According to some researchers, the US government-recommended diets for preventing heart disease do not contain enough essential fats, the kind of fatty acids found in vegetables, lean meats, fish, and eggs. The National Cholesterol Educational Program of the National Heart, Lung, and Blood Institute diet recommends 10 per cent of energy from each of saturated, monounsaturated, and polyunsaturated fatty acids (PUFA). The American Heart Association diet provides similar guidelines and recommends that people eat a total fat intake of less than 30 per cent of energy. The World Health Organization guidelines set a range of 4-10 per cent for PUFA intake, 10 per cent being for populations whose diet is rich in saturated fats, such as the US. However these organizations provide no comprehensive basis for recommendations for specific types of essential fatty acids (EFAs) or other polyunsaturated fatty acids such as those found in fish or animal cells. The American Heart Association (AHA) report on nutrition and health recommends intake of PUFAs up to 10 per cent of calories. The report authors state that "the case has not been made for a high degree of essential fatty acid deficiency in the US population." According to Dr. Siguel, EFA deficiency is quite common in patients who follow low fat diets or the NIH or AHA dietary recommendations. He showed that EFA deficiency is caused by diets low in PUFAs, and by diets high in saturated fat or high in carbohydrates, such as low fat diets. His research found overwhelming evidence that EFA deficiency is quite common in the US population, with more than 75 per cent of adult Americans having suboptimal levels of omega-3 fatty acids, omega-6 essential fatty acids, or both. Moreover, a diet may comply with AHA and NIH guidelines to have 10 per cent of calories as PUFA, but may provide most of the calories as omega-6s rather than as an adequate mixture of omega-3s and omega-6s. According Dr. Alexander Leaf, Americans should be eating more of the omega-3 EFA linolenic acid to reduce heart attacks. His recommendations are based on studies conducted in France and other countries that show that supplementing the diet with oils rich in linolenic acid reduces mortality and the likelihood of a heart attack. This recommendation is based on the assumption that Americans do not have enough of the omega-3 EFA. A diet high in essential fats can be extremely effective to lower abnormal lipids in some people. The NIH and AHA diets may not be adequate to lower cholesterol and triglycerides substantially, and therefore too many people may be told they must take lipid-lowering drugs.