Nourishing Traditions: The Cookbook That Challenges Politically Correct Nutrition and The... (4 page)

  The relative good health of the Japanese, who have the longest life span of any nation in the world, is generally attributed to a lowfat diet. Although the Japanese eat few dairy fats, the notion that their diet is low in fat is a myth; rather, it contains moderate amounts of animal fats from eggs, pork, chicken, beef, seafood and organ meats. With their fondness for shellfish and fish broth, eaten on a daily basis, the Japanese probably consume more cholesterol than most Americans. What they do
not
consume is a lot of vegetable oil, white flour or processed food (although they do eat white rice). The life span of the Japanese has increased since World War II along with an increase in animal fat and protein in the diet.
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Those who point to Japanese statistics to promote the lowfat diet fail to mention that the Swiss live almost as long on one of the fattiest diets in the world. Tied for third in the longevity stakes are Austria and Greece—both with high-fat diets.
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  As a final example, let us consider the French. Anyone who has eaten his way across France has observed that the French diet is loaded with saturated fat in the form of butter, eggs, cheese, cream, liver, meats and rich pates. Yet the French have a lower rate of coronary heart disease than many other western countries. In the United States, 315 of every 100,000 middle-aged men die of heart attacks each year; in France the rate is 145 per 100,000. In the Gascony region, where goose and duck liver form a staple of the diet, this rate is a remarkably low 80 per 100,000.
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This phenomenon has recently gained international attention and was dubbed the French Paradox. (The French do suffer from many degenerative diseases, however. They eat large amounts of sugar and white flour and in recent years have succumbed to the timesaving temptations of processed foods.)

A chorus of establishment voices, including the American Cancer Society, the National Cancer Institute and the Senate Committee on Nutrition and Human Needs, claims that animal fat is linked not only with heart disease but also with cancers of various types. Yet when researchers from the University of Maryland analyzed the data they used to make such claims, they found that vegetable fat consumption was correlated with high rates of cancer and animal fat was not.
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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 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. Saturated fatty acids are found mostly in animal fats and tropical oils, and your body also makes them from carbohydrates.

  
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 many 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, however, 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 EFAs from the foods we eat. Polyunsaturated fatty acids have kinks or turns at the position of the double bond and hence do not pack together easily. They remain liquid, even when refrigerated. The unpaired electrons at the double bonds make these oils highly reactive. They go rancid easily, particularly omega-3 linolenic acid, and must be treated with care. Polyunsaturated oils should never be heated or used in cooking. In nature, polyunsaturated fatty acids are usually found in the
cis
form, which means that both hydrogen atoms at the double bond are on the same side.

All fats and oils, whether of vegetable or animal origin, are some combination of saturated fatty acids, monounsaturated fatty acids and polyunsaturated linoleic acid and linolenic acid. In general, animal fats such as butter, lard and tallow contain about 40-60 percent saturated fat and are solid at room temperature. Vegetable oils from northern climates contain a preponderance of polyunsaturated fatty acids and are liquid at room temperature. But vegetable oils from the tropics are highly saturated. Coconut oil, for example, is 92 percent saturated. These fats are liquid in the tropics but hard as butter in northern climates. Vegetable oils are more saturated in tropical regions because the increased saturation helps maintain stiffness in plant leaves. Olive oil with its preponderance of oleic acid is the product of a temperate climate. It is liquid at warm temperatures but hardens when refrigerated.

Researchers classify fatty acids not only according to their degree of saturation but also by their length.

  
Short-chain
fatty acids have four to six carbon atoms. These fats are always saturated. Four-carbon butyric acid is found mostly in butterfat from cows, and six-carbon capric acid is found mostly in butterfat from goats. These fatty acids have antimicrobial properties—that is, they protect us from viruses, yeasts and pathogenic bacteria in the gut. They do not need to be acted on by the bile salts but are directly absorbed for quick energy. For this reason, they are less likely to cause weight gain than olive oil or commercial vegetable oils.
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Short-chain fatty acids also contribute to the health of the immune system.
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Medium-chain
fatty acids have eight to twelve carbon atoms and are found mostly in butterfat and tropical oils. Like the short-chain fatty acids, these fats have antimicrobial properties, are absorbed directly for quick energy, and contribute to the health of the immune system.

  
Long-chain
fatty acids have from 14 to 18 carbon atoms and can be either saturated, monounsaturated or polyunsaturated. Stearic acid is an 18-carbon saturated fatty acid found chiefly in beef and mutton tallows. Oleic acid is an 18-carbon monounsaturated fat which is the chief component of olive oil. Another monounsaturated fatty acid is the 16-carbon palmitoleic acid which has strong antimicrobial properties. It is found almost exclusively in animal fats. The two essential fatty acids are also long chain, each 18 carbons in length. Another important long-chain fatty acid is gamma-linolenic acid (GLA) which has 18 carbons and three double bonds. It is found in evening primrose, borage and black currant oils. A healthy body can make GLA out of omega-6 linoleic acid. GLA is used in the production of substances called prostaglandins, localized tissue hormones that regulate many processes at the cellular level.

  
Very-long-chain
fatty acids have 20 to 24 carbon atoms. They tend to be highly unsaturated, with four, five or six double bonds. Some people can make these fatty acids from EFAs, but others, particularly those whose ancestors ate a lot of fish, lack enzymes to produce them. These "obligate carnivores" must obtain elongated fatty acids from animal foods like organ meats, egg yolks, butter and fish oils. The most important very-long-chain fatty acids are dihomo-gamma-linolenic acid (DGLA) with 20 carbons and three double bonds, arachidonic acid (AA) with 20 carbons and four double bonds, eicosapentaenoic acid (EPA) with 20 carbons and five double bonds, and docosahexaenoic acid (DHA) with 22 carbons and six double bonds. All of these except DHA are used in the production of prostaglandins. In addition, AA and DHA play important roles in the function of the nervous system.
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