Dr. Price analyzed the nutrient content of native diets and found that they consistently provided about ten times more fat-soluble vitamins than the American diet of the 1930’s. This ratio is probably more extreme today as Americans have deliberately reduced animal fat consumption. Dr. Price realized that these fat-soluble vitamins promoted the beautiful bone structure, wide palate, flawless uncrowded teeth and handsome, well-proportioned faces that characterized members of isolated traditional groups.
American children in general do not eat fish or organ meats, at least not to any great extent, and blubber and insects are not a part of the western diet; many will not eat eggs. The only good source of fat-soluble vitamins in the American diet, one sure to be eaten, is butterfat. Butter added to vegetables and spread on bread, and cream added to soups and sauces, ensure proper assimilation of the minerals and water-soluble vitamins in vegetables, grains and meat.
The Wulzen Factor: Called the “antistiffness” factor, this compound is present in raw animal fat. Researcher Rosalind Wulzen discovered that this substance protects humans and animals from calcification of the joints-degenerative arthritis.
It also protects against hardening of the arteries, cataracts and calcification of the pineal gland.  Calves fed pasteurized milk or skim milk develop joint stiffness and do not thrive. Their symptoms are reversed when raw butterfat is added to the diet. Pasteurization destroys the Wulzen factor-it is present only in raw butter, cream and whole milk.
The Price Factor or Activator X: Discovered by Dr. Price, Activator X is a powerful catalyst which, like vitamins A and D, helps the body absorb and utilize minerals. It is found in organ meats from grazing animals and some sea food. Butter can be an especially rich source of Activator X when it comes from cows eating rapidly growing grass in the spring and fall seasons. It disappears in cows fed cottonseed meal or high protein soy-based feeds.  Fortunately, Activator X is not destroyed by pasteurization.
Arachidonic Acid: A 20-carbon polyunsaturate containing four double bonds, found in small amounts only in animal fats. Arachidonic acid (AA) plays a role in the function of the brain, is a vital component of the cell membranes and is a precursor to important prostaglandins. Some dietary gurus warn against eating foods rich in AA, claiming that it contributes to the production of “bad” prostaglandins, ones that cause inflammation. But prostaglandins that counteract inflammation are also made from AA.
Short- and Medium-Chain Fatty Acids: Butter contains about 12-15% short- and medium-chain fatty acids. This type of saturated fat does not need to be emulsified by bile salts but is absorbed directly from the small intestine to the liver, where it is converted into quick energy. These fatty acids also have antimicrobial, antitumor and immune-system-supporting properties, especially 12-carbon lauric acid, a medium-chain fatty acid not found in other animal fats.
Highly protective lauric acid should be called a conditionally essential fatty acid because it is made only by the mammary gland and not in the liver like other saturated fats.  We must obtain it from one of two dietary sources-small amounts in butterfat or large amounts in coconut oil. Four-carbon butyric acid is all but unique to butter. It has antifungal properties as well as antitumor effects. 
Omega-6 and Omega-3 Essential Fatty Acids: These occur in butter in small but nearly equal amounts. This excellent balance between linoleic and linolenic acid prevents the kind of problems associated with overconsumption of omega-6 fatty acids.
Conjugated Linoleic Acid: Butter from pasture-fed cows also contains a form of rearranged linoleic acid called CLA, which has strong anticancer properties. It also encourages the buildup of muscle and prevents weight gain. CLA disappears when cows are fed dry hay or processed feed. 
Lecithin: Lecithin is a natural component of butter that assists in the proper assimilation and metabolization of cholesterol and other fat constituents.
Cholesterol: Mother’s milk is high in cholesterol because it is essential for growth and development. Cholesterol is also needed to produce a variety of steroids that protect against cancer, heart disease and mental illness.
Glycosphingolipids: This type of fat protects against gastrointestinal infections, especially in the very young and the elderly. For this reason, children who drink skimmed milk have diarrhea at rates three to five times greater than children who drink whole milk. 
Trace Minerals: Many trace minerals are incorporated into the fat globule membrane of butterfat, including manganese, zinc, chromium and iodine. In mountainous areas far from the sea, iodine in butter protects against goiter. Butter is extremely rich in selenium, a trace mineral with antioxidant properties, containing more per gram than herring or wheat germ.
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:
Duck and Goose Fat are semisolid at room temperature, containing about 35% saturated fat, 52% monounsaturated fat (including small amounts of antimicrobial palmitoleic acid) and about 13% polyunsaturated fat. The proportion of omega-6 to omega-3 fatty acids depends on what the birds have eaten. Duck and goose fat are quite stable and are highly prized in Europe for frying potatoes.
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.
Lard or pork fat is about 40% saturated, 48% monounsaturated (including small amounts of antimicrobial palmitoleic acid) and 12% polyunsaturated. Like the fat of birds, the amount of omega-6 and omega-3 fatty acids will vary in lard according to what has been fed to the pigs. In the tropics, lard may also be a source of lauric acid if the pigs have eaten coconuts.
Like duck and goose fat, lard is stable and a preferred fat for frying. It was widely used in America at the turn of the century. It is a good source of vitamin D, especially in third-world countries where other animal foods are likely to be expensive. Some researchers believe that pork products should be avoided because they may contribute to cancer. Others suggest that only pork meat presents a problem and that pig fat in the form of lard is safe and healthy.
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. 
For further information please see Sally and Dr. Enig’s newer article on canola oil .
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.
From: Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and the Diet Dictocrats by Sally Fallon with Mary G. Enig, PhD (NewTrends Publishing 2000, http://www.newtrendspublishing.com/ 877-707-1776)