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matveev1981 posted a topic in Vote ArticlesRecently I came across strange article claiming that some unsaturated fatty acids are not beneficial and even dangerous to human, especially it relates to omega-3 fatty acids. I firstly thought that article was written just to attract attention, and there is not a word of truth, just stupid fabrication. But then I found another similar article in a science journal by chance, though I am no scientist and just having browsed the net. So I wonder if this is a myth or a true fact?
The foundation of a healthy diet is balance, variety and moderation. The maintenance of a healthy body requires the intake of carbohydrate (sugar, starch or fibre), fat, protein, vitamins and minerals. The World Health Organisation states that a healthy adult diet should therefore ideally contain a balance of fruit, vegetables, legumes (e.g. lentils and beans), nuts and whole grains (e.g. unprocessed cereals or brown rice), with a minimum of five portions (400g) of fruit and vegetables to be consumed daily. To achieve the optimum level of nutrition, a healthy diet should consist of: Approximately one third starchy foods such as bread, rice or pasta (preferably whole grain varieties, as the increased fibre content is beneficial to the intestine),  Some protein rich foods such as meat, fish or lentils Some milk or other dairy products Limited amounts of fat, salt and sugar Fats should make up less than a third of daily caloric intake, and the unsaturated fats found in fish, avocado, nuts, sunflower and olive oils are preferable to the saturated fats found in fatty meats, coconut oil, cream, cheese and lard. This is because unsaturated fats can provide beneficial fatty acids such as omegas 3 and 6, that are known to help decrease cholesterol levels. Indeed studies have shown that a diet containing a maximum of 10% of daily caloric intake from saturated fat significantly decreases the risk of heart disease.,  Studies have also shown that coronary heart disease (CHD) risk is reduced by 10-15% for each 5% of energy intake that is exchanged from saturated to polyunsaturated (but not monounsaturated) fats. Exchanging saturated fat with carbohydrates increases CHD risk, by 7% for each 5% exchanged. Trans fats commonly found in processed or ‘fast’ foods such as pizza, pies and margarines should also be avoided, as they can also increase the risk of raised cholesterol, type 2 diabetes and stroke. Meat is a good source of protein which also contains vitamins and minerals including iron, zinc and B group vitamins, making it one of the main dietary sources of vitamin B12. Opting for lean meat and skinless poultry can help to reduce the fat intake associated with eating meat. However, certain meat-cooking processes, such as BBQing, have recently been shown to be carcinogenic, and some meat products can contain endocrine-disrupting chemicals, so care should be taken when choosing and preparing meat for consumption. Fish is an alternative significant source of protein which also contains numerous vitamins and minerals. Oily fish is also rich in omega-3 fatty acids which, as stated above, are considered beneficial for health via the prevention of heart disease and reduction of cholesterol levels. However, as with meat, many of the high-temperature cooking processes used on fish can lead to the formation of carcinogenic compounds, such as polyaromatic hydrocarbons. Dairy products such as milk, cheese and yoghurt are also good sources of protein and are rich in calcium, essential for healthy bones. There has previously been controversy over the effect of dairy products in the diet, as some can be quite high in fat. However, observational studies have shown that dairy fat does not necessarily contributes to obesity. Fruit and vegetables are an essential source of dietary vitamins and minerals, and there is increasing evidence that eating at least five portions a day reduces the risks of heart disease, stroke and some cancers. Studies have demonstrated the efficacy of a Mediterranean style diet, which includes lots of fruits and vegetables, in reducing both cancers and cardiovascular disease , ,, ,  However it is important to note that not all fruits and vegetables are equal. For example, a fresh piece of fruit is inherently more healthy than its fried equivalent, a glass of sugar-loaded, low fibre fruit juice or a processed alternative. Care should be taken to always wash and peel fruits and vegetables though, as they are commonly contaminated with pesticide residues, even when organic options are chosen, due to the widespread contamination of our environment.,  Sugar should ideally contribute less than 10% of daily caloric intake, or ideally less than 5% for additional health benefits. This is about 50g, or 12 teaspoons, for a person consuming the recommended 2000 calories a day. Sugar is routinely added to numerous foods and drinks by manufacturers, cooks and consumers, but it also occurs naturally in honey, syrups and fruit juices and so monitoring intake can prove difficult., ,  Salt intake should also be limited to 5g (one teaspoon) per day, although iodised salt can be beneficial, as it provides the essential mineral iodine. Reduction in overall salt intake helps prevent high blood pressure and reduces the risk of heart disease. In fact it has been shown that reducing sodium intake to <2 g/day can lower systolic blood pressure by 3.47 mmHg, and diastolic blood pressure by 1.81 mmHg.,  Consuming more calories than are required by the body will ultimately result in weight gain. When monitoring dietary calorie intake, drinks are often forgotten, yet sugary drinks, beer and alcohol all have a high calorific value. Fats and sugars are good sources of energy, but excessive consumption can also result in obesity and the increased risk of type 2 diabetes, some cancers, heart disease and stroke., , ,  Dairy products can also have a high caloric value and should be consumed as part of a balanced diet, choosing low fat options when possible. However it is important to remember that children under two years should not be given skimmed milk, as it lacks essential fatty acids and fat soluble vitamins, which are important for development. Many eating habits are learned in childhood, so it is important that parents and educators explain the importance of a balanced diet and healthy eating choices early in life. By eating a healthy diet ourselves, and by instilling good eating habits in children we may be able to tackle some of the problems facing the modern world today, such as the increased prevalences of obesity and cancer.  Lichtenstein, A et al. (2006). Diet and lifestyle recommendations revision 2006: a scientific statement from the American Heart Association Nutrition Committee.American Heart Association Nutrition Committee, 114(1), 82-96.  Schatzkin, A et al. (2008). Prospective Study of Dietary Fiber, Whole Grain Foods, and Small Intestinal Cancer. Gastroenterology, 135(4), 1163-1167.  Jenkins , D et al. (1987). Starchy foods and fiber: reduced rate of digestion and improved carbohydrate metabolism , Journal of Gastroenterology.Scandinavian Journal of Gastroenterology, 22(129), 132-141.  Covington, M. (2004). Omega 3 Fatty Acids. American Family Physician, 70(1), 133-140.  Perk, J. et al. (2012). European Guidelines on cardiovascular disease prevention in clinical practice . European Heart Journal, 33(13), 1635-1701.  Piepole, M. et al. (2016). 2016 European Guidelines on cardiovascular disease prevention in clinical practice. European Heart Journal, 37(1), 2315 - 2381.  Go, AS. et al. (2016). Heart disease and stroke statistics - a 2014 update: a report from the American Heart Association. Circulation, 139(3), e28-292  Mozaffarian, D. (2009). Health effects of trans-fatty acids: experimental and observational evidence. European Journal of Clinical Nutrition, 63(2).  Williams, P. (2007). Nutritional composition of red meat. Journal of the Dieticians Association of Australia, 64(S4), 113-119.  European Commission. (2002) Polycyclic aromatic hydrocarbons - occurrence in foods, dietary exposure and health effects. Retrieved April 2016 from, http://ec.europa.eu/food/fs/sc/scf/out154_en.pdf  Sanchez-Zamorano LM, et al. (2016) The Western dietary pattern is associated with increased serum concentrations of free estradiol in postmenopausal women: implications for breast cancer prevention. Nutr Res, 36(8), 845-54.  Kraytz, M. et al. (2013). The relationship between high-fat dairy consumption and obesity, cardiovascular, and metabolic disease Kratz M1, Baars T, Guyenet S.European Journal of Nutrition, 52(1), 1-24.  Liu, S. et al. (2000). Fruit and vegetable intake and risk of cardiovascular disease: the Women's Health Study. The American Journal of Clinical Nutrition, 72(4), 922-928.  Report of the joint who/fao expert consultation. (2002). Diet, nutrition and the prevention of chronic diseases. WHO Technical Report Series, 916,  Aune, D. et al. (2012). Fruits, vegetables and breast cancer risk: a systematic review and meta-analysis of prospective studies. Breast Cancer Research and Treatment, 134(2), 479-493.  Williams, M. et al. (2005). The role of dietary factors in cancer prevention: beyond fruits and vegetables. Nutrition in Clinical Practice, 20(4), 451-459.  Slavin, J.L. & Lloyd, B. (2012). Health benefits of fruits and vegetables. Advances in Nutrition, 3(4), 506-516.  European Commission (2008) Annex II: pesticides - plant protection products referred to in Article 5(1). Retrieved October 2016 from, http://ec.europa.eu/agriculture/organic/eu-policy/expert-advice/documents/final-reports/final_report_egtop_on_plant_protection_products_en.pdf  The Expert Committee on Pesticide Residues in Food. (2015) Report on the Pesticide Residues Monitoring Programme for Quarter 1 2015. Retrieved October 2016 from, http://webarchive.nationalarchives.gov.uk/20151023155227/http://www.pesticides.gov.uk/Resources/CRD/PRiF/Documents/Results%20and%20Reports/2015/Q1%202015%20FINAL.pdf  World health organisation. (2003). Global Strategy on Diet, Physical Activity and Health. WHO Technical Report Series, 916.  World health organisation. (2015). Sugars intake for adults and children. Guideline. Retrieved October 2016 from, http://apps.who.int/iris/bitstream/10665/149782/1/9789241549028_eng.pdf  Malik, V.S et al. (2010). Sugar-sweetened beverages, obesity, type 2 diabetes mellitus, and cardiovascular disease risk. US National Library of Medicine, 121(11),1356-1364.  Meneton, P et al. (2005). Links Between Dietary Salt Intake, Renal Salt Handling, Blood Pressure, and Cardiovascular Diseases. Physiological Reviews, 85(2), 679-715.  World health organisation. (2012). Sodium intake for adults and children. Guideline. Retrieved October 2016 from, http://apps.who.int/iris/bitstream/10665/77985/1/9789241504836_eng.pdf  Steinberger, J & Daniels, S.R. (2003). Obesity, Insulin Resistance, Diabetes, and Cardiovascular Risk in Children. American Heart Association , 107(1), 1448-1453.  Vartanian, LR. et al. (2007) Effects of soft drink consumption on nutrition and health: a systematic review and meta-analysis. Am J Public Health. 97(4). 667-75.  Azeem, S. et al. (2015). Diet and Colorectal Cancer Risk in Asia - a Systematic Review. Asian Pacific Journal of Cancer Prevention, 16(13), 5389-5396.  Ley, S. et al. (2014). Prevention and management of type 2 diabetes: dietary components and nutritional strategies. Lancet, 383(9933), 1999-2007.  De souza, R. et al. (2015). Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies. BMJ, 351(H3978), .  Richelsen, B. (2013). Sugar-sweetened beverages and cardio-metabolic disease risks. Current Opinion in Clinical Nutrition and Metabolic Care, 16(4), 478-484
Fats in our diet are a valuable source of energy (1 g is equivalent to 9 kcal), and they are essential in a healthy balanced diet. While some fats are beneficial, others, if consumed in excessive amounts, have detrimental effects on health. Fats are classified by their chemical structure, falling into several groups including saturated fats, mono-/polyunsaturated fats and trans fats. The fatty acid chains in saturated fats consist of only single bonds, indicating that there are no bonds available for further binding. Foods that contain high levels of saturated fat include whole milk, butter, cheese, lard, palm oil, coconut oil, “fatty” meat and meat products, fried food, and some cakes, biscuits and pastries. All of the above should be eaten in small amounts as saturated fats have a proven association with increased cholesterol levels, which can progress to clogged arteries and increased risk of heart disease and stroke. There have been numerous studies confirming the benefits of reducing saturated fats in our diets. For example, replacing saturated fats with unsaturated fats reduces cholesterol levels, thus decreasing the risks of heart disease and stroke.,  Both epidemiological and randomised clinical trials have consistently evidenced that replacing saturated fat with unsaturated fat, is beneficial in coronary heart disease. The fatty acid chains in unsaturated fats contain either one double bond (monounsaturated fat) or more than one double bond (polyunsaturated fat). Foods rich in these types of fats include vegetable oils such as olive, rapeseed or sunflower oils, avocados, nuts and seeds. It has been demonstrated these fats help decrease the risk of heart disease.,  Omega-3 fatty acids are a group of polyunsaturated fats found mainly in oily fish such as mackerel, salmon or sardines. Omega-3 fatty acids have many health benefits, and are associated with good heart health as they reduce the risk of blood clots and assist in the regulation of heart rhythm.,  They are also important during pregnancy and breastfeeding, supporting infant development.,  Trans-fats are the most harmful to our bodies. This group of fats are manufactured by partially hydrogenating vegetable oils, resulting in a firmer, better tasting fat with an increased shelf life. They are found in most processed and ‘fast’ foods, that are already very high in saturated fats. Manufactured trans-fats have been shown to have an even more adverse impact on cholesterol levels than saturated fats, which in turn is associated with diabetes and cardiovascular disease.,  Whilst knowing which fats are more healthy than others can certainly help in reducing the risks associated with fat consumption, some fats can actually become more harmful during cooking, depending on the processes involved. Vegetable oil, for example can accumulate by-products known to pose a significant risk of cardiovascular disease when heated repeatedly. Cooking can also change the ratio of healthier unsaturated fatty acids to unhealthy saturated fats and trans fats. Reducing fat in the diet is advisable to prevent obesity and its related complications, such as type 2 diabetes. Even beneficial mono-/polyunsaturated fats should be consumed in moderation, as they still have a high calorific value. In fact studies on mice have shown that a high fat diet induces greater weight gain than a low fat diet, even if their calorific intake is the same. A reduction of saturated and trans-fats in the diet can be achieved by avoiding processed and ‘fast’ foods as much as possible and choosing food prepared at home from fresh, low fat ingredients. Lean sources of protein, low fat dairy foods, legumes, fresh fruit and vegetables are a healthier choice than foods high in fat, although beneficial oils such as olive, canola and sunflower oil can be used for cooking and salad dressings.  Nelson, D & Cox, M. (2008). Lehninger principles of biochemistry. (5 ed.)  Jakopsen, M.U. (2009). Major types of dietary fat and risk of coronary heart disease: a pooled analysis of 11 cohort studies. The American Journal of Clinical Nutrition. 85(5). 1425-1432  Mozaffarian, D. et al. (2010). Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials. PLos Med. 7(3). e1000252  Siri-tarino, P.W. et al. (2010). Saturated fatty acids and risk of coronary heart disease: modulation by replacement nutrients. Current atherosclerosis reports. 12(6). 384-390  Covas, M.I. (2007). Olive oil and the cardiovascular system. Nutritional Pharmacology. 55(3). 175-186  Gillingham, L.G. et al. (2011). Dietary monounsaturated fatty acids are protective against metabolic syndrome and cardiovascular disease risk factors. Lipids. 46(3). 209-228  Swanson, D. et al. (2012). Omega-3 fatty acids EPA and DHA: health benefits throughout life. Advances in Nutrition. 3(1). 1-7  Calder, P.C. et al. (2009). Omega-3 polyunsaturated fatty acids and human health outcomes. BioFactors. 35(3). 266-272  Stender, S. et al. (2006). A trans world journey. Atherosclerosis Supplements, 7(2), 47-52.  Micha, R. et al. (2009). Trans fatty acids: effects on metabolic syndrome, heart disease and diabetes. Nature Reviews: Endocrinology. 5(6). 335-344  Bhardwaj, S. et al. (2011). Overview of trans fatty acids: Biochemistry and health effects. Diabetes & Metabolic Syndrome: Clinical Research & Reviews. 5(3). 161-164  Ng, CY. et al. (2014) Heated vegetable oils and cardiovascular disease risk factors. Vascul Pharmacol. 61(1). 1-9  Bhardwaj, S. et al. (2016) Effect of heating/reheating of fats/oils, as used by Asian Indians, on trans fatty acid formation. Food Chem. 212. 663-70  Petro, A.E. et al. (2004). Fat, carbohydrate, and calories in the development of diabetes and obesity in the C57BL/6J mouse. Metabolism: clinical and experimental. 53(4). 454-457
nikolay posted a topic in FoodWhat is healthy salmon Salmon is renowned for its health benefits, as it is high in omega-3 and -6, which are essential fatty acids (EFAs). Omega-3- and -6 are polyunsaturated EFAs that play vital roles within the human body. It is thought that increasing polyunsaturated EFA consumption can reduce the risk of many diseases, including heart disease, multiple sclerosis and a variety of mental disorders. As many people are deficient in omega 3, eating ‘oily’ fish such as salmon is one potential way to help increase omega-3 levels and to reduce the incidence of such diseases. Less than half the world’s salmon comes from the fish’s natural wild environment, with the rest coming from fish farms, also known as aquacultures. Although wild salmon is still available, global stocks have been in decline for decades. Aquaculture on the other hand continues to flourish, with 90.4 million tonnes of farmed fish produced in 2012 alone. Whilst wild salmon feed on their natural prey (other living organisms), farmed salmon are fed fat-rich commercial feeds. There are therefore some important differences in their nutritional composition; for example, farmed salmon has almost three times the fat content of wild salmon, a large constituent of which are EFAs. It might be easy to assume that an increased EFA content might mean that farmed salmon are more beneficial to our health, however this is also coupled with an increased omega-6/omega-3 ratio. In order to gain the main benefits of EFA consumption, omega-6 and -3 intake needs to be balanced. Many people today are consuming too much omega-6 relative to omega-3, which distorts this balance and negates some of the beneficial effects of EFA consumption. It has been speculated that the negative effects of an increased omega-6/omega-3 ratio in humans are due to increased inflammation within the body, and furthermore that it may play a role in the increased incidence of chronic diseases such as heart disease. In addition to differing nutritional compositions, farmed and wild salmon contain varying levels of contaminants. Whilst wild fish do accumulate contaminants, farmed salmon contain much higher levels, which originate from their feed and contaminations of their environment.  Studies have shown that the levels of contamination can vary depending on the geographical location of the farm. One study showed that European farms have more contaminants than American farms, with farms in Chile seeming to have the least. These contaminants include polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), dioxins, and several chlorinated pesticides.  Some of the most dangerous of these contaminants are PCBs, which have been strongly associated with cancer and other health problems. Studies have shown that this PCB contamination can occur directly from farmed salmon feed,  with one investigation of salmon from worldwide origins demonstrating that farmed salmon had almost ten time the PCB levels of wild salmon (51,216 vs 5,302 pg/g). The study suggested that the cancer-risks associated with consuming these contaminants may potentially outweigh the benefits of EFA consumption. Evidence regarding contamination with trace element is a little more conflicting: arsenic levels have been found to be higher in farmed salmon, but levels of cobalt, copper and cadmium higher in wild salmon. Given the lower levels of contamination and the reduced omega-6/omega-3 ratio in wild salmon compared to farmed salmon, it seems that wild salmon would be the safest option for your table, particularly when considering the benefits of polyunsaturated EFA consumption. However, as with all constituents of a balanced diet, intake should be moderated to avoid the potential ill effects of overconsumption.  Simopoulos, AP. (2013) Dietary omega-3 fatty acid deficiency and high fructose intake in the development of metabolic syndrome, brain metabolic abnormalities, and non-alcoholic fatty liver disease. Nutrients. 5(8). 2901-23. Foran, JA. et al. (2005) Quantitative analysis of the benefits and risks of consuming farmed and wild salmon. J Nutr. 135(11). 2639-43.  FAO (2014) The State of World Fisheries and Aquaculture. Retrieved April 2016 from, http://www.fao.org/3/a-i3720e.pdf  Hamilton, MC. et al. (2005) Lipid composition and contaminants in farmed and wild salmon. Environ Sci Technol. 39(22). 8622-9. Blanchet, C. et al. (2005) Fatty acid composition of wild and farmed Atlantic salmon (Salmo salar) and rainbowtrout (Oncorhynchus mykiss). Lipids. 40(5). 529-31. Simopoulos, A. (2006) Evolutionary aspects of diet, the omega-6/omega-3 ratio and genetic variation: nutritional implications for chronic diseases. Biomed Pharmcother. 60(9). 502-7.  Hites, RA. et al. (2004) Global assessment of polybrominated diphenyl ethers in farmed and wild salmon. Environ Sci Technol. 38(19). 4945-9.  Easton, MDL. et al. (2002) Preliminary examination of contaminant loadings in farmed salmon, wild salmon and commercial salmon feed. Chemosphere. 46(7). 1053-74.  Foran, JA. et al. (2005) Risk-based consumption advice for farmed Atlantic and wild Pacific salmon contaminated with dioxins and dioxin-like compounds. Environ Health Perspect. 113(5). 552-6.  Carlson, DL. & Hites, RA. (2005) Polychlorinated biphenyls in salmon and salmon feed: global differences and bioaccumulation. Environ Sci Technol. 39(19). 7389-95.  Foran, JA. et al. (2004) A survey of metals in tissues of farmed Atlantic and wild Pacific salmon. Environ Sci Technol. 23(9). 2108-10.