Fat is indispensable in providing the essential fatty acids - linoleic acid and a-linolenic acid. These are essential nutrients that the body cannot make for itself. They are vital for the structure and function of all cells, and as chemical messengers. Fat is also essential for the provision and absorption of the fat-soluble vitamins A, D, E and K. As most people recognize, fat is a concentrated source of energy (calories) and acts as a fuel for the body.

Why does the body need fat?
- Source of antioxidant vitamins
- Component of cell membranes and essential for cell growth
- Helps regulate metabolism
- Is used in the manufacture of hormones e.g. estrogen and thyroid
- Source of energy

How Much Fat Do I Need?
Too much quantity of fat is a main cause of obesity in the world. The type of fat affects your lipid profile which, if elevated, is a risk factor for coronary heart disease. Limit total fat intake to less then 25-30% of your total calories consumed each day. A minimum fat intake is 35 grams per day. For example a 30-50 year old women who needs 2,000 calories per day should consume between 50-70 grams of fat each day.

Know Your Fats:
Saturated fat is the main dietary cause of high blood cholesterol. Saturated fats are found mainly in animal products such as beef, lamb, poultry, pork, veal, whole and 2% dairy products, butter and eggs. Foods from plants that contain saturated fats include coconut oil, palm oil, and cocoa butter. These fats raise blood cholesterol. High blood cholesterol levels (particularly high LDL cholesterol compared to HDL cholesterol) may contribute to heart disease.

Trans Fatty Acids (TFA) are found in small amounts in various animal products such as beef, pork, lamb and butter and whole milk. TFA are also formed during the process of hydrogenation (add hydrogen): making margarine, cooking oils, processed foods and shortening. TFA tend to raise total blood cholesterol levels, raise LDL (bad) cholesterol and decrease HDL (good) cholesterol.

Polyunsatuated and Monosaturated fats are the two unsaturated fats. They are found mainly in fish, nuts, seeds and oils from plants. Some examples of foods that contain these fats include: salmon, tuna, herring, avocado, olives, walnuts and soybean, grapeseed, safflower, canola and olive oils. These fats may help lower your blood cholesterol level when used in place of saturated and trans fats.

Therefore, it is important to look at the type of fat that you are consuming. It's a good idea to avoid saturated fat and particularly avoid trans or partially hydrogenated fat. Replace these types of fat with other fats such as monounsaturated and polyunsaturated fat.

What are Omega-3 (n-3) and Omega-6 (n-6) Fatty Acids?

Omega-3 and omega-6 fatty acids are polyunsaturated fatty acids. Both the n−3 α-linolenic acid and n−6 linoleic acid are essential nutrients which must be obtained from food. There is strong scientific evidence that n−3 fatty acids significantly reduce blood triglyceride level and reduces the risk of coronary heart disease. Some benefits have been reported in conditions such as rheumatoid arthritis.

Omega-6 Fatty Acids

Linoleic Acid: Food sources of LA include vegetable oils, such as soybean, safflower and corn oil, nuts, seeds and some vegetables.

Some Food Sources of Linoleic Acid (18:2n-6) (146)

Food

Serving

Linoleic Acid (g)

Safflower oil

1 tablespoon

10.1

Sunflower seeds, oil roasted

1 oz

9.7

Pine nuts

1 oz

9.4

Sunflower oil

1 tablespoon

8.9

Soybean oil

1 tablespoon

6.9

Pecans, oil roasted

1 oz

6.4

Brazil nuts

1 oz

5.8

 Arachidonic Acid: Animals, but not plants, can convert LA to AA. Therefore, AA is present in the diet in small amounts in meat, poultry and eggs.


Omega-3 Fatty Acids

Alpha-Linolenic Acid (ALA): Flaxseeds, walnuts, and their oils are among the richest dietary sources of ALA. Canola oil is also an excellent source of ALA.

Some Food Sources of Alpha-linolenic Acid (18:3n-3) (146)

Food

Serving

Alpha-Linolenic acid (g)

Flaxseed oil

1 tablespoon

8.5

Flaxseeds

1 tablespoon

2.2

Walnut oil

1 tablespoon

1.4

Canola oil

1 tablespoon

1.2

Soybean oil

1 tablespoon

0.9

Walnuts, black

1 oz

0.6

Tofu, firm

½ cup

0.7

Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA): Oily fish are the major dietary source of EPA and DHA.

Some Food Sources of EPA (20:5n-3) and DHA (22:6n-3) (3)

Food

Serving

EPA (g)

DHA (g)

Amount providing
1 g of EPA + DHA

Herring, Pacific

3 oz*

1.06

0.75

1.5 oz

Sardines, Pacific

3 oz

0.45

0.74

2.5 oz

Salmon, Atlantic

3 oz

0.28

0.95

2.5 oz

Oysters, Pacific

3 oz

0.75

0.43

2.5 oz

Trout, rainbow

3 oz

0.40

0.44

3.5 oz

Tuna, canned, white

3 oz

0.20

0.54

4 oz

Crab, Dungeness

3 oz

0.24

0.10

9 oz


Thanks to Susie Parker- Simmons for assistance with this topic,
Sports Dietitian (RD) & Physiologist
Nutrition Advisor,
Sony Ericsson WTA Tour

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