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FAT INTAKE AND DISEASE

Like all nutrients, fat is beneficial in appropriate quantities. However as a population, Australians are generally more likely to over consume fat, than under consume.
General recommendations advise that < 30% of total energy intake per day should come from fat. Less than 10% of which should be from saturated fats. Cholesterol intake should remain below 250-300mg per day

Research shows an increased fat intake to be related to an increased risk of:
•    obesity    •    cardiovascular disease(CVD)
•    stroke    •    heart attack
•    diabetes    •    impaired glucose tolerance
•    hypertension    •    atherosclerosis
•    gallstones    •    high cholesterol (esp. LDL)
•    high triglycerides    •    cancers(breast, colon, prostate)
•    exacerbation of existing conditions  

The 3 types of fats that we consume in our diet are:

Saturated Fatty Acids

•    found primarily in animal foods
•    solid at room temperature

Sources: lard, meat fat, egg yolk, whole fat dairy, shortening, butter, Coconut oil, palm kernel oil and palm oil

Diets high in saturated fats:
•    contribute to increased blood cholesterol (esp. LDL)
•    increase clot formation
•    increase platelet aggregation
•    increase risk of coronary heart disease (CHD), cardiovascular disease (CVD)
•    increase the risk of impaired glucose tolerance

Monounsaturated Fatty Acids

•    liquid or semi-solid at room temperature
•    derived from vegetable sources

Sources:    nuts, olive oil, canola (rapeseed) oil, avocado

Diets high in monounsaturated fats: (compared to saturated fats)
•    appear to be antithrombotic
•    decrease LDL cholesterol
•    decrease clot formation
•    may be beneficial in decreasing hypertension

Studies examining the Mediterranean diet (high in olive oil) show low incidence of CHD despite >30% of energy intake coming from fat.

Polyunsaturated Fatty Acids

•    liquid at room temperature

Essential Fatty Acids

There are two fatty acids that the body cannot make, therefore they must be provided by the diet.

Linoleic acid (omega-6)
•    Essential in cell membranes, immune response.
•    In excess, produce eicosanoids that strongly increase inflammation, constrict blood vessels and promote blood clotting.
•    Obtained from leafy vegetables, grains, seeds, nuts, legumes, vegetable oils (cottonseed, safflower, corn, sesame, sunflower), butter, cocoa butter, evening primrose oil, spirulina, lean meat and chicken (arachodonic acid).

Linolenic acid (omega-3)
•    essential in neurological responses, vision, learning, skin membranes, growth, fertility
•    precursor to DHA (docasahexaenoic acid) & EPA (eicosapentaenoic acid)
•    Produce eicosanoids that reduce inflammation, dialate blood vessels and inhibit blood clotting.
•    Obtained from oils (flaxseed, walnut, soybean, canola), nuts, seeds, soybeans and fish from cold, deep oceans such as tuna, salmon, mackeral, sardines, anchovies, herring and shellfish (shrimp and oysters).

Consumption of omega-3 fatty acids is associated with a decrease in:
•    LDL cholesterol levels
•    triglcyeride levels
•    clotting within arteries
•    blood pressure
•    post-exercise inflammation
•    the risk of atherosclerosis and heart disease, type 2 diabetes, osteoporosis, asthma and some cancers

The dietary ratio of omega-6 to omega-3 fatty acids is key determinant for the health benefits of essential fatty acids.

The ideal ratio of omega-6 : omega-3 is 2 : 1, however in Australia, the ratio is closer to 8 : 1(omega 6 : omega 3)

Processed Fats

Trans Fatty Acids
•    Found when liquid (typically polyunsaturated fats) are partially hydrogenated to make them solid.
•    Found in processed foods e.g. margarine.
•    Believed to increase LDL cholesterol similar to saturated fats.

Heating
•    Saturated fats are the most stable in response to heat. Take away shops often use saturated palm based fats for this reason.
•    Unsaturated fats in the presence of oxygen, heat and light decompose to give a range of compounds, some of which are potentially toxic. Fats which   are over heated, or used for long periods of time progressively darken and become bitter and rancid.


Article contributed by:

Australian Fitness Academy
701 Glenhuntly Road
Caulfield South VIC 3162
03 9532 7800
www.fitnesseducation.com.au