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پیشگیری از عوامل خطر تغذیه ای بیماری های غیر واگیر

پیشگیری از عوامل خطر تغذیه ای بیماری های غیر واگیر. معاونت بهداشتی Dr Naghiaee Clinical Biochemistry,PhD. Fat&oil. Fats or lipids are substances in food and in the body that do not dissolve in water but soluble in organic solvents. Roles of dietary fats. Provision of energy

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پیشگیری از عوامل خطر تغذیه ای بیماری های غیر واگیر

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  1. پیشگیری از عوامل خطر تغذیه ای بیماری های غیر واگیر معاونت بهداشتی Dr Naghiaee Clinical Biochemistry,PhD

  2. Fat&oil Fats or lipids are substances in food and in the body that do not dissolve in water but soluble in organic solvents

  3. Roles of dietary fats • Provision of energy • Supply of essential nutrients • Fat soluble vitamins • Essential fatty acids • Flavour, texture and palatability • Eicosanoids – Hormone like substances • Regulate blood pressure • Regulate blood clot formation • Regulate immune response to injury and infection

  4. Stearic acid: 18 17 10 9 2 1 CH3-CH2-(CH2)6-C-C-(CH)6-CH2-COOH 18: 0  HCOOH Formic acid 1:0CH3COOH Acetic acid 2:0CH3CH2COOH Propionic acid 3:0CH3(CH2)2COOHButyric acid 4:0CH3(CH2)14COOH Palmitic acid 16:0 CH3(CH2)16COOH Stearic acid18:0 • (شکل 2) 4

  5. Fatty acids: Degree of saturation • Saturated fatty acids(SFA) such as stearic acid carry the maximum number of hydrogen atoms and have NO double bonds between carbon atoms • Unsaturated fatty acids have at least one double bond between carbons: • Monounsaturated fatty acids(MUFA) lack two hydrogen atoms and one double bond between carbons e.g. oleic acid • Polyunsaturated fatty acid (PUFA) is a fatty acid that lacks four or more hydrogen atoms and has tow or more double bonds between carbons

  6. Stearic acid H H H H H H H H H H H H H H H H H O H-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-O-H H H H H H H H H H H H H H H H H H Carboxyl group Methyl group Stearic acid is the simplest of the 18-carbon fatty acids. Stearic acid is a saturated fatty acid. A saturated fatty acid carries the maximum number of hydrogen atoms and NO double bonds between carbon atoms

  7. اسیدهای چرب اشباع: ادامه... • * مهمترین اسیدهای چرب اشباع : • 1- استیک اسید یا اتانوئیک اسید با2 کربن( سرکه وحاصل متابولیسم مواد سه گانه ). • 2- بوتیریک اسید یا بوتانوئیک اسید با4 کربن( کره). • 3- میریسیدیک اسید یا دکابوتانوئیک اسید با14 کربن • ( گردو ،نخل ،نارگیل ، مورد و کره ). • 4- پالمیتیک اسید يا دکا هگزانوئیک اسید با16 کربن( نخل و تمام جانداران). • 5- استئاریک اسید یا دکا اکتانوئیک اسید با18 کربن( پی ود مبه گوسفند). • 6- آراشیدیک اسید یا دودکانوئیک اسید با20 کربن (چربیهای حیوانی و بادام زمینی ). • 7- بهنیک اسید یا دودکااتانوئیک اسید با22 کربن (دانه ها ). • 8- لیگنوسریک اسید یا دو دکا بوتانوئیک اسید با 24 کربن (نخل ومغز بادام زمینی ). 8

  8. Oleic acid H H H H H H H H H H H H H H H O H-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-O-H H H H H H H H H H H H H H H H H H Oleic acid, an 18-carbon monounsaturated fatty acid

  9. Linoleic acid H H H H H H H H H H H H H O H-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-O-H H H H H H H H H H H H H H H H H H Linoleic acid, an 18-carbon polyunsaturated fatty acid Linoleic acid is an essential fatty acid

  10. Omega fatty acids • Omega 9(oleic acid as olive oil,canola oil) • Omega 6(linoleic&arashidonic acids as sunflower,corn,soybean,safflower) • Omega 3(linolenic,ALA) -Eicosapentaenoic(EPA) -Docosahexaenoic(DHA) (as cotton,soybean,salmon,cod,mackerel,tuna)

  11. Disorders of deficency

  12. Cis-Trans fatty acids Saturated Fatty Acid Cis Fatty Acid Trans Fatty Acid H H H H H C C C C C C Carbon-CarbonDouble Bond H H H Carbon-CarbonSingle Bond Hydrogen atoms are on opposite sides of the chain of carbon atoms at the carbon-carbon double bond.

  13. H H H H 2 2 2 H C C C C C 3 C C C C H H H H 2 2 2 2 Fatty-acid Nomenclature شکل 4: نمایش ساختمان شیمیائی دو اسید چرب حاوی پیوند دوگانه نوع Cis وTrans. 15

  14. A trans fatty acid has its hydrogens on the opposite sides of the double bond • Trans molecules are more linear • The relationship between trans-fatty acid intake and heart disease has been the subject of much recent research • Dairy foods and meat have small amounts of naturally occurring trans fat • Cows produce small amounts of trans fat in digestion • Milk contains both conjugated and non conjugated forms

  15. Trans fatty acids are not essential and provide no known benefit to human health…A UL is not set for trans fatty acids because any incremental increase in trans fatty acid intake increases CHD risk. Because trans fatty acids are unavoidable in ordinary, non-vegan diets, consuming 0 percent of energy would require significant changes in patterns of dietary intake.

  16. Are trans fats worse than saturated fats? Source: Ascherio et. al. New Eng. J. Med. 340:1994 (1999)

  17. Hydrogenation Oxidation of unsaturated fats yields a variety of products that smell and taste rancid • Manufacturers can protect against rancidity in 3 ways: • Air tight and refrigerated containers • Add anti-oxidants – additives • Saturate some or all of the fat by adding hydrogen molecules - hydrogenation

  18. Disadvantages of hydrogenation • Makes polyunsaturated fats more saturated removing any health consequences of polyunsaturated fat • Some molecules that remain unsaturated change shape from cis to trans • In nature, most unsaturated fatty acids are cis-fatty acids meaning that the hydrogens next to the double bond are on the same side of the carbon chain

  19. Current recommendations for saturated fatty acids

  20. Current recommendations for unsaturated fatty acids

  21. Current recommendations for trans fatty acids

  22. Current recommendations for ALA

  23. اکسیده شدن اسیدهای چرب غیر اشباع: • تعریف : اسیدهای چرب غیر اشباع در مجاورت اکسیژن ومواد اکسیدکننده (نور ، فلزات سنگین ، هوا ، حرارت و فشاراکسیژن) درمحل پیوندهای دوگانه اکسیده شده (Per oxidation)ومتناسب با فشار اکسیژن ترکیبات مختلفی را تولید می کنند. • محصولات حاصل از اکسیده شدن: • اپوکسید( Epoxide )،کتوهیدروکسید( Ketohydroxide)،ان دی اول (Endiol)،پراکسید(Peroxide)،دی اسید(Di acid)، اسید الکل (Acid-Alcohol)، اسید آلدئید(Acid- Aldhyde )و... • اثرات محصولات حاصل از اکسیده شدندر خارج بدن:تغییرpH ،مزه وبو که آن را تند یا ترش شدن غذاها يا (Rancidity) می نامند. 29

  24. اکسیده شدن اسیدهای چرب غیر اشباع: ادامه... • اثرات محصولات حاصل از اکسیده شدندر داخل بدن:تشکیل رادیکالهای آزاد (Free Radical) که باعث اسیب به انواع بيومولکولهای بدن و در نتیجه ایجاد بیماری ( پيري زودرس ، عوارض التهابي ، سرطان ، بيماري عروق كرونر و...)می شوند. • قبلا“ برای جلوگیری از اکسیده شدن چربیهای غیر اشباع ، آنهارا جامد می کردند (Hardening=Hydrogenation)ولی با توجه به آن که این عمل موجب تولید مواد خطرناک می شود امروزه انجام این عمل تقربیا“ منسوخ شده است. به جای آن در صنعت غذاسازی وکنسرو سازی از مواد ضد اکسیداسیون مصنوعی که خطرات جانبی زیاد نداشته باشند مانند پروپیل گالات ، بوتولید هیدروکسی تولوئن(BHT) وبوتولید هیدروکسی آنیزول(BHA) استفاده می شود. 30

  25. Triglycerides • Saturated: • A saturated fat is composed of triglycerides in which most of the fatty acids are saturated • Tend to be solid at room temperature • Tend to be of animal origin • Exceptions include palm oil, coconut oil and cocoa butter • Become rancid very slowly

  26. Unsaturated: • Tend to be liquid at room temperature • Tend to be of plant origin • Become rancid more quickly than saturated fats • Monounsaturated fat is composed of triglycerides in which most of the fatty acids are monounsaturated e.g. olive oil • Polyunsaturated fat is composed of triglycerides in which most of the fatty acids are polyunsaturated e.g. sunflower oil, safflower oil

  27. Cholesterol • Main sterol in the body. • Major component of cell membranes • Precursor of steroid hormones(adrenal&gonadal) • Precursor of bile acids

  28. Types &sources Cholesterol • Internal • External Yolk,chiken,meat,liver,brain,milk & dairy product,butter,… Plant sources have no Cholesterol

  29. Lipoproteins • Lipid is transported throughout the body attached to protein, the greater the proportion of protein the higher density of the lipoprotein molecule. • Types : -chilomicron -Very low density lipoproteins(VLDL) • High density lipoproteins (HDL) • low density lipoproteins (LDL)

  30. Lipoproteins • Raised LDL cholesterol is a risk factor for coronary heart disease (CHD) • High levels of HDL cholesterol appear protective for CHD • High intakes of PUFAs can lower HDL • High intakes of MUFAs can decrease LDL without also decreasing HDL

  31. Dietary Values for Fat • Adults :15-35%total energy • Pregnancy women:20-35%total energy • Children : 50-60%of energy breastmilk is fat. < 1 year 30gr /day 3% total energy of linoleic acid(4/4gr for <6 months&4/6gr for6-12 months) In weaning 30-40% total energy must be fat.

  32. Saturated fatty acids should provide an average for the population of 10% of total dietary energy Cis-monounsaturated fatty acids (principally oleic acid) should continue to provide on average 12% of dietary energy Cis-polyunsaturated fatty acids should continue to provide an average of 6% of total dietary energy. For infants, children and adults linoleic acid should provide at least 1% of total energy and alpha linolenic acid at least 0.2% of energy. PUFA intakes of individuals should not exceed 10% of total energy intake. Trans fatty acid intake in the population should not increase further than the current estimated average of 5g/d or 2% of dietary energy

  33. Types of oils • Cooking oil • Margarine • Shortening • Salad oils • Medium chain triglycerides(MCT)

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