Recent advances have been made in the scientific understanding of how diet and specific foods within a balanced diet promote human health and prevent chronic illnesses such as cardiovascular diseases, cancers, and neurodegenerative disorders. Not surprisingly, consumers are turning toward foods with medicinal properties as promising dietary interventions for disease prevention and health maintenance. As part of this trend, interest in the Mediterranean diet (MD) and specific foods that are integral to this diet have grown significantly. A common feature of the MD is a high consumption of olives and olive oil as the primary sources of dietary fat. While scientific research is continuously finding new health benefits of olive oil, people throughout history have been using it for a wide range of therapeutic and culinary uses. Folk medicine valued it for assisting with digestion, mitigating the effects of excess alcohol consumption, reducing muscle aches, and maintaining skin, hair and muscle health. Olive oil was also used as an aphrodisiac, laxative, sedative and a tonic to treat ailments as diverse as colic, paralysis, rheumatic pain, hypertension and sciatica. History and science increasingly support the myriad health benefits of consuming olive fruit and its oil, particularly as part of a balanced diet.
Traditional Mediterranean diets are rich in plant foods (vegetables, fruit, grains, seeds and nuts), olives and olive oil, and low in saturated animal fats. The work of epidemiologist and nutritionist Ancel Keys was among the first scientific research to help popularize the MD. In 1952, based on the low rates of heart disease in the Mediterranean region, Keys and his colleagues began a series of investigations of dietary and other coronary risk factors in seven countries, including Finland, Greece, US, Italy, Yugoslavia, Netherlands and Japan. The research investigated links between coronary heart disease mortality and lifestyle factors, especially the intake of monounsaturated and saturated fats. Results of the study found major differences in disease rates in relation to the amount of monounsaturated and saturated fat intake as percentages of total caloric intake. In relation to population size, countries with a high intake of saturated fats had a significantly higher number of deaths; however, those who consumed a diet high in monounsaturated fats, especially the diet in Crete, had the lowest rates of heart disease of any of the groups in the study.