Chemical Structure Of Oleic Acid Biology Essay

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Fatty acid is one of the classifications of lipids. There are two groups of fatty acids which is saturated and unsaturated. Unsaturated fatty acid refers to the presence of one or more double bonds between carbons. While saturated fatty acid has all bonding positions between carbons occupied by hydrogen and it does not have double bond.

In general, fatty acids are a component of both the fat we consume and the fat in our body. As we all know, our body fat stores energy for long term survival. Fatty acids in foods exist in a natural cis configuration but it can be modifies to form an artificial configuration known as trans fatty acid. In other meaning, cis fatty acid occurs naturally but trans fatty acid is a result of processed food through hydrogenation of oil.


Figure 1 Chemical structure of oleic acid (cis fatty acid )


Figure 2 Chemical structure of Elaidic acid, an isomer of oleic acid,

but a trans fatty acid.

Trans fatty acid basically is monounsaturated or polyunsaturated fat which altered by partial hydrogenation. In biochemistry, trans fatty acid are manufactures by adding hydrogen bonds to unsaturated sites on the carbon chains of fatty acids (reduce the number of double bonds) and fat automatically will be more stable, thus it does not spoil quickly. This process of partial hydrogenation forces the oils which are naturally liquid at room temperature to become semi solid. Partial hydrogenation is applied in food industry by heating vegetables oils in the presence of metal catalyst and hydrogen and also by bacrerial activity in the rumen of ruminants. This hydrogenation is accompanied by thermal isomerization, in which double bonds remain but may be moved in their positions on the carbon chain and produce several geometrical and positional isomers ( Figure 1 and 2 ). Other factors that influence hydrogenation are pressure, duration and source of fats. Hydrogenation will increase the melting point of fats, which makes it possible to convert fats in liquid form to semi-solids.

Trans fatty acid do give benefit for our food industry. Conversion of fats from liquid to semi solid is useful in dietary products, increasing shelf life and flavor stability of unsaturated fatty acids. In 1911, cotton seed oil was first hydrogenated to produce vegetable shortening. The partial hydrogenation become popular in the 1930's with the development of margarine. Nowadays, trans fatty acids are produced artificially and commercially in a wide range. Most foods made with partially hydrogenated oils such as baking, fried foods, snack food industry, frozen pizza and some margarine products.

Is a trans fatty acid give side effect to us? "Trans fatty acids may help preserve food so that it tastes good, but your body can not break them down and use them correctly. Normal fats are very supple and pliable but trans fatty acid is a stiff that can build up in the body and create havoc" says Brian Olshanky, MD, University of Iowa. [1] Like other fatty acids, trans fatty acids from diet will deposited in adipose tissue as well. Trans fatty intake is always correlated with heart disease, diabetes, cancer, obesity and immune dysfunction. Trans fat is found in many common foods including some margarine, meat, milk fat, fast foods, certain chocolate bars, donuts, biscuits, cakes and pastry.

When we consume trans fat it will significantly raise the 'bad' low density lipoprotein (LDL) and lower levels of heart-healthy high density lipoprotein (HDL). This will cause clogging in arteries due to the plaque formation and cause heart disease. For women with heart disease, consuming too many trans fat foods will increase their risk of dying suddenly from cardiac arrest. [2] Besides, eating too much trans fat food will lead to obesity due to high calorie content in food. Trans fats are metabolized differently in the liver, thus overconsumption of these fats can lead to liver disease. This disease due to abnormal accumulation of fats inside the liver cells and usually occurs in people who are obese and diabetic. The risk of the development of Type 2 diabetes was associated with trans fatty acid intake. The intake of high-fat meal of fatty acid composition, elaidic acid ( 9 trans-18: 1) compared with oleic acid ( 9 cis-18:1) gave rise to higher insulin levels in the blood at the same blood sugar level, which indicates that elaidic acid produces increased insulin resistance ( Bray, Lovejoy, Smith, DeLany, Lefevre, Hwang, Ryan, and York, 2002). Researchers at Harvard's School of Public Health, United States, estimated that trans fats contribute to 30,000 deaths a year.

Basically, trans fat is not bad in moderation, but in excessive intake of it may lead to many health problems. Vegetables oils are best consumed when in their natural, unhydrogenated form (olive and sesame oils). Avoiding margarine with partially hydrogenated oils, instead try the newer margarines that are light or made with yogurt and do not contain trans fat. Avoiding this means we should giving up some delicious food and feel less satisfied with our meal. However, in order to get a healthy diet and prevent severe diseases, trans fat food must be avoided. Eat foods that are naturally low in fat such as whole grains, fruits and vegetables. Limit the intake of animal products (egg yolk, cheese), processed foods, fried foods, and commercially prepared baked goods. As consumer, look on food labels like 'hydrogenated' or 'partially hydrogenated' because those foods are loaded with bad fats and should be avoided. It is preferable to use liquid vegetable oil, soft margarine and trans fatty acid free. But fat restricted diet differs in young children, as children must eat cholesterol and fat because they need enough cholesterol and fat for brain development.

Why trans fatty acid being 'killer' to us?

Shortening consist of almost one-fifth trans fats and some brands of margarine contain almost one-fourth trans fats.

During hydrogenation, trans fats are actually toxic substances for our cell membranes.

Trans fat have no cholesterol and no trace compounds that may be beneficial to health.

Trans fat may be only a small part of our total dietary but small changes in our diet can lead to diseases.

The Government of Canada's Role

In order to provide Canadians with the information they need to make healthy lifestyles choices, the Government of Canada introduced mandatory nutrition labeling for pre-packaged foods. Canada was the first country in the world to introduce mandatory labeling of trans fat. The intent is to help consumers make healthy food choices. In addition, Health Canada and Heart Stroke Foundation of Canada worked through a task force made up of various stakeholders to develop recommendations and strategies for reducing trans fats in Canadians foods to the lowest level possible.

Some of Canada's Food Guide:

Eat at least one dark vegetable green and one orange vegetable each day.

Choose grain products that are low in fat, sugar or salt.

Drink skim, 1% or 2% milk each day.

Have meat alternatives such as beans, lentils and tofu often.

Unsaturated vegetable oils such as canola, corn, olive, soybean, sunflower.

Drink water regularly.

After all, trans fatty acid and severe diseases is just as obvious as the one between smoking and lung cancer. Yet, while smoker trying to reduce their tobacco use, the news about trans fat seems to have less impact towards us. It is clearly shown people nowadays just ignore trans fat consumption. While we consume trans fat foods and enjoy the pleasure of taste, we fail to make the connection between what is going in our mouths and what it is doing to our bodies. The more trans fat we consume, the more likely we develop life-altering issues. Remember, the choices we make today will surely affect the future of our foods.