Nutritional Quality of Rapeseed Oil and Health Benefits of Omega Fatty Acids - Essay Example

Nutritional Quality of Rapeseed Oil and Health Benefits of Omega Fatty Acids Introduction Recent research has thrown light on the importance of omega fatty acids in reducing the risk of sudden cardiac death. The fatty acids decrease the bad cholesterol and triglyceride levels and thus decrease the risk of coronary artery disease. One of the sources of omega fatty acids is rapeseed oil. In this essay, the nutritional quality of rapeseed oil and the health benefits of omega fatty acids will be discussed through review of appropriate literature pertaining to the topic. Nutritional Quality of Rapeseed Oil Rapeseed or Brassica napus belongs to the family Brassicaceae to which mustard and cabbage also belong. The plant bears yellow flowers. Rapeseed is popular for the oil that can be produced from it. The most popular brand is the canola oil, which is a refined form of rapeseed oil. Until a few years ago, Rapeseed oil was used as an efficient lubricant for steam engines. Currently, the oil is used as biofuel and human edible oil and the by-product is used as animal food (USDA, 2010). The oil has high levels of erucic acid and glucosinolate because of which it tastes bitter. Canola oil has lesser amount of acid and glucosinolate and hence is palatable. It has higher quantities of omega fatty acids which reduce LDL cholesterol and serum triglyceride levels (USDA, 2010). Canola oil has low saturated fat and high levels of monounsaturated oil. Infact, when compared to other vegetable edible oils like sunflower oil, corn oil and peanut oil, canola oil has very low ratio of saturated to unsaturated fats. The main omega fatty acid present in the oil is alpha-linolenic acid, which is an omega-3 fatty acid. 1.3 grams of this fatty acid is present in one serving of the oil. 1ml of the oil yields 12 calories and 1.4 grams of fat. Only 10 percent of the fat is saturated. The oil has no cholesterol, protein, carbohydrate or sodium. The oil is rich in vitamin E which is a valuable anti-oxidant (Ingle, 2010). Despite the popularity of the rapeseed oil as safe and beneficial edible oil, many experts have condemned the nutritional benefits of the oil. Some researchers are of the opinion that the useful ingredients of the oil are destroyed in industrial manufacturing and that during such a process, trans-fatty acids develop which are not only harmful to the body but also are detrimental to the beneficial actions of the useful ingredients of the oil. Some experts opine that Canola oil or the irradiated rapeseed oil can cause certain problems of the central nervous system like tremors, palsy, shaking, uncoordination of movements, slurring of speech, blurring of vision, difficulty in urination, breathing difficulties, arrhythmias of the heart and numbness of extremities (Klepper, 1998). Health benefits of omega fatty acids Fats are very essential for various structural, functional and metabolic aspects of the body. They are a major source of energy. When ingested, fats get converted into fatty acids which are basically chains of carbon atoms linked to each other by single or double chemical bonds. Each fatty acid has 2 terminals, one of which has methyl group and the other has carboxyl group. Fatty acids are basically of 2 types, the short chain fatty acids and the long chain fatty acids. While short chain fatty acids have less than 6 carbons in them, the long chain ones have more than 12 carbon atoms. Fatty acids are sources of energy for heart, muscle and other organs. They are the building blocks for cell membranes. They are one of the forms of energy storage. Fatty acids, which are not used up for energy in the body are converted to triglycerides. Triglycerides are molecules which have 3 fatty acids attached to one glycerol compound. Triglycerides are the mode of storage of fatty acids in the body. Fatty acids can also be classified based on the number of bonds between carbon atoms. Those which have single bonds are saturated fatty acids and fats which contain such fatty acids are known as saturated fats. Examples of foods containing such fats include butter, lard, cream, whole milk, chocolate and eggs (Lee and Kulick, 2009). Saturated fats have been incriminated in the development of coronary artery disease. Fatty acids which contain one double bond are known as monounsaturated fatty acids and fats which contain such fatty acids are known as monosaturated fats. Examples of foods rich in monosaturated fat include nuts, olive, peanuts, avocados and canola oil (Lee and Kulick, 2009). Research has shown that this category of fats has bad-cholesterol lowering properties and thus, increased consumption of foods rich in these fats decreases the risk of coronary artery disease. Fatty acids containing more than one double bond are known as polyunsaturated fatty acids and foods rich in these fats are corn, sunflower, vegetable oils and soy. Polysaturated fatty acids which cannot be synthesized in the body are known as essential fatty acids. They have to be acquired through ingestion of foods rich in them. There are several types of essential polysaturated fats, one such being omega fatty acids. Omega fatty acids are of two types, omega-3-fatty acids and omega-6-fatty acids. Omega-3-fatty acids have "double bond in the third carbon position from the methyl terminal" (Lee and Kulick, 2009). Foods high in such fatty acids are walnut, flaxseed, canola oil, trout and salmon. Those which have the "the initial double bond in the sixth carbon position from the methyl group" (Lee and Kulick, 2009) are known as omega-6-fatty acids and foods rich in these fatty acids are sunflower, soy, vegetable oils and corn. Omega-3-fatty acids have important health-related benefits. Examples of these fatty acids are docohexanoic acid, linolenic acid and eicosapentanoic acid. The recommended doses of omega-3 fatty acids, according to the American Heart Association are 3 grams per day, in those with established coronary artery disease (AHA, 2010). Research on animals like dogs, marmosets and rats has proved that omega-3 fatty acids prevent ventricular fibrillation in heart attacks which are experimentally induced. Through this evidence it has been presumed that omega-3 fatty acids prevent ventricular fibrillation in human beings also. Since ventricular fibrillation is the most common cause of sudden death in victims of heart attack, it has been thought that omega-3 fatty acids prevent sudden death (Lee and Kulick, 2009) According to 16- year observational Nurses Health Study conducted in 1976, increased omega-3 fatty acid levels in blood subsequent to ingestion of fish was associated with decreased risk of development of coronary artery disease by as much as 29 percent (cited in Lee and Kulick, 2009). Infact, the study proved that those who ate fish once a week had 29 percent lower risk of developing coronary artery disease while those who ate fish atleast five times a week had "a 34% reduction in the risk of coronary heart disease and a 45% reduction in the risk of death from heart disease (usually sudden cardiac death)" (cited in Lee and Kulick, 2009). Similarly, another long term observational study which spread over 12 years found that "men who consumed one or more fish meals per week had a 50% lower risk of developing sudden cardiac death than men who rarely ate fish (less than one fish meal per month)." These are just observational studies. However, for evidence based practice, randomized controlled trials have much more value. There are 2 randomized controlled trials that ascertain the benefits of mega-3 fatty acids. They are the GISSI- Prevention trial published in 2002 and Lyon Diet Study published in 1999 (Lee and Kulick, 2009). According to the GISSI- Prevention study, omega-3 fatty acids decrease the death rate from coronary artery disease by 20 percent, mainly by preventing ventricular fibrillation. In the Lyon Diet Heart Study, consuming Mediterranean diet which is rich in omega-3- fatty acids decreased the risk of sudden cardiac death by a whopping 50 percent. The diet also decreased the chances of repeat heart attacks. This is in contrast to the GISSI study in which repeat attacks of heart attack could not be prevented by consumption of omega-3 fatty acids (Lee and Kulick, 2009). Apart from the beneficial effects of omega-3 fatty acids on the heart, these substances have several other benefits too. According to a study by Morris, Sacks and Rosner (1993), ingestion of fish oil causes reduction in blood pressure because of omega-3 fatty acids. There is some consensus on the opinion that omega-3 fatty acids decreases the risk of stroke. According to a study published in JAMA (Iso, 2001), increased intake of fish oil decreases the risk of stroke in women. The decreased risk is because of decrease in atherosclerosis secondary to decrease in triglyceride levels and LDL-cholesterol levels and also due to decrease in blood pressure. Other than the cardiovascular system, omega-3 fatty acids have a significant impact on the central nervous system. Green et al (2006) reported the role of decreased omega-3 fatty acids in the development of certain anxiety disorders like social anxiety disorder, even in the absence of depression. Another study by Naliwako et al (2004) threw light on the antidepressant properties of omega-3 fatty acids. Other than these benefits, there are some reports that omega-3 fatty acids have a potential to decrease the development of psychotic disorders in children and adolescents with predisposing factors for psychotic disorders. This is evident from the study by Amminger et al (2010) in which the authors recommended long chain omega-3 fatty acids in the prevention of psychotic disorders. Ethyl-eicosapentanoate, an omega-3 fatty acid has been proven to decrease inflammation and improve memory through various neurotrophic and cholinergic mechanisms through pathways of "IL-1-glucocorticoid- ACh release and IL-1-NGF-ACh release" (Taepavarapruk and Song, 2010). Other beneficial effects noted in the central nervous system are treatment of neurocognitive symptoms of schizophrenia, decrease in relapse of symptoms in bipolar disorder and improvement of symptoms in depression. According to a randomized controlled study from the Harvard University (Calabresse, 1999), patients who took ethyl-eicosapentanoate, also with psychopharmacotherapy had much lower rates of relapse and remission when compared to those who took only psychopharmacotherapy. Similar reports were demonstrated by Mischoulon et al (2009) in both unipolar and bipolar depression patients. Omega fatty acids beneficial effects on the immune system too. In a Danish study on infants, it was found that supplementation of infant milk with omega-3 fatty acids derived from fish oil improved the maturation of the immune system without causing any reduction in the immune system activation (Damsgaard et al (2007). There is some research to show the benefits of omega-3 fatty acids in the management of rheumatoid arthritis. Several randomized controlled trials have demonstrated improvements in symptoms like morning stiffness and joint tenderness in patients who regularly take omega-3 fatty acids for atleast 3 months. However, some experts are of the opinion that much research is warranted to advocate the use of such treatment for rheumatoid arthritis (National Standard Research Collaboration, 2010). Some reports have demonstrated the benefits of omega-3 fatty acids in decreasing the chances of developing angina pectoris. As far as asthma is concerned, there are controversial reports about the benefits of omega-3 fatty acids. Similarly, there are controversial reports about the suppressive effects of omega-3 fatty acids on atherosclerotic plaques (National Standard Research Collaboration, 2010). There is immense research happening to ascertain the role of omega-3 fatty acids in cancer prevention and treatment. While some researchers opine that these substances decrease the risk of development of colon, breast and prostate cancer, some others argue otherwise. More randomized controlled long-term trials are necessary to establish such benefits (National Standard Research Collaboration, 2010). Omega-3 fatty acids protect transplant organs from cyclosporine toxicity. Thus, intake of omega-3 fatty acids either in the form of capsules or in the form of fish oil causes improvements in kidney function and blood pressure (National Standard Research Collaboration, 2010). One of the most important inflammatory disorder that can be managed with omega-3 fatty acids is Crohns disease. Though the results are conflicting, several studies have proved the beneficial role of omega-3 fatty acids in the treatment of Crohns disease when given adjunct to standard therapy (National Standard Research Collaboration, 2010). Other areas in which research is still in a primitive state, but potential benefits of omega-3-fatty acids have been found are, cystic fibrosis, dementia, eczema, IgA nephropathy, lupus erythematosus, nephrotic syndrome, preeclampsia, psoriasis, schizophrenia, ulcerative colitis, diabetes mellitus, hypercholesterolemia and transplant rejection prevention (National Standard Research Collaboration, 2010). While omega-3 fatty acids have many health related benefits, omega-6 fatty acids have more negative health benefits than positive ones. Infact, an increase in the ratio of omega-6 fatty acids to omega- 3 fatty acids induces depression and causes many proinflammatory and prothrombotic diseases. Increase in omega-6 fatty acids is associated with arrhythmia, sudden cardiac arrwest, stroke, rheumatoid arthritis, inflammation, osteoporosis, obesity, cancer, psychotic disorders and several other inflammatory diseases (Calder and Philip, 2006). There is some research to prove the increased risk of development of breast cancer in postmenopausal women who consume high amounts of oils rich in omega-6 fatty acids. The main dietary sources of omega-6 fatty acids are sunflower oil, rape seed oil, soybean oil and palm oil. Conclusion Omega-3 fatty acids are essential fatty acids and hence have to be taken in through food. There are mainly 2 types of such fatty acids, omega-3 fatty acids and omega-6 fatty acids. The former have many beneficial effects on the health of human beings. The most widely researched and proven health benefit is the prevention of sudden cardiac arrest. Omega-3 fatty acids decrease ventricular fibrillation, which is the most common cause of sudden cardiac arrest and thus decrease the risk of sudden cardiac arrest. Another proven health benefit is the decrease in risk of coronary artery disease secondary to improvement in triglyceride and bad cholesterol levels. Other health benefits are decreased risk of certain types of cancer, decrease in stroke, angina, inflammatory diseases and rheumatoid arthritis. However, much research is warranted to ascertain such benefits. Omega-3 fatty acids can be derived from several sources, the most important of which is fish. Another important source is the rapeseed oil, available as canola oil. There are conflicting reports about the nutritional value of this oil. Omega-3 fatty acids, the benefits of these fatty acids is lost because of other toxic substances present in the oil. References American Heart association or AHA. (2010). Fish and Omega-3 Fatty Acids. Retrieved on 1st of March, 2010 from http://www.americanheart.org/presenter.jhtml?identifier=4632 Amminger, G.P., Schäfer, M., Papageorgiou, K., et al. (2010). Long-Chain -3 Fatty Acids for Indicated Prevention of Psychotic Disorders: A Randomized, Placebo-Controlled Trial. Arch Gen Psychiatry, 67(2), 146-154. Calder, P. C. (2006). n−3 polyunsaturated fatty acids, inflammation, and inflammatory diseases. American Journal of Clinical Nutrition, 83 (6), 1505S–1519S. Calabrese, J.R., Rapport, D.J., Shelton, M.D. (1999). Fish oils and bipolar disorder: A promising but untested treatment. Arch Gen Psychiatry, 56 (5), 413–414. Damsgaard, C., T., Lauritzen, L., Kjær, T., Holm, P., Fruekilde, M., Michaelsen, K., F. (2007). Fish oil supplementation modulates immune function in healthy infants. J Nutr., 137 (4), 1031–1036 Iso, H., Rexrode, K.M., Stampfer, M.J., Manson, J.E., Colditz, G.A., Speizer, F.E., Hennekens, C.H., Willett, W.C. (2001). Intake of fish and omega-3 fatty acids and risk of stroke in women. JAMA, 285 (3), 304–312. Ingle, D. (2010). Canola Oil Nutrition facts. Retrieved on 1st of March, 2010 from http://health.learninginfo.org/nutrition-facts/canola-oil.htm Keppler, C.C. (1998). The Canola Oil Hoax. Retrieved on 1st of March, 2010 fromhttp://www.aspartame.ca/page_oho3.htm Lee, D., Kulick, D. (2009). Omega-3 Fatty Acids. MedicineNet.com. Retrieved on 1st of March, 2010 from http://www.medicinenet.com/omega-3_fatty_acids/article.htm Morris, Martha C.; Sacks, Frank; Rosner, Bernard (1993). Does fish oil lower blood pressure? A meta-analysis of controlled trials. Circulation 88 (2), 523–533. National Standard Research Collaboration. (2010). Omega-3 fatty acids, fish oil, alpha-linolenic acid. Mayoclinic.com. Retrieved on 1st of March, 2010 from http://www.mayoclinic.com/health/fish-oil/NS_patient-fishoil/DSECTION=evidence Naliwaiko, K., Araújo, R.L., da Fonseca, R.V., Castilho, J.C., Andreatini, R., Bellissimo, M.I., Oliveira, B.H., Martins, E.F., Curi, R., Fernandes, L.C., Ferraz, A.C. (2004). Effects of fish oil on the central nervous system: a new potential antidepressant?. Nutritional Neuroscience, 7 (2), 91–99. Taepavarapruk, P., and Song, C. (2010). Reductions of acetylcholine release and nerve growth factor expression are correlated with memory impairment induced by interleukin-1B administrations: effects of omega-3 fatty acid EPA treatment. Journal of neurochemistry, 112, 1054-1064. USDA, ARS, National Genetic Resources Program.Germplasm Resources Information Network - (GRIN) [Online Database].National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved on 1st of March, 2010 from http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?7661 Read More