looking for

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How much trans fat can I eat a day?

The recommended TFA intake amounts are no more than 5 grams a

day for men and 4 grams for women (that's 2% of our daily energy

intake). Currently, most of us are eating within the recommended

amounts A relatively small proportion of people may have a very high

intake of TFAs.These people need to take steps to cut their intake or

their health could be affected.

AVAILABILITY OF FATS IN VARIOUS PRODUCTS

This diagram shows the approximate comparison of Saturated, MonoUnsaturated and Poly Unsaturated fat content of Some Food

Canola oil

Corn oil

Olive oil

Soybean oil

Beef

Sausages

Pork

HamChicken

Cheese (Regular)

Cheese (light)

Milk (Whole)

Milk 2 %

Ice cream

0 % 20% 40% 60% 100%
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the fat facts final

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