For several decades, public health authorities have warned that high blood cholesterol can increase your risk of heart attack, leading to a disproportionate fear of the substance and calls to reduce the amount of cholesterol you eat, especially in foods such as eggs and shellfish. Harvard's School of Public Health calls the mania a "red herring," because the truth is, the amount of cholesterol you get in foods has a minimal impact on the amount of cholesterol circulating in your blood. Rather than being a toxic invader and health horror, cholesterol is, in fact, essential to life. It's a waxy, fat-like substance that performs an array of health functions. The "Dietary Guidelines for Americans 2010" says men can consume about 300 mg per day and women 240 mg.
Cholesterol is in Every Cell in Your Body
Cholesterol is a ubiquitous substance in your body. Every cell in your body needs cholesterol to be healthy. Your cells are covered by a membrane that is composed of mostly cholesterol, along with fat and protein. Cholesterol provides a measure of rigidness to all cell membranes. Cells must be porous to let nutrients and hormones in and out, but without cholesterol, they would be too fluid and might be destroyed by their internal pressure. Brain cells also have a small amount of cholesterol in them, and cholesterol helps to maintain neurotransmitters involved in brain function.
Your Body Makes Its Own Cholesterol
Your liver produces cholesterol and it also is responsible for removing cholesterol from your body as needed. It can make between 800 and 1,500 mg per day, constructing it from saturated fats and simple sugars. Your intestines absorb cholesterol. To travel through the blood and conduct its business, cholesterol is transported through protein carriers called lipoproteins. Doctors measure two classes of lipoproteins, high-density and low-density, to determine your cholesterol profile. Your cells latch on to these proteins to draw out the cholesterol, but when you have too much low-density cholesterol, you can get a buildup of plaques in the walls of your arteries. This buildup can block the flow of blood and put you at risk of heart attack. High-density cholesterol's job is to scavenge for cholesterol and take it back to your liver for removal.
Cholesterol Performs Important Functions
Cholesterol isn't evil. A common misperception about the substance is that the lower your total cholesterol is, the better. Although genetics play a role in how well your body produces and removes cholesterol, most bodies have exceptional control of cholesterol, increasing and lowering production based on the amount already circulating in your blood. Your body uses cholesterol to make major hormones, such as testosterone, estrogen, progesterone, cortisone and aldosterone, which are important to sexuality, coping with stress and balancing sodium and fluid levels. Even your skin has cholesterol in it. Cholesterol makes skin resistant to certain toxins and retain water in the body. Cholesterol also helps formulate vitamin D, which is both a vitamin and hormone. Without enough vitamin D, your bones would be brittle and weak and you'd have problems absorbing calcium. Most of the cholesterol you make --- up to 70 percent --- works to produce bile salts, which are used to help you digest food.
Fat Content in Foods Affects Your Cholesterol Level
You may think that the amount of cholesterol in the foods you eat raises your cholesterol significantly. The truth is, there's only a weak relationship between dietary and blood cholesterol. You absorb only a fraction of your cholesterol directly from foods. The types of fats you eat play a much greater role in determining your cholesterol levels. Harvard's School of Public Health reports that unsaturated fats improve your cholesterol levels by decreasing low-density and increasing high-density cholesterol. Saturated and trans fats, on the other hand, boost bad cholesterol.
References
- Harvard School of Public Health: Fats and Cholesterol: Out with the Bad, In with the Good
- Share Guide: The Truth about Cholesterol
- Iowa State University Extension: Cholesterol in Your Body
- Texas A&M System AgriLife Extension: How the Body Produces & Uses Cholesterol
- Women to Women: The Truth about Cholesterol and Fat
- Hepatitis A-Z: The Cholesterol Controversy
