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The influential Framingham Heart Study involved a sample of 5,209 adults in Framingham, Massachusetts to study the epidemiology or risk factors of those who had cardiovascular disease in comparison to those who did not (Stoll, 2001). This study, starting in 1948 and continuing through the 2000s, would identify such high risk dangers as cigarette smoking and increased cholesterol and elevated blood pressure as major causes of heart disease. Today the study is more often criticized for projecting overly-risk standards and for not being generally applicable. In the UK there is less consumption of trans fat than in the United States, where the ratios of omega fatty acids have grown widely disproportionate. Research, yet has advanced and become more valuable in in the discrimination of various fatty acids and the roles they play in body and tissue metabolism.
In this study I will discuss the present policy and review some of the issues of omega-3. I will then discuss some of the science upon which it is based. In my conclusion I will affirm that the present policy adopted by the British Nutrition Foundation appears adequate and practical.
The Contemporary Footing
Among its various recommendations, in 2008 the UK Associate Parliamentary Food and Health Forum recommended further research on the "effects of selected essential fatty acids on the cognitive skills, mood and behavior" on healthy children and those suffering from behavioural disorders (Halling, 2010). In a recent book editorial Griselda Halling, of Independent Nutrition, notes this call for more research on "the essential requirement for omega-3 fatty acids" (Halling, 2010) She offers definite advice on the essential fatty acids, highlighting the omega-3 fatty acids EicosaPentanoic Acid (EPA), and DocasaHexaenoic Acid (DHA), explaining that there is a "growing body of evidence indicating that a deficiency of amega-3" may point to several developmental disorders such as ADHD, and dyslexia, among others, and "that children with ADHD may have low levels of essential fatty acids". CWT Guideline explain that oily fish should be served at lease once a week. In her position advising independent schools, Halling's advice to parents includes being aware of the levels of trans fats and also the adequacy of omega-3 provision (Halling, 2010).
Ms Halling underscores present public nutritional policy, the need for further research and also the understanding that a diet for omega-3 fatty acids is necessary for body and tissue growth and development. In her notes Ms Halling points to a popularly received 2006 study led by research fellow Dr. Alex Richardson and Madeleine Portwood. The British Broadcasting Company, among its bevy of reports over the years on the omega-3 phenomenon, wrote about the study, before it came out, in 2003 (BBC, 2003). Their report noted that Portwood claimed that 40% of 100 children from 12 Durham school showed statistical significant school performance improvement after receiving a a daily course of Omega 3 supplement capsules for a duration of six months. The study was a randomised double-blind controlled trail with half of the students receiving the Omega capsules while the other half received placebos. Those students who showed improvement were apparently receiving the benefits of EPA. The BBC quoted two other research specialist, a developmental psychologist from the University of Colorado and also a psychologist from the University of York who yet gave precaution on relating omega-3s to corrective cures of dyslexia.
A more recent story from the BBC underlined how claims of fatty acids have appeared to have taken off from the fancy of the public and marketers. In "The cult of omega-3" (O'Neill, 2010), the BBC interviewed Dr. Lee Hooper, who published a study on omega-3 in the British Medical Journal in 2006. Dr. Hooper's systematic study did not find the necessary evidence to back the claim that omega-3 improves children's learning abilities. Yet, she did say that it probably did have positive effects on "arthritis, pain and stiffness" and for those recovering from a heart attack. Beyond hard science, Dr. Hooper pointed out how omega-3 had come to represent a "trend nutrient" that appears to reflect the "herd-instinct" that periodically seeks a "new food panacea" that can solve all problems.
The Hard Science
Low-Density Lipoprotein (LDL) is termed "bad cholesterol" because it can become overloaded with excess fats and build them on blood vessel walls as plague, although it functions in its good tasks of supplying cells with needed fats (Best, 2010). High-Density Lipoprotein is "good cholesterol" because it can pick up and carry excess fats back to the liver. Other fats in the body are called fatty acids, either, from their composition soluble in water or oil, and existing primarily unattached as free molecules. Fatty acids are chains of carbon acids that are either single-bonds, or "saturated" with hydrogen atoms, or having at least one double-bond between the carbon atoms. With one double-bond, fatty acids are called mono-unsaturated, and with more than one double-bond they are called poly-unsaturated (Best).
Membrane fluidity is good for cell functioning in the body and is a good result of polyunsaturated fatty acids. But they can have a negative effect as carbon-carbon double bonds can also produce unstable lipid peroxide compounds resulting in causes of cancer. This is a characteristic of fast-food restaurants not changing the polyunsaturated fatty oil in which they fry foods all day (Best, 2010).
Cis configuration of unsaturated fatty acids indicate carbon chains on the same side of the double-bond and 'trans' signify carbon chains on the opposite sides of double bonds. Butter and lard represent saturated fats and fatty acids with trans double-bonds are such as margarine. Vegetable oils have cis double-bonds and are mainly liquid. The food processing industry use hydrogenation of vegetable oils to reduce the number of double bonds resulting in trans fatty acids. Such acids reduce membrane fluidity causing adverse functions on cell membranes.
The body cannot manufacture two fatty acids which it needs, linoleic acid and alpha-linolenic acid. These are called the essential fatty acids (EFAs). Linoleic acid has 2 double-bonds in its 18-carbon chain and while alpha-linoleic acids in having three double-bonds in its 18-carbon chain. Fatty acids have a carboxylic acid at one end a a methyl group at the other end. Omega is the last letter in the Greek alphabet and identifies how many carbon atoms the methyl group is located from the nearest double-bond. In the case of linoleic acid, having only two double bonds, the methyl group is 6 carbon atoms away from the double bond and is call an omega-6 fatty acid (n-6, or x-6). For alpha-linoleic acid, the methyl group is only 3 carbon atoms away and is called omega 3 (n-3, x-3) (Best, 2010).
The human body cannot make these polyunsaturated fatty acids (PUFAs), also called lipids, the omega-6 or omega-3 fatty acids and hence must get them through food and diet. The body's chemistry cannot produce double-bonds in these long chains near the the carboxylic acid, or delta, end of the molecules.
Linoleic acid (LA) and alpha-linoleic acid (ALA) produce distinct families of important and vital omega-6 and omega 3 fatty acids by interacting with specific and similar enzymes. In fact both fatty acids compete for the same enzymes that will help them make other fatty acids by forming more double bonds and adding more carbon. Because they compete and because the process of more fatty acids take time, deficiencies may be produced in one or the other affecting physical being.
The fatty acids that linoleic acid and alpha-linoleic acid produce are vital for the functioning of several bodily processes. From omega-6 (linoleic) come gamma-linolenie acid (GLA); dihomo-gamma-linoleic acid (DGLA) and arachidonic acid. Gamma-linoleic acid (GLA), produced from linoleic acid (omega-3) is known to reduce inflammation. It has a folk history of curing allergies, although there is no definite scientific evidence for the claim. Arachidonic acid, is a long chain omega-3 fatty acid with four cis double bonds is used to produce enzyme substances that control inflammation. Inflammation may accompany several medical conditions including arthritis, allergies, asthma, obesity, atherosclerosis among others. Too much arachidonic acid would cause inflammation over-response. It must be related in balance to the other fatty acids, DHA, EPA, ALA, and GLA, all working together to slow down inflammation in the body. Arachidonic acid is found in egg yolks and meat organs and also oily fish (Rolfes, 2009). Omega-6 fatty acids are in vegetable oils.
The omega-3 (alpha-linolenic) family results in alpha-loinolenic acid which produces eicosapentanoic Acid (EPA), producing docasahexaenoic Acid (DHA), among other essential substances such as prostaglandins.
In general omega-3 polyunsaturated fats which are considered as good fats are alpha-linolenic acid (ALA), and the fats it produces, EPA and DHA. These are often contrasted with saturated fats and trans fats, which tend to solidify in the body. Omega-3 fatty acids are found in the oils of whole grains, and in fish, fresh fruits and vegetables, garlic, and moderate wine. The highest concentration of ALA is found in flaxseed oil. Canola oil also has a good concentration of omega-3 fatty oils. Public health agencies usually suggest a diet of two weekly services of oily fish, such as salmon, halibut, shrimp, snapper, sardines, anchovies, scallops as a source of EPA and DHA. Nuts provide omega-3 oils, such as walnuts and almonds in the form of ALA. Fish Capsules of fish oil supplement are not as effective as pure fish. Omega-3 helps lower cholesterol by lowering triglycerides and raising HLD cholesterol, resulting in better control over diabetes and obesity. EPA and DHA are important in normal growth and development, with particular relevance in the eye and the brain.
Both arachidonic acid and EPA are used by the body to eicosanoids (Rolfes, 2009). These are regulatory type compounds that affect different kinds of cell responses, many of them taking place in the immmune response system. Eicosanoids produced by arachidonic and EPA may tend to oppose or supplement each other and participate in the balancing effect alluded to earlier regarding arachidonic.
Cell membranes mainly consist of cholesterol and fat. Nearly half of the brain consists of fat made up of docosahexaenoic acid (DHA), derived from omega-3 fatty acid. DHA seems to help in the development process of the brain. Several studies have shown certain connections between DHA and brain activity. It has been identified as showing ability to stave off dementia.
There also been evidence that it can stave off dementia. Children with attention deficit disorder have demonstrated low levels of DHA. Some studies have reported that people with depression show low levels of oomega-3 fatty acids in the blood stream, and researchers have shown a link between DHA deficiency and Alzheimer's disease. But just as these studies have shown positive relationships, there have been just as many studies that have disproved such relationships, or have placed them in the low or no significance categories.
It has been shown that over centuries the human body had maintained a one-to-one ratio level of omega-3 to omega-6. The American Cancer Association promotes this ratio as the most desirable. In America the ratio is upended, appearing as 10 to 20 times more omega-6 than omega-3, explaining in some part the high occurrence of cholesterol afflictions in such populations.
Muskiet et al (2004) noticed that our diet has changed over the past century, and that, consequently, it is "not the same as those on which our genes are based." If we think about this we can go a little further and see how the progress of science, or the different methods it has evolved, as produced different technologies resulting in the different ways in which food is produced. Along with these different technologies comes different ways of seeing, appreciating, and judging our world. Hence it is possible to say that not only can we see the course of different sorts of diets over the centuries and even decades, but we have also formulated different sorts of mindsets in viewing and accepting these diets. Also our bodies have become different. Muskiet et others, in their research and opinion article, note that we presently have increased our intakes of saturated fatty acids. which include such as linoleic acid and trans-fatty acids, while at the same time reducing our intakes of n-3 fatty acids, alpha-linoleic (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) acid. Arachidonic Acid (AA) is identified as most important long chain polyunsaturated (LCP) fatty acid in the n-6 series, and EPA and DHA stand out similarly as LCPs in the n-3 series. AA and DHA are abundant in the brain and the retina. LCPs provide important membrane properties like "fluidity, flexibility, permeability and modulation of membrane-bound", and AA and LCPs, as noted above, produce eicosanoids, important for "inflammatory reactions, blood pressure control and platelet aggregation". Humans are "poor DHA synthesizers"..
The Muskiet article addresses randomized controlled trials where preterm and term infants were provided formulas with and without LCP. The reviewers found that "formula without LCP cause biochemically demonstrable low LCP status in various body compartments, including the brain... and that LCP-enriched formulas augment LCP levels", reaching the levels of breastfed infants. Another study demonstrated higher IQ in term infants at the age of four years who had LC(n-3)P and LC(n-6)P during the first quarter of life. There is present a consensus for LCP formula supplements for infants.
The review/research from Muskiet et al demonstrates the kind of science that would be needed to determine any efficacy between LCP, both n-3 and n-6, and learning disabilities. I believe the research calls for long range studies from birth.
The British Nutrition Foundation suggests, as recent as 7 January 2011, on its web page on 'Healthy eating on a budget' that an inexpensive good source of omega-3 fats would be "canned oily fish such as sardines and salmon". Elsewhere on the site the Foundation notes that omega-3 and omega-6 fatty acids can also benefit heart health, and are good for the brain (BNF, 2011).
Advising the older population and the general one as well, it is best to quote in full the Foundation's message, as it roots present nutrition public policy, established since 16 July 2009, which I agree to:
As for the general population, it is advised that older people of all ages consume two portions of fish each week, one of which should be oily. Oily fish contains long chain omega-3 fatty acids which can help protect against heart disease and have been shown to be particularly important for those who have already had a heart attack. In older people, omega-3 fatty acids may also help to alleviate some of the symptoms of rheumatoid arthritis, with beneficial effects on swollen and tender joints, grip strength and mobility. There is some evidence that these fatty acids may also help to preserve eye health, prevent cognitive decline and improve immune function. But because oily fish may contain contaminants (such as dioxins and PCBs), it is not advised to eat more than 4 portions per week (a portion is 140g) (BNF, 2009).