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Effects of dietary α‐linolenic acid on the conversion and oxidation of 13 C‐α‐linolenic acid
Author(s) -
Vermunt Susanne H. F.,
Mensink Ronald P.,
Simonis Marianne M. G.,
Hornstra Gerard
Publication year - 2000
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02664762
Subject(s) - linolenic acid , oleic acid , docosapentaenoic acid , eicosapentaenoic acid , docosahexaenoic acid , fatty acid , chemistry , food science , clinical chemistry , biochemistry , linoleic acid , polyunsaturated fatty acid , zoology , biology
The effects of a diet rich in α‐linolenic acid vs. one rich in oleic acid on the oxidation of uniformly labeled 13 C‐α‐linolenic acid and its conversion into longer‐chain polyunsaturates (LCP) were investigated in vivo in healthy human subjects. Volunteers received a diet rich in oleic acid ( n =5) or a diet rich in α‐linolenic acid ( n =7; 8.3 g/d) for 6 wk before and during the study. After 6 wk, subjects were given 45 mg of 13 C‐α‐linolenic acid dissolved in olive oil. Blood samples were collected at t =0, 5, 11, 24, 96, and 336 h. Breath was sampled and CO 2 production was measured each hour for the first 12 h. The mean (±SEM) maximal absolute amount of 13 C‐eicosapentaenoic acid (EPA) in plasma total lipids was 0.04 ±0.01 mg in the α‐linolenic acid group, which was significantly lower ( P =0.01) than the amount of 0.12±0.03 mg 13 C‐EPA in the oleic acid group. Amounts of 13 C‐docosapentaenoic acid (DPA) and 13 C‐docosahexaenoic acid (DHA) tended to be lower as well. The mean proportion of labeled α‐linolenic acid (ALA) recovered as 13 CO 2 in breath after 12 h was 20.4% in the ALA and 15.7% in the oleic acid group, which was not significantly different ( P =0.12). The cumulative recovery of 13 C from 13 C‐ALA in breath during the first 12 h was negatively correlated with the maximal amounts of plasma 13 C‐EPA ( r =−0.58, P =0.047) and 13 C‐DPA ( r =−0.63, P =0.027), but not of 13 C‐DHA ( r =−0.49, P =0.108). In conclusion, conversion of 13 C‐ALA into its LCP may be decreased on diets rich in ALA, while oxidation of 13 C‐ALA is negatively correlated with its conversion into LCP. In a few pilot samples, low 13 C enrichments of n−3 LCP were observed in a diet rich in EPA/DHA as compared to oleic acid.