Polyunsaturated fatty acids in relation to childhood and maternal allergic diseases

• The aim of this thesis was to study polyunsaturated fatty acid (PUPA) in relation to the appem11nce of anergic diseases in children and mothers in late pregnancy and during the lactation period and to the development of atopy in children, as well as the influence of maternal PUF A on their babies.The levels of docosahexaenoic acid (DHA, C22:6n-3) and total n-3 long-chain polyunsaturated fatty acids (LCP) were lower (p = 0.01 and< 0.05) and the ratio of total n-6 to n-3 LCP was higher (p < 0.01) in serum phospholipids (PL) in 22 allergic school children than in 23 controls. The levels of docosapentaenoic acid (DPA, C22:5n-3) and the ratio of arachidonic acid (AA, C20:4n-6) to its precursor dihomo-y-linolenic acid (DHGLA, C20:3n-6) were also lower in 12 children with positive skin prick test (SPT), as compared to SPT negative children (both p < 0.05). Higher levels of C20:2n-6 and lower EPA were recorded in allergic children with serum IgE above the median level (56kU/L), as compared to those with lower IgE levels,The levels of DHGLA, eicosapentaenoic acid (EPA, C20:5n-3), DPA and DHA were all lower in milk total lipid (TL) obtained from atopic, as compared to non-atopic mothers after one month oflactation (all p < 0.05). Similarly, the lower levels of DHGLA, AA, EPA, DPA and DHA were also observed in serum 1L of the atopic mothers at the time of delivery (all P < 0.05), while the levels of a-linolenic acid and C20:2n-6 were higher. Several ratios of n-6 to n- 3 LCP in mature milk at 1 and 3 months were significantly higher in atopic than non-atopic mothers (all p < 0.05). An n-3 fatty acid C20:4n-3 was present in human milk, but not in the blood samples of the mothers and children.The levels of most of the individual PUFA con·elated well in blood of non-allergic children and in colostrum and mature milk of non-atopic mothers (r > 0.5, p < 0.01 as significant), but the correlations were largely absent in the atopic groups. Furthmore, a correlation between linoleic acid (LA, C18:2n-6) and AA levels was observed in serum samples of non-allergic (r = 0.64, p < 0.001), but not allergic mothers at delivery (r = 0.25, p > 0.05).There were some correlations between AA and its precursor DHGLA and metabolite C22:4n-6 and between several n-3 and n-6 LCP, i.e. DPA and C22:4n-6, DHA and DHGLA and AA in semm phospholipids from cord blood of children without a family history of allergy (FHA) and who did not develop allergic diseases during the first 6 years of life. These relationships between the LCP levels were not seen in children with a FHA and in those who developed allergic diseases in later life. Furthermore, an abnormal PUF A composition in maternal blood and breast milk was related to the appearance of allergy in their children.The LA levels correlated in 22 non-allergic mothers and their babies at the time of delivery (r = 0.53, p = 0.01). Furthermore, the serum levels of maternal DHGLA correlated with some LCP levels in cord serum of their babies, i.e. AA, C22:4 and DHA (all r= 0.65, p = 0.001). None of these relationships were observed in 25 allergic mothers and their babies.The findings confirmed an abnormal PUF A composition in allergic children, in allergic mothers at the time of delivery and early lactation period and in newborn infants who developed allergic diseases during the first 6 years of life. The latter finding indicates that an abnormality of PUF A composition may be primary in allergic diseases. An impaired 0-6-desaturase activity in allergic diseases could not be confirmed, The presence of n-3 series fatty acid C20:4n-3 in human milk but not blood samples may contribute to the anti-inflammatory effect of human milk,

Nyckelord

fatty acids

allergic diseases

atopic diseases

children

mothers

cord blood

serum

colostrum

human milk

IgE

skin prick test

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MEDICIN

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