General conclusions and recommendations of the consultation

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Minimum desirable intakes of fats and oils
Upper limits of fat/oil intakes
Saturated and unsaturated fatty acids, and cholesterol
Isomeric fatty acids
Substances associated with fats and oils
Essential fatty acids
Scientific and programmatic needs

Minimum desirable intakes of fats and oils

Adults. Adequate amounts of dietary fat are essential for health. In addition to their contribution to meeting energy needs, intakes of dietary fat must be sufficient to meet requirements for essential fatty acids and fat soluble vitamins. The minimum intake consistent with health varies throughout a person's life and among individuals. Adequate intake of dietary fat is particularly important prior to and during pregnancy and lactation. Increasing the availability and consumption of dietary fats is often a priority for overcoming the problems of protein-energy malnutrition. Recommendations to populations concerning desirable ranges of fat intakes may vary according to prevailing conditions, especially dietary pattems and the prevalence of diet-related non-communicable diseases.

Recommendations on minimum intakes of adults:

• For most adults, dietary fat should supply at least 15 percent of their energy intake.
• Women of reproductive age should consume at least 20 percent of their energy from fat.
• Concerted efforts should be made to ensure adequate consumption of dietary fat among populations where less than 15 percent of the dietary energy supply is from fat.

Infants and young children. Both the amount and quality of dietary fat consumed can affect child growth and development. These influences are mediated through energy levels and through the action of specific fatty acids and various non-glyceride components of the fat. Breast-milk provides between 50-60 percent energy as fat, and during the weaning period (that is, the transition from full breast-feeding to no breast-feeding), care needs to be taken to prevent dietary fat intakes from falling too rapidly or below the required levels. The use of fat, especially vegetable oils, in the foods fed to weanling infants and young children is an effective way to maintain the energy density of their diets.

The consumption of adequate amounts of essential acids is also important for normal growth and development. Arachidonic acid and docosahexaenoic acid (DHA) are particularly important for brain development, and breast-milk is a good source of these fatty acids.

Particular problems exist for preterm infants who had an insufficient intra-uterine supply of arachidonic acid and DHA and who were born with low fat reserves.

Recommendations regarding infant and young child feeding:

• Infants should be fed breast-milk if at all possible.
• The fatty acid composition of infant formulas should correspond to the amount and proportion of fatty acids contained in breast-milk.
• During weaning and at least until two years of age, a child's diet should contain 30-40 percent of energy from fat and provide similar levels of essential fatty acids as are found in breast-milk.

Upper limits of fat/oil intakes

Excessive dietary fat intake has been linked to increased risk of obesity, coronary heart disease and certain types of cancer. The mechanisms by which these are linked are complex, varied and, in many instances, not clearly understood. Elevated levels of serum cholesterol and LDL constitute major risk factors for atherosclerosis and coronary heart disease. The degree of risk of these and other factors may vary according to, inter alia: type and level of fatty acid intakes, percentage of energy from total fat, dietary cholesterol, lipoprotein levels, intakes of antioxidants and dietary fibre, activity levels and health status. Low-fat diets are often lower in cholesterol and higher in antioxidants and dietary fibre. Among adults, there is no nutritional advantage to consuming high-fat diets once essential energy and nutrient needs are met.

Recommendations on upper limits of dietary intakes:

• Active individuals who are in energy balance may consume up to 35 percent of their total energy intake from dietary fat if their intake of essential fatty acids and other nutrients is adequate and the level of saturated fatty acids does not exceed 10 percent of the energy they consume.
• Sedentary individuals should not consume more than 30 percent of their energy from fat, particularly if it is high in saturated fatty acids which are derived primarily from animal sources.

Saturated and unsaturated fatty acids, and cholesterol

The saturated fatty acids - lauric, myristic and palmitic - elevate serum cholesterol and low density lipoprotein (LDL) levels. Stearic acid does not elevate serum cholesterol or LDL levels, however, other health effects are, as yet, undefined. Polyunsaturated linoleic acid moderately reduces serum cholesterol and LDL levels. Monounsaturated oleic acid appears to be neutral in regard to LDL, but raises high density lipoproteins (HDL) modestly. Dietary cholesterol elevates serum cholesterol and LDL levels, but the extent of the increase is highly variable.

Recommendations on intakes of saturated and unsaturated fatty acids:

• Intakes of saturated fatty acids should provide no more than 10 percent of energy.
• Desirable intakes of linoleic acid should provide between 4 and 10 percent of energy. Intakes in the upper end of this range are recommended when intakes of saturated fatty acids and cholesterol are relatively high.
• Reasonable restriction of dietary cholesterol (less than 300 mg/day) is advised.

Isomeric fatty acids

Unsaturated vegetable oils are frequently partially hydrogenated to produce more solid, plastic or stable fats. During this process, an assortment of cis and trans isomers is formed. Compared to oleic acid, the trans isomers in partially hydrogenated vegetable oils tend to elevate serum LDL levels and may lower HDL levels. High intakes of trans fatty acids are undesirable, but it is, as yet, uncertain whether the use of trans or saturated fatty acids is preferable where such fatty acids are required to formulate food products.

Recommendations concerning isomeric fatty acids:

• Consumers should substitute liquid oils and soft fats (that is, those which are soft at room temperature) for hard fats (more solid at room temperature) to reduce both saturated fatty acids and trans isomers of unsaturated fatty acids.
• Food manufacturers should reduce the levels of trans isomers of fatty acids arising from hydrogenation.
• Governments should monitor the levels of isomeric fatty acids in the food supply.
• Governments should limit the claims concerning the saturated fatty acid content of foods which contain appreciable amounts of trans fatty acids, and should not allow foods that are high in trans fatty acids to be labelled as being low in saturated fatty acids.

Substances associated with fats and oils

Substantial evidence indicates that relatively high intakes of fruits and vegetables - sources of various antioxidants, carotenoids and other non-glyceride components - reduce the risk of coronary heart disease and some cancers. Yet, specific conclusions and recommendations concerning the general health benefits and desirable intakes of these substances cannot be made on the basis of current evidence.

Processing and refining techniques used to eliminate or reduce negative characteristics of edible oils can also lead to the loss of various nutritionally beneficial components such as antioxidants and carotenoids. However, producers can minimize such losses through appropriate processing, refining and storage techniques and they are encouraged to do so.

Recommendations on antioxidants and carotenoids:

• In countries where vitamin A deficiency is a public health problem, the use of red palm oil, wherever readily or potentially available, should be encouraged. If the oil is refined, processing techniques that preserve the carotenoid and tocopherol content of red palm oil should be utilized.
• Tocopherol levels in edible oils need to be adequate to stabilize the unsaturated fatty acids present. Therefore, foods high in polyunsaturates should contain at least 0.6 mg tocopherol equivalents per gram of polyunsaturated fatty acid.

Higher levels may be necessary for fats that are rich in fatty acids containing more than two double bonds.

Essential fatty acids

The n-6 and n-3 fatty acids have critical roles in the membrane structure and as precursors of eicosanoids, which are potent and highly reactive compounds. Various eicosanoids have widely divergent, and often opposing effects on, for example, smooth muscle cells, platelet aggregation, vascular parameters (permeability, contractility), and on the inflammatory processes and the immune system. Since they compete for the same enzymes and have different biological roles, the balance between the n-6 and the n-3 fatty acids in the diet can be of considerable importance.

A number of studies have shown that the consumption of foods (such as oil-rich fish) containing the long-chain n-3 fatty acids, eicosapentaenoic acid (EPA) and DHA, is associated with decreased risk of coronary heart disease (CHD), probably because of mechanisms not related to serum lipoprotein levels.

Essential fatty acids are especially important for normal fetal and infant growth and development, in particular, for brain development and visual acuity. In well-nourished women, approximately 2.2 grams of essential fatty acids are deposited in maternal and fetal tissues each day throughout pregnancy.

Recommendations concerning essential fatty acid intakes:

• The ratio of linoleic to a-linolenic acid in the diet should be between 5:1 and 10:1.
• Individuals with a ratio in excess of 10:1 should be encouraged to consume more n-3 rich foods such as green leafy vegetables, legumes, fish and other seafood.
• Particular attention must be paid to promoting adequate maternal intakes of essential fatty acids throughout pregnancy and lactation to meet the requirements of fetal and infant development.

Scientific and programmatic needs

Adequate information on nutritional status, dietary intakes and the composition of foods is required for designing and monitoring programmes to improve nutrition, including the promotion of appropriate intakes of dietary fats and oils.

Governments and health authorities in all countries need to be aware of the escalating risk of non-communicable diseases that follow the adoption of inappropriate dietary practices and less active life-styles.

Recommendations on dietary information and programme needs:

• Standard methods and reference materials should be used in the analysis of the fatty acid content of foods and in the preparation of nutrient databases.
• Adequate food composition data on fats should be widely available and accessible with each food item being identified by unambiguous descriptive factors.
• The standard Atwater factor of 9.0 kilocalories (37.7 KJ) per gram of fat should be used for calculating the energy value of fat in all nutrition surveys and food composition tables.
• Periodic surveys of the weight status (body mass index) of adults are desirable in all countries to help identify trends and populations affected by or at greater risk of undernutrition and diet-related non-communicable diseases and to monitor the impact of interventions.

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