Early dietary intervention with structured triacylglycerols containing docosahexaenoic acid. Effect on brain, liver, and adipose tissue lipids

Influence of Dietary Triacylglycerol Structure on the Accumulation of Docosahexaenoic Acid [22:6(n-3)] in Organs in a Short-Term Feeding Trial with Mildly Omega-3 Deficient Rats

SCOPE

To study the effect of positional distribution of docosahexaenoic acid (DHA) in dietary triacylglycerols (TAG) on the tissue fatty acid content and composition of mildly (n-3) deficient rats.

METHODS AND RESULTS

In a 5-day feeding trial, mildly (n-3) deficient rats received 360 mg daily structured TAGs: sn-22:6(n-3)-18:0-18:0, sn-18:0-18:0-22:6(n-3), sn-18:0-22:6(n-3)-18:0, or tristearin. A fifth group receives standard (n-3) adequate feed AIN-93G from birth till the end of the trial. The DHA-fed groups show significantly higher DHA levels in the liver and visceral fat compared to the tristearin or normal feed groups showing that the dose and the short feeding period of DHA were sufficient to restore the DHA content in the organs of (n-3) deficient rats. Feeding sn-1 DHA resulted in higher levels of DHA in the liver TAG compared to sn-3 DHA feeding, although the difference did not reach statistical significance.

CONCLUSION

These findings indicated a possible difference in the tissue accumulation and/or metabolic fate of DHA from the sn-1 and sn-3 positions of TAG.

Metabolic fate of DHA from regio- and stereospecific positions of triacylglycerols in a long-term feeding trial in rats

This study investigated the impact of regio- and stereospecific position of docosahexaenoic acid (DHA) in dietary triacylglycerols (TAGs) on the fatty acid composition of tissues and organs in rats. Four-week feeding with TAGs containing DHA in sn-1, 2, or 3 position and palmitic acid in the remaining positions at a daily dosage of 500 mg TAG/kg body weight significantly increased the DHA content in all organs and tissues in rats, except in the brain, where the change in DHA level was not statistically significant. The group fed sn-1 DHA showed a significantly higher content of DHA in the plasma TAG than the group fed sn-3 DHA. The sn-3 DHA group had higher levels of DHA in the visceral fat compared to the sn-1, sn-2, as well as all other groups. This is the first study showing that DHA from sn-1 and sn-3 positions of dietary TAGs have differential accumulation in tissues. The new findings improved the current knowledge on the significance of TAG isomeric structure for the bioavailability and metabolic fate of DHA.

Structured Lipids Engineering for Health: Novel Formulations Enriched in n-3 Long-Chain Polyunsaturated Fatty Acids with Potential Nutritional Benefits

Structured lipids (SLs) offer a promising avenue for designing novel formulations enriched in n-3 long-chain polyunsaturated fatty acids (LCPUFAs) with potential health benefits. Triacylglycerols (TAGs), the most common fats in the human diet, are both non-toxic and chemically stable. The metabolic efficiency and digestibility of TAGs are significantly influenced by the position of fatty acids (FAs) within the glycerol backbone, with FAs at the sn-2 position being readily absorbed. Over the past two decades, advancements in SL research have led to the development of modified TAGs, achieved either through chemical or enzymatic processes, resulting in SLs. The ideal structure of SLs involves medium-chain FAs at the sn-1,3 positions and long-chain n-3 LCPUFAs at the sn-2 position of the glycerol backbone, conferring specific physicochemical and nutritional attributes. These tailored SL formulations find wide-ranging applications in the food and nutraceutical industries, showing promise for dietary support in promoting health and mitigating various diseases. In particular, SLs can be harnessed as functional oils to augment TAG metabolism, thereby impeding the development of fatty liver, countering the onset of obesity, and preventing atherosclerosis and age-related chronic diseases. In scrutinising prevailing research trajectories, this review endeavours to provide an in-depth analysis of the multifaceted advantages and repercussions associated with the synthesis of SLs. It elucidates their burgeoning potential in enhancing health and well-being across a range of demographic cohorts. Specifically, the implications of SL utilisation are discussed in the context of healthcare environments and early childhood developmental support.

Fatty acid positional distribution (sn-2 fatty acids) and phospholipid composition in Chinese breast milk from colostrum to mature stage

This study quantified the fatty acid profile with emphasis on the stereo-specifically numbered (sn) 2 positional distribution in TAG and the composition of main phospholipids at different lactation stages. Colostrum milk (n 70), transitional milk (n 96) and mature milk (n 82) were obtained longitudinally from healthy lactating women in Shanghai. During lactation, total fatty acid content increased, with SFA dominating in fatty acid profile. A high ratio of n-6:n-3 PUFA was observed as 11:1 over lactation due to the abundance of linoleic acid in Chinese human milk. As the main SFA, palmitic acid showed absolute sn-2 selectivity, while oleic acid, linoleic acid and α-linolenic acid, the main unsaturated fatty acids, were primarily esterified at the sn-1 and sn-3 positions. Nervonic acid and C22 PUFA including DHA were more enriched in colostrum with an sn-2 positional preference. A total of three dominant phospholipids (phosphatidylethanolamine (PE), phosphatidylcholine (PC) and sphingomyelin (SM)) were analysed in the collected samples, and each showed a decline in amount over lactation. PC was the dominant compound followed by SM and PE. With prolonged breast-feeding time, percentage of PE in total phospholipids remained constant, but PC decreased, and SM increased. Results from this study indicated a lipid profile different from Western reports and may aid the development of future infant formula more suitable for Chinese babies.

Enzymatic synthesis of extra virgin olive oil based infant formula fat analogues containing ARA and DHA: one-stage and two-stage syntheses

Structured lipids (SLs) with high palmitic acid content at the sn-2 position enriched with arachidonic acid (ARA) and docosahexaenoic acid (DHA) were produced using extra virgin olive oil, tripalmitin, ARA and DHA single cell oil free fatty acids. Four types of SLs were synthesized using immobilized lipases, Novozym 435 and Lipozyme TL IM, based on one-stage (one-pot) and two-stage (sequential) syntheses. The SLs were characterized for fatty acid profile, triacylglycerol (TAG) molecular species, melting and crystallization profiles, tocopherols, and phenolic compounds. All the SLs had >50 mol % palmitic acid at the sn-2 position. The predominant TAGs in all SLs were PPO and OPO. The total tocopherol content of SL1-1, SL1-2, SL2-1, and SL2-2 were 70.46, 68.79, 79.64, and 79.31 μg/g, respectively. SL1-2 had the highest melting completion (42.0 °C) and crystallization onset (27.6 °C) temperatures. All the SLs produced in this study may be suitable as infant formula fat analogues.

The intramolecular position of docosahexaenoic acid in the triacylglycerol sources used for pediatric nutrition has a minimal effect on its metabolic use

Docosahexaenoic acid (DHA) plays an important role in normal development of the brain and retina in the human. In utero, DHA is incorporated in the fetus, and its accretion continues throughout early postnatal life. Although human breast milk contains this fatty acid, several organizations recommend supplementing infant formulas with DHA for infants and premature infants. Traditionally, certain types of fish oil have been used for fortifying some infant formulas, but with the decline in world fisheries, the search for alternative sources of DHA continues. Among the viable ingredient sources of DHA is oil derived from single-cell organisms (marine microorganisms); however, these oil sources display different positional specificity of DHA in the glycerol lipids compared with that found in human breast milk lipids. In the latter, the DHA is mainly esterified in the central position of the glycerol backbone. Because of these differences in human milk and oils derived from single-cell organisms, recent research in biotechnology has focused on developing new structured triacylglycerols with an intramolecular structure resembling that found in human milk lipids. This research is justified by the potential differences in metabolism of DHA based on the hypothetical bioavailability and benefits in DHA found in human milk lipids. Presented herein is a review of the published research on the metabolism of DHA from different triacylglycerol sources including in vitro studies and animal studies. Despite small differences observed in digestion, the current data reveal a minimal effect on the parameters of development studied for the intramolecular position in which DHA is esterified.

Lipids and infant formulas

The ultimate goal in the design of infant formula is to achieve the outcome seen in breast fed infants. This review of lipids in infant formulas for term infants begins by referring to the lipid composition of human milk, and relates that to differences in lipid digestion and metabolism which exist between breast fed and formula fed infants and which may significantly influence fatty acid bioavailability.

Recommendations are made for the lipid content and fatty acid composition of term infant formulas (especially for lauric, linoleic, α-linolenic, long chain 20 and 22C n-3 and n-6 polyunsaturated fatty acids and thetransfatty acids).

Further research is required to define more clearly the long term nutritional, growth and developmental effects of structured lipids in formulas for term infants. More information is required on the differential handling of LCPUFA and other fatty acids at the organ and cellular level. There is a need for large (multi-centre) randomized studies to determine the short and long term functional effects of LCPUFA supplementation. Further research and development is required to determine a commercial source of LCPUFA which is safe, effective and economic. Further information is required on the short and long term effects of cholesterol intake during infancy, and in particular its relationship to LCPUFA metabolism. Long term studies should be initiated to determine the relationship of infant diet (especially saturated fatty acid and cholesterol intake) to the development of cardiovascular disease.

Depression and long chain n-3 fatty acids in adipose tissue in adults from Crete

BACKGROUND

Only one study has investigated the relationship of essential fatty acids in the adipose tissue with depression in adults and suggested an inverse relationship between docosahexaenoic acid (22:6 n-3) (DHA) and depression.

OBJECTIVE

To examine the relation between adipose tissue polyunsaturated fatty acids especially n-3 and n-6 fatty acids, an index of long-term or habitual fatty acid intake, and depression in adults.

DESIGN

Cross-sectional study of healthy adults from the island of Crete.

SETTING

The Preventive Medicine and Nutrition Clinic, University of Crete, Greece.

SUBJECTS

A total of 130 healthy adults (59 males, 71 females) aged 22-58 years. The sample was a sub-sample of the Greek ApoEurope study group.

METHODS

Fatty acids were determined by gas chromatography in adipose tissue. Information about depression was obtained through the Zung Self-rating Depression Scale.

RESULTS

Adipose tissue DHA was inversely related with depression. Multiple linear regression analysis taking into account the possible confounding effect of age, gender, body mass index, smoking and educational level confirmed this association.

CONCLUSIONS

The inverse relationship between adipose DHA and depression in adults, replicates findings of a previous study. This relationship indicates that a low long-term dietary intake of DHA is associated with an increased risk for depression in adults.

[The role of nutritional factors on the structure and function of the brain: an update on dietary requirements]

The brain is an organ elaborated and functioning from substances present in the diet. Dietary regulation of blood glucose level (via ingestion of food with a low glycemic index ensuring a low insulin level) improves the quality and duration of intellectual performance, if only because at rest the adult brain consumes 50 p. 100 of dietary carbohydrates, 80 p. 100 of them for energy purposes. The nature of the amino acid composition of dietary proteins contributes to good cerebral function; tryptophan plays a special role. Many indispensable amino acids present in dietary proteins help to elaborate neurotransmitters and neuromodulators. Omega-3 fatty acids provided the first coherent experimental demonstration of the effect of dietary nutrients on the structure and function of the brain. First it was shown that the differentiation and functioning of cultured brain cells requires omega-3 fatty acids. It was then demonstrated that alpha-linolenic acid (ALA) deficiency alters the course of brain development, perturbs the composition and physicochemical properties of brain cell membranes, neurones, oligodendrocytes, and astrocytes (ALA). This leads to physicochemical modifications, induces biochemical and physiological perturbations, and results in neurosensory and behavioral upset. Consequently, the nature of polyunsaturated fatty acids (in particular omega-3) present in formula milks for infants (premature and term) conditions the visual and cerebral abilities, including intellectual abilities. Moreover, dietary omega-3 fatty acids are certainly involved in the prevention of some aspects of cardiovascular disease (including at the level of cerebral vascularization), and in some neuropsychiatric disorders, particularly depression, as well as in dementia, notably Alzheimer's disease. Their deficiency can prevent the satisfactory renewal of membranes and thus accelerate cerebral aging. Iron is necessary to ensure oxygenation, to produce energy in the cerebral parenchyma, and for the synthesis of neurotransmitters. The iodine provided by the thyroid hormone ensures the energy metabolism of the cerebral cells. The absence of iodine during pregnancy induces severe cerebral dysfunction, leading to cretinism. Manganese, copper, and zinc participate in enzymatic mechanisms that protect against free radicals, toxic derivatives of oxygen. The use of glucose by nervous tissue implies the presence of vitamin B1. Vitamin B9 preserves memory during aging, and with vitamin B12 delays the onset of signs of dementia, provided it is administered in a precise clinical window, at the onset of the first symptoms. Vitamins B6 and B12, among others, are directly involved in the synthesis of neurotransmitters. Nerve endings contain the highest concentrations of vitamin C in the human body. Among various vitamin E components, only alpha-tocopherol is involved in nervous membranes. The objective of this update is to give an overview of the effects of dietary nutrients on the structure and certain functions of the brain.

Are olive oil diets antithrombotic? Diets enriched with olive, rapeseed, or sunflower oil affect postprandial factor VII differently

BACKGROUND

The incidence of ischemic heart disease (IHD) in Crete was lower than expected on the basis of blood lipid concentrations of participants in the Seven Countries Study. A favorable effect of a high intake of olive oil on thrombogenesis may have contributed to this finding.

OBJECTIVE

We compared the effects of virgin olive oil with those of rapeseed and sunflower oils on blood coagulation factor VII (FVII), a key factor in thrombogenesis.

DESIGN

In a randomized and strictly controlled crossover study, 18 healthy young men consumed diets enriched with 5 g/MJ (19% of total energy) olive oil, sunflower oil, or rapeseed oil for periods of 3 wk. On the final day of each period, participants consumed standardized high-fat meals (42% of energy as fat). Fasting and nonfasting blood samples were collected after each period.

RESULTS

Mean (+/-SEM) nonfasting peak concentrations of activated FVII (FVIIa) were 11.3 +/- 5.1 U/L lower after olive oil than after sunflower oil, an 18% reduction (P < 0.05). Olive oil also tended to cause lower FVIIa peak concentrations than did rapeseed oil (mean difference: 8.6 U/L, a 15% reduction; P = 0.09). There were no significant differences between diets with respect to nonfasting factor VII coagulant activity (FVII:c), prothrombin fragment 1+2 (F1+2), and tissue factor pathway inhibitor (TFPI) concentrations, or with respect to fasting plasma values of FVII protein, FVII:c, FVIIa, F1+2, or TFPI.

CONCLUSION

A background diet rich in olive oil may attenuate the acute procoagulant effects of fatty meals, which might contribute to the low incidence of IHD in Mediterranean areas.