Nutrition Chapter 5 - FATS

Other names for fat

• Lipo

• Adipose

• Triglyceride

• glycerol

Characteristics of fats

• Greasy substances NOT soluble in water

• Provide a more concentrated source of energy than carbs

• Fat rich foods are more expensive than carbs

Fats are made of what?

• Carbon

• Oxygen

• hydrogen

• 1gram of fat provides ? Calories

• Generally, no more than 20-35% of total calories should come from fat (10% or less from saturated fat sources)

Functions of fat

• Provides energy when one cannot eat

• Fats are a necessary part of the cell walls

• Fats contain essential fatty acids and act as carriers for fat soluble Vits A, D, E, K

• Adipose fat protects vital organs and bones

• Fat insulates against the cold

Sources

• Animals – meats, butter, cheese, cream, milk, egg yolks

• Plants – cooking oils made from sunflower, safflower, sesame seed, corn, peanuts, soybeans, olives, coconut, nuts and chocolate

Sources

• Visible fats:purchased and used as fats like butter and oils

• Invisible fats: found in other foods, meat, fried foods, pastries

Classification of fats

• Most lipids in the body are triglycerides.

• These are in body cells and circulate in the blood

• You can test these levels in the blood to let you know if you need to cut back on the fat in your diet

• Still not sure what a triglyceride is?

What is a Triglyceride exactly?

• 3 fatty acids attached to a framework of glycerol…chemistry

• These are mostly lipids in the blood

Triglycerides

• This is the chemical name for fats• Triglycerides are the primary form of fat in food• Triglycerides combine with glycerol to supply

energy to the body• Triglycerides allow fat soluble vitamins to be

transported• Triglycerides end up forming into adipose tisse

that protects the body

Fatty Acids

• This is what “fat” breaks down into in order to be able to be digested

• We can get essential fatty acids in our diet.

Classification of fatty acids

• Fatty acids are classified in 2 ways:

• Essential

• Nonessential

Essential Fatty Acids

• EFA’s are fatty acids that our body cannot make by itself

• We obtain them through diet

• They are essential to the body and it is essential that you get them through your diet

Linoleic acid

• Is one of three fatty acids essential for humans found in our diet

• Linoleic acid is found in safflower, corn and sunflower oils (polyunsaturated veg.oils)

Saturated fats

• Has to do with how many hydrogen atoms each carbon atom carries…. chemistry

• Animal foods, chocolate and coconut contain more saturated fatty acids than unsaturated.

Saturated fats

• Foods containing a high proportion of saturated fats are usually solid at room temp

• These are responsible for atherosclerosis or plaque in the arteries

Monounsaturated

• One place among the carbon atoms where there are fewer H atoms attached…chemistry

• Examples are avacado, cashews, olive oil, peanut oil

Polyunsaturated

• 2 or more places where the carbon atom has fewer H atoms attached

• Examples: cooking oils made from safflower, sunflower or sesame seeds or from soybeans or corn, soft margarines whose major ingredient is veg. oil, mayo made with oil, and fish

Polyunsaturated Fats

• These are the omega 3 fatty acids, these help lower the risk for heart disease

• If you had a choice to eat monosaturated vs. poly saturated, you would choose poly because our body uses fat for energy, polys are bigger and will last longer, but we should still eat both of these

Trans fatty acids

• Produced by adding H atoms to a liquid fat making it solid

• Like when H atoms are added to a liquid, it gets firm like butter or margarine

• These are not good for you

Cholesterol

• Is a fat-like substance that exists in animal foods and body cells

• Cholesterol is made in the liver• Cholesterol is necessary in the diet

• Lipitor helps to stop the production of cholesterol within the liver if a person makes too much

Sources of cholesterol

• Organ meats * coconut

• Egg yolk

• Fat meats

• Shellfish

• Dairy

• Olives

• avacodos

Trouble with cholesterol

• It’s a contributing factor in heart disease due to hypercholesterolemia

• Causes atherosclerosis which is a soft build up of stuff sand then it hardens turning it to arteriosclerosis or plaque

Athersclerosis vs. Arteriosclerosis

• Soft build-up of cholesterol and fat in blood vessels, can be seen as streaks in the artery – this is atherosclerosis

• Eventually over the years, this soft stuff gets hard and causes reduced space for blood flow= M.I. Or CVA – this is arteriosclerosis

How do we unclog the vessels?

• Balloon angioplasty inflation of a balloon to push the plaque away, then balloon is removed

• Stent keeps vessel wide open

• Scrapping /Roto-rooter type device that breaks up the hard plaque and vacuums it out instantly

Cholesterol levels

• Serum (blood) levels should not exceed 200mg/dl of blood

Cumulative effects of high cholesterol cause trouble therefore…

• Eat healthier

• Eat low fat foods

• Eat foods higher in polyunsaturated foods that contain omega 3’s

• Increase exercise

• Wt loss

What happens to fat in digestion?

• When fat enters the stomach, what happens to it?

• The stomach acts on fats by sending out gastric lipase to emulsify the fat (like cream and egg yolks)

Fat leaves the stomach and goes where?

• Through the pylorus , through the pyloric sphincter and into the small intestine called what?

• Duodenum….there the liver shoots out bile to help further emulsify fat, the _______ takes bile to store it and the pancreas sends out pancreatic enzymes to do what?

• Pancreatic enzymes turn fats into fatty acids and glycerol to make them smaller and easier to digest so that absorption through or into where?

Change words around on your slides here

• Through the lacteals , out of the intestine walls and on into cells and then to the liver

• But there is 1 problem…

If fats are insoluble in water….

• How do fats get into the blood after they go through the liver?

• Special carriers must be provided for the fats to be absorbed and transported by the blood to body cells

• These special carriers are called “lipoproteins”• Lipo means fat and proteins are strong and big

enough to take the fat to the bloodstream and cells

2 types of lipoproteins occur

• LDL – low density lipoproteins – carries cholesterol TO tissues

(Bad cholesterol)

• HDL – high density lipoproteins – removes excess cholesterol FROM the tissues (Good cholesterol)

LDL

• Carries most of the cholesterol to the cells

• You don’t need this level to be high, we only need so much cholesterol in our cells plus the liver already makes cholesterol…we don’t need too much

HDL

• Lipoproteins that carry cholesterol from cells to the liver for eventual excretion out of the kidneys

• You want this level to be elevated meaning you want this level to be nice and elevated to do a good job of removing the cholesterol out of your body

• Exercise and wine increases HDL levels

Metabolism of fats

• The liver controls fat metabolism

• The liver hydrolyzes (adds water) the triglycerides (the fat in the blood) and forms new ones from this hydrolysis process, when needed

Metabolism of fats

• The metabolism of fats occurs in the cells, where fatty acids are broken down to carbon dioxide and water= energy

• CO2 and H2O are removed from the body by circulatory system, respiratory system and excretory system like urination

Lecithin

• Is a fatty substance found in plant and animal foods

• It’s a natural emulsifier that helps transport fats in the bloodstream

• It is used commercially to make food products smooth

High fat diet and health

• High fat diets are associated with cancers of:

• Colon

• Breast

• uterus

The End