Dietary Fat: An Introduction and Recommendations PDF

An Introduction to Dietary Fat Fat Types, Recommendations, Trends and Making Healthy Choices  Julia Childs “Fat give things flavour” “With enough butter, anything is good.”  Why do we need dietary fat? Important source of food energy (needs change th...

An Introduction to Dietary Fat Fat Types, Recommendations, Trends and Making Healthy Choices  Julia Childs “Fat give things flavour” “With enough butter, anything is good.”  Why do we need dietary fat? Important source of food energy (needs change through the life-cycle) Provides and enables the absorption of fat soluble vitamins (A, D, E & K) Provides the essential fatty acids Makes food palatable - dissolves flavors and has a characteristic mouth-feel  Setting recommendations Points to consider: Amounts required to meet needs for: – Energy – Fat-soluble vitamins – Essential fatty acids requirements. Amounts required to decrease risk of chronic disease Structure and Naming WHAT IS DIETARY FAT?  Saturated versus Unsaturated Fatty Acids Degree of saturation – Affects the temperature at which the fat melts In general, the more unsaturated the fatty acids, the more liquid the fat is at room temperature In general, the more saturated the fatty acids, the firmer the fat is at room temperature Summary of the proportion of packaged foods meeting Health Canada’s recommended trans fat limits: 2005–2009 (purple bars) compared with 2010–2011 (red bars). Data are from the Trans Fat Monitoring Program (2005–2009) and the Food Label Information Program (2010–2011). Replacing the trans fats Alternatives to partial hydrogenation? Full hydrogenation Fractionation Highly saturated traditional fats Interesterification of blends of fractionated and/or fully hydrogenated fats  Interesterification: What and why? Replacement of the partial hydrogenation Glycerol Fatty acids process sn-1 Specific positional composition and/or Glycerol Glycerol sn-2 sn-3 functionality Glycerol Use to produce hard stock fats A simplified example of the process of interesterification.  Interesterification (IE) oleic sn-1 Glycerol Non-IE Palm oil palmitic sn-2 0% solids at 37°C oleic sn-3 palmitic sn-1 palmitic sn-1 Glycerol IE Palm oil Glycerol sn-2 Interesterification palmitic oleic sn-2 15% solids at 37°C oleic sn-3 palmitic sn-3 palmitic sn-1 Glycerol palmitic sn-2 palmitic sn-3 Change the melting properties of a fat without generation of trans fatty acids oleic sn-1 Glycerol Can reduce the saturated fat content by ~10% palmitic sn-2 Higher proportion of SFA in sn-2 position palmitic sn-3 Next time… How much fat do we eat? TRENDS IN FAT CONSUMPTION Definitions Fat or lipid Class of naturally occurring organic compounds which are generally hydrophobic in nature. Various type of lipids include fatty acids, triacylglycerides, sterols and phospholipids. Fatty Acids Carboxylic acid with aliphatic carbon chain Common lengths: C4 – C28 Definitions Triglycerides Most abundant dietary lipid Consist of 3 fatty acids and 1 glycerol molecule Phospholipids Amphipathic and major lipid found in biological membranes Consists of 2 fatty acids, glycerol, phosphate group and organic molecule Sterols Amphipathic lipids with hydroxyl group – alcohols Conserved 4 ring structure  Classifying Lipids Lipids Triglycerides Fatty Acids Phospholipids Glycolipids Sterols Unique structures Unique biological functions Different sources Different implications on health  Fat as a source of energy Fat provides 9 kcal/g (37kJ/g) compared with ~4 kcal/g for protein (18kJ/g) and carbohydrate (17kJ/g) % energy from fat = ((fat in g x 9) / total energy intake in kcal)*100 – eg 90g of fat consumed by a man consuming 2400 kcal/d is approximately 34% of the energy The higher % energy from fat the more energy dense the diet: Breast milk 52% Asian and African rural diet 10-15% Japanese diet 25-30% Traditional Inuit diet 40-60% European and American diet 35-42%  Trends in Fat Consumption and Source Blasbalg, TL et al. Am J Clin Nutr 2011;93:950–62  Trends in Fat Consumption and Source Blasbalg, TL et al. Am J Clin Nutr 2011;93:950–62  Fats as a Function of Total Energy Consumption ChartsBin statistics collector team 2011, Daily Fat Intake Per Capita, ChartsBin.com, viewed 16th October, 2013, http://chartsbin.com/view/1156; FAO Statistics Division 2010, Food Balance Sheets, Food and Agriculture Organization of the United Nations, Rome, Italy, viewed 17th March, 2011, Next time…  Essential Fatty Acids Omega-6 – Linoleic Acid  Leafy vegetables, seeds, nuts, grains, vegetable oils (corn, safflower, soybean, canola, cottonseed, sunflower) Omega-3 – α Linolenic acid (ALA)  Fats and oils (canola, soybean, walnut, wheat germ, margarine and shortening made from canola and soybean oil).  Nuts and seeds (walnuts, soybean kernels  Vegetables – EPA and DHA  Human Milk  Shellfish and fish (mackerel, salmon, bluefish, menhaden, herring, trout, sardines, tuna -all except tuna provide at least 1 g of omega 3 fatty acids per 100 g of fish), Seal blubber  Not essential because they can be made from linolenic acid EPA - eicosapentaenoic acid DHA - docosahexaenoic acid Cholesterol is only found in animal products Effects of Different Fats on Cholesterol Functions of Fat Recommendations concerning intakes of fats for healthy people  Dietary Fat Recommendations < 30% of energy from fat (2000 kcal diet this is > 65 g / day) ≤ 7% of energy from saturated (+ trans) ≥ 10% polyunsaturated ≥ 13% monounsaturated **< 300 mg cholesterol / day**  How to Meet Recommendations Choose foods with lower fat Eat less animal fat, particularly those from red meats, replace with poultry and fish. Eat less hydrogenated fat, less processed foods  Saturated Fat Debate 2015 2018 1955 1980 Calories, Fat, and Saturated Fat in Cooked Ground Meat Patties 5-43 Copyright © 2021 by Nelson Education Ltd.  Lipids in Grain Products 5-44 Copyright © 2021 by Nelson Education Ltd.  Food Fat, Saturated Fat, and Calories Copyright © 2021 by Nelson Education Ltd. 5-45  Food Feature: Defensive Dining At home: Avoid adding saturated fat to foods Copyright © 2021 by Nelson Education Ltd. 5-46