Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005) / Chapter Skim
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8. Dietary Fats: Total Fat and Fatty Acids
8. Dietary Fats: Total Fat and Fatty Acids
Pages 422-541
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From page 422... ...
Therefore, neither an AI nor RDA is set for saturated fatty acids. There is a positive linear trend between total saturated fatty acid intake and total and low density lipoprotein (LDL)
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From page 423... ...
There is insufficient evidence to set a UL for n-9 cis monounsaturated fatty acids. Linoleic acid is the only n-6 polyunsaturated fatty acid that is an essential fatty acid; it serves as a precursor to eicosanoids.
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From page 424... ...
. The fatty acids can be classified into the following categories: · Saturated fatty acids · Cis monounsaturated fatty acids · Cis polyunsaturated fatty acids -- n-6 fatty acids -- n-3 fatty acids · Trans fatty acids Dietary fat derives from both animal and plant products.
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From page 425... ...
These sources provide a series of saturated fatty acids for which the major dietary fatty acids range in chain length from 8 to 18 carbon atoms. These are: · 8:0 Caprylic acid · 10:0 Caproic acid · 12:0 Lauric acid · 14:0 Myristic acid · 16:0 Palmitic acid · 18:0 Stearic acid The saturated fatty acids are not only a source of body fuel, but are also structural components of cell membranes.
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From page 426... ...
n-6 Polyunsaturated Fatty Acids The primary n-6 polyunsaturated fatty acids are: · 18:2 Linoleic acid · 18:3 -Linolenic acid · 20:3 Dihomo -- linolenic acid · 20:4 Arachidonic acid · 22:4 Adrenic acid · 22:5 Docosapentaenoic acid Linoleic acid cannot be synthesized by humans and a lack of it results in adverse clinical symptoms, including a scaly rash and reduced growth. Therefore, linoleic acid is essential in the diet.
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From page 427... ...
n-3 Polyunsaturated Fatty Acids n-3 Polyunsaturated fatty acids tend to be highly unsaturated with one of the double bonds located at 3 carbon atoms from the methyl end. This group includes: · 18:3 -Linolenic acid · 20:5 Eicosapentaenoic acid · 22:5 Docosapentaenoic acid · 22:6 Docosahexaenoic acid -Linolenic acid is not synthesized by humans and a lack of it results in adverse clinical symptoms, including neurological abnormalities and poor growth.
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From page 428... ...
. Additionally, the biohydrogenation of several other polyunsaturated fatty acids has been shown to produce vaccenic acid as an intermediate (Griinari and Bauman, 1999)
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From page 429... ...
Activation of lipoprotein lipase apolipoprotein CII, an apoprotein present on chylomicrons, results in the hydrolysis of the chylomicron triacylglycerol fatty acids. Most of the fatty acids released in this process are taken up by adipose tissue and re-esterified into triacylglycerol for storage.
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From page 430... ...
. Fatty acids released from adipose tissue or to a lesser extent during hydrolysis of chylomicron and very low density lipoprotein (VLDL)
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From page 431... ...
However, unsaturated fatty acids are well absorbed regardless of chain length. Studies with human infants have shown the absorption to be 75, 62, 92, and 94 percent of palmitic acid, stearic acid, oleic acid, and linoleic acid, respectively, from vegetable oils (Jensen et al., 1986)
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From page 432... ...
The saturated fatty acids, in contrast to cis mono- or polyunsaturated fatty acids, have a unique property in that they suppress the expression of LDL receptors (Spady et al., 1993)
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From page 433... ...
As for other fatty acids, the oxidation of monounsaturated fatty acids results in production of carbon dioxide and water. n-6 Polyunsaturated Fatty Acids Absorption.
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From page 434... ...
reported that an intake of 30 g/d of linoleic acid resulted in a 40 to 54 percent lower conversion of stable isotopically labeled linoleic and -linolenic acid to their metabolites compared to an intake of 15 g/d in healthy men. High dietary intakes of n-3 fatty acids result in reduced tissue arachidonic acid concentrations and synthesis of arachidonic acid-derived eicosanoids, with consequent effects on the balance of n-6 and n-3 fatty acid-derived eicosanoids that are produced.
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From page 435... ...
The pathway leading from EPA to more highly unsaturated fatty acids involves the addition of two 2-carbon units, then a second 6 desaturation, after which the 24-carbon-chain fatty acid is transported to the peroxisomes and converted to DHA through one step of -oxidation (Sprecher et al., 1995; Voss et al., 1991)
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From page 436... ...
. Other animal studies have suggested that the deleterious effects seen with high intakes of trans fatty acid do not occur with amounts comparable to those consumed in a normal human diet containing sufficient amounts of linoleic acid (Bruckner et al., 1982; Zevenbergen et al., 1988)
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From page 437... ...
. Despite these observations, it should be noted that adipose tissue trans fatty acid profiles can be confounded by the retention of intermediate products of -oxidation (Emken, 1995)
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From page 438... ...
Because adipose tissue lipids in free-living, healthy adults contain about 10 percent of total fatty acids as linoleic acid, biochemical and clinical signs of essential fatty acid deficiency do not appear during dietary fat restriction or malabsorption when they are accompanied by an energy deficit. In this situation, release of linoleic acid and small amounts of arachidonic acid from adipose tissue reserves may prevent development of essential fatty acid deficiency.
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From page 439... ...
. In rapidly growing infants, feeding with milk containing very low amounts of n-6 fatty acids results in characteristic signs of an essential fatty acid deficiency and elevated plasma triene:tetraene ratios (see "n-6:n-3 Polyunsaturated Fatty Acid Ratio")
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From page 440... ...
. The compensatory increase in 22 carbon chain n-6 fatty acids results in maintenance of the total amount of n-6 and n-3 polyunsaturated fatty acids in neural tissue.
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From page 441... ...
cis-Monounsaturated Fatty Acids Monounsaturated fatty acids are a potential fuel source for the body and are a critical structural fatty acid for cell membranes and other functions. Monounsaturated fatty acids undoubtedly are required for many body functions.
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From page 442... ...
Optimal plasma or tissue lipid concentrations of linoleic acid, arachidonic acid, and other n-6 fatty acids or the ratios of certain n-6:n-3 fatty acids have not been established. Because the n-6 fatty acid intake is generally well above the levels needed to maintain a triene:tetraene ratio below 0.2 (even for very low fat diets)
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From page 443... ...
Biochemical changes of n-3 fatty acid deficiency include a decrease in plasma and tissue docosahexaenoic acid (DHA) concentrations.
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From page 444... ...
In these tissues, the phospholipid sn-1 chain is usually a saturated fatty acid (e.g., 16:0) and DHA is found on the sn-2 position.
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From page 445... ...
. The decrease in DHA concentration in the brain and retina is compensated for by an increase in the n-6 fatty acid docosapentaenoic acid, and this leads to maintenance of the total polyunsaturated fatty acid content of the membrane.
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From page 446... ...
. The effect of low n-6:n-3 ratios (high n-3 fatty acids)
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From page 447... ...
They can serve as a source of fuel energy for the body. However, there are no known requirements for trans fatty acids and conjugated linoleic acid for specific body functions.
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From page 448... ...
22:6n-3 (DHA) Jensen et al., n = 20 each group VER 1997 4 mo 18:2n-6 18:3n-3 18:2n-6:18:3n-3 ratio Birch et al., 1998 n = 21 formula Sweep VEP n = 20 formula + acuity DHA 6, 17, 26, 52 wk 18:2n-6 n = 19 formula + 18:3n-3 DHA + AA Visual acuity 20:4n-6 (AA)
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From page 449... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 449 Fatty Acid Content (% of fatty acids) Results Formula Formula + LC-PUFA Infants consuming formula 11.1 10.8 supplemented with LC-PUFA 0.70 0.73 scored significantly higher than -- 0.30 standard formula group -- 0.44 -- 0.30 Formula Formula + LC-PUFA VEP acuity better in infants fed 16.79 17.44 supplemented formula than in 1.58 1.52 infants fed standard formula 0.05 0.27 -- 0.01 0.36 Formula Formula + DHA + AA Infants fed formula supplemented 21.9 21.8 with DHA + AA had higher 2.2 2.0 visual acuity than infants fed -- 0.43 standard formula at 2 mo, but -- 0.10 not at 4, 6, 9, or 12 mo Formula Formula + LC-PUFA No differences in DQ values 11.1 10.8 0.70 0.73 -- 0.30 -- 0.44 -- 0.30 Formula + Formula + No differences in VEP or visual Formula DHA DHA + AA acuity 21.9 20.7 21.7 2.2 1.9 1.9 -- -- 0.43 -- 0.23 0.12 Formula #1 #2 #3 #4 No differences in VER 17.6 17.3 16.5 15.6 Infants fed formula with a ratio of 0.4 0.95 1.7 3.2 4.8 weighed less than infants fed 44.0 18.2 9.7 4.8 formula with a ratio of 44 Formula + Formula + Sweep VEP acuity better in infants Formula DHA DHA + AA fed supplemented formulas than 14.6 15.1 14.9 in infants fed standard formula at 1.49 1.54 1.53 6, 17, and 52 wk, but not 26 wk -- 0.02 0.72 Visual acuity not different between -- 0.35 0.36 groups continued
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From page 450... ...
development 22:6n-3 (DHA) 12, 24 mo aLC-PUFA = long chain polyunsaturated fatty acids.
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From page 451... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 451 Fatty Acid Content (% of fatty acids) Results Formula + Formula + No differences in VEP acuity Formula DHA DHA + GLA 12.01 11.95 12.67 1.20 1.20 1.17 -- -- 0.54 -- 0.06 0.06 -- 0.32 0.32 Formula + Formula + No differences in mental and Formula DHA DHA + AA psychomotor development 21.9 20.7 21.7 Vocabulary production and 2.2 1.9 1.9 comprehension lower in the -- -- 0.43 formula + DHA group -- 0.23 0.12 Formula Formula + LC-PUFA No differences in mental and 12.4 15.9 psychomotor development 1.1 1.4 -- 0.30 -- 0.32 10:1 Formula 5:1 Formula No differences in VEP acuity 16.9 16.6 1.7 3.3 Formula + Formula + No differences in VEP acuity or Formula DHA DHA + AA Bayley scales of mental and 16.8 16.8 16.6 psychomotor development 1.5 1.2 1.0 -- -- 0.34 -- 0.35 0.34 cGLA = -linolenic acid, AA = arachidonic acid, DHA = docosahexaenoic acid.
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From page 452... ...
These results are consistent with epidemiological evidence that show interactions between dietary fat, physical activity, and weight gain (Sherwood et al., 2000)
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From page 453... ...
Consequently, the desirable range of n-6:n-3 fatty acids may differ with life stage. The regulation of n-6 and n-3 fatty acid metabolism is complex as the conversion of linoleic acid to arachidonic acid is inhibited by EPA and
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From page 454... ...
concluded that intake ratios less than 4:1 were likely to result in fatty acid profiles markedly different from those from infants fed human milk. Based on the limited studies, the linoleic acid:-linolenic acid or total n-3:n-6 fatty acids ratios of 5:1 to 10:1, 5:1 to 15:1, and 6:1 to 16:1 have been recommended for infant formulas (Aggett et al., 1991; ISSFAL, 1994; LSRO, 1998)
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From page 455... ...
. Impact of Trans Fatty Acids on n-6 and n-3 Metabolism The trans isomers of oleic acid and linoleic acid, which are present in hydrogenated vegetable oils and meats, have been suggested to have adverse effects on growth and development through inhibition of the desaturation of linoleic acid and -linolenic acid to arachidonic acid and DHA, respectively (Sugano and Ikeda, 1996)
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From page 456... ...
, and on experimental work that shows that inhibition of the 6 desaturation of linoleic acid is not of concern with linoleic acid intakes above about 2 percent of energy (Zevenbergen et al., 1988) , it seems unlikely that inhibition of essential fatty acid metabolism by trans fatty acids is of concern for practical human diets.
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From page 457... ...
, with additional energy and nutrients provided by complementary foods, thus achieving total energy and essential nutrient needs of the infant 7 through 12 months of age. The AI for the older infants is set based on the average intake of fat ingested from human milk and complementary foods (Chapter 1)
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From page 458... ...
458 DIETARY REFERENCE INTAKES TABLE 8-2 Total Fat Content in Term Human Milk of Women in the United States and Canada Study Total Fat Population/ Total Fat Content Total Stage of Content (% of total Energyb Reference Lactationa (g/L) energy)
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From page 459... ...
These data generally conclude that there is no effect of fat intake on growth when consumed at levels as low as 21 percent of energy and provided that the energy intake is adequate (Boulton and Magarey, 1995; Fomon et al., 1976; Lagström et al., 1999; Lapinleimu et al., 1995; Niinikoski et al., 1997a, 1997b; Obarzanek et al., 1997; Shea et al., 1993) (see Chapter 11)
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From page 460... ...
Studies on the essential fatty acid status of older individuals have established that about 2 percent energy from n-6 polyunsaturated fatty acids (linoleic acid) will prevent abnormal elevation of the triene:tetraene ratio (20:3n-9:20:4n-6)
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From page 461... ...
, with additional energy and nutrients provided by complementary foods, thus achieving total energy and essential nutrient needs. The AI for older infants is set based on the average intake of n-6 polyunsaturated fatty acids ingested from human milk and complementary foods (Chapter 1)
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From page 462... ...
462 DIETARY REFERENCE INTAKES TABLE 8-3 n-6 Polyunsaturated Fatty Acid Content in Term Human Milk of Women in the United States and Canada Content in Human Milk % of Total Reference n n-6 Fatty Acid Fatty Acids % of Total Energya Putnam et al., 9 18:2 15.8 ± 0.61 8.62 1982 20:2 0.4 ± 0.03 0.22 20:3 0.4 ± 0.03 0.22 20:4 0.6 ± 0.03 0.33 22:4 0.2 ± 0.02 0.11 22:5 0.1 ± 0.02 0.05 Total 17.50 9.55 Bitman et al., 6 18:2 15.58 ± 1.99 8.50 1983 20:2 0.18 ± 0.20 0.10 20:3 0.53 ± 0.15 0.29 20:4 0.60 ± 0.29 0.33 22:4 0.07 ± 0.16 0.04 22:5 0.03 ± 0.08 0.02 Total 16.99 9.28 Harris et al., 8 18:2 15.3 ± 3.3 8.35 1984 20:3 0.3 ± 0.1 0.16 20:4 0.4 ± 0.1 0.22 Total 16.0 8.73 Finley et al., 172 18:2 16.49 ± 4.80 9.00 1985 20:2 0.38 ± 0.15 0.21 20:3 0.28 ± 0.09 0.15 20:4 0.29 ± 0.08 0.16 Total 17.44 9.52 Innis and 12 18:2 12.7 ± 1.8 6.93 Kuhnlein, 20:2 0.4 ± 0.1 0.22 1988 20:4 0.7 ± 0.0 0.38 22:5 0.2 ± 0.1 0.11 Total 14.0 7.64 Chen et al., 198 18:2 10.47 ± 2.62 5.72 1995a 18:3 0.08 ± 0.06 0.04 20:2 0.17 ± 0.37 0.09 20:3 0.26 ± 0.09 0.14 20:4 0.35 ± 0.11 0.19 22:4 0.04 ± 0.05 0.02 22:5 0.01 ± 0.02 0.01 Total 11.38 6.21
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From page 463... ...
Children and Adolescents Ages 1 Through 18 Years Method Used to Set the AI No specific information is available on the amount of linoleic acid required to correct the symptoms of an n-6 polyunsaturated fatty acid deficiency. In the absence of this information, an AI is set based on the median intake of linoleic acid consumed in the United States where the presence of an n-6 fatty acid deficiency is basically nonexistent in the free-living population (Appendix Table E-9)
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From page 464... ...
In the absence of this information, an AI is set based on the median intake of linoleic acid in the United States where the presence of an n-6 fatty acid deficiency is basically nonexistent in the free-living population (Appendix Table E-9)
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From page 465... ...
There is no evidence that maternal dietary intervention with n-6 fatty acids has any effect on fetal or infant growth and development in women meeting the requirements for n-6 fatty acids. Because of a lack of evidence for determining the requirement during pregnancy, the AI is set based on the median linoleic acid intake of pregnant women in the United States where a deficiency is basically nonexistent in noninstitutionalized populations (Appendix Table E-9)
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From page 466... ...
Numerous studies have shown that infants fed formulas with no DHA have lower plasma and red blood cell DHA concentrations than infants fed human milk or formulas with DHA (Auestad et al., 1997; Carlson et al., 1986, 1996a; Innis et al., 1996; Makrides et al., 1995; Ponder et al., 1992; Putnam et al., 1982)
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From page 467... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 467 TABLE 8-4 n-3 Polyunsaturated Fatty Acid Content in Term Human Milk of Women in the United States and Canada Content in Human Milk % of Total Reference n n-3 Fatty Acid Fatty Acids % of Total Energya Putnam et al., 9 18:3 0.8 ± 0.09 0.44 1982 20:5 0.1 ± 0.03 0.05 22:5 0.1 ± 0.01 0.05 22:6 0.1 ± 0.01 0.05 Total 1.1 0.59 Bitman et al., 6 18:3 1.03 ± 0.21 0.56 1983 20:5 trace trace 22:5 0.11 ± 0.15 0.06 22:6 0.23 ± 0.14 0.13 Total 1.37 0.75 Harris et al., 8 18:3 0.8 ± 0.5 0.44 1984 20:5 trace trace 22:5 trace trace 22:6 0.1 ± 0.1 0.05 Total 0.9 0.49 Finley et al., 172 18:3 1.56 ± 0.43 0.85 1985 22:6 0.06 ± 0.004 0.03 Total 1.62 0.88 Innis and 12 18:3 0.6 ± 0.2 0.33 Kuhnlein, 1988 20:5 0.2 ± 0.2 0.11 22:5 0.4 ± 0.1 0.22 22:6 0.4 ± 0.1 0.22 Total 1.6 0.88 Chen et al., 198 18:3 1.16 ± 0.37 0.63 1995a 20:4 0.06 ± 0.06 0.03 20:5 0.05 ± 0.05 0.03 22:5 0.08 ± 0.06 0.04 22:6 0.14 ± 0.10 0.08 Total 1.49 0.81 Innis and King, 103 18:3 1.4 ± 0.07 0.76 1999 20:5 0.1 ± 0.01 0.05 22:5 0.2 ± 0.02 0.11 22:6 0.2 ± 0.03 0.11 Total 1.9 1.03 aCalculated using the following values: 40 g of fat/L of milk, 8.87 kcal/g of fat, 650 kcal/L of milk.
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From page 468... ...
n-3 Polyunsaturated fatty acids provide DHA that is important for the developing brain and retina. Human milk is assumed to meet the n-3 fatty acid requirements of the infants fed human milk.
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From page 469... ...
Definitive evidence that this is due to the absence of arachidonic acid or explained by antagonism between DHA and n-6 fatty acids is not available. DHA is added to infant formula ingredients in the form of oils from fish oils, egg total lipids, egg phospholipids, and oil from single cell microorganisms.
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From page 470... ...
. EPA and DHA contribute approximately 10 percent of the total n-3 fatty acid intake and therefore this percent contributes toward the AI for -linolenic acid (Appendix Tables E-10, E-12, and E-14)
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From page 471... ...
. Dietary fatty acids are almost completely absorbed, and an increase in blood DHA concentration following the increase in intake with fish oil supplementation is to be expected.
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From page 472... ...
Assuming an intake of n-6 fatty acids of 5 percent energy, with this being mostly linoleic acid, the -linolenic acid intake at a 5:1 ratio would be 1 percent of energy.
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From page 473... ...
INTAKES OF TOTAL FAT AND FATTY ACIDS Total Fat Food Sources Both animal- and plant-derived food products contain fat. The principal foods that contribute to fat intake are butter, margarine, vegetable oils, visible fat on meat and poultry products, whole milk, egg yolks, nuts, and baked goods (e.g., cookies, doughnuts, and cakes)
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From page 474... ...
Monounsaturated fatty acids provide approximately 20 percent of energy in human milk (Table 8-6)
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From page 475... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 475 TABLE 8-5 Saturated Fatty Acid Content in Term Human Milk of Women in the United States and Canada Content in Human Milk Saturated % of Total Reference n Fatty Acid Fatty Acids % of Total Energya Putnam et al., 9 8:0 0.3 0.16 1982 10:0 1.4 0.76 12:0 6.2 3.38 14:0 7.6 4.15 16:0 20.5 ± 0.70 11.19 18:0 9.0 ± 0.46 4.91 20:0 0.3 ± 0.02 0.16 21:0 0.1 ± 0.02 0.05 24:0 0.5 ± 0.01 0.27 Total 45.9 25.03 Bitman et al., 6 10:0 0.97 ± 0.28 0.53 1983 12:0 4.46 ± 1.17 2.43 14:0 5.68 ± 1.36 3.10 15:0 0.31 ± 0.07 0.17 16:0 22.20 ± 2.28 12.12 17:0 0.49 ± 0.36 0.27 18:0 7.68 ± 1.85 4.19 20:0 0.32 ± 0.11 0.17 21:0 0.17 ± 0.12 0.09 Total 42.28 23.07 Harris et al., 8 10:0 trace trace 1984 12:0 4.2 ± 1.3 2.29 14:0 5.9 ± 0.7 3.22 16:0 22.8 ± 1.6 12.45 18:0 8.2 ± 1.2 4.48 Total 41.1 22.44 Finley et al., 172 8:0 0.16 ± 0.11 0.09 1985 10:0 1.10 ± 0.30 0.60 12:0 5.56 ± 1.68 3.03 14:0 8.01 ± 2.46 4.37 16:0 23.28 ± 3.35 12.71 18:0 8.06 ± 1.58 4.40 Total 46.17 25.20 Innis and 12 10:0 1.2 ± 0.2 0.66 Kuhnlein, 12:0 5.2 ± 0.7 2.84 1988 14:0 6.7 ± 0.5 3.66 16:0 22.1 ± 2.7 12.06 18:0 8.2 ± 0.8 4.48 Total 43.4 23.70 continued
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From page 476... ...
Certain oils, such as blackcurrant seed oil and evening primrose oil, are high in -linolenic acid (18:3n-6) , which is an intermediate in the conversion of linoleic acid to arachidonic acid.
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From page 477... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 477 TABLE 8-6 Monounsaturated Fatty Acid Content in Term Human Milk of Women in the United States and Canada Content in Human Milk Monounsaturated % of Total Reference n Fatty Acid Fatty Acids % of Total Energya Putnam et al., 9 18:1 37.6 ± 0.75 20.52 1982 20:1 0.9 ± 0.07 0.49 22:1 0.1 ± 0.02 0.05 Total 38.6 21.06 Bitman et al., 6 16:1 3.83 ± 0.39 2.09 1983 18:1 35.51 ± 2.73 19.38 Total 39.34 21.47 Harris et al., 8 16:1 2.5 ± 0.6 1.36 1984 18:1 32.6 ± 3.3 17.79 20:1 0.5 ± 0.1 0.27 Total 35.6 19.42 Finley et al., 172 16:1 3.02 ± 0.77 1.65 1985 18:1 31.72 ± 3.81 17.31 Total 34.74 18.96 Innis and 12 16:1 3.3 ± 0.6 1.80 Kuhnlein, 18:1 36.3 ± 2.7 19.81 1988 20:1 0.7 ± 0.3 0.38 22:1 0.2 ± 0.1 0.11 Total 40.5 22.10 Chen et al., 198 14:1 0.28 ± 0.08 0.15 1995a 16:1 2.68 ± 0.69 1.46 17:1 0.21 ± 0.06 0.11 18:1 36.09 ± 3.51 19.70 20:1 0.53 ± 0.22 0.29 22:1 0.02 ± 0.03 0.01 Total 39.81 21.72 Innis and King, 103 14:1 0.2 ± 0.01 0.11 1999 16:1 2.5 ± 0.08 1.36 18:1 35.7 ± 0.41 19.49 20:1 0.6 ± 0.05 0.33 22:1 0.2 ± 0.02 0.11 24:1 0.1 ± 0.01 0.05 Total 39.3 21.45 aCalculated using the following values: 40 g of fat/L of milk, 8.87 kcal/g of fat, 650 kcal/L of milk.
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From page 478... ...
n-6 polyunsaturated fatty acids are consumed in the form of linoleic acid. Other n-6 polyunsaturated fatty acids, such as arachidonic acid and -linolenic acid, are present in small amounts in the diet.
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From page 479... ...
More recent data from food frequency questionnaires collected in the United States suggest average trans fatty acid intakes of 1.5 to 2.2 percent of energy (Ascherio et al., 1994; Hu et al., 1997) , or 5.2 percent of total dietary fat (Lemaitre et al., 1998)
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From page 480... ...
. Most recently, trans fatty acid intake was estimated from existing CFSII data (Allison et al., 1999)
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From page 481... ...
. Saturated Fatty Acids Hazard Identification Elevated LDL Cholesterol Concentration and Risk of CHD.
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From page 482... ...
FIGURE 8-3 Calculated changes in serum low density lipoprotein cholesterol concentration in response to percent change in dietary saturated fatty acids. Three regression equations were used to establish the response curves.
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From page 483... ...
. Similar to that observed for saturated fatty acid intake and LDL cholesterol concentration, there is a positive linear relationship between serum total and LDL cholesterol concentrations and risk of coronary heart disease (CHD)
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From page 484... ...
A number of studies have attempted to ascertain the relationship between saturated fatty acid intake and body mass index, and these results are mixed. Saturated fatty acid intake was shown to be positively associated with body mass index or percent of body fat (Doucet et al., 1998; Gazzaniga and Burns, 1993; Larson et al., 1996; Ward et al., 1994)
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From page 485... ...
reported no difference in insulin secretion or sensitivity in men who consumed a 33 percent saturated, monounsaturated, or polyunsaturated fatty acid diet. There was no difference in postprandial glucose or insulin concentration when healthy adults were fed butter or olive oil (Thomsen et al., 1999)
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From page 486... ...
n-9 Monounsaturated fatty acid intake may result in an increase in energy intake from saturated fatty acids due to the simultaneous occurrence of saturated and n-9 monounsaturated fatty acids in animal fats. The n-7 monounsaturated fatty acid, palmitoleic acid, behaves like saturated fatty acids in raising LDL cholesterol concentration (Nestel et al., 1994)
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From page 487... ...
Numerous studies have shown suppression of various aspects of human immune function in vitro or ex vivo in peripheral blood mononuclear cells, or in isolated neutrophils or monocytes in individuals provided n-3 polyunsaturated fatty acids as a supplement or as an experimental diet compared with baseline values before the intervention (Table 8-8)
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From page 488... ...
Fish oil (2 g EPA, 1 g DHA) 8 men 7 wk Thompson et al., 1991 6 men, 6 women MaxEPA (2.16 g EPA)
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From page 489... ...
, TNF and IL-2 (older women only) Depressed PBMC proliferation, IL-1 in PBMCs and monocytes with n-3 fatty acids PBMC secretion of IL-1, TNF-, PGE2 or LTB4 not affected by n-3 fatty acids Depressed neutrophil chemiluminescence (marker of neutrophil function)
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From page 490... ...
3 other groups of 8 fed other oils, but all comparable to placebo 12-wk parallel aEPA = eicosapentaenoic acid, DHA = docosahexaenoic acid. bLTB4 = leukotriene B4, 5-HETE = 5-hydroxyeicosatetraenoic acid, PBMC = peripheral blood mononuclear cell, IL = interleukin, TNF = tumor necrosis factor, PGE2 = prosta In studies using multitreatment parallel designs, potential adverse effects of n-3 fatty acids on immune function that were observed include decreased expression of monocyte major histocompatibility complex antigens and cell surface adhesion proteins (Hughes et al., 1996)
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From page 491... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 491 Resultsb Depressed PBMC IL-1, TNF-, IL-2 and IFN-, PGE2, and LTB4, serum-soluble IL-2 receptors Depressed PBMC TNF-, IL-1, TxB2, and PGE2 with flaxseed oil-enriched diet Greater decreases in PBMC TNF-, IL-1, and TxB2 in both groups after fish-oil supplementation Depressed monocyte surface proteins: HLA-DR, HLA-DP, HLA-DQ, ICAM-1, LFA-1 No effect on whole blood IL-1, TNF-, or IL-1 receptor antagonist Decreased white blood cells PBMC proliferation and delayed-type hypersensitivity not different between groups Depressed PBMC IL-1 and TNF- production, in vitro PBMC PGE2 and LTB4 secretion No effect of fish oil on PBMC NK cell activity, proliferation, types of blood lymphocytes, IL-1, IL-1, TNF-, IL-2, IL-10, and IFN glandin E2, NK cell = natural killer cell, IFN- = interferon-, TxB2 = thromboxane B2, HLA = human leukocytes antigen, ICAM = intercellular adhesion molecule, LFA = leukocyte function-associated antigen. PBMCs and monocytes (Mølvig et al., 1991)
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From page 492... ...
Bleeding and Increased Risk of Hemorrhagic Stroke. One of a number of factors that has been suggested to link n-3 polyunsaturated fatty acid intake with reduced risk of CHD is reduced platelet aggregation, and therefore prolonged bleeding time.
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From page 493... ...
Oxidative Damage. Long-chain polyunsaturated fatty acids, particularly DHA and EPA, are vulnerable to lipid peroxidation, resulting in oxidative damage of various tissues.
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From page 494... ...
Special Considerations A few special populations have been reported to exhibit adverse effects from consuming n-3 polyunsaturated fatty acids. Despite the favorable effects of n-3 fatty acids on glucose homeostasis, caution has been suggested for the use of n-3 fatty acids in those individuals who already exhibit glucose intolerance or diabetic conditions (Glauber et al., 1988; Kasim et al., 1988)
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From page 495... ...
The relative effect of trans fatty acids in meat and dairy products on LDL cholesterol concentration would be small compared to hydrogenated oils because of the lower levels that are present, and because any rise in concentration would most likely be due to the abundance of saturated fatty acids. HDL Cholesterol Concentrations.
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From page 496... ...
bLDL-C = low density lipoprotein cholesterol, HDL-C = high density lipoprotein cholesterol, Lp(a) = lipoprotein(a)
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From page 497... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 497 Blood Lipid Concentrationsb TFA LDL-C HDL-C Lp(a) (% of energy)
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From page 498... ...
. The preponderance of the data suggests that hydrogenated fat/trans fatty acids, relative to saturated fatty acids, result in lower HDL cholesterol concentrations (Ascherio et al., 1999; Zock and Mensink, 1996; Zock et al., 1995)
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From page 499... ...
concentrations that are significantly different between treatment groups have a different superscript. differential effects of hydrogenated fat/trans fatty acids on LDL and HDL cholesterol concentrations, concern has been raised regarding their effect on the total cholesterol or LDL cholesterol:HDL cholesterol ratio (Ascherio et al., 1999)
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From page 500... ...
500 DIETARY REFERENCE INTAKES TABLE 8-11 Dietary Trans Fatty Acids (TFA) , Hydrogenated Fat, and Blood Lipid Concentrations: Free-Living Trials Reference Study Population Dieta Nestel et al., 26 mildly 4-wk crossover, 42% fat 1992a hypercholesterolemic Control 1 men, 2757 y Control 2 Blend 1 Blend 2 Nestel et al., 27 mildly 3-wk crossover, 3637% 1992b hypercholesterolemic fat men, 3063 y Control 18:1 TFA 16:0 Seppänen- 57 men and women, 12-wk crossover to 1 of 2 Laakso et al., middle-aged diets, 3943% fat 1993 Margarine Rapeseed Olive oil Wood et al., 38 healthy men, 3060 y 6-wk crossover, 38% fat 1993a Butter Butter-sunflower Butter-olive Hard margarine Soft margarine Wood et al., 29 healthy men, 3060 y 6-wk crossover, 37% fat 1993b Butter Crude palm Margarine Refined palm Refined palm+sunflower Sunflower oil Chisholm 49 hypercholesterolemic 6-wk crossover, 2627% et al., 1996 men and women, fat avg 47 y Butter Margarine
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From page 501... ...
DIETARY FATS: TOTAL FAT AND FATTY ACIDS 501 Blood Lipid Concentrationsc TFA (% of LDL-C HDL-C Lp(a) energy)
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From page 502... ...
Solid line represents the best-fit regression for trans fatty acids. Dotted line represents the best-fit regression for saturated fatty acids.
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From page 503... ...
concentrations reported to date that is associated with trans fatty acid intake for the most part would not be predicted to have a physiologically significant effect on cardiovascular disease risk. How ever, an unresolved issue at this time is the potential effect of relatively high levels of trans fatty acids in individuals with initially high concentra tions of Lp(a)
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From page 504... ...
CHD. Similar to saturated fatty acids, there is a positive linear trend between trans fatty acid intake and LDL cholesterol concentrations (Judd et al., 1994; Lichtenstein et al., 1999; Zock and Katan, 1992)
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From page 505... ...
It is possible to consume a diet low in trans fatty acids by following the dietary guidance provided in Chapter 11. RESEARCH RECOMMENDATIONS Total Fat · Studies are needed that examine the effects of alterations in the level of total fat in the context of a low saturated fatty acid diet on blood lipid concentrations and glucose-insulin homeostasis in individuals with defined metabolic syndromes, such as type 1 and type 2 diabetes.
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From page 506... ...
Oxidation, and Blood Pressure Study TFA (% of Reference Population Dieta energy) Clotting Wood et al., 29 men, 6-wk crossover, 1993b 3060 y 37% fat Butter 0.2 Crude palm oil 0 Margarine 3.0 Refined palm oil 0 Refined palm+sunflower 0 Sunflower oil 0 Almendingen 31 men, 3-wk crossover, et al., 1996 avg 27 y 3336% fat PHSO 8.5 PHFO 8.0 Butter 0.9 Mutanen and 80 men and 5-wk crossover to Aro, 1997 women, 1 of 2 diets, 2052 y 3334% fat High 18:0 0.4 High TFA 8.7 Turpeinen et al., 80 men and 5-wk crossover to 1998 women, 1 of 2 diets, 2052 y 3234% fat 18:0 0.4 TFA 8.7 Sanders et al., 16 men and 1 test-meal crossover, 2000 women, 7% or 65% fat 1832 y 18:1 0.1 18:1 trans 24.7 18:0 0 16:0 0.2 MCT 0 Low fat 0 Oxidation Cuchel et al., 14 men 32-d crossover, 1996 and women, 30% fat 4478 y Corn oil 0.44 Corn oil+margarine 4.16
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From page 507... ...
plasminogen activity, or PAI-1 activity 3.62 3.61 No difference in TxB2 production or ADP induced platelet aggregation in vitro Significant increase in collagen-induced aggregation with 18:0 diet FVIIc FVIIa No significant differences in factor VII (% standard)
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From page 508... ...
across a range of n-6 polyunsaturated fatty acid intakes. · Using good biomarkers for low density lipoprotein oxidation and cancer susceptibility, assessments are needed of the potential adverse effects of diets at levels of n-6 polyunsaturated fatty acids greater than 10 percent of energy.
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From page 509... ...
· Further research is needed to address the potentially important relationships between the amount of n-3 and n-6 fatty acids and glucose tolerance suggested by studies of fatty acid composition in affected individuals. n-3 Polyunsaturated Fatty Acids · Randomized clinical trials are needed of EPA+DHA, EPA, and DHA to evaluate their impact on cancer (i.e., colon, breast, prostate)
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From page 510... ...
Hudgins et al., 76 men, 2378 y No dietary intake 1991 Cross-sectional information Troisi et al., 748 men, 4385 y Food frequency 1992 Cross-sectional questionnaire, multivariate analysis Willett et al., Women, 431 Food frequency 1993 CHD cases questionnaire, Cohort, 8-y multivariate follow-up analysis Ascherio et al., 239 MI cases Food frequency 1994 282 controls questionnaire, Case-control multivariate analysis Kromhout et al., 12,763 men, Weighed food 1995 4059 y record Cohort, 25-y follow-up Ascherio et al., 43,757 men, Food frequency 1996 4075 y questionnaire, Cohort, 6-y multivariate follow-up analysis
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From page 511... ...
1.78 0.97 Total TFA in adipose tissue was 4.4% Total TFA content in adipose tissue was not of total fatty acids significantly related to risk factors of CHD (e.g., age, BMI, LDL, cholesterol, blood pressure) TFA intake was directly related to total An increased TFA intake from 2.1 to 4.9 g/d (r = 0.07, P = 0.04)
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From page 512... ...
512 DIETARY REFERENCE INTAKES TABLE 8-13 Continued Dietary and Other Reference Study Designa Information Gillman et al., Men, 4564 y 24-h recall, 1997 267 CHD cases multivariate Cohort, 21-y analysis follow-up Hu et al., 1997 Women, 3459 y Food frequency 939 MI cases questionnaire, Cohort, 14-y multivariate follow-up analysis Pietinen et al., Smoking men, Food frequency 1997 5069 y questionnaire, 1,399 coronary multivariate events analysis 635 coronary deaths Cohort, 6.1-y follow-up Tavani et al., Women, 1874 y Questionnaire on 1997 429 MI cases selected indicator 866 controls foods, Case-control multivariate analysis Cancer Kohlmeier et al., Women, 5074 y No diet 1997 291 breast cancer information cases 407 controls Case-control
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From page 513... ...
death 1.0 1.00 1.7 1.05 2.0 1.12 2.7 0.90 6.2 1.39 Margarine The association with margarine could intakes RR of MI explain about 6% of MI in this population No or low 1.0 Medium or high 1.5 Adipose TFA OR of breast Risk for breast cancer is based on concentration cancer the relative concentration of TFA and PUFA TFA 1.46 TFA within 3.65 lowest PUFA tertile TFA within highest PUFA tertile 0.97 continued
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From page 514... ...
· An assessment of major sources of trans fatty acids currently in the marketplace is needed, along with development of alternatives similar to that done for foods high in saturated fatty acids. · Studies that distinguish trans fatty acid isomers from plants and animals with respect to the relative impact on blood lipid and lipoprotein concentrations are needed.
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From page 515... ...
1995. Neurodevelopment quotient of healthy term infants at 4 months and feeding practice: The role of long-chain polyunsaturated fatty acids.
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From page 516... ...
1997. Visual acuity, eryth rocyte fatty acid composition, and growth in term infants fed formulas with long chain polyunsaturated fatty acids for one year.
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From page 517... ...
2000. A randomized con trolled trial of early dietary supply of long-chain polyunsaturated fatty acids and mental development in term infants.
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From page 518... ...
1974. The oxidative desaturation of unsaturated fatty acids in ani mals.
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From page 519... ...
1995a. Trans fatty acid isomers in Canadian human milk.
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From page 520... ...
fatty acid status and alters selected risk factors for heart disease in vegetarian subjects.
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From page 521... ...
1995. Do trans fatty acids impair linoleic acid metabolism in children?
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From page 522... ...
1996. No effect of short-term dietary supplementation of saturated and poly- and monounsaturated fatty acids on insulin secretion and sensitivity in healthy men.
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From page 523... ...
1995. Cytokine secretion and eicosanoid production in the peripheral blood mononuclear cells of MS patients under going dietary supplementation with n-3 polyunsaturated fatty acids.
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From page 524... ...
1978. Essential fatty acid deficiency in total parenteral nutrition: Time course of development and suggestions for therapy.
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From page 525... ...
1992. Effect of fish oil on the fatty acid composition of human milk and maternal and infant erythrocytes.
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From page 526... ...
1999. Variability in the trans fatty acid content of foods within a food category: Implications for estimation of dietary trans fatty acid intakes.
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From page 527... ...
1994. Dietary trans fatty acids: Effects on plasma lipids and lipoproteins of healthy men and women.
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From page 528... ...
1990. Dietary n-3 polyunsaturated fatty acids and amelioration of cardiovascular disease: Possible mechanisms.
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From page 529... ...
1995. Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: The Seven Countries Study.
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From page 530... ...
2000b. A critical appraisal of the role of dietary long-chain polyunsaturated fatty acids on neural indices of term infants: A randomized controlled trial.
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From page 531... ...
1991. Dietary supple mentation with -3-polyunsaturated fatty acids decreases mononuclear cell proliferation and interleukin-1 content but not monokine secretion in healthy and insulin-dependent diabetic individuals.
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From page 532... ...
1997. Coagulation and fibrinolysis factors in healthy subjects consuming high stearic or trans fatty acid diets.
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From page 533... ...
1993. Relationship of dietary saturated fatty acids and body habitus to serum insulin concentrations: The Normative Aging Study.
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From page 534... ...
1998. Fatty acid desaturase activities and polyunsaturated fatty acid composi tion in human fetal liver between the seventeenth and thirty-sixth gestational weeks.
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From page 535... ...
1990. Doseresponse studies on the effect of n-3 polyunsaturated fatty acids on lipids and haemostasis.
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From page 536... ...
1998. Formula supplementation with long-chain polyunsaturated fatty acids: Are there developmental benefits?
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From page 537... ...
1995. Reevaluation of the pathways for the biosynthesis of polyunsaturated fatty acids.
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From page 538... ...
2000a. Long chain polyunsaturated fatty acid formation in neonates: Effect of gestational age and intrauterine growth.
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From page 539... ...
1998. Divergent incorporation of dietary trans fatty acids in different serum lipid fractions.
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From page 540... ...
1993a. Effect of butter, mono and polyunsaturated fatty acid-enriched butter, trans fatty acid margarine, and zero trans fatty acid margarine on serum lipids and lipoproteins in healthy men.
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From page 541... ...
1993. Effects of stearic acid and trans fatty acids versus linoleic acid on blood pressure in normotensive women and men.
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Key Terms
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