**2.2 Dietary sources of fatty acids**

The n-3 EFA, ALA is found in the highest quantity in linseed oil, and considerable amounts are found in hempseed oil (20%) as well (Erasmus, 1993); however, from the dietary point of view its most important sources are walnut and rapeseed oils (Beare-Rogers et al., 2001). The n-6 EFA, LA can be found in the highest proportion in primrose (81%; Erasmus, 1993) and grapeseed oils, but its most important dietary sources are sunflower, corn and pumpkin seed oils (Table 1; Beare-Rogers et al., 2001). Compared to vegetable sources, animal lipid sources contain smaller quantities of ALA and LA (Table 2).

Flesh of herbivorous animals is very rich in the most important n-6 metabolite, AA (Table 2). On the other hand, haslets of terrestrial animals, like liver and kidney contains DHA also in relative high concentrations.

The most important n-3 LCPUFAs, EPA and DHA can be found in fatty sea fishes (Table 3). The DHA content of sea fishes may vary according to season, area of catching and to age and gender of the fish (Racine & Deckelbaum, 2007). Marine fish contains higher levels of n-3 PUFAs, EPA and DHA, while lower n-6 PUFAs, LA and AA compared to freshwater species. In a Chinese study, the edible meat of cultured freshwater fish contained more n-3

Fatty Acid Supply in Pregnant Women with Type 1 Diabetes Mellitus 441

Blue fish, mature (31.3%)\* 2.2 n.d. 4.2 13.8 Horse mackerel (12.8%) \* 1.1 n.d. 1.4 6.6 Rainbow trout (9.0%)# 5.4 1.4 0.8 10.8 Sardine (11.3%)\* 2.2 1.4 2.6 14.7 Striped mullet (11.0%)\* 2.7 0.73 3.1 11.7

Anchovy (7.1%)\* 2.8 1.4 2.4 16.2 Atlantic mackerel (6.1%)\* 2.1 0.68 2.8 25.3 Crucian carp, wild (6.02%)\$ 11.4 4.0 3.6 5.0 Mackerel (7.45%)# 1.9 2.3 1.7 15.9 Silver carp (5.36%)\$ 2.4 4.4 4.9 15.5 White herring (6.88%)\$ 1.2 3.6 2.8 11.8

Anchovy (3.49%)# 1.5 2.2 1.4 25.5 Crucian carp, cultured (3.60%)\$ 17.0 2.6 4.0 6.7 Swordfish (1.93%)# 0.7 1.0 1.1 9.3 Tuna (1.16%)# 2.3 1.3 1.8 16.9 data modified from: \* Tanakol et al., 1999 [Black & Marmara Sea]; # Soriguer et al., 1997 [Atlantic Ocean

Table 3. Fat content and fatty acid composition (g fatty acid/100 g fat) of selected sea fishes

LCPUFAs play an important role in the maturation of the developing nervous system. AA and DHA are accreted in large amounts into the fetal nervous system: into the cortex and retinal cell membranes during the third trimester of pregnancy and in the first months of life (Farquharson et al., 1992; Martinez & Mougan, 1998). DHA can be predominantly found in the grey matter and retina (Horrocks & Yeo, 1999), while the highest AA content is in the amygdala (Brenna & Diau, 2007). In a primate study (Diau et al., 2005), the highest DHA content was found in globus pallidus (15.8%), while the lowest in the optic nerve (4.5%). AA content was the highest in the amygdale (13.7%) and the lowest in the optic tract (6.8%). Grey matter was richer is both AA and DHA, but there was a discontinuity between grey and white matter DHA concentration, while this great difference wasn't seen in AA

The human body has the enzymes needed to synthesise LCPUFAs from their parent essential fatty acids, but the synthesis is a very slow, limited process. In vivo human studies showed that from ALA only a little part is metabolised into EPA and DHA: when supplementing ALA in low dose (<100 mg) only 1.5-7.0% EPA and max. 0.3% DHA were synthesised, while supplementing ALA in high dose (>100 mg) resulted in the synthesis of 0.2-9.0% EPA and 3.8- 10.4% DHA. Hence, rise of EPA by 20-100% can be seen in a dose-dependent manner after the administration of ALA. In contrast, the change in DHA values is rather negligible in healthy

*High fat fishes (>8%)\** 

*Medium fat fishes (4-8%)\** 

*Low fat fishes (2-4%)\** 

**2.3 Fatty acids during pregnancy** 

concentrations.

& Mediterranean Sea]; \$Li et al., 2011 [East China Sea & Quiantang River]

**LA ALA AA DHA** 

PUFAs, EPA and DHA, than the meat of wild freshwater fish (Li et al., 2011). Fatty acid composition of fishes living in the Mediterranean Sea showed seasonal variation (mackerel: lowest in winter-14.44%, highest in spring-38.27%; European eel: lowest in autumn-7.88%, highest in spring-9.46%; Soriguer et al., 1997).


\* data modified from Beare-Rogers et al., 2001 # data modified from Erasmus, 1993

Table 1. Fatty acid composition (g fatty acid/100 g fat) of selected vegetable sources, fats and oils


Table 2. Fatty acid composition (g fatty acid/100 g fat) of selected terrestrial animal lipid sources (data modified from Beare-Rogers et al., 2001)

PUFAs, EPA and DHA, than the meat of wild freshwater fish (Li et al., 2011). Fatty acid composition of fishes living in the Mediterranean Sea showed seasonal variation (mackerel: lowest in winter-14.44%, highest in spring-38.27%; European eel: lowest in autumn-7.88%,

> Corn oil\* 39.4-65.6 0.5-1.5 Grapeseed oil\* 58-78 <1.0 Linseed oil\* 17-30 47-55 Olive oil\* 3.5-20.0 0.0-1.5 Palm kernel oil\* 6.5-12 <0.5 Pumpkin seed oil# 42-57 0-15 Rapeseed oil\* 11-23 5-13 Sesame oil\* 41.5-47.9 0.3-0.4 Soya bean oil 49.8-57.1 5.5-9.5 Sunflower oil (high LA content)\* 65.7 − Walnut oil\* 52.9 10.4

Table 1. Fatty acid composition (g fatty acid/100 g fat) of selected vegetable sources, fats

Chicken flesh 26.5 1.1 1.7 0.6 Duck flesh 13.9 1.5 − − Heart (beef) 20.9 10.5 0.5 − Kidney (lamb) 9.7 3.4 6.4 1.5 Kidney (veal) 13.4 1.7 7.8 0.7 Lamb 6.2 0.7 0.7 − Liver (chicken) 14.0 4.2 0.3 2.0 Liver (pork) 13.6 17.2 1.3 1.0 Milk (cow) 2.6 1.6 − − Rabbit 20.2 5.2 − − Turkey flesh 24.2 1.3 2.3 0.5 Veal 9.4 0.6 2.3 − Venison 14.6 3.3 4.7 − Table 2. Fatty acid composition (g fatty acid/100 g fat) of selected terrestrial animal lipid

**LA ALA AA DHA** 

**LA ALA** 

highest in spring-9.46%; Soriguer et al., 1997).

\* data modified from Beare-Rogers et al., 2001

sources (data modified from Beare-Rogers et al., 2001)
