Fats in the Diet
Fats in the American diet are a growing concern. You have probably heard by now, most Americans get too much fat in their diet. Eating too much fat can lead to heart disease, cancer, and obesity. Limiting the intake of fat can have a positive effect on health. The type of fat consumed is also important. Choose a diet that is low in saturated fat, trans fat and cholesterol. Eat a diet with fats that contain polyunsaturated and monounsaturated in limited amounts.
Saturated fats are associated with raising LDL cholesterol in your blood. Typically the more saturated fat in the diet the more LDL cholesterol in your blood. Sources of saturated fats include: whole milk, cream, butter, cheese, fatty cuts of beef and pork, coconut, palm and palm kernel oils
Trans fats also raise LDL cholesterol in your blood but also lower the HDL cholesterol in your blood. Trans fats also have a negative effect on inflammation and insulin resistance. Sources of trans fats include: deep fried foods, cakes, cookies, doughnuts, pastry, crackers, snack chips, margarine, imitation cheese
Cholesterol also raises LDL cholesterol in your blood but not as much as trans fats. Sources of cholesterol include: eggs, milk products, meat, poultry, and shell fish
Polyunsaturated and Monounsaturated fats
Replacing saturated and trans fats with monounsaturated and polyunsaturated fats may be an effective way of preventing heart disease. Omega-3 and Omega-6 are essential fatty acids require by the body. Omega-3 fatty acids have been given a lot of attention lately because of their role in reducing the risks of heart disease and strokes. Sources of monounsaturated fats: olive oil, canola oil, peanut oil, and avocados. Sources of polyunsaturated fats: vegetable oils (safflower, sesame, soy), nuts and seeds. Sources of Omega-3 fats include vegetable oils, (canola, soybean, flaxseed)
Although most Americans get too much fat in the diet, it is important to note that it is a necessary component of the diet. Too little fat in the diet can have adverse effects. In the body, triglycerides provide protection against shock, help the body use carbohydrates and proteins efficiently,provide a reserve for energy, and insulate against temperature extremes among many other things.
In order to understand fats, it is important to look at its chemical structure. The difference between many fats is its chemical structure. The different chemical structure of fats leads to the different properties. Properties of fat produce different outcomes in foods. Some fats can raise your cholesterol level while others have fat protective properties for your heart. Fats in our diet provide us with delicious flavors and textures in foods.
Fats are known as a class called lipids. The lipid family includes triglycerides (fats and oils), phospholipids and sterols.
Triglycerides are fats and oils, which are made up of:
- Glycerol and Fatty Acids
- Fatty Acids differ depending on the number double bonds
- Fatty acids with no double bonds are saturated
- Fatty acids with one double bond are monounsaturated
- Fatty acids with more than one double bond are polyunsaturated
- Fatty acids with one double bond located on the third carbon are Omega 3
- Fatty acids with one double bond located on sixth carbon are Omega 6
Phospholipids have a unique chemical structure that allows them to be soluble in water and fat.
Sterols have a multiple-ring structure.
Chemistry of Triglycerides
Since this is not a chemistry class I will try and simply this. Fats are composed of carbon, hydrogen and oxygen atoms. The atoms are linked together to form compounds. The arrangement of these atoms in the compounds gives fats their name.
Every triglyceride contains one molecule of glycerol and three fatty acids. Glycerol contains three carbons and served as the backbone for many triglycerides. Fatty acids are chains of carbon.
A fatty acid is a chain of carbon with hydrogens attached with an acid group known as (COOH) at one end and a methyl group at the other.
The longer the chain of linked carbons the longer the fatty acid. Most fatty acids contain an even number of carbons and are usually up to 24 carbons. Typically carbon can hold 4 bonds. When a carbon is holding all 4 bonds to carbon it is saturated. The bonds between the carbons identify whether a fatty acid is saturated or unsaturated. Monounsaturated fatty acids have one double bond. Polyunsaturated fatty acids have two or more double bonds.
The chemistry of the fat whether it is short or long chained, saturated or unsaturated with its first double bond here or there contributes to the characteristics of foods and the effect it has on our health.
Saturation of Fats
The degree to which fats are saturated influences the firmness of fats at room temperature. In general the more saturated a fat is the more solid at room temperature while the polyunsaturated fats are more liquid at room temperature. The saturation influences stability. Polyunsaturated fatty acids are more unstable, and can become rancid more easily.
To prevent rancidity manufacturers may add antioxidants to make the product more stable. To protect from rancidity store fats in an airtight, non-metallic container protected from light and heat. Trans fatty acids occur when manufacturers chemically alter fatty acids to improve shelf life. Trans fatty acids have been linked to heart disease.
Triglycerides are the chief form of fat in the diet and the major storage form of fat in our body.
Phospolipids have a unique chemical structure that allows them to be soluable in both water and fat. In the body phospolipids are part of the cell membrane. In the food service industry phospolipids work as emulsifiers to mix fats and waters. Manufacturers often add phospolipids to salad dressing to prevent separation. Lecithin is a common phospolipid added to salad dressing
Sterols have a multiple ring structure that is different than any other structure of fat. Examples of sterols in the body include: cholesterol, bile, Vitamin D and some hormones. In food animal based foods contain cholesterol. Cholesterol does not come from any plant based food.