Response to and range of acceptable fat intake in adults

Abstract

Cellular energy metabolism depends on two main energy substrates: glucose and fatty acids. The major determinants of the fuel mix oxidized are glucose availability and insulin secretion that both promote glucose oxidation. Fatty acid oxidation occurs mainly when glucose availability is reduced, for instance during the postabsorptive period, or when energy expenditure is increased, for instance during exercise of long duration. When eucaloric diets with high carbohydrate and low fat content are ingested, de novo lipogenesis is stimulated in adults, but the rate of conversion of glucose to fatty acids is low, which means that carbohydrate intake does not have much in¯uence on fat requirements. The lower limit of fat intake depends on three factors: the fat requirement to meet energy needs, the need for essential fatty acids, and the amount of fat in the diet that is necessary to absorb fat-soluble vitamins. The lower limit of fat intake to meet the energy needs of adults is assumed to be between 10 and 15% of dietary energy, provided that enough carbohydrates are available. For adults, the requirement for essential fatty acids is in the range of 3 ± 5% of dietary energy for linoleic acid, and 0.5 ± 1.0% of dietary energy for linolenic acid. Fat energy should not be below 10% of total energy intake in order to ensure an unrestricted absorption of fat-soluble vitamins, particularly vitamins A and E. The recommendations on upper limits of fat intake for adults must take into account the degree of physical activity. International recommendations indicate that active individuals in energy balance may consume up to 35% of their total energy intake as dietary fat, whereas sedentary individuals should not consume more than 30% of their energy from fat. Saturated fatty acids should not exceed 10% of the energy intake. IntroductionWhile protein and energy requirements have been studied extensively in humans (Scrimshaw et al, 1972), the relative contribution of carbohydrates and fats to cover energy needs has received less attention. In many rural communities of developing countries, carbohydrates contribute between 70 and 75% to total energy intake, while fat intake contributes only 12 ± 15% (FAOUN, 1970). By contrast, the traditional adult Eskimo diet in the last century contained about 7% carbohydrate and 50% fat energy (Bang et al, 1980). A range of fat intake between 12 and 50% of total energy intake appears to be compatible with a normal body composition and the maintenance of good health in individuals who are adapted to these types of diets and to their environment. This does not imply, however, that these extreme values of fat and carbohydrate intakes can be recommended for adults of developed countries with a sedentary lifestyle. Lower limit of fat intake in adultsThe lower limit of fat intake depends on three factors: the fat requirement to meet energy needs, the need for essential fatty acids, and the amount of fat in the diet that is necessary to absorb the fat soluble vitamins.Fat requirement to meet energy nee...

Fats and Fatty Acid Requirements for Adults

“…Therefore, the minimum level (MIL) of fat intake should not be less than 15%E, while paying attention to the adequate intake of essential fatty acids and energy needs. Nevertheless, it has to be considered that this lower limit of fat intake for adults is difficult to define because only a few investigations have addressed this topic [Walker and Walker, 1978;Jequier, 1999;Bourne et al, 2002].…”

Dietary fat intake and red blood cell fatty acid composition of children and women from three different geographical areas in South Africa

“…In children, low fat (25-30%E) intake has been shown to be associated with growth failure and a lower intake of fat soluble vitamins [2]. In adults a minimum fat intake of 15%E is required to ensure sufficient energy and EFA intake, and to facilitate fat soluble vitamin absorption [25].…”

Intravenous Lipid Emulsions in Parenteral Nutrition

“…Average enteral fat requirements decrease with increasing age but remain substantial at 30-40% of total energy for 2-to 4 y-old children, 25-35% for up to 18-y-old adolescents (3,4), and 20-30% for adults (5). For parenterally fed infants, recommended intravenous fat doses range from 2.5 to 3 g $ kg 21 $ d 21 .…”