Tags

Type your tag names separated by a space and hit enter

Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)?
Int J Vitam Nutr Res. 1998; 68(3):159-73.IJ

Abstract

A diet including 2-3 portions of fatty fish per week, which corresponds to the intake of 1.25 g EPA (20:5n-3) + DHA (22:6n-3) per day, has been officially recommended on the basis of epidemiological findings showing a beneficial role of these n-3 long-chain PUFA in the prevention of cardiovascular and inflammatory diseases. The parent fatty acid ALA (18:3n-3), found in vegetable oils such as flaxseed or rapeseed oil, is used by the human organism partly as a source of energy, partly as a precursor of the metabolites, but the degree of conversion appears to be unreliable and restricted. More specifically, most studies in humans have shown that whereas a certain, though restricted, conversion of high doses of ALA to EPA occurs, conversion to DHA is severely restricted. The use of ALA labelled with radioisotopes suggested that with a background diet high in saturated fat conversion to long-chain metabolites is approximately 6% for EPA and 3.8% for DHA. With a diet rich in n-6 PUFA, conversion is reduced by 40 to 50%. It is thus reasonable to observe an n-6/n-3 PUFA ratio not exceeding 4-6. Restricted conversion to DHA may be critical since evidence has been increasing that this long-chain metabolite has an autonomous function, e.g. in the brain, retina and spermatozoa where it is the most prominent fatty acid. In neonates deficiency is associated with visual impairment, abnormalities in the electroretinogram and delayed cognitive development. In adults the potential role of DHA in neurological function still needs to be investigated in depth. Regarding cardiovascular risk factors DHA has been shown to reduce triglyceride concentrations. These findings indicate that future attention will have to focus on the adequate provision of DHA which can reliably be achieved only with the supply of the preformed long-chain metabolite.

Authors+Show Affiliations

Vitamin Research Department, F. Hoffman-Roche Ltd, Basel, Switzerland.

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

9637947

Citation

Gerster, H. "Can Adults Adequately Convert Alpha-linolenic Acid (18:3n-3) to Eicosapentaenoic Acid (20:5n-3) and Docosahexaenoic Acid (22:6n-3)?" International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift Fur Vitamin- Und Ernahrungsforschung. Journal International De Vitaminologie Et De Nutrition, vol. 68, no. 3, 1998, pp. 159-73.
Gerster H. Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? Int J Vitam Nutr Res. 1998;68(3):159-73.
Gerster, H. (1998). Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift Fur Vitamin- Und Ernahrungsforschung. Journal International De Vitaminologie Et De Nutrition, 68(3), 159-73.
Gerster H. Can Adults Adequately Convert Alpha-linolenic Acid (18:3n-3) to Eicosapentaenoic Acid (20:5n-3) and Docosahexaenoic Acid (22:6n-3). Int J Vitam Nutr Res. 1998;68(3):159-73. PubMed PMID: 9637947.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Can adults adequately convert alpha-linolenic acid (18:3n-3) to eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3)? A1 - Gerster,H, PY - 1998/6/25/pubmed PY - 1998/6/25/medline PY - 1998/6/25/entrez SP - 159 EP - 73 JF - International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition JO - Int J Vitam Nutr Res VL - 68 IS - 3 N2 - A diet including 2-3 portions of fatty fish per week, which corresponds to the intake of 1.25 g EPA (20:5n-3) + DHA (22:6n-3) per day, has been officially recommended on the basis of epidemiological findings showing a beneficial role of these n-3 long-chain PUFA in the prevention of cardiovascular and inflammatory diseases. The parent fatty acid ALA (18:3n-3), found in vegetable oils such as flaxseed or rapeseed oil, is used by the human organism partly as a source of energy, partly as a precursor of the metabolites, but the degree of conversion appears to be unreliable and restricted. More specifically, most studies in humans have shown that whereas a certain, though restricted, conversion of high doses of ALA to EPA occurs, conversion to DHA is severely restricted. The use of ALA labelled with radioisotopes suggested that with a background diet high in saturated fat conversion to long-chain metabolites is approximately 6% for EPA and 3.8% for DHA. With a diet rich in n-6 PUFA, conversion is reduced by 40 to 50%. It is thus reasonable to observe an n-6/n-3 PUFA ratio not exceeding 4-6. Restricted conversion to DHA may be critical since evidence has been increasing that this long-chain metabolite has an autonomous function, e.g. in the brain, retina and spermatozoa where it is the most prominent fatty acid. In neonates deficiency is associated with visual impairment, abnormalities in the electroretinogram and delayed cognitive development. In adults the potential role of DHA in neurological function still needs to be investigated in depth. Regarding cardiovascular risk factors DHA has been shown to reduce triglyceride concentrations. These findings indicate that future attention will have to focus on the adequate provision of DHA which can reliably be achieved only with the supply of the preformed long-chain metabolite. SN - 0300-9831 UR - https://www.unboundmedicine.com/medline/citation/9637947/Can_adults_adequately_convert_alpha_linolenic_acid__18:3n_3__to_eicosapentaenoic_acid__20:5n_3__and_docosahexaenoic_acid__22:6n_3_ L2 - https://medlineplus.gov/dietaryfats.html DB - PRIME DP - Unbound Medicine ER -