One of the best examples of the impact of the consumption of fats and oils on human health comes from Poland. Up until the year 1990, intake of saturated fat as a percentage of calories had been increasing from year to year. Thereafter, it has been decreasing, mainly due to lower intake of foods of animal origin such as butter. Consumption of butter, for example, was about 6 kg per person, per year in 1970. It increased to about 9 kg per person in 1990. Subsequently, it decreased and in the year 2000 was reduced by about half. Between 1990 and 2000, the consumption of vegetable oils doubled. Data from the same period of time showed that the mortality (death) due to cardiovascular diseases, increased in proportion to the increase in intake of saturated fat (up to 1990). Mortality rates due to cardiovascular disease began to decline since the early 1990 in proportion to the decreased intake of saturated fat and also as intake of vegetable oils increased.
Dietary changes in Finland constitute another good example of the impact that fats and oils have in terms of disease prevention and development. The region of Finland known as North Karelia had higher rates of heart disease than almost any other European countries between 1940 and 1960. In 1970, the Finnish government made efforts to promote replacing the use of foods high in saturated fat with foods made with and containing vegetable oils. For example, people who consumed regular cow’s milk were encouraged to switch to either reduced fat milk or to soy milk. Similarly, those who used hard margarines and butter were urged to use soft margarines (soft margarines have much lower content of saturated fat compared to hard margarines).
In the spring of 1972, 86 percent of men and 82 percent of women used mainly butter as a spread on bread. In early 2000, only about 10 percent of men and 4 percent of women use butter for the same purpose. While in the early 1970s the use of soft margarine was not very common at the beginning of 2000 about 42 percent of men and 47 percent of women used reduced fat margarines (fat in such margarines provided less than 60 percent of calories). In the spring of 1972, only about 2 percent of people used vegetable oil for frying, and at the beginning of 2000 this number increased to about 40 percent. These dietary changes over time resulted in a change in the ratio of intake of unsaturated fat and saturated fats from 0.25 to 1.48. During this period of time, the average serum cholesterol level decreased from 267 to 226 (15.4 percent) in men and 275 to 249 (9.9 percent) in women. Although the serum cholesterol level should be much further reduced for the most protective effect, preferably to below 150 mg/dl, these changes practically instantaneously resulted in reduced the rates of death due to cardiovascular disease and cancer. Mortality due to cardiovascular disease dropped by 80 percent, and a 67 percent drop in mortality due to cancer was seen.
Lower mortality rates were observed in each of the studied age groups. For example, among those between 65 and 74 years of age, a 69 percent lower mortality was reported in men and an 82 percent lower mortality was reported in women. Similarly, among those between 55 and 64 years old, an 80 percent lower mortality in men and 92 percent lower mortality in women was reported. These examples illustrate the profound impact that replacing animal fat with vegetable oils has in terms of disease prevention.
In 2009, the American Journal of Clinical Nutrition published a manuscript describing the effect of fat intake on the occurrence of coronary heart disease. The conclusions of this article were based on 11 studies, which included a total of nearly 350,000 participants. According to the results, the risk of death from coronary heart disease would be reduced by 26 percent if 5 percent of calories from saturated fats were replaced with the same amount of unsaturated fatty acid. As already mentioned, meats, added fat, dairy products, eggs, baked goods, cheese, margarines and fries contribute more to the overall trans fats, saturated fat and cholesterol intake than any other items. Thus, the best way to reduce fat intake is by limiting or eliminating these products and consuming a diet that is primarily based on unrefined plant foods. People who are not willing to eliminate these products can significantly reduce intake of these detrimental fats by eating fat-free dairy products, soft margarines, or lean meat (preferably fish). It would be best if people who eat meat reduce its consumption to specific days (such as holidays or birthdays) or to no more than one day a week. Unfortunately, in many households, meat in its various forms is not only consumed daily, but also in almost every meal. The same is true of foods of animal origin and refined plant foods.
The following are good examples of different types of high fat products and in some case lower fat alternatives are suggested. Just 30 grams (about 1 oz.) of cheddar cheese contains about 6 grams of saturated fat, while the same amount of cheddar made of skimmed milk, only 1 gram. One glass of regular milk contains 4.5 grams of fat, while skim milk contains only 1.5 grams. A cup of regular ice cream contains 5 grams of fat and ice cream made of zero fat milk contains no fat at all. One type of croissant contains more than half of the daily recommended amount of saturated fat. About the same amounts of fat is found in a large portion of popcorn chicken. An extra-large serving of fries contains about 30 percent of the daily recommended amount of saturated fat. Most of the burgers offered in fast food restaurants contain from two-thirds to more than 200 percent of the recommended daily amount of saturated fat. Unfortunately, saturated fat in fast food restaurants can be found not only in the burgers. For example, a strawberry shake (medium size) comprises about 150 percent of the recommended daily amount of fat. Pizza is another example of a product with a high content of saturated fat. For example, a personal pizza with pepperoni contains more than 60 percent of the daily recommended amount of saturated fat. Just one slice of vegetarian pizza contains a similar amount.
Fruits and vegetables (including beans) and grains generally contain a small amount of fats and oils. One of the exceptions is avocado, which, like most other plant products such as nuts and seeds, contain mostly beneficial oils, especially monounsaturated fat. Plant foods do not contain cholesterol, but contain plant sterols and stanols, which are associated with reduction in risk factors of heart disease, such as serum cholesterol.
In the table below a few additional ways to reduce the amount of saturated fat consumed are suggested.Of all the oils available in grocery stores, olive oil is one of the most beneficial to human health. Research clearly shows that the frequent use of olive oil helps in reducing the risk of many chronic diseases such as heart disease, cancer, stroke, and hypertension. For example, a study published in the medical journal Archives of Internal Medicine showed that olive oil is effective in reducing blood pressure. In this experiment, patients were divided into two groups. One group was instructed to add olive oil (men 4 tablespoons and women 3 tablespoons) to their diet and the other was advised to add the same amount of sunflower seed oil. After 6 months, 8 of the11 patients who consumed olive oil no longer needed to take antihypertensive medication. However, none of those ingesting the sunflower seed oil discontinued using medications.
In another study, it was estimated that individuals who used olive oil had a 47 percent lower risk of coronary heart disease compared to those who did not use it. The researchers who conducted the study stated that “exclusive use of olive oil during food preparation seems to offer significant protection against CHD (coronary heart disease – author), irrespective of various clinical, lifestyle and other characteristics of the participants.”
Modern research also indicates that olive oil can help prevent cancer. One such study was carried out with 755 women living in the Canary Islands. The women, who consumed the highest amount of olive oil, had a 48 percent lower risk of developing breast cancer compared to women consuming the least amount of olive oil. A study conducted in Italy and Switzerland, assessed the impact of olive oil consumption on risk of developing cancer of the colon (large intestine) and rectum. This time, the researchers assessed risk based on the amount of olive oil used in frying. From other studies, it is known that carcinogenic compounds (e.g. oxygen radicals) can develop when fats and/or oils are heated to a high temperature. Researchers compare the risk among 886 individuals with to 4,765 individuals without cancer. The results indicated that the use of olive oil reduced the cancer risk by 11 percent.
At a conference about the impact of olive oil on human health held in Cordoba in Spain, an organization, the Centro de Excelencia Foundation sobre Aceite de Oliva y Salud stated that the use of olive oil reduces the risk of cardiovascular disease, probably protects against age-related decline in cognitive abilities and Alzheimer’s disease, is associated with healthier aging and longevity. In the conference’s report we also read: “The protective effect of virgin olive oil can be most important in the first decades of life, which suggests that the dietetic benefit of virgin olive oil intake should be initiated before puberty, and maintained through life.” These statements are consistent with the recommendations of the Advisory Committee of the American Heart Association, which concluded that “a diet high in MUFA (monounsaturated fatty acids, olive oil predominantly contains this type of fat – author) (versus a high-carbohydrate diet) improves glycemic control in individuals with NIDDM (none-insulin dependent diabetes mellitus – author) who maintain body weight. Individuals with elevated triglycerides or insulin levels also may benefit from a high-MUFA diet.”
Another study conducted in Greece showed that those with the greatest long-term consumption of olive oil (consumption of almost every day in a lifetime) had about 4 times lower risk of developing arthritis compared to those who consumed olive oil, on average, only about six times per month. The same researchers showed that increasing the consumption of olive oil to two times a week, reduced the risk of developing arthritis by half.
In most countries the most frequently consumed oils are the omega-6 group. Sunflower oil or soybean oil are examples of oils from the omega-6 family. Unfortunately, excess intake of refined oils from the omega-6 family increases the risk of certain chronic diseases. A study published in the European Journal of Clinical Nutrition conducted in Spain showed that people who consumed the highest amounts of omega-6 had a 3 times greater risk of fractures due to osteoporosis, compared with those with the lowest intake of these oils. The same study revealed that people who had the greatest ratio of olive oil to omega-6 had an 80 percent reduced risk of fractures. Thus replacing vegetable oils with virgin olive oil can further protect individuals from developing certain health conditions.
One of the most common questions asked about olive oil is regarding its use in frying and baking. This is because in some sources, including many websites, one can find information that says that olive oil should not be using for frying or baking due to the fact that this oil has relatively low smoking and burning temperatures. According to the International Olive Oil Council the smoke temperature of olive oil is 210 degrees C (410oF), and according to the Institute of Shortening and Edible Oils, it is 215 degrees C (420oF). In comparison, the smoke temperature of canola seed oil is approximately 205 degrees (400oF). Smoke temperature of oils and fats has been known for many decades. In 1940, two scholars, Detwiler and Markley, published oil burning temperatures in the Journal of the American Oil Chemists Society. The smoke and burning temperatures of selected oils are included in the table below. The values are based on the above mentioned publication.As can be seen in the table above, smoke and burning temperatures of olive oil are comparable to those of other commonly used oils. Based on this data, we can say that olive oil can be used in place of other vegetable oils for frying, baking and other kind of food preparation.
The research reviewed above indicates that the use of olive oil in place of other vegetable oils and animal fats can reduce the risk of developing the most common chronic health conditions. Thus, the use of olive oil, whether raw or in frying or baking should be recommended in primary prevention. It must be kept in mind, however, that the benefits of olive oil pertain to virgin olive oil and not to other types, such as lite, refined, pure or pomace olive oils.
The use of some types of fat including trans fats, saturated fats and cholesterol is detrimental. Thus, in order to reduce a risk of chronic health conditions, the use of meats, lard, butter, mayonnaise as well as milk and dairy products, especially the regular fat variety should be replaced with products such as nuts, seeds, olives and vegetable oils, especially olive oil.