Facts on Fat

Fat often gets a bad rap, and sometimes, rightly so. It is essential for many bodily processes, yet, like just about anything else, too much can be a bad thing.

Stored fat is also known as adipose tissue, and it is distributed throughout the body. The amount and distribution of adipose tissue can be good or bad in terms of a person’s cardiovascular health.

Some adipose tissue is located just below the skin, and is therefore known as subcutaneous. Other adipose tissue can be located close to organs in the middle of the body, where it is known as visceral adipose tissue (VAT).  Some fats in the muscle are known as intramuscular triacylgerol (IMTG), or intramuscular adipose tissue. This IMTG can be used as an immediate fuel source for muscle metabolism, while VAT is quite bad for people’s risk of heart disease.

Fatty Acids & Health

The primary fuel source in the body is a molecule known as a triglyceride. This molecule is a glycerol connected to three fatty acids. After an enzyme known as hormone-sensitive lipase breaks the glycerol molecule apart from the fatty acids, both the glycerol and the fatty acids can be used for fuel.

Some fatty acids have carbon atoms with a single bond to each other and as well as to two hydrogen bonds. This is known as a “saturated” bond. If there is a double bond between the carbon atoms, then there is no space for hydrogen atoms to attach and this is known as an “unsaturated” bond.

Taken to a more familiar level, saturated fats come primarily from animal sources and are semi-solid at room temperature. Unsaturated fats sometimes exhibit an unsaturated bond and are an “oil” or liquid form at room temperature. The term “omega” is applied to this type of unsaturated bond. Cold-water fish such as salmon, tuna, and mackerel are high in Omega 3 fatty acids. These fats are beneficial and may lower blood cholesterol. Saturated fats are not, however, and can act to raise “bad” cholesterol.

Blood Cholesterol Profile & Cardiovascular Health

The blood cholesterol profile is a combination of several factors- the high-density lipoproteins (HDLs), the low-density lipoproteins (LDLs), and triglycerides. The situation is more complex than that, however. There are other forces at work in the cholesterol game. Related to LDL is Very Low Density Lipoprotein (VLDL), which is in turn related to the transport vehicle for all triglycerides, known as the chylomicron. In general, HDL transport fats from the body to the liver to be oxidized and the LDL and VLDL transport fat to the organs and other tissues to be stored. This is the basis for the generalization of HDLs as “good” cholesterol and the LDLs as “bad” cholesterol. Having a high overall cholesterol (>200 mg/dl) is just one risk factor for developing cardiovascular disease. Other factors such as a high LDL, a low HDL or a low Total-to-HDL ratio are also taken into account.

As technology advances, it is becoming possible to accurately pinpoint the risk of cardiovascular disease and coronary artery disease using these factors, together with other lipid and non-lipid factors. Non-lipid factors include High Sensitivity C-Reactive Protein, homocysteine, and alpha lipoic acid. Taken together with other measures including waist and hip ratios, body fat, and blood pressure, it is possible to arrive at a fairly accurate picture of a person’s risk for cardiac health issues.

Reference

The National Federation of Professional Trainers. Sports Nutrition Manual. 2nd Ed. Lafayette, IN: NFPT, 2006.