Omega-3 Fatty Acid Compositionof Habitual Diets

in Australia

Melbourne Australia

Neil J MannDepartment of Food Science

BackgroundBackground

Generally agreed amongst lipid researchers that the western diet has:

High n-6 : n-3 PUFA intake

Low total n-3 PUFA intake

This leads to an over emphasis of arachidonic acid (20:4 n-6) derived eicosanoids (TXA2 PGE2 LTB4 etc) with subsequent increased risk of vascular disease and inflammatory conditions.

Recommended dietary intakes for n-6 Recommended dietary intakes for n-6 and n-3 PUFAand n-3 PUFA

Workshop on the essentiality of / and recommended dietary intakes forn-6 and n-3 fatty acids. (NIH Bethesda Maryland USA, April 1999).

Fatty acid Grams/day % Energy (2000 kcal diet)

Linoleic acid 4.44 2.0(Upper limit) 6.67 3.0

-linolenic acid 2.22 1.0EPA (min) 0.22 0.1DHA (min) 0.22 0.1EPA + DHA 0.65 0.3

Adequate intakes (AI) for adults

Determination of n-3 PUFA intakeDetermination of n-3 PUFA intake

To make public health recommendations we need to know what amounts of fatty acids are being consumed by different dietary groups.

In many tables of fatty acid content of foods, information is reported as g fatty acid/100g food (to one decimal place).

Except in certain foods, such as fish, LC PUFA are present in only trace amounts.

Most fatty acid databases cannot be used to estimate long chain PUFA intake (AA EPA DHA etc).

Because the trace levels disappear ! But these small (ignored) contributions can accumulate to significant levels of

biological importance in the context of a total diet.

Due to the low levels of LC PUFA present in foods, composition Due to the low levels of LC PUFA present in foods, composition tables can round them down to zero when reported to a single tables can round them down to zero when reported to a single decimal place (g/100g food).decimal place (g/100g food).

For example 100g lamb chops contain:For example 100g lamb chops contain:

(130mg LA, 52mg AA, 44mg EPA, 36mg DPA and 10mg DHA)(130mg LA, 52mg AA, 44mg EPA, 36mg DPA and 10mg DHA)

This would appear in a composition table as shown:This would appear in a composition table as shown:

18:2 n-618:2 n-6

(LA)(LA)

20:4 n-620:4 n-6

(AA)(AA)

20:5 n-320:5 n-3

(EPA)(EPA)

22:5 n-322:5 n-3

(DPA)(DPA)

22:6 n-322:6 n-3

(DHA)(DHA)

0.10.1 0.10.1 0.00.0 0.00.0 0.00.0

Determination of n-3 PUFA intake (contd)Determination of n-3 PUFA intake (contd)

AimsAims

1.1. Create a fatty acid database of current food supply to Create a fatty acid database of current food supply to two decimal places in g/100gtwo decimal places in g/100g

2.2. Determine the consumption level of fatty acids in Determine the consumption level of fatty acids in specific dietary groupsspecific dietary groups

3.3. Investigate the main dietary sources of LC n-3 PUFA Investigate the main dietary sources of LC n-3 PUFA in the dietsin the diets

The database consists of 1077 foods with full fatty acid analysis (at present)

The reported analytical data contains 11 sat fatty acids, 7 MUFA, 10 PUFA (6 n-6, 4 n-3) and 3 trans fatty acids

The database concentrates on foods with greater than 1% total fat by weight

1. The fatty acid database

2. The dietary study

Healthy male subjects were recruited from 4 habitual diet groups.Healthy male subjects were recruited from 4 habitual diet groups.

Vegan:Vegan: Consumed plant foods only.Consumed plant foods only. n=18n=18

Ovolacto vegetarian:Ovolacto vegetarian: Consumed eggs and dairy products Consumed eggs and dairy products

and plant foods.and plant foods.

n=42n=42

High meat eater:High meat eater: Consumed Consumed >> 280 g meat/day. 280 g meat/day. n=17n=17

Moderate meat eater:Moderate meat eater: Consumed 50-260g meat/day. Consumed 50-260g meat/day. n=54n=54

2. The dietary study

Characteristics of subjects in the dietary groups (mean Characteristics of subjects in the dietary groups (mean ++ s.d) s.d)

High meatHigh meat Moderate Moderate

meatmeat

OvolactoOvolacto

vegetarianvegetarian

VeganVegan

Age (y)Age (y) 34.2 34.2 ++ 9.4 9.4abab 38.3 38.3 ++ 7.3 7.3aa 34.9 34.9 ++ 9.0 9.0bb 33.0 33.0 ++ 7.7 7.7bb

BMIBMI 27.0 27.0 ++ 3.4 3.4aa 26.4 26.4 ++ 3.4 3.4aa 23.6 23.6 ++ 2.8 2.8bb 23.3 23.3 ++ 3.5 3.5bb

Waist/Hip Waist/Hip ratioratio

0.88 0.88 ++ 0.06 0.06abab 0.88 0.88 ++ 0.05 0.05aa 0.86 0.86 ++ 0.04 0.04bb 0.85 0.85 ++ 0.05 0.05bb

Values on the same line with different superscripts are significantly different at (p<0.05).

2. The dietary study

Daily intake of selected items by the 4 dietary groups (mean Daily intake of selected items by the 4 dietary groups (mean ++ s.d) s.d)

High meatHigh meat Moderate Moderate meatmeat

OvolactoOvolacto VegansVegans

White meat (g)White meat (g) 109.6 109.6 ++ 51.6 51.6aa 53.7 53.7 ++ 27.1 27.1bb 0.2 0.2 ++ 0.7 0.7cc 0.00 0.00 ++ 0.00 0.00cc

Red meat (g)Red meat (g) 270.4 270.4 ++ 118.0 118.0aa 108.9 108.9 ++ 41.1 41.1bb 0.00 0.00 ++ 0.00 0.00cc 0.00 0.00 ++ 0.00 0.00cc

Fish (g)Fish (g) 27.7 27.7 ++ 23.9 23.9aa 26.1 26.1 ++ 18.3 18.3aa 1.4 1.4 ++ 3.4 3.4bb 0.7 0.7 ++ 1.8 1.8bb

Energy (MJ)Energy (MJ) 1.67 1.67 ++ 3.31 3.31aa 1.13 1.13 ++ 2.48 2.48bb 1.15 1.15 ++ 2.46 2.46bb 1.18 1.18 ++ 2.44 2.44bb

Protein (% E)Protein (% E) 19.4 19.4 ++ 1.3 1.3aa 17.9 17.9 ++ 2.2 2.2bb 14.7 14.7 ++ 2.2 2.2cc 14.1 14.1 ++ 2.4 2.4cc

Carbo (% E)Carbo (% E) 40.3 40.3 ++ 4.4 4.4aa 45.7 45.7 ++ 6.8 6.8bb 50.9 50.9 ++ 6.4 6.4cc 57.4 57.4 ++ 5.4 5.4dd

Total fat (% E)Total fat (% E) 37.8 37.8 ++ 4.2 4.2aa 32.8 32.8 ++ 6.1 6.1bb 32.7 32.7 ++ 6.2 6.2bb 28.2 28.2 ++ 4.3 4.3cc

2. The dietary study

LC fatty acid intake (mg/day) for the 4 habitual diet groups.LC fatty acid intake (mg/day) for the 4 habitual diet groups.

GroupGroup 20:4n-6 20:4n-6

(AA)(AA)

20:5n-320:5n-3

(EPA)(EPA)

22:5n-322:5n-3

(DPA)(DPA)

22:6n-322:6n-3

(DHA)(DHA)

Total Total LC LC n-3n-3

High meatHigh meat 240240aa 7070aa 9090aa 120120aa 290290a a

Moderate Moderate meatmeat

100100bb 4040bb 3030bb 7070aa 140140b b

OvolactoOvolacto 3030cc 00cc 00cc 1010bb 1010cc

VegansVegans 00dd 00cc 00cc 00cc 00cc

2. The dietary study

Combining the two meat eating groups into one “omnivore Combining the two meat eating groups into one “omnivore group” we see the following mean daily intake patterns:group” we see the following mean daily intake patterns:

GroupGroup 18:2n-6 18:2n-6 18:3n-318:3n-3 LC n-3LC n-3 n-6:n-3n-6:n-3

Omnivores (n=71)Omnivores (n=71) 14.2 g 14.2 g 1.5 g1.5 g 190 mg190 mg 9.5 : 1 9.5 : 1

Ovolacto (n=42)Ovolacto (n=42) 18.4 g 18.4 g 1.4 g1.4 g 10 mg 10 mg 12.9 : 112.9 : 1

Vegan (n=18)Vegan (n=18) 21.6 g 21.6 g 1.2 g1.2 g 0 mg 0 mg 18.7 : 118.7 : 1

Recommended < 6.7 g > 2.2 g > 650 mg

2. The dietary study

The results for omnivores closely approximate those The results for omnivores closely approximate those reported in an evaluation of the Australian population reported in an evaluation of the Australian population based on the National Nutrition Survey (1995) and use based on the National Nutrition Survey (1995) and use of this fatty acid database. of this fatty acid database.

(Meyer, Mann, Howe, Lewis & Sinclair. Lipids 38[4], 2003)(Meyer, Mann, Howe, Lewis & Sinclair. Lipids 38[4], 2003)

Australian adult mean daily intakes

Total n-6 Total n-3 n-6 : n-3 LC n-6 LC n-3

11.3 g 1.4 g 8.1 : 1 100 mg 188 mg

2. The dietary study

USA n-6 : n-3 intake ratio approximately USA n-6 : n-3 intake ratio approximately 11 : 111 : 1(Production and consumption data; Hunter, Am J Clin Nutr, 1990)(Production and consumption data; Hunter, Am J Clin Nutr, 1990)

““Natural” human diets as represented by modeling of Natural” human diets as represented by modeling of paleolithic diets and current hunter-gatherers give very paleolithic diets and current hunter-gatherers give very different results:different results:

18:2 n-6 18:3 n-3 18:2 : 18:3 LC n-6 LC n-3 n-6 : n-3

8.8 g 12.6 g 0.7 : 1 1.8 g 1.1 g 0.9 : 1

(Eaton, Eaton, Mann, Cordain, Sinclair, World Rev Nutr Diet, 83, 1998)

2. The dietary study

Plasma PL fatty acid concentrations (mg/100ml)Plasma PL fatty acid concentrations (mg/100ml)

18:218:2 18:318:3 20:420:4 20:520:5 22:522:5 22:622:6 TotalTotal n6:n3n6:n3 n-6n-6 n-3 n-3 n-6 n-6 n-3 n-3 n-3 n-3 n-3 n-3 LC n-3LC n-3

H. MeatH. Meat 24.524.5 0.30.3 12.912.9a 1.41.4a 1.51.5a 3.93.9a 6.96.9a 6.0:16.0:1a

M. MeatM. Meat 26.926.9 0.20.2 12.712.7a 1.21.2a 1.51.5a 3.93.9a 6.66.6a 6.5:16.5:1a

OvolactoOvolacto 27.027.0 0.30.3 9.89.8b 0.70.7b 1.11.1b 2.22.2b 4.04.0b 9.6:19.6:1b

VeganVegan 25.425.4 0.30.3 10.110.1b 0.60.6b 1.11.1b 2.02.0b 3.73.7b 9.9:19.9:1b

2. The dietary study

Correlation of dietary intake of fatty acids and plasma statusCorrelation of dietary intake of fatty acids and plasma status

Significant correlationSignificant correlation No correlationNo correlation

18:018:0 18:2 n-618:2 n-618:118:1 18:3 n-318:3 n-320:4 n-620:4 n-620:5 n-320:5 n-322:5 n-322:5 n-3 18:2 n-6 with 20:4 n-618:2 n-6 with 20:4 n-622:6 n-322:6 n-3 18:3 n-3 with 20:5 n-318:3 n-3 with 20:5 n-3

3. Dietary sources of LC n-3 PUFA

Australians are Australians are notnot big fish eaters (approx 26 g/day). big fish eaters (approx 26 g/day). Australians are moderate to high red meat eaters Australians are moderate to high red meat eaters

(approx 170 g/day).(approx 170 g/day). Australian sheep / cattle are almost entirely pasture Australian sheep / cattle are almost entirely pasture

fed, hence accumulate 18:3 n-3 from grass and fed, hence accumulate 18:3 n-3 from grass and produce appreciable levels of EPA and DPA.produce appreciable levels of EPA and DPA.

Grain fed animals tend to accumulate 18:2 n-6 and Grain fed animals tend to accumulate 18:2 n-6 and and have very low levels of LC n-3 PUFA. and have very low levels of LC n-3 PUFA.

3. Dietary sources of LC n-3 PUFA

Selected fatty acid levels in beef rump (mg/100g lean meat)Selected fatty acid levels in beef rump (mg/100g lean meat)

TotalTotal 18:218:2 18:3 18:3 20:5 20:5 22:5 22:5 22:6 22:6 fatfat n-6 n-6 n-3 n-3 n-3 n-3 n-3 n-3 n-3 n-3

Grass fedGrass fed 2800 2800a 190 190 a 49 49 a 40 40 a 58 58 a 7.7 7.7Grain fed*Grain fed* 4800 4800 b 255255 b 21 21 b 21 21 b 48 48 b 6.5 6.5

USDAUSDA 4900 4900 200200 17 17 0 0 0 0 0 0

* Pasture then 200 days grain fed* Pasture then 200 days grain feda,b data in columns with differing superscripts significantly different (p<0.05) data in columns with differing superscripts significantly different (p<0.05)

Concluding CommentsConcluding Comments

A comprehensive, accurate fatty acid composition database is A comprehensive, accurate fatty acid composition database is needed to assess dietary LC n-3 intake.needed to assess dietary LC n-3 intake.

Non-meat/fish eaters consume virtually no LC n-3 PUFANon-meat/fish eaters consume virtually no LC n-3 PUFA

Omnivores are consuming 190 mg LC n-3 PUFA per dayOmnivores are consuming 190 mg LC n-3 PUFA per day

This is well below the recommended 650 mg/dayThis is well below the recommended 650 mg/day

Omnivores have higher plasma PL n-3 PUFA levels than Omnivores have higher plasma PL n-3 PUFA levels than vegetarians and a lower n-6 : n-3 plasma ratiovegetarians and a lower n-6 : n-3 plasma ratio

Red meat from pasture fed animals is a major contributor to Red meat from pasture fed animals is a major contributor to LC n-3 PUFA intake in AustraliaLC n-3 PUFA intake in Australia