When finding out about your diet and overall health, you'll often hear the terms "lipid" and "cholesterol." Both of these names refer to a variety of different substances, some good for your health, some not so good. Lipids in particular cover a whole range of fats and similar substances, including cholesterol itself. In general, a diet too high in lipids and cholesterol can lead to problems, from heart disease to obesity.
Lipids
Lipids include a variety of naturally occurring fat-like substances, including oils, steroids and waxes. Lipid types vary greatly in structure. However, all true lipids are hydrophobic, so they won't mix with water, which is why oil floats on puddles and fatty cream rises to the top of milk. Lipids also share similarities in their solubility in solvents such as chloroform and benzene. In terms of nutrition, you'll often see references to monounsaturated, polyunsaturated and saturated fats. In chemical terms, this relates to the number of hydrogen atoms connected to fatty acid tails. In simple terms, this makes saturated fats solid at room temperature.
Lipids in the Body
Membranes in your cell walls consist mainly of lipids. These keep the cell flexible and allow the transfer of certain molecules back and forth, an essential biological process. Other lipids in the body may present health problems in larger quantities. For example, excess saturated fats may eventually lead to circulation and heart problems. Saturated fats tend toward congealing together, so they can block blood vessels. Doctors call the blockage buildup plaque. Lipids from animal products tend to present more potential health problems than vegetable fats.
Cholesterol
Cholesterol plays a crucial role in the stability of body cells and the production of hormones such as estrogen. Cholesterol comes in two main forms, often referred to as either "good" or "bad" cholesterol. However, these names really relate to the substances that carry each type of cholesterol around the body. Low-density lipoproteins, or LDL, carry cholesterol from the liver to other parts of the body. LDL is known as bad cholesterol. Good cholesterol relates to high-density lipoproteins, or HDL. This carries cholesterol to the liver.
Cholesterol and Health
Eating saturated fat increases the amount of bad cholesterol in your blood. An initiative called the National Cholesterol Education Program recommends limits for total blood cholesterol after a 12-hour period without eating food. Ideal total cholesterol levels are under 200 mg per deciliter. High cholesterol means more than 240 mg per dL, according to the Colorado State University Extension website. In terms of LDL "bad cholesterol," it's desirable to have under 100 mg per dL. Unlike overall cholesterol and LDL numbers, doctors recommend you have high levels of HDL, with over 60 mg per dL desirable.
References
- UC Clermont College Biology Home Page.; Lipids: Fats, Oils, Waxes, etc.; March 12, 2011
- Michigan State University Department of Chemistry: Lipids
- Colorado State University Extension; Cholesterol and Fats; J. Anderson, et al.; December 2008
- University of Delaware Cooperative Extension; Cholesterol; Sue Snider, Ph.D.; March 1, 1997
