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FACTS ABOUT FATS
Topics you will find:
Why You Need Fats For related topics see:
Fats provide energy. Gram for gram fats are the most efficient source of food energy. Each gram of fat provides nine calories of energy for the body, compared with four calories per gram of carbohydrates and proteins. Fats build healthy cells. Fats are a vital part of the membrane that surrounds each cell of the body. Without a healthy cell membrane, the rest of the cell couldn't function. Fats build brains. Fat provides the structural components not only of cell membranes in the brain, but also of myelin, the fatty insulating sheath that surrounds each nerve fiber, enabling it to carry messages faster. Fats help the body use vitamins. Vitamins A, D, E, and K are fat-soluble vitamins, meaning that the fat in foods helps the intestines absorb these vitamins into the body. Fats make hormones. Fats are structural components of some of the most important substances in the body, including prostaglandins, hormone-like substances that regulate many of the body's functions. Fats regulate the production of sex hormones, which explains why some teenage girls who are too lean experience delayed pubertal development and amenorrhea. Fat provides healthier skin. One of the more obvious signs of fatty acid deficiency is dry, flaky skin. In addition to giving skin its rounded appeal, the layer of fat just beneath the skin (called subcutaneous fat) acts as the body's own insulation to help regulate body temperature. Lean people tend to be more sensitive to cold; obese people tend to be more sensitive to warm weather. Fat forms a protective cushion for your organs. Many of the vital organs, especially the kidneys, heart, and intestines are cushioned by fat that helps protect them from injury and hold them in place. (True, some of us "overprotect" our bodies.) As a tribute to the body's own protective wisdom, this protective fat is the last to be used up when the body's energy reserves are being tapped into. Fats are pleasurable. Besides being a nutritious energy source, fat adds to the appealing taste, texture and appearance of food. Fats carry flavor. Fat is also the reason why cookies melt in your mouth, french fries are crispy, and mom's apple pie has a flaky crust. To trim the confusing fat story into terms that help you make wise food choices, there are first three basic types of fats you need to understand: monounsaturated fats (MUFAs), polyunsaturated fats (PUFAs) and saturated fats (SATFAs) MUFAs and PUFAs are good fats; SATFAs are bad fats. How do you tell a good fat from a bad one? The good fats (MUFAs and PUFAs) are like oil. They flow through your arteries. The bad fats (SATFAs) act like sludge, sticking to the arteries. FA's are chemically known as fatty acids, but we call them fat. What makes a good fat a healthy fat and a bad fat an unhealthy one has to do with the chemical structure of the fat called saturation. The fat molecule is composed mostly of hydrogen atoms attached to carbon atoms in a carbon chain. On this molecule there are open spaces, like parking spots. When all the available spots, or parking spaces, on the carbon atom are filled (i.e., saturated) with hydrogenated atoms, the fat is said to be saturated. If one or more places on the carbon are not filled with hydrogen, the fat is called unsaturated. A fat molecule with one empty space is called a monounsaturated fat, and is found in such foods as olive oil, canola oil, and nut oils. If two or more spots on the atom are empty, the fat is known as a polysaturated fat, or, which is found primarily in vegetable oils and seafood. Saturated vs. unsaturated fats. At room temperature, some fats are solids (such as butter and lard) and some are liquids. The liquids are usually called oils. A saturated fat is solid at room temperature; an unsaturated fat is liquid at room temperature. Whether or not fats help or harm the body depends upon their degree of saturation. Here's why. Unsaturated fat molecules (MUFAs and PUFAs) are a curved molecule with negative charges that repel each other so they don't stick together, resembling little bits of popcorn in a popper. Because these molecules don't stick together, they flow - both in the food and in the arteries. The molecules of a saturated fat are flat. They pile up like pages in a book and stick to each other. MUFAs and PUFAs are liquid at room temperature; SATFAs are solid at room temperature. Consider for a moment the fat molecules in your bloodstream. Do you want them to flow like oil or clump together like butter in your body? Another interesting fat fact is that your body makes all the SATFAs it needs. You don't have to eat saturated fats. Is your body trying to tell you something? Yet, the body needs oiling. It needs MUFAs and PUFAs, which are why these fats are called essential fatty acids (EFAs). Your body can't live without them. While it can't live without MUFAs and PUFAs, we will live a lot longer if we eat less SATFAs.
Fatty acids are the basic building blocks and the main nutritional component of fats. The body requires about twenty fatty acids in order to live and operate. It can make all but two of these: linolenic and linoleic. These two are called "essential fatty acids" because they are essential for life and health. However, the human body cannot make these substances; they can be supplied only by food or supplements. EFAs occur mostly in seafood and plant foods, with only trace amounts found in meat.
All about omegas. The two most important essential fatty acids are linolenic acid (also known as an omega 3 fatty acid) and linoleic acid (also known as an omega 6 fatty acid). The omega number describes where the important carbon atom is located on the fat molecule. If this atom is third from the end, the fatty acid is known as an omega 3 fatty acid (omega 3 is the last letter of the Greek alphabet and means "end"). If it's sixth from the end, it's known as an omega 6 fatty acid (vegetable oils, nuts, and seeds). Omega 3 fatty acids especially have a valuable role in reducing the risk of heart disease and building healthy brain cells. The standard American diet (SAD) is sadly deficient in omega 3s, found mainly in plant foods (especially canola oil and flax oil, soybeans, and walnuts) and seafood.
The nutritional "bad word" every label reader should be aware of is "hydrogenated." Zapping an unsaturated oil with high pressure hydrogen can turn the oil into saturated fat. (Hydrogen is forced into the empty parking spaces on the fat molecule.) This hydrogenation process is how vegetable oil is turned into margarine. Hydrogenated fats have two major economic advantages over natural saturated fats. They are cheaper and they have a longer shelf life. Hydrogenated fats and partially hydrogenated fats are everywhere in processed foods - added to cookies, crackers, and peanut butter, for example. Hydrogenated fats are also used instead of oil for frying in many restaurants and fast-food establishments because they stand up better to heat and can be used longer. Hydrogenated oils are saturated fats and behave that way in the body. Crackers or cookies made with hydrogenated fats may proclaim themselves to be cholesterol-free, but a closer look at the label will show that the product still contains plenty of artery-clogging saturated fat. There's also a problem with these fats that the label won't tell you about. Hydrogenated fats contain another kind of fat that falls outside of the saturated and unsaturated categories. These are trans fatty acids, or trans fats, so-named because the hydrogenation process transports hydrogen atoms across the fat molecule to a new location. Dr. Udo Erasmus in his book Fats that Heal, Fats that Kill aptly describes trans fatty acids as a "molecule that has its 'head on backwards'." Trans fats are as bad (or worse) for your arteries as saturated fats. A number of studies have shown that trans fats raise cholesterol levels in the blood. However, as of 1999, label laws in the United States do not require food manufacturers to include information about trans fats in nutrition labeling. So, a product whose label says it is low in heart-damaging saturated fat, may still contain a large amount of trans fats and be no better for you than a fast-food cheeseburger. You would never know this from the label. Also, because hydrogenated fats are so widely used in restaurants for deep-fat frying, the french fries so popular with children may be full of cholesterol-raising trans fats, even if the establishment's advertising claims it uses 100 percent vegetable oil for cooking. Label loopholes. The real irony is that this labeling loophole also keeps consumers from being able to recognize foods that are low in trans fats. Most of the hydrogenated fats used by food processors are only partially hydrogenated. Some of these partially hydrogenated fats contain less saturated fat and fewer trans fats than others however, unless the product is a brand of tub margarine specifically trying to market itself to the few customers in the know about trans fat, there is no way of knowing how heart-threatening a particular food product is. Of course, one of the difficulties with putting information about trans fats on the nutrition label is that different batches of hydrogenated oils may contain different amounts of trans fats. Food processors would have to standardize the hydrogenation process and the oils they use to be able to give consumers accurate information. Trans fats have found their way into most of the packaged foods bought by uninformed and unsuspecting consumers. Butter, which has gotten a bad rap because of saturated fat and cholesterol, has been replaced by margarine, which may also be bad news for cholesterol levels. True, foods made with hydrogenated fats are cheaper and last longer, but consumers pay a larger price in the long run, since trans fats provide little nutritional benefit to the body, except as an energy source. What's good for business in the short run is often bad for the body in the long run. When manufacturers chemically change a food, all sorts of unanticipated problems may result. This is especially true of hydrogenated fatty acids. Here's a summary of what literature has said about the problems of hydrogenated fats and trans fats:
Here are some commercial foods that are notoriously high in hydrogenated fats:
Avoiding hydrogenated fats. Consumers can improve the quality of the food they buy. The principle of supply and demand suggests that if you demand less hydrogenated fat and more truthful labeling, food packagers will produce it. Here's what you can do:
Food manufacturers argue that health concerns about the hydrogenation of fats are more theoretical than real. Yet, a study of 80,000 women in the Harvard School of Public Health Nurses' study proved that the kind of fats a person eats is more important than the amount. In this study, women who consumed the most trans fats had a 53 percent greater chance of suffering a heart attack.
Now that you understand why you need fats, here's how fats rank:
Listed from best to worst fats:
RATING FATS*
Yellow light. Fats in this category contain a balance of saturated and unsaturated fatty acids which, if eaten in moderation, contribute to the health and well-being of the body. Look for lowfat varieties. In addition, many of these foods are rich sources of other nutrients as well.
Red light. You could eliminate all the fats in this category and you would be healthier for it. Any nutrient that might be in any of these fats could be obtained from other fats with better nutritional credentials.
Fats make up sixty percent of the brain and the nerves that run every system in the body. So, it stands to reason that the better the fat in the diet, the better the brain. So, with all the fat eaten by the average American, why don't we have more geniuses in this country? The average American brain is getting enough fat, but it's not getting the right kind of fat. Think of your brain as the master gland that sends chemical messengers throughout the body, telling each organ how to work. An important group of these chemical messengers are the prostaglandins (so-called because they were originally discovered in the prostate gland). Prostaglandins initiate the body's self-repair system. The body needs two kinds of fat to manufacture healthy brain cells (the message senders) and prostaglandins (the messengers). These are omega 6 fatty acids (found in many oils, such as safflower, sunflower, corn, and sesame oils) and omega 3 fatty acids (found in flax, pumpkin seeds and walnuts, and coldwater fish, such as salmon and tuna). The foods from which oil can be extracted are generally the foods highest in essential fatty acids. Most important to brain function are the two essential fatty acids, linoleic (or omega 6) and alpha linolenic (or omega 3). These are the prime structural components of brain cell membranes and are also an important part of the enzymes within cell membranes that allow the membranes to transport valuable nutrients in and out of the cells. When the cells of the human body - and the human brain - are deprived of the essential fatty acids they need to grow and function, the cells will try to build replacement fatty acids that are similar, but may actually be harmful. Higher blood levels of "replacement fatty acids" are associated with diets that are high in hydrogenated fats and diets that contain excessive amounts of omega 6 fatty acids. Levels of replacement fatty acids have been found to be elevated in persons suffering from depression or Attention Deficit Disorder. A diet rich in omega 3 fatty acids (such as the LNA from flax oil or the EPA and DHA from fish oils) not only provides the body with healthy fats, but it also lowers the blood level of potentially harmful ones, such as cholesterol and, possibly, even reversing the effects of excess trans fatty acids. Using the lock and key analogy will help you understand how the brain communication system works. Neurotransmitters are biochemical messengers that carry information from one brain cell to another, sort of like sparks flying across the gap between nerve cells. Each cell membrane contains a series of locks. The various message carriers (prostaglandins and neurotransmitters) are like keys. The keys and the locks must match. When the cell membrane is unhealthy because it is made of the wrong kind of replacement fatty acids, the keys won't fit, and brain function suffers. Nutrients may also fail to fit in a mismade lock. The eye is a perfect example of the importance of getting the right kind of fat. The retina of the eye contains a high concentration of the fatty acid DHA, which the body forms from nutritious fats in the diet. The more nutritious the fat, the better the eye can function. And since most people are visual learners, better eyes mean better brains. Western diets contain too much of the omega 6 fatty acids and too little of the omega 3's. Omega 3 fatty acids are found in ground flax seeds and flaxseed oil, coldwater fish (primarily salmon and tuna), canola oil, soybeans, walnuts, wheatgerm, pumpkin seeds, and eggs. Smart fats for growing brains*. Fats can also influence brain development and performance, especially at either end of life -- growing infants and elderly people. In fact, there are two windows of time in which the brain is especially sensitive to nutrition: the first two years of life for a growing baby and the last couple decades of life for a senior citizen. Both growing and aging brains need nutritious fats. The most rapid brain growth occurs during the first year of life, with the infant's brain tripling in size by the first birthday. During this stage of rapid central nervous system growth, the brain uses sixty percent of the total energy consumed by the infant. Fats are a major component of the brain cell membrane and the myelin sheath around each nerve. So, it makes sense that getting enough fat, and the right kinds of fat, can greatly affect brain development and performance. In fact, during the first year, around fifty percent of an infant's daily calories come from fat. Mother Nature knows how important fat is for babies; fifty percent of the calories in mother's milk is fat. Different species provide different types of fat in their milk, fine-tuned to the needs of that particular animal. For example, mother cows provide milk that is high in saturated fats and low in brain-building fats, such as DHA. This helps their calves grow rapidly, though it may not do much for their brains. In adult cows, the brain is small compared with the body. Cows don't have to do a lot of thinking to survive. In human infants, the brain grows faster than the body. Highly developed brains are important to human beings, so human milk is low in body- building saturated fats and rich in brain-building fats, such as the fatty acid DHA (docosahexaenoic acid), an omega 3 fatty acid. DHA is the primary structural component of brain tissue, so it stands to reason that a deficiency of DHA in the diet could translate into a deficiency in brain function. In fact, research is increasingly recognizing the possibility that DHA has a crucial influence on neurotransmitters in the brain, helping brain cells better communicate with each other. Asian cultures have long appreciated the brain-building effects of DHA. In Japan, DHA is considered such an important "health food" that it is used as a nutritional supplement to enrich some foods, and students frequently take DHA pills before examinations. Just how important is DHA for brain development? Consider these research findings:
Tastes like fat, looks like fat, but it's not fat! A dieter's dream? Read on. The newest fake fat (e.g., olestra) is so fake that the body rejects it, even though the mouth seems to get the pleasure of fat. This fat substitute is made by joining together molecules of vegetable oil and sugar into a compound with molecules so big that they are not absorbed through the intestines and into the bloodstream. So far, so good. You get the taste of fat without the calories. Sound like a good deal? Wrong! Since this fake fat can't get into the blood, it has to get out of the body somehow, so it makes its greasy way through the intestines, taking along some of the fat-soluble vitamins (vitamins A,D,E, and K) and other nutrients that depend upon fat for absorption, such as carotenoids. These nutrients that should have gotten into the body, go out with the waste. So, even though the fat you may not want is not absorbed, some of the nutrients in the foods you do want are not absorbed either. "No problem" say the food chemists "we'll just add more of the nutrients you lose into the food you eat." Beginning in May of 1998 the FDA requires snack food packagers to put the following warning (in small print on the back of the package, of course). "This product contains olestra. Olestra may cause abdominal cramping or loose stools. Olestra inhibits the absorption of some vitamins and other nutrients. Vitamins A,D, E and K have been added." So to a bag of potato chips the manufacturer of olestra must add 3,400 IU of vitamin K, 240 IU of vitamin D, 56 IU of vitamin E, and 160 mcg of vitamin K. (This is beginning to sound like the "enriched" white bread story.) The problem with decreased absorption of carotenoids (plant phytonutrients that fight against cancer, heart disease, and may contribute to better vision) also seems to have been discounted. Besides causing bloating, diarrhea, and cramping abdominal pain in some people, these synthetic fats allow people to simply change brands without changing their eating habits. They believe they can eat more fat without guilt, which further contributes to the development of a "fat tooth"-the need to taste fat in order for the food to be satisfying. Another heavy fact is these synthetic subs encourage eaters to overdose on fat-filled foods that have no nutritional value. In a study reported in Pediatrics, the official journal of the American Academy of Pediatrics, children ate more food when olestra was substituted for ordinary dietary fat. The potato chips contain half as much fat, so you may feel you have the license to eat twice as many. But our advice is don't be a guinea pig. Wait a while to see the long-term health risks of this new experiment. We all know that if we eat too much fat, most of us will get fat. What many people do not realize is that even eating excess sugar can make you fat. Here's how. Sugar is a prime energy source for the body. Sugar molecules are constantly traveling to each cell to provide energy. Within each cell is a tiny furnace, called the mitochondria. The sugar or glucose molecules enter the furnace and are burned as energy for the cell. This energy- conversion process creates carbon molecules that are building blocks for both cholesterol and saturated fatty acids. When you eat more sugar than your body needs for energy, excess carbon molecules are produced. If carbon is produced faster than it can be converted by the body into carbon dioxide, water, and energy, the excess saturated fatty acids and cholesterol are then deposited as fat or carried in the bloodstream as cholesterol. The body does this because the excess carbon molecules would otherwise be toxic to its metabolic processes. However, while the body can turn excess sugar into fat, it can't turn fat back into sugars. It must burn off the excess fat as fuel through exercise. Another side to the sugar-becoming-fat story is the survival mechanism of the body operates on the feast or famine principle. When you feast on excess high-carbohydrate foods, the body stores these excess calories as fat as a way of storing energy in case of famine.
If you really want to both trim the amount of fat in your diet and eat the right kinds of fats, here are some important fat facts to consider: 1. Fishy fats. Ever wonder why cold-water fish contain more monounsaturates and are healthier to eat than warm-water swimmers? The fat in the fish is adapted to the temperature of the water. The more unsaturated a fat is, the more oily it becomes. That's why fish fat flows i.e. it's oily. The oil in fish acts as an antifreeze in the cold water, so the colder the water the better the oil has to be. Coldwater fish are naturally higher in unsaturated, healthier fats. The fat an animal contains is perfectly suited for its survival. If a fish contained the same amount of fat as a steer and the steer was loaded with fish oil, the steer would feel like flubber and the fish would sink. Also, consider the skin of the fish. The healthiest fish oils are found under the skin. Unlike poultry, it's best to eat the fish with the skin on.
2. Fat calories are fatter. If you are trying to lose weight or stay lean, be especially vigilant about counting fat calories, since these are absorbed and stored as fat more quickly than calories from carbohydrates or proteins. Calories from fat are more fattening than those from carbohydrates or proteins, for three reasons.
3. Fowl fats. Even most confirmed chicken fryers know that chicken fat is bad for you. Most fowl fat lies just under the skin. Once you remove that flavorful fatty stuff, the underlying meat, especially if white, is fairly lean, containing around seven percent fat. As an added fat perk, fowl fat is rich in omega fatty acids. So, choose chicken breast over chicken thighs, bake instead of fry the bird, and remove the skin. Also, pick your poultry. Turkey is leaner than chicken and white meat is leaner than dark. Dark meat contains almost twice as much fat as white meat.
4. Green fats. While we don't think of plants as rich sources of fat, some are. While it's true that plants don't contain a lot of fat, what little fat they contain is high in essential fatty acids. Plants use omega 3 fatty acids to store sunlight energy. The darker and greener the leaves, the more essential fatty acids these leaves usually contain. So, do your brain and your body a favor, choose spinach and kale for your salad makings and leave the iceberg in the bin.
5. Slimming fats. Essential fatty acids (omega 3 and 6) are the fats that are least likely to succeed in making their way to the thighs and waist. Essential fatty acids actually stimulate metabolism by speeding up the rate at which the body burns fats and glucose. So, I consumed most of my daily fat requirements from fish and flax, and my cravings for fattening fats were reduced. (See The L.E.A.N. Program). 6. Farm fats. Fish that swim and fowl that run have healthier fat profiles than those in a cage or pond, for two reasons. It's common sense that meat that exercises is leaner than meat that just sets or floats. Also, plants that grow in the field or food that grows in the sea are nutritionally better than factory-made feeds. In fact, farm-raised meat may contain as much as forty percent more fat than free-roaming or free-swimming varieties. 7. Fertile fats. The amount of estrogen in the blood seems to be dependent on the amount of fat in a woman's body. Once a female drops below fifteen percent of her normal body weight as fat, menstruation is likely to stop temporarily. Gymnasts in training, adolescents with anorexia, and overly lean teens are likely to have delayed menstruation. 8. Polluted fats. Chemical pesticides and pollutants tend to be stored in body fat. So, theoretically, the higher the fat content of the food, the more pesticides and pollutants it could contain. For this reason, be careful of high-fat foods, such as butter and beef. For high-fat foods, buying organic varieties makes nutritional sense. 9. Blood fats. Healthy fats, especially omega 3 fatty acids found in flax and fish oils, can be thought of as blood thinners. Saturated fats are blood thickeners, clogging the arteries and leading to cardiovascular disease. 10. Nut fats. If you're a peanut butter lover, as I am, be sure to look at the label to detect whether or not it contains the bad fat word - "hydrogenated." Hydrogenating the peanut oil solidifies it so it doesn't separate from the solids and float to the top. In old-fashioned, unhydrogenated peanut butter, the oil has to be stirred back into the peanut butter when you first open the jar. Sure, it's a little bit of work, but your arteries will thank you.
11. Cooking fats. Remember, oils higher in monounsaturates spoil more quickly. Fat-savvy eaters consume antioxidants (literally anti-rust or anti-spoiling nutrients), such as vitamin E along with vitamin C and beta carotene with their healthy fats and oils. Cooking foods, such as onions and garlic (rich in antioxidants), may lessen the damaging effect of heat on oils. All those Mediterranean cooks who start a dish by slicing onions, mincing garlic, and cooking it all in olive oil may be on to something. 12. A little bit of fat. Don't burn extra calories worrying about eating all of your fats as essential fatty acids. Only about two percent of your total caloric intake needs to be essential fatty acids, which amounts to one to two teaspoons per day, or three to seven grams. A couple teaspoons of flax oil or one serving of fish should do it. Plant and fish oils are much richer sources of essential fatty acids than meat, yet meat is a rich source of essential amino acids and protein. 13. Fats and fiber. Because fiber gives you a sense of fullness sooner, eating a fiber-filled meal is likely to prompt you to eat less fat. On the other hand, you are likely to consume more fat when the menu is low in fiber. 14. Less of a fat tooth. The western taste bud is programmed to enjoy the fatty taste and mouth feel of foods. Reprogram your taste buds. The more you lower the total fat in your diet, the less your taste buds will crave fat. 15. Sluggish fats. Don't feel you have to eat a high-fat meal in order to have plenty of energy. Because fat is slower to digest, high-fat meals make you feel full longer, yet also make you feel more sluggish. High-fat meals don't leave you feeling energetic. They make a person want to sit rather than run. 16. Baby fats. Babies need fat - lots of it. Adult fat restrictions should not be applied to infants. Human milk contains around 50 percent of its calories in fats. Not only do infants need more fats, they need more of the right kind of fats, especially for brain growth. Since the brain grows more in the first two years than any other time in a person's life, it's most important to provide the infant with the right amount of the right fats at this crucial time. Breastfeeding is your best bet for delivering exactly what the baby needs. As of 1999, infant formulas available in the United States do not contain DHA, which is the most abundant omega-3 long-chain fat in breast milk. 17. Brain fats. The principal fat in the brain is DHA, and the best sources of this fat are products from the sea (seafood and seaweed).
* Rating foods in order of priority has inherent problems, since the keyword to healthy nutrition is what Grandmother always said - balance. Best to eat a balanced diet containing many kinds of these fats, not just one or two of the top ten. Do not overdose even on those at the top of the list. * An informative book on best fats for growing brains is: SMART FATS by Dr. Michael Schmidt.
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