Chapter 8: Fats Seen and Unseen
- Page ID
- 56987
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)To understand the role of fat in the diet, we must know some basic principles of fats in nutrition. We begin by looking at the nutritive values of dietary fats, and then look at the various types of fats—relating their chemistry to their physical properties as food, and to their functions in the body.
- 8.1: Prelude to Fats Seen and Unseen
- Once again we come back to the nutrition goals of balance and moderation—hardly soul-stirring battle cries, but profoundly important. As the facts of dietary fat are examined, the true perspective of the good and not-so-good of this essential nutrient become clear, and we take another step toward becoming our own nutrition expert.
- 8.2: Fat is Not Evil
- There has been a lot said about the dangers of eating too much fat. There are good reasons for focusing attention on dietary fat. But for the unwary, these dire warnings can be misleading. For the evils associated with dietary fats are related to excessive use, not to harm in fat itself. In fact, fat is an essential nutrient.
- 8.3: What is a Fat?
- Fats are a group of chemical compounds which do not dissolve in water, but do dissolve in organic solvents (solvents which have a chemical backbone of carbon, such as ether or chloroform). To put it simply, fat added to water floats to the top, as on the surface of chicken soup (thus the classic statement that oil and water don’t mix). Similarly, if we dribble gravy on our clothing, water will not sponge it away. Instead, we use cleaning fluid (an organic solvent) to remove it.
- 8.4: Phospholipids
- Phospholipids are similar in structure to triglycerides. They differ from triglycerides only in that a phosphorus-containing substance replaces one of the three fatty acids. There are several kinds of phospholipids— the phosphorus-containing portion can vary, as can the kinds of fatty acids.
- 8.5: Cholesterol
- Cholesterol is found in all cell membranes in the body and helps regulate the fluidity (“softness”) of these membranes. Flat in structure, it fits easily between the phospholipid molecules that form cell membranes. Cholesterol has many important functions in the body—it’s needed to make such essential substances as sex hormones, and the bile acids used in digestion.