Fats by The GI and Bariatric Nutrition Center

Fats: the good, the bad, and the ugly. Where do I begin to talk about fat? It is a subject about which we are confused, misinformed, and highly opinionated, all at the same time.

We love fat – on and in our food – because it tastes great. We hate it on our thighs and butts because it looks like cottage cheese, and reminds us we don’t look like smooth-skinned fashion models. Many of us believe that the fat in our diets is solely responsible for obesity in America.. Who can forget the mantra of the 1980s and early 1990s: "Eat all you want, as long as it’s not fat." Millions of Americans stuffed their faces with bagels, pasta, and boxes of fat-free cookies, and gained weight like crazy. So much for that theory.

Many of us also believe that fat clogs our arteries and gives us heart disease. Sounds plausible at first. After all, didn’t Nathan Pritikin reverse his own heart disease on an extremely low fat, low protein regime where 80% of his calories came from carbohydrate? He did. He also developed leukemia, and eventually committed suicide. In retrospect, it was probably the severe calorie restriction that unclogged Nathan’s arteries. And it was probably the deficiency of essential fats, combined with protein deprivation that put him at risk for depression and a compromised immune system. Let’s begin with a chemistry lesson... Note: Don’t let the chemistry overwhelm you. It is absolutely essential that you understand the underlying chemistry because you are constantly exposed to so much pseudo-scientific information. Print this page so that you can read the material repeatedly, and at your leisure. If there is a concept you still don’t understand, contact me.

Fats (or fatty acids) are composed of carbon and hydrogen. Carbon atoms are linked together in a chain formation, with varying amounts of hydrogen attached. Now, if the chain of carbon atoms has a hydrogen attached to every available space, the result is a saturated fatty acid. Saturated fats tend to be solid at room temperature. Examples: Butter, lard, cream cheese. (Now, the next time someone talks about saturated fats, you’ll know what they mean. It means the molecule is saturated with hydrogen!)

Take away a couple of the hydrogen atoms from the fatty acid, and create a double bond between two of the carbon atoms. And you now have a monounsaturated

fat. (Remember, mono = one.) Olive oil is an example of a fat that contains monounsaturated fatty acids. Monunsaturated fats are liquid at room temperature, but will partially harden when refrigerated. A fatty acid with more than one double bond is referred to as a polyunsaturated fatty acid. (Remember, poly = many.)

Many vegetable oils – corn, safflower – are high in polyunsaturated fatty acids They are liquid, both at room temperature and in the refrigerator. Polyunsaturated oils are highly reactive. They can easily interact with oxygen and go rancid. These oils should always be stored in the refrigerator to minimize oxidation. In nature, wherever you find oils, you also find vitamin E. It is there as a preservative. When oils are processed and bottled, the vitamin E content is removed and sold to the pharmaceutical companies. Keep in mind that the more vegetable oil you consume, the more vitamin E you will need to take in supplemental form.

Some unsaturated oils are named according to the position of the double bond in the chain of carbon atoms. An omega-3 fatty acid has a double bond in the 3rd position from the Omega end of the chain. ("Omega" is the last letter in the Greek alphabet.) An Omega-6 fatty acid has a double bond in the 6th position from the Omega end of the chain.

Omega-3 and Omega-6 fatty acids are referred to as essential fatty acids. They are essential because they must be obtained from food and cannot be manufactured in the body. Food sources of Omega-3 fatty acids include cold water fish, flax seed, and raw nuts.

Hydrogenated fats...

Packaged foods – crackers, cookies – often contain hydrogenated fats. Hydrogen is added to the oil in the laboratory, which changes the unsaturated oil into one which is saturated. This has the advantage, to the manufacturer, of greatly increasing the shelf life of the food item. Otherwise the oil in the packaged food would quickly go rancid. Unfortunately, adding hydrogen changes the structure of the molecule and it forms what is known as trans fatty acids. Trans fatty acids are found primarily in the American food supply. They are believed by many health experts to be partly responsible for our high incidence of heart disease in America.

Thermally oxidized fats...

Vegetable oils are typically the fats of choice for deep-fat frying. The reason? They can be heated to a high temperature before they start to smoke. But, you may recall that just a moment ago I said that oils can go rancid very quickly. Add heat to the equation and you speed up the oxidation process. To make things even more interesting, the oils that are used in deep fat frying are rarely changed. They are reused over and over, day after day. Chemicals start to form – aldehydes, ketones, alcohols – chemicals that we were never designed to ingest. Feed this mess to baby rats in the laboratory and they start to develop stomach tumors, liver tumors, and stunted growth. Some of them even die.

Read on. It gets worse! In the potato chip industry, the oils that are used in processing are never changed. To shut down production long enough to change the oil would be too cost prohibitive. So, instead, oil is added to the top to bring the level up to where it should be. The oil in use reaches what is known as steady state rancidity. Meaning: It is just as rancid today, as it was yesterday, as it will be tomorrow.

At the present time, in America, we consume: an an an an

excess of excess of excess of excess of

saturated fat (fatty meats, processed meats, cheeses,) hydrogenated fats (packaged foods, margarine,) thermally oxidized fats (fried chicken, fried cutlets, french fries,) and rancid fat (bologna, salami, hot dogs, other processed meats.)

And many of us get an excess of Omega 6 fatty acids (corn oil,) and not nearly enough Omega 3 fatty acids. The ratio of Omega 6 to Omega 3 for many of us is 25: 1. It should be closer to 3:1. In fact, in the human brain the ratio of these two essential oils should be 1:1.

In food terms, what I have just said to you is add some nuts, flax seed, and olive oil to your diet, and get off the processed meats, and deep fat fried foods.

More about Fat... Quiz time: Did you know that fats do not float freely in our blood stream? They must be escorted through the body by a protein carrier. Do you know why? (Read on, and

see if you can find the answer.) Besides serving as a concentrated source of fuel for the body, fat serves a number of other functions. Structurally, body fat provides insulation against the cold. It protects internal organs – kidneys, heart, pancreas – cushioning them against injury. Fat is also a component of all cell membranes where it helps to control which chemicals enter and exit cells. And fat provides the raw material for prostaglandins (hormone-like substances) and steroid hormones. Nutritionally, fat carries fat-soluble vitamins – A, D, E, and K – and essential fatty acids. Fat also makes foods taste good, and increases satiety. (Satiety refers to a sense of fullness.) Foods which contain some fat take longer to digest than low fat foods, thereby helping us to stay full longer. Fat also has a protein-sparing effect. Meaning: If there is fat available as an energy source we can use protein as protein, and not burn it for fuel.

Digestion & Absorption of fats:

"Lipases" are the enzymes of fat digestion. There are four fat-digesting lipase enzymes: lingual lipase gastric lipase pancreatic lipase intestinal lipase.

Most digestion of fats occurs in the intestine. Fat is first emulsified by bile. It becomes soluble in water, and then is easily broken down by pancreatic and intestinal lipase.

The end products of fat digestion are: fatty acids, glycerol, phospholipids, cholesterol, and monoglycerides

On the surface of the lining of the small intestine, these substances are loosely combined into micelles, which pass into the cells of the lining. Inside these cells, the micelles are repackaged into chylomicrons which are absorbed into the lymph system. Chylomicrons are carried via lymph to the heart and are then added into general

circulation (blood.)

Lipoproteins... Lipoproteins are the fat/protein combinations, composed of varying amounts of cholesterol, triglycerides, protein and phospholipids. They are classified according to density. Answer to Quiz time: Fats must be escorted through the body on a protein carrier because fat is lighter than water. It floats. If it weren't for lipoproteins, fats circulating in the bloodstream would rise to our heads. (And weâ&#x20AC;&#x2122;d all be a bunch of fatheads.) :-) Chylomicrons are mostly triglycerides. They transport the end products of fat digestion to the heart and general circulation by way of the lymph system. VLDL (very low density lipoproteins) are mostly triglycerides. They transport triglycerides synthesized by the liver to body tissues. LDL (low density lipoproteins) are highest in cholesterol. HDL (high density lipoproteins) are highest in protein.

Normally, enzymes in the liver break down chylomicrons within a few hours. The liver handles the triglycerides, fatty acids, and glycerol in a number of ways: Triglycerides may be broken down to fatty acids and glycerol, or sent to fat cells for storage. Fatty acids and glycerol can be reassembled into triglycerides, or used to meet the energy needs of the liver, or sent back to the blood stream for use by cells throughout the body. Fatty acids can be used to make cholesterol.

Triglycerides...

A triglyceride is a molecule of fat. It is composed of three fatty acids attached to a molecule of glycerol. A triglyceride looks like the letter E. If you are ever told as a

result of a blood test that your triglyceride level is too high, it means you have too much fat in your blood. Your triglyceride level can go up from overeating, or from too much refined carbohydrate (sugar and starch.)

Fatty acids... A fatty acid is a chain of carbon atoms with hydrogen atoms attached. A saturated fatty acid is completely filled with hydrogen. It has no double bonds. A monounsaturated fatty acid is not completely filled with hydrogen It has one double bond. A polyunsaturated fatty acid has even less hydrogen. It has many double bonds.

Facts about Cholesterol... Did you know that cholesterol is: Produced in the liver from acetyl coenzyme A, which can be formed from either fat, protein, or glucose? Needed for formation of steroid hormones (testosterone, estrogen?) A component of all cell membranes? Needed for synthesis of vitamin D? Needed for immunity? Needed for optimum mental health?

Did you know that it is possible to have too little cholesterol? Did you know that if you are taking a cholesterol lowering medication you may be at increased risk for both liver problems and congestive heart failure? Reason: Cholesterol lowering medications block the action of an enzyme that is used to synthesize cholesterol. But that same enzyme is involved in the synthesis of Coenzyme Q10 which is needed for energy production in your cells. A heart deprived of adequate CoQ10 is at greater risk for failure. Action to take: (a) Lower your cholesterol by alternate means, or (b) take a supplement of Co Q10.