Which of the n−3 FA should be called essential?

We made a comparative analysis of the uptake, tissue deposition and conversion of dietary alpha-linolenic acid (ALA) to its long chain metabolites eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with preformed EPA + DHA. Diets containing linseed oil [with ALA at approximately 2.5 (4 g/kg diet), 5 (8 g/kg diet), 10 (16 g/kg diet), 25% (40 g/kg diet)] or fish oil [with EPA + DHA at approximately 1 (1.65 g/kg diet), 2.5 (4.12 g/kg diet), 5% (8.25 g/kg diet)] or groundnut oil without n-3 polyunsaturated fatty acids (n-3 PUFA) were fed to rats for 60 days. ALA and EPA + DHA in serum, liver, heart and brain increased with increments in the dietary ALA level. When preformed EPA + DHA were fed, the tissue EPA + DHA increased significantly compared to those given ALA. Normalized values from dietary n-3 PUFA to tissue EPA + DHA indicated that 100 mg of dietary ALA lead to accumulation of EPA + DHA at 2.04, 0.70, 1.91 and 1.64% of total fatty acids respectively in liver, heart, brain and serum. Similarly 100 mg of preformed dietary EPA + DHA resulted in 25.4, 23.8, 15.9 and 14.9% of total fatty acids in liver, heart, brain and serum respectively. To maintain a given level of EPA + DHA, the dietary ALA required is 12.5, 33.5, 8.3 and 9.1 times higher than the dietary EPA + DHA for liver, heart, brain and serum respectively. Hence the efficacy of precursor ALA is lower compared to preformed EPA + DHA in elevating serum and tissue long chain n-3 PUFA levels.

Section: Introductionmentioning

confidence: 99%

Lower Efficacy in the Utilization of Dietary ALA as Compared to Preformed EPA + DHA on Long Chain n‐3 PUFA Levels in Rats

Talahalli

Baskaran

Sambaiah

et al. 2010

“…However, it should be emphasized that an essential FA requirement has been unequivocally demonstrated only in mammals (1). In other organisms they may be better called essential nutrients, as defined by Lauritzen and Hansen (2). In addition, specific aspects of crustacean lipid nutrition are the requirement for sterols (3) and possibly some phospholipids (4).…”

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confidence: 99%

Daphnia magna can tolerate short‐term starvation without major changes in lipid metabolism

Bychek

Dobson²,

Harwood

et al. 2005

Daphnia magna is a common crustacean that is adapted to brief spells of fasting. Lipids are naturally a major component of their diet and are stored as energy reserves. However, there has been some controversy in the literature on the extent to which dietary lipids are used directly for complex lipid formation in Daphnia. We examined lipid metabolism in D. magna by labeling the animals using [1-14C]acetate and then followed the turnover of radiolabeled lipids during a pulse chase. Daphnia were either fed or maintained without food during the chase period. The decrease in radioactivity during the chase was relatively unaffected by feeding, although there were some differences in the distribution of radioactivity between lipid classes or individual FA. The polar lipids, which were four times better labeled than nonpolar lipids, contained the most radioactivity in the zwitterionic phosphoglycerides, PE and PC. Under the experimental conditions, the turnover of the polar membrane lipids was unaffected by feeding. Within nonpolar lipids, TAG accounted for up to about 80% of the label, followed by DAG. Overall, our data show that D. magna is capable of high rates of lipid radiolabeling de novo and, in addition, is able to use--and indeed may be dependent on--some dietary components such as the PUFA linoleate and alpha-linolenate. The results also clearly show that Daphnia is able to tolerate brief spells of fasting (24 h) with very little change to its lipid metabolism.

“…These recommendations have been summarized in detail by Roche (5), Stanley (6), and Sanderson et al (7). Recently, experts also have debated and agreed on the essentiality of n-3 PUFA in the diet (8,9). Even though India has no specific recommendations for the intake of n-3 PUFA, several studies conducted by the National Institute of Nutrition, an organization of the Indian Council of Medical Research, have suggested that an intake of 0.75 en% from α-linolenic acid (LNA) and 0.2 en% from EPA and DHA would have a positive impact on the prevention of coronary heart disease in India (3,(10)(11)(12).…”

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confidence: 99%

Supplementation and delivery of n−3 fatty acids through spray‐dried milk reduce serum and liver lipids in rats

Ramaprasad

Baskaran

Sambaiah

et al. 2004

Indian diets comprising staples such as cereals, millets, and pulses provide 4.8 energy % from linoleic acid (18:2n-6) but fail to deliver adequate amounts of n-3 FA. Consumption of long-chain n-3 PUFA such as EPA (20:5n-3) and DHA (22:6n-3) is restricted to those who consume fish. The majority of the Indian population, however, are vegetarians needing additional dietary sources of n-3 PUFA. The present work was designed to use n-3 FA-enriched spray-dried milk powder to provide n-3 FA. Whole milk was supplemented with linseed oil to provide alpha-linolenic acid (LNA, 18:3n-3), with fish oil to provide EPA and DHA, or with groundnut oil (GNO), which is devoid of n-3 PUFA, and then spray-dried. Male Wistar rats were fed the spray-dried milk formulations for 60 d. The rats given formulations containing n-3 FA showed significant increases (P < 0.001) in the levels of LNA or EPA/DHA in the serum and in tissue lipids as compared with those fed the GNO control formulation. Rats fed formulations containing n-3 FA had 30-35% lower levels of serum total cholesterol and 25-30% lower levels of serum TAG than control animals. Total cholesterol and TAG in the livers of rats fed the formulations containing n-3 FA were lower by 18-30% and 11-18%, respectively, compared with control animals. This study showed that spray-dried milk formulations supplemented with n-3 FA are an effective means of improving dietary n-3 FA intake, which may decrease the risk factors associated with cardiovascular disease.