Fat Chemistry

Posted on | July 8, 2008 | Comments Off on Fat Chemistry

A quick history of trans fatsWith all the talk about the nation’s obesity epidemic in recent years, we have been bombarded with information about fat content in food. But it’s not always easy to sort out the so-called “good” fat from the “bad.” In this week’s video, embedded with this blog, I offer a basic science lesson about the various fat types. To get the full background, watch the video or read the full transcript below. Meantime, here are a few essentials:

A balanced diet is about taking in the recommended portions of protein, carbohydrates and fats. The American Heart Association recommends that fats should make up 30% or less of our daily diet. The right combination of fats is critical to life. Fats are an important source of energy, they’re essential for growth and development, and they help regulate blood pressure, heart rate, blood clotting, nerve transmissions and temperature control.

One of the biggest factors in judging fats is cholesterol, the waxy substance that’s critical to the production of some hormones and vitamin D, but can also increase the risk for heart disease. The biggest influence on blood cholesterol is the mix of fats in the diet – which raise or lower the so-called “good” cholesterol, or HDL, and “bad” cholesterol, or LDL. The interplay of these two substances in your bloodstream is what determines your risk of health conditions such as heart attack.

The various types of fats, which affect your cholesterol, are categorized according to the placement of carbon and hydrogen atoms in their chemical structure, and their degree of saturation with hydrogen. They include “saturated fat,” which raises both HDL and LDL, and unsaturated fat, which tends to lower “bad” LDL and raise “good” HDL. Within unsaturated fat are two categories: “monounsaturated fat,” and “polyunsaturated fat.” A chemical process of heating an unsaturated fat yields a “trans fat,” which have the worst effect — raising LDL and lowering HDL.

We first started making trans fats when concerns surfaced about the health effects of saturated fats in butter. By hydrogenating vegetable oil – that is, adding hydrogen atoms to create trans fats – we discovered that liquid vegetable oil turned solid and could be sold as sticks of margarine. From the 1950s to the 1980s, we thought what we were doing was healthy. But research over the years has proven that “trans fats” are actually quite bad for us.

In general, the unsaturated fats lower rates of heart attack and stroke. Trans-fats, those liquid-to-solid hydrogen creations, are the evil twin. They raise LDL cholesterol and lower HDL cholesterol, increasing your chance of heart attack and stroke.

And finally, what about those saturated fats? Still bad, but not as bad as trans fats. Saturated fats raise LDL and HDL, but the net overall effect is more harmful than it is good.

For more detail, please watch this week’s video or read the full transcript. Meantime – pay attention to your fat intake!