Fats from animal and vegetable sources provide a concentrated source of energy in the diet; they also provide the building blocks for cell membranes and a variety of hormones and hormone-like substances. Fats as part of a meal slow down absorption so that we can go longer without feeling hungry. In addition, they act as carriers for important fat- soluble vitamins A, D, E and K. Dietary fats are needed for the conversion of carotene to vitamin A, for mineral absorption and for a host of other processes.
Politically Correct Nutrition is based on the assumption that we should reduce our intake of fats, particularly saturated fats from animal sources. Fats from animal sources also contain cholesterol, presented as the twin villain of the civilized diet.
The Truth About Saturated Fat
The Lipid Hypothesis
The theory-called the lipid hypothesis-that there is a direct relationship between the amount of saturated fat and cholesterol in the diet and the incidence of coronary heart disease was proposed by a researcher named Ancel Keys in the late 1950’s. Numerous subsequent studies have questioned his data and conclusions. Nevertheless, Keys’ articles received far more publicity than those presenting alternate views.
The vegetable oil and food processing industries, the main beneficiaries of any research that found fault with competing traditional foods, began promoting and funding further research designed to support the lipid hypothesis.
The “Evidence” Supporting The Lipid Hypothesis
These “experts” assure us that the lipid hypothesis is backed by incontrovertible scientific proof. Most people would be surprised to learn that there is, in fact, very little evidence to support the contention that a diet low in cholesterol and saturated fat actually reduces death from heart disease or in any way increases one’s life span. Consider the following: Before 1920 coronary heart disease was rare in America; so rare that when a young internist named Paul Dudley White introduced the German electrocardiograph to his colleagues at Harvard University, they advised him to concentrate on a more profitable branch of medicine.
The new machine revealed the presence of arterial blockages, thus permitting early diagnosis of coronary heart disease. But in those days clogged arteries were a medical rarity, and White had to search for patients who could benefit from his new technology. During the next forty years, however, the incidence of coronary heart disease rose dramatically, so much so that by the mid fifties heart disease was the leading cause of death among Americans.
Today heart disease causes at least 40% of all US deaths. If, as we have been told, heart disease results from the consumption of saturated fats, one would expect to find a corresponding increase in animal fat in the American diet. Actually, the reverse is true. During the sixty-year period from 1910 to 1970, the proportion of traditional animal fat in the American diet declined from 83% to 62%, and butter consumption plummeted from eighteen pounds per person per year to four.
During the past eighty years, dietary cholesterol intake has increased only 1%. During the same period the percentage of dietary vegetable oils in the form of margarine, shortening and refined oils increased about 400% while the consumption of sugar and processed foods increased about 60%.
The Framingham Heart Study is often cited as proof of the lipid hypothesis. This study began in 1948 and involved some 6,000 people from the town of Framingham, Massachusetts. Two groups were compared at five-year intervals-those who consumed little cholesterol and saturated fat and those who consumed large amounts. After 40 years, the director of this study had to admit:
“In Framingham, Mass, the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the person’s serum cholesterol… We found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active.” The study did show that those who weighed more and had abnormally high blood cholesterol levels were slightly more at risk for future heart disease; but weight gain and cholesterol levels had an inverse correlation with fat and cholesterol intake in the diet.
Understanding The Chemistry Of Fats
Clearly something is wrong with the theories we read in the popular press-and used to bolster sales of lowfat concoctions and cholesterol-free foods. The notion that saturated fats per se cause heart disease as well as cancer is not only facile, it is just plain wrong. But it is true that some fats are bad for us. In order to understand which ones, we must know something about the chemistry of fats.
Fats-or lipids-are a class of organic substances that are not soluble in water. In simple terms, fatty acids are chains of carbon atoms with hydrogen atoms filling the available bonds. Most fat in our bodies and in the food we eat is in the form of triglycerides, that is, three fatty-acid chains attached to a glycerol molecule.
Elevated triglycerides in the blood have been positively linked to proneness to heart disease, but these triglycerides do not come directly from dietary fats; they are made in the liver from any excess sugars that have not been used for energy. The source of these excess sugars is any food containing carbohydrates, particularly refined sugar and white flour.
Fatty Acid Classifications By Saturation
Fatty acids are classified in the following way:
Saturated: A fatty acid is saturated when all available carbon bonds are occupied by a hydrogen atom. They are highly stable, because all the carbon-atom linkages are filled-or saturated-with hydrogen. This means that they do not normally go rancid, even when heated for cooking purposes. They are straight in form and hence pack together easily, so that they form a solid or semisolid fat at room temperature. Your body makes saturated fatty acids from carbohydrates and they are found in animal fats and tropical oils.
Monounsaturated: Monounsaturated fatty acids have one double bond in the form of two carbon atoms double-bonded to each other and, therefore, lack two hydrogen atoms. Your body makes monounsaturated fatty acids from saturated fatty acids and uses them in a number of ways.
Monounsaturated fats have a kink or bend at the position of the double bond so that they do not pack together as easily as saturated fats and, therefore, tend to be liquid at room temperature. Like saturated fats, they are relatively stable. They do not go rancid easily and hence can be used in cooking. The monounsaturated fatty acid most commonly found in our food is oleic acid, the main component of olive oil as well as the oils from almonds, pecans, cashews, peanuts and avocados.
Polyunsaturated: Polyunsaturated fatty acids have two or more pairs of double bonds and, therefore, lack four or more hydrogen atoms. The two polyunsaturated fatty acids found most frequently in our foods are double unsaturated linoleic acid, with two double bonds-also called omega-6; and triple unsaturated linolenic acid, with three double bonds-also called omega-3. (The omega number indicates the position of the first double bond.)
Your body cannot make these fatty acids and hence they are called “essential.” We must obtain our essential fatty acids or EFA’s from the foods we eat.
The Dangers Of Polyunsaturates
The public has been fed a great deal of misinformation about the relative virtues of saturated fats versus polyunsaturated oils. Politically correct dietary gurus tell us that the polyunsaturated oils are good for us and that the saturated fats cause cancer and heart disease. The result is that fundamental changes have occurred in the Western diet.
At the turn of the century, most of the fatty acids in the diet were either saturated or monounsaturated, primarily from butter, lard, tallows, coconut oil and small amounts of olive oil. Today most of the fats in the diet are polyunsaturated from vegetable oils derived mostly from soy, as well as from corn, safflower and canola.
Modern diets can contain as much as 30% of calories as polyunsaturated oils, but scientific research indicates that this amount is far too high. The best evidence indicates that our intake of polyunsaturates should not be much greater than 4% of the caloric total, in approximate proportions of 2 % omega-3 linolenic acid and 2 % omega-6 linoleic acid.
Excess consumption of polyunsaturated oils has been shown to contribute to a large number of disease conditions including increased cancer and heart disease; immune system dysfunction; damage to the liver, reproductive organs and lungs; digestive disorders; depressed learning ability; impaired growth; and weight gain.
One reason the polyunsaturates cause so many health problems is that they tend to become oxidized or rancid when subjected to heat, oxygen and moisture as in cooking and processing. Rancid oils are characterized by free radicals-that is, single atoms or clusters with an unpaired electron in an outer orbit. These compounds are extremely reactive chemically.
They have been characterized as “marauders” in the body for they attack cell membranes and red blood cells and cause damage in DNA/RNA strands, thus triggering mutations in tissue, blood vessels and skin. Free radical damage to the skin causes wrinkles and premature aging; free radical damage to the tissues and organs sets the stage for tumors; free radical damage in the blood vessels initiates the buildup of plaque.
Is it any wonder that tests and studies have repeatedly shown a high correlation between cancer and heart disease with the consumption of polyunsaturates? New evidence links exposure to free radicals with premature aging, with autoimmune diseases such as arthritis and with Parkinson’s disease, Lou Gehrig’s disease, Alzheimer’s and cataracts.
Too Much Omega-6
Problems associated with an excess of polyunsaturates are exacerbated by the fact that most polyunsaturates in commercial vegetable oils are in the form of double unsaturated omega-6 linoleic acid, with very little of vital triple unsaturated omega-3 linolenic acid. Recent research has revealed that too much omega-6 in the diet creates an imbalance that can interfere with production of important prostaglandins. This disruption can result in increased tendency to form blood clots, inflammation, high blood pressure, irritation of the digestive tract, depressed immune function, sterility, cell proliferation, cancer and weight gain.
Too Little Omega-3
A number of researchers have argued that along with a surfeit of omega-6 fatty acids the American diet is deficient in the more unsaturated omega-3 linolenic acid. This fatty acid is necessary for cell oxidation, for metabolizing important sulphur-containing amino acids and for maintaining proper balance in prostaglandin production. Deficiencies have been associated with asthma, heart disease and learning deficiencies.
Most commercial vegetable oils contain very little omega-3 linolenic acid and large amounts of the omega-6 linoleic acid. In addition, modern agricultural and industrial practices have reduced the amount of omega-3 fatty acids in commercially available vegetables, eggs, fish and meat. For example, organic eggs from hens allowed to feed on insects and green plants can contain omega-6 and omega-3 fatty acids in the beneficial ratio of approximately one-to-one; but commercial supermarket eggs can contain as much as nineteen times more omega-6 than omega-3!
The Benefits Of Saturated Fats
The much-maligned saturated fats-which Americans are trying to avoid-are not the cause of our modern diseases. In fact, they play many important roles in the body chemistry:
- Saturated fatty acids constitute at least 50% of the cell membranes. They are what gives our cells necessary stiffness and integrity.
- They play a vital role in the health of our bones. For calcium to be effectively incorporated into the skeletal structure, at least 50% of the dietary fats should be saturated.
- They lower Lp(a), a substance in the blood that indicates proneness to heart disease.
- They protect the liver from alcohol and other toxins, such as Tylenol.
- They enhance the immune system.
- They are needed for the proper utilization of essential fatty acids. Elongated omega-3 fatty acids are better retained in the tissues when the diet is rich in saturated fats.
- Saturated 18-carbon stearic acid and 16-carbon palmitic acid are the preferred foods for the heart, which is why the fat around the heart muscle is highly saturated. The heart draws on this reserve of fat in times of stress.
- Short- and medium-chain saturated fatty acids have important antimicrobial properties. They protect us against harmful microorganisms in the digestive tract. The scientific evidence, honestly evaluated, does not support the assertion that “artery- clogging” saturated fats cause heart disease. Actually, evaluation of the fat in artery clogs reveals that only about 26% is saturated. The rest is unsaturated, of which more than half is polyunsaturated.
Modern Methods Of Processing Fats
It is important to understand that, of all substances ingested by the body, it is polyunsaturated oils that are most easily rendered dangerous by food processing, especially unstable omega-3 linolenic acid. Consider the following processes inflicted upon naturally occurring fatty acids before they appear on our tables:
Extraction: Oils naturally occurring in fruits, nuts and seeds must first be extracted. In the old days this extraction was achieved by slow-moving stone presses. But oils processed in large factories are obtained by crushing the oil-bearing seeds and heating them to 230 degrees.
The oil is then squeezed out at pressures from 10 to 20 tons per inch, thereby generating more heat. During this process the oils are exposed to damaging light and oxygen. In order to extract the last 10% or so of the oil from crushed seeds, processors treat the pulp with one of a number of solvents-usually hexane. The solvent is then boiled off, although up to 100 parts per million may remain in the oil. Such solvents, themselves toxic, also retain the toxic pesticides adhering to seeds and grains before processing begins.
High-temperature processing causes the weak carbon bonds of unsaturated fatty acids, especially triple unsaturated linolenic acid, to break apart, thereby creating dangerous free radicals. In addition, antioxidants, such as fat-soluble vitamin E, which protect the body from the ravages of free radicals, are neutralized or destroyed by high temperatures and pressures. BHT and BHA, both suspected of causing cancer and brain damage, are often added to these oils to replace vitamin E and other natural preservatives destroyed by heat.
There is a safe modern technique for extraction that drills into the seeds and extracts the oil and its precious cargo of antioxidants under low temperatures, with minimal exposure to light and oxygen. These expeller-expressed, unrefined oils will remain fresh for a long time if stored in the refrigerator in dark bottles.
Extra virgin olive oil is produced by crushing olives between stone or steel rollers. This process is a gentle one that preserves the integrity of the fatty acids and the numerous natural preservatives in olive oil. If olive oil is packaged in opaque containers, it will retain its freshness and precious store of antioxidants for many years.
Hydrogenation: This is the process that turns polyunsaturates, normally liquid at room temperature, into fats that are solid at room temperature-margarine and shortening. To produce them, manufacturers begin with the cheapest oils-soy, corn, cottonseed or canola, already rancid from the extraction process-and mix them with tiny metal particles-usually nickel oxide.
The oil with its nickel catalyst is then subjected to hydrogen gas in a high-pressure, high- temperature reactor. Next, soap-like emulsifiers and starch are squeezed into the mixture to give it a better consistency; the oil is yet again subjected to high temperatures when it is steam-cleaned.
This removes its unpleasant odor. Margarine’s natural color, an unappetizing gray, is removed by bleach. Dyes and strong flavors must then be added to make it resemble butter. Finally, the mixture is compressed and packaged in blocks or tubs and sold as a health food.
Partially hydrogenated margarines and shortenings are even worse for you than the highly refined vegetable oils from which they are made because of chemical changes that occur during the hydrogenation process. Under high temperatures, the nickel catalyst causes the hydrogen atoms to change position on the fatty acid chain.
Before hydrogenation, pairs of hydrogen atoms occur together on the chain, causing the chain to bend slightly and creating a concentration of electrons at the site of the double bond. This is called the cis formation, the configuration most commonly found in nature. With hydrogenation, one hydrogen atom of the pair is moved to the other side so that the molecule straightens. This is called the trans formation, rarely found in nature.
Most of these man-made trans fats are toxins to the body, but unfortunately your digestive system does not recognize them as such. Instead of being eliminated, trans fats are incorporated into cell membranes as if they were cis fats-your cells actually become partially hydrogenated! Once in place, trans fatty acids with their misplaced hydrogen atoms wreak havoc in cell metabolism because chemical reactions can only take place when electrons in the cell membranes are in certain arrangements or patterns, which the hydrogenation process has disturbed.
In the 1940’s, researchers found a strong correlation between cancer and the consumption of fat-the fats used were hydrogenated fats although the results were presented as though the culprit were saturated fats. In fact, until recently saturated fats were usually lumped together with trans fats in the various U.S. data bases that researchers use to correlate dietary trends with disease conditions. Thus, natural saturated fats were tarred with the black brush of unnatural hydrogenated vegetable oils.
Altered partially hydrogenated fats made from vegetable oils actually block utilization of essential fatty acids, causing many deleterious effects including sexual dysfunction, increased blood cholesterol and paralysis of the immune system.
Consumption of hydrogenated fats is associated with a host of other serious diseases, not only cancer but also atherosclerosis, diabetes, obesity, immune system dysfunction, low- birth-weight babies, birth defects, decreased visual acuity, sterility, difficulty in lactation and problems with bones and tendons.
Yet hydrogenated fats continue to be promoted as health foods. The popularity of partially hydrogenated margarine over butter represents a triumph of advertising duplicity over common sense. Your best defense is to avoid it like the plague.
Homogenization: This is the process whereby the fat particles of cream are strained through tiny pores under great pressure. The resulting fat particles are so small that they stay in suspension rather than rise to the top of the milk. This makes the fat and cholesterol more susceptible to rancidity and oxidation, and some research indicates that homogenized fats may contribute to heart disease.
The media’s constant attack on saturated fats is extremely suspect. Claims that butter causes chronic high cholesterol values have not been substantiated by research-although some studies show that butter consumption causes a small, temporary rise-while other studies have shown that stearic acid, the main component of beef fat, actually lowers cholesterol.
Margarine, on the other hand, provokes chronic high levels of cholesterol and has been linked to both heart disease and cancer. The new soft margarines or tub spreads, while lower in hydrogenated fats, are still produced from rancid vegetable oils and contain many additives.
One frequently voiced objection to the consumption of butter and other animal fats is that they tend to accumulate environmental poisons. Fat-soluble poisons such as DDT do accumulate in fats; but water-soluble poisons, such as antibiotics and growth hormones, accumulate in the water fraction of milk and meats.
Vegetables and grains also accumulate poisons. The average plant crop receives ten applications of pesticides-from planting to storage-while cows generally graze on pasture that is unsprayed. Aflatoxin, a fungus that grows on grain, is one of the most powerful carcinogens known.
It is correct to assume that all of our foods, whether of vegetable or animal origin, may be contaminated. The solution to environmental poisons is not to eliminate animal fats-so essential to growth, reproduction and overall health-but to seek out organic meats and butter from pasture-fed cows, as well as organic vegetables and grains. These are becoming increasingly available in health food stores and supermarkets and through mail order and cooperatives.
Composition Of Different Fats
Before leaving this complex but vital subject of fats, it is worthwhile examining the composition of vegetable oils and other animal fats in order to determine their usefulness and appropriateness in food preparation:
Chicken Fat is about 31% saturated, 49% monounsaturated (including moderate amounts of antimicrobial palmitoleic acid) and 20% polyunsaturated, most of which is omega-6 linoleic acid, although the amount of omega-3 can be raised by feeding chickens flax or fish meal, or allowing them to range free and eat insects. Although widely used for frying in kosher kitchens, it is inferior to duck and goose fat, which were traditionally preferred to chicken fat in Jewish cooking.
Beef and Mutton Tallows are 50-55% saturated, about 40% monounsaturated and contain small amounts of the polyunsaturates, usually less than 3%. Suet, which is the fat from the cavity of the animal, is 70-80% saturated. Suet and tallow are very stable fats and can be used for frying. Traditional cultures valued these fats for their health benefits. They are a good source of antimicrobial palmitoleic acid.
Olive Oil contains 75% oleic acid, the stable monounsaturated fat, along with 13% saturated fat, 10% omega-6 linoleic acid and 2% omega-3 linolenic acid. The high percentage of oleic acid makes olive oil ideal for salads and for cooking at moderate temperatures. Extra virgin olive oil is also rich in antioxidants.
It should be cloudy, indicating that it has not been filtered, and have a golden yellow color, indicating that it is made from fully ripened olives. Olive oil has withstood the test of time; it is the safest vegetable oil you can use, but don’t overdo. The longer chain fatty acids found in olive oil are more likely to contribute to the buildup of body fat than the short- and medium-chain fatty acids found in butter, coconut oil or palm kernel oil.
Peanut Oil contains 48% oleic acid, 18% saturated fat and 34% omega-6 linoleic acid. Like olive oil, peanut oil is relatively stable and, therefore, appropriate for stir-frys on occasion. But the high percentage of omega-6 presents a potential danger, so use of peanut oil should be strictly limited.
Sesame Oil contains 42% oleic acid, 15% saturated fat, and 43% omega-6 linoleic acid. Sesame oil is similar in composition to peanut oil. It can be used for frying because it contains unique antioxidants that are not destroyed by heat. However, the high percentage of omega-6 militates against its use.
Safflower, Corn, Sunflower, Soybean and Cottonseed Oils all contain over 50% omega-6 and, except for soybean oil, only minimal amounts of omega-3. Safflower oil contains almost 80% omega-6. Researchers are just beginning to discover the dangers of excess omega-6 oils in the diet, whether rancid or not. Use of these oils should be strictly avoided.
They should never be consumed after they have been heated, as in cooking, frying or baking. High oleic safflower and sunflower oils, produced from hybrid plants, have a composition similar to olive oil, namely, high amounts of oleic acid and only small amounts of polyunsaturated fatty acids and, thus, are more stable than traditional varieties. However, it is difficult to find truly cold-pressed versions of these oils.
Canola Oil contains 5% saturated fat, 57% oleic acid, 23% omega-6 and 10%-15% omega-3. The newest oil on the market, canola oil was developed from the rape seed, a member of the mustard family. Rape seed is unsuited to human consumption because it contains a very-long-chain fatty acid called erucic acid, which under some circumstances is associated with fibrotic heart lesions.
Canola oil was bred to contain little if any erucic acid and has drawn the attention of nutritionists because of its high oleic acid content. But there are some indications that canola oil presents dangers of its own.
It has a high sulphur content and goes rancid easily. Baked goods made with canola oil develop mold very quickly. During the deodorizing process, the omega-3 fatty acids of processed canola oil are transformed into trans fatty acids, similar to those in margarine and possibly more dangerous. A recent study indicates that “heart healthy” canola oil actually creates a deficiency of vitamin E, a vitamin required for a healthy cardiovascular system. Other studies indicate that even low-erucic-acid canola oil causes heart lesions, particularly when the diet is low in saturated fat.
Flax Seed Oil contains 9% saturated fatty acids, 18% oleic acid, 16% omega-6 and 57% omega-3. With its extremely high omega-3 content, flax seed oil provides a remedy for the omega-6/omega-3 imbalance so prevalent in America today. Not surprisingly, Scandinavian folklore values flax seed oil as a health food.
New extraction and bottling methods have minimized rancidity problems. It should always be kept refrigerated, never heated, and consumed in small amounts in salad dressings and spreads.
Tropical Oils are more saturated than other vegetable oils. Palm oil is about 50% saturated, with 41% oleic acid and about 9% linoleic acid. Coconut oil is 92% saturated with over two-thirds of the saturated fat in the form of medium-chain fatty acids (often called medium-chain triglycerides).
Of particular interest is lauric acid, found in large quantities in both coconut oil and in mother’s milk. This fatty acid has strong antifungal and antimicrobial properties. Coconut oil protects tropical populations from bacteria and fungus so prevalent in their food supply; as third-world nations in tropical areas have switched to polyunsaturated vegetable oils, the incidence of intestinal disorders and immune deficiency diseases has increased dramatically. Because coconut oil contains lauric acid, it is often used in baby formulas. Palm kernel oil, used primarily in candy coatings, also contains high levels of lauric acid.
These oils are extremely stable and can be kept at room temperature for many months without becoming rancid. Highly saturated tropical oils do not contribute to heart disease but have nourished healthy populations for millennia.
In summary, our choice of fats and oils is one of extreme importance. Most people, especially infants and growing children, benefit from more fat in the diet rather than less. But the fats we eat must be chosen with care. Avoid all processed foods containing newfangled hydrogenated fats and polyunsaturated oils.
Instead, use traditional vegetable oils like extra virgin olive oil and small amounts of unrefined flax seed oil. Acquaint yourself with the merits of coconut oil for baking and with animal fats for occasional frying. Eat egg yolks and other animal fats with the proteins to which they are attached. And, finally, use as much good quality butter as you like, with the happy assurance that it is a wholesome-indeed, an essential-food for you and your whole family.
Organic butter, unrefined coconut oil, extra virgin olive oil, and expeller-expressed flax oil in opaque containers are available in health food stores and gourmet markets.