More Facts on Fats

Lipids and Health

The Fats

• Saturated – triglycerides containing

saturated fatty acids

• Unsaturated– Contain unsaturated fatty acids– Double bond usually has cis

conformation

• Hydrogenated– Addition of hydrogens to

unsaturated fats to make them more solid at room temperature

• Trans fats– Contain unsaturated fatty acids

in trans conformation

Lipids & Cholesterol• Lipids are hydrophobic

– Blood contains water– Lipids are conjugated with proteins in order to be

transported in blood– Lipid + protein = lipoprotein

• 3 types of lipoproteins:– High-density lipoproteins (HDL) aka good cholesterol

• Carry cholesterol from the rest of the body to the liver– Low-density lipoproteins (LDL) aka bad cholesterol

• Carry cholesterol from liver to the rest of the body– Very low-density lipoproteins (VLDL) - this one is an

ugly one• Carry triglycerides from liver to adipose tissue

• Excess cholesterol can be detected by measuring the amount of lipoproteins present in the blood

Atherosclerosis

"Hardening of the arteries"- Slow process that may

start in childhood- Over time, walls of

arteries become damaged - Fatty tissues release compounds that promote healing through plaque build-up

Plaque• Fatty substance made up of cholesterol,

fat and calcium

• Builds up over damaged area, but causes the artery to become narrowed

• Narrowed tube = higher pressure (think of putting your thumb over end of hose)

• Higher pressure sometimes causes more damage to the artery walls

Risk Factors• Atherosclerosis may start when certain

factors damage the inner layers of the arteries. These factors include:

• Smoking • High amounts of certain fats and

cholesterol in the blood • High blood pressure• High amounts of sugar in the blood due to

insulin resistance or diabetes

So…• Arteries that are blocked cannot provide

the heart with needed oxygen/nutrients

• Lack of oxygen leads to death of tissue

• Also can cause embolism- chunk of plaque breaks off and enters bloodstream

• Clot enters major artery going to heart leads to heart attack; to brain = stroke

Bypass Surgery

• Surgeons take a segment of a healthy blood vessel from another part of the body and make a detour around the blocked part of the coronary artery.

LDL (aka "Bad" Cholesterol)

• Transports ~ 75% of cholesterol to cells• If LDL is oxidized, (combines with free-radicals),

LDL is modified• penetrates and damages the walls of arteries-

causes inflammatory response• Body's response can promote further damage:

– WBC's and other inflamm. factors gather and form a plaque

– Damage to endothelium– Increase risk for blood clots– Reduces levels of nitric oxide (needed for relaxation

of vessels)

HDL(aka "Good" Cholesterol)

• Removes cholesterol from walls of arteries and returns it to the liver

• Prevents oxidation of LDL (has antioxidant properties)

• Reduces narrowing of vessels, and risk of heart attack

• High levels of HDL are beneficial to health

• Fish oils, omega-3, 6 fatty acids

Role of Omega-3 & Omega-6 Fats?

• High in whole grains, fresh fruits and vegetables, fish, olive oil, garlic (0mega-3) and meat (omega-6)

• reduce inflammation and help prevent risk factors associated with chronic diseases such as heart disease, cancer, and arthritis

• important for cognitive (brain memory and performance) and behavioral function

• Balance of omega-3 and omega-6 needed

Omega 3 Omega 6

Triglycerides(good? Bad?)

• Are now becoming known as a major problem for the heart

• Interaction between HDL and TG- shows a decrease in HDL as TG levels rise (relationship is under study)

• Imbalance of HDL/TG associated with obesity, insulin resistance, and diabetes

• Also may lead to blood clots and inflammatory responses