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The following is an extract from:Nutrient Reference Values for Australia and New ZealandIncluding Recommended Dietary IntakesENDORSED BY THE NHMRC ON 9 SEPTEMBER 2005© Commonwealth of Australia 2006ISBN Print 1864962372ISBN Online 1864962437The Nutrient Reference Values (NRVs) was a joint initiative of the Australian National Health and MedicalResearch Council (NHMRC) and the New Zealand Ministry of Health (MoH). The NHMRC would like tothank the New Zealand MoH for allowing the use of the NRV material in the development of this website.NHMRC publications contact:Email: nhmrc.publications@nhmrc.gov.auInternet: http://www.nhmrc.gov.auFree Call: 1800 020 103 ext 9520FATS: TOTAL FAT & FATTY ACIDSNutrient Reference Values for Australia and New Zealand 35FATS: TOTAL FAT AND FATTY ACIDSBACKGROUNDFats are the most concentrated form of energy for the body (37 kJ/g). They also aid in the absorption ofthe fat-soluble vitamins, A, D, E and K and other fat-soluble biologically-active components. Chemically,most of the fats in foods are triglycerides, made up of a unit of glycerol combined with three fatty acidswhich may be the same or different. The differences between one triglyceride and another are largelydue to the fatty acids content. Other dietary fats include phospholipids, phytosterols and cholesterol.There are three major types of naturally-occurring fatty acids – saturated, cis-monounsaturated andcis-polyunsaturated. A fourth form, the trans fatty acids, are produced by partial hydrogenation ofpolyunsaturated oils in food processing and they also occur naturally in ruminant animal foods.Saturated fats are found mainly in animal-based foods and polyunsaturates and monounsaturatespredominate in plant-based foods.Saturated fatty acids contain no double bond; they are fully saturated with hydrogen. They are themain type of fatty acids found in milk, cream, butter and cheese, meats from most of the land animals,palm oil and coconut oil as well as in products such as pies, biscuits, cakes and pastries. Saturated fattyacids have both physiological and structural functions. They can be synthesised by the body so are notrequired in the diet.The main monounsaturated fatty acid is oleic acid with one double bond. Olive, canola and peanut oilsare rich in oleic acid. The monounsaturates are also synthesised by the body and are thus not requiredin the diet.Polyunsaturated fatty acids contain two or more double bonds. The most common is linoleic acid(LA, 18:2). It is described as ‘n-6’ due to the position of the double bonds and occurs in seed oils,eg sunflower, safflower and corn. Other n-6 fatty acids include γ-linolenic (18:3), dihomo-γ-linolenic(20:3), arachidonic acid (20:4) and adrenic acid (22:4). LA is the precursor of arachidonic acid, asubstrate for eicosanoid production which is also involved in the regulation of gene expression(Ou et al 2001). LA is also found as a structural component of cell membranes and is important incell signalling. High intakes of n-6 polyunsaturated fats have been associated with blood lipid profilesassociated with a lower risk of coronary heart disease (eg lower total and LDL cholesterol, increasedHDL cholesterol and reduced triacylglycerol) (Arntzenius et al 1985, Becker et al 1983, Sonnenberget al 1996).Smaller amounts of polyunsaturated fatty acids with double bonds in the n-3 position also occur inthe diet. These are sometimes referred to as omega fatty acids. Humans are unable to insert a doublebond at the n-3 position of a fatty acid and thus require a dietary source. The parent fatty acid of then-3 series is α-linolenic (ALA, 18:3). ALA is found in legumes, canola oils and margarines, linseed oilsand products, certain nuts such as walnuts, and in small amounts in leafy vegetables. Canola oils andmargarines and linseed oils are rich sources and legumes contribute some. A second group of n-3 fattyacids are the long chain (LC) acids eicosapentaenoic acid (EPA, 20:5), docosahexaenoic acid (DHA,22:6) and docosapentaenoic acid (DPA, 22:5) that are found predominantly in oily fi sh such as mackerel,herrings, sardines, salmon and tuna and other seafood. Whilst α-linolenic acid predominates in westerndiets, the fi sh oils, DHA, EPA and DPA predominate in other communities consuming their traditionaldiet, such as the Inuit (Holman et al 1982).ALA primarily functions as a precursor for the synthesis of EPA which in turn forms DHA but mayalso have an independent role in protection against coronary heart disease via different mechanisms(Crawford et al 2000). Conversion of ALA to EPA and DHA is limited and varies according to the intakesof other fatty acids (Burdge et al 2003, Emken 2003, Pawlosky et al 2001). Thus, a typical intake of ALAmay be less able to satisfy the physiological requirements for LC n-3 fatty acids than the smaller andoften more variable intakes of pre-formed LC n-3 fatty acids.FATS: TOTAL FAT & FATTY ACIDS36 Nutrient Reference Values for Australia and New ZealandDHA plays an important role as a structural membrane lipids, particularly in nerve tissue and theretina, and can also act as a precursor to certain eicosanoids. EPA is the precursor of the 3 seriesof prostaglandins and the 5 series of leukotrienes. In recent years, research has shown bothcardiovascular and anti-inflammatory benefits of LC n-3 fatty acids (Albert et al 1998, 2002, Burr et al1989, Dallongeville et al 2003, Djousse et al 2001, Dolecek 1992, GISSI-Prevenzione Investigators1999, Hu et al 1999, Pischon et al 2003, WHO 2003). Early on, because of the nature of the fish oilsused in studies, these benefits were attributed to EPA and its impact on eicosanoid production(Simopoulos 1991) but recent studies suggest that DHA is the primary mediator of cardiovascularbenefits, influencing gene expression of key metabolic regulators, particularly in endothelial cells(Mori et al 1999). The potential role of DPA, as a very minor component of fi sh oil, has been largelyignored, despite the fact that recent research shows DPA contributes almost 30% of total LC n-3 inour diet (Howe et al 2003, 2005).Until dose-response relationships have been established, the relative efficacy of EPA, DPA and DHAremains uncertain. Moreover, the extent of their interconversion is also uncertain. Hence it is notpossible to differentiate between intake requirements for EPA, DPA and DHA at this stage.A lack of dietary n-6 or n-3 polyunsaturated fatty acids is characterised by rough, scaly skin, dermatitis,increased transepidermal water loss, reduced growth and a high triene: tetraene ratio (Goodgame et al1978, Holman et al 1982, Jeppersen et al 2000, Mascioli et al 1996, O’Neill et al 1977). They cannot beformed in the body and is therefore essential in the diet. Studies on patients given fat-free parenteralfeeding have provided insight into the levels at which essential fatty acid deficiency occurs but are notsufficient to establish an average requirement (Fleming et al 1976, Goodgame et al 1978, Jeppersen et al1998, Riella et al 1975).There is some evidence that the ratio of n-6 to n-3 fatty acids may be important. Jensen et al (1997)reported that infants fed formulas containing an LA:ALA ratio of 4.8:1 had lower arachidonic acidconcentrations and impaired growth compared to infants fed ratios of 9.7:1 or above. However, morerecent large trials of ratios of 5:12 and 10:1 found no evidence of reduced growth or other problems(Simmer 2002). Various authorities have recommended ratios of LA:ALA or n-6:n-3 ratios ranging from5:1 to 10:1 or 5:1 to 15:1 or 6:1 to 16:1 for infant formula (ESPGAN, Committee on Nutrition 1991,ISSFAL 1994, LSRO 1998).A number of studies have looked at the n-6:n-3 ratio in relation to heart disease with inconsistentresults (Dolecek & Graditis 1991, Ezaki et al 1999, Hu et al 1999, Kromhout et al 1985, Lands et al 1990,1992, Nelson et al 1991, Shekelle et al 1985). However, on the basis of these results, the FAO:WHOConsultation on Fats and Oils (1994) recommended that the ratio of LA to ALA in the diet should bebetween 5:1 and 10:1 and suggested that individuals with a ratio greater than 10:1 should be encouragedto consume more n-3-rich foods. In contrast, an expert workshop in the Netherlands (de Deckere 1998)concluded that setting an n-6:n-3 ratio would not be helpful. They also proposed that there should beseparate recommendations for plant (18:3) and marine (20:5, 22:5, 22:6) n-3 fatty acids.Based on the concept of essentiality and given the lack of dose-response data to derive EARs for thosecomponents considered essential, AIs have been set for LA (n-6 in infants), ALA and the combined LCn-3 fatty acids, DHA:EPA:DPA. The AIs are based on median population intakes in Australia.For children, adolescents and adults an EAR, RDI or AI for total fat was not set as it is the typeof fats consumed that relate to essentiality and to many of the physiological and health outcomes.A suggested range of per cent energy as fat in relation to chronic disease prevention is addressed inthe ‘Chronic disease’ section. In infancy, as fat is the major single source of energy in breast milk, an AIrecommendation for total fat has been made based on breast milk composition. Recommendations forfatty acids in infancy are also based on total n-6 or n-3 derived from the composition of breast milk.FATS: TOTAL FAT & FATTY ACIDSNutrient Reference Values for Australia and New Zealand 37RECOMMENDATIONS BY LIFE STAGE AND GENDER InfantsAIFats0–6 monthsTotal fat31 g/dayn-6 polyunsaturated fats4.4 g/dayn-3 polyunsaturated fats0.5 g/day7–12 monthsTotal fat30 g/dayn-6 polyunsaturated fats4.6 g/dayn-3 polyunsaturated fats0.5 g/day Rationale: The AI for 0–6 months was set by multiplying together the average intake of breast milk(0.78 L/day) and the average concentration of fat, n-6 or n-3 in breast milk (40; 5.6 and 0.63 g/L,respectively) from nine studies reviewed by FNB:IOM (2002) and rounding. The AI for 7–12 months wasset by multiplying together the average intake of breast milk (0.6 L/day) and the average concentrationof fat, n-6 or n-3 in breast milk (40; 5.6 and 0.63 g/L respectively) from nine studies reviewed byFNB:IOM (2002) and adding the median intake from complementary foods (5.7, 1.2 and 0.11 g/day,respectively) from the US CSFII data for 1994–96 (FNB:IOM 2002). Children, adolescents & adultsAIFatsLinoleic acidα-linolenic acidTotal LC n-3(DHA+EPA+DPA)Boys and girls1–3 yr5 g/day0.5 g/day40 mg/day4–8 yr8 g/day0.8 g/day55 mg/dayBoys9–13 yr10 g/day1.0 g/day70 mg/day14–18 yr12 g/day1.2 g/day125 mg/dayGirls9–13 yr8 g/day0.8 g/day70 mg/day14–18 yr8 g/day0.8 g/day85 mg/dayAdults 19+ yrMen13 g/day1.3 g/day160 mg/dayWomen8 g/day0.8 g/day90 mg/day Rationale: The AIs for LA and ALA were based on the highest median intakes of any of the genderrelated age groups taken from an analysis of the National Nutrition Survey of Australia of 1995 (Howe etal 2003, 2005). For LC n-3, to overcome a marked gender disparity caused by particularly higher relativeintakes in younger adult males (19–30 years), the AI was based on the median intake for all adults ofthe relevant gender. As national data were not available for New Zealand, similar values were assumed.The AIs do not necessarily reflect optimal intakes but are the values found in a population with noapparent essential fatty acid defi ciency. (The ‘Chronic disease prevention’ section includes a suggesteddietary target.)FATS: TOTAL FAT & FATTY ACIDS38 Nutrient Reference Values for Australia and New Zealand PregnancyAIFatsLinoleic acidα-linolenic acidTotal LC n-3(DHA+EPA+DPA)14–18 yr10 g/day1.0 g/day110 mg/day19–50 yr10 g/day1.0 g/day115 mg/day Rationale: Demand for n-6 and n-3 fatty acids for placental and fetal tissue must be met from maternalstores or by increased dietary intake, but there is a lack of data for assessing additional needs. The AIsfor pregnancy were therefore based on that of the non-pregnant women, with an additional amountbased on the increased average body weight in pregnancy (x 1.25). LactationAIFatsLinoleic acidα-linolenic acidTotal LC n-3(DHA+EPA+DPA)14–18 yr12 g/day1.2 g/day140 mg/day19–50 yr12 g/day1.2 g/day145 mg/day Rationale: There is a lack of data about the requirements in pregnancy, so the AIs were based on thatfor non-pregnant, non-lactating women plus that of the infant. As the infant recommendation includesonly an AI for total n-3 based on milk concentration, this amount was apportioned between ALA and LComega-3 in the same ratio as in the maternal AI when assessing the additional requirement.UPPER LEVEL OF INTAKE – TOTAL FAT AND FATTY ACIDS Linoleic acid:No UL was set because there is no known level at which adverse effectsmay occur.α-linolenic acid:No UL was set because there is no known level at which adverse effectsmay occur. The longer chain DHA, EPA and DPA fatty acids derived fromALA are more biologically-potent than ALA itself. LC n-3 fatty acids (DHA, EPA, DPA):Infants 0–12 monthsNot possible to establishChildren, adolescents and adults3,000 mg/day Rationale: There is some evidence to suggest that high levels of these fatty acids may impair immuneresponse and prolong bleeding time. However the immune function tests were performed in vitro and itis unclear how the results would translate to the in vivo situation. Prolonged bleeding times have beenseen in the Inuit, but it is not known if they were caused by high LC n-3 consumption. The US Foodand Drug Administration (DHHS 1997) has set a ‘Generally Regarded as Safe’ level of 3000 mg/day forLC n-3 which has been adopted here as the upper level of intake for children, adolescents and adults.(Note that is unlikely that this level of intake would be reached by consumption of seafood alone. 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