Moderate dietary intake of myristic and alpha-linolenic acids increases lecithin-cholesterol acyltransferase activity in humans

Impaired Reverse Cholesterol Transport is Associated with Changes in Fatty Acid Profile in Children and Adolescents with Abdominal Obesity

BACKGROUND

Abdominal obesity is an important cardiovascular disease risk factor. Plasma fatty acids display a complex network of both pro and antiatherogenic effects. High density lipoproteins (HDL) carry out the antiatherogenic pathway called reverse cholesterol transport (RCT), which involves cellular cholesterol efflux (CCE), and lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) activities.

OBJECTIVES

Our aim was to characterize RCT and its relation to fatty acids present in plasma in pediatric abdominal obesity.

METHODS

Seventeen children and adolescents with abdominal obesity and 17 healthy controls were studied. Anthropometric parameters were registered. Glucose, insulin, lipid levels, CCE employing THP-1 cells, LCAT and CETP activities, plus fatty acids in apo B-depleted plasma were measured.

RESULTS

The obese group showed a more atherogenic lipid profile, plus lower CCE (Mean±Standard Deviation) (6 ± 2 vs. 7 ± 2%; P < 0.05) and LCAT activity (11 ± 3 vs. 15 ±5 umol/dL.h; P < 0.05). With respect to fatty acids, the obese group showed higher myristic (1.1 ± 0.3 vs. 0.7 ± 0.3; P < 0.01) and palmitic acids (21.5 ± 2.8 vs. 19.6 ± 1.9; P < 0.05) in addition to lower linoleic acid (26.4 ± 3.3 vs. 29.9 ± 2.6; P < 0.01). Arachidonic acid correlated with CCE (r = 0.37; P < 0.05), myristic acid with LCAT (r = -0.37; P < 0.05), palmitioleic acid with CCE (r = -0.35; P < 0.05), linoleic acid with CCE (r = 0.37; P < 0.05), lauric acid with LCAT (r = 0.49; P < 0.05), myristic acid with LCAT (r = -0.37; P < 0.05) ecoisatrienoic acid with CCE (r = 0.40; P < 0.05) and lignoseric acid with LCAT (r = -0.5; P < 0.01).

CONCLUSIONS

Children and adolescents with abdominal obesity presented impaired RCT, which was associated with modifications in proinflammatory fatty acids, such as palmitoleic and myristic, thus contributing to increased cardiovascular disease risk.

Arthrospira Platensis (Spirulina) Supplementation on Laying Hens' Performance: Eggs Physical, Chemical, and Sensorial Qualities

The present study evaluated the effects of dietary supplementation of spirulina on laying hens' performances: Eggs' physical, chemical, and sensorial qualities. A total of 45 Lohman White hens, 44 weeks of age, were randomized into 3 groups of 15 birds. Hens were given 120 g/d of a basal diet containing 0% (control), 1.5%, and 2.5% of spirulina for 6 weeks. Albumen height and consequently Haugh unit were significantly affected by dietary supplementation of spirulina (p < 0.05) and by weeks on diet (p < 0.05). This supplement did not affect (p > 0.05) egg yolk weight or height. However, spirulina increased egg yolk redness (a*) from 1.33 (C) to 12.67 (D1) and 16.19 (D2) and reduced (p < 0.05) the yellowness (b*) parameter from 62.1(C) to 58.17 (D1) and 55.87 (D2). Egg yolks from hens fed spirulina were darker, more red, and less yellow in color than egg yolks from hens fed the control-diet (p < 0.0001). However, spirulina did not affect (p > 0.05) egg yolks' total cholesterol concentration. In conclusion, a significant enhancement of egg yolk color was found in response to spirulina supplementation. Further investigations are needed to evaluate the impact of spirulina on egg yolks' fatty acids profile.

Daily Consumption of Virgin Coconut Oil Increases High-Density Lipoprotein Cholesterol Levels in Healthy Volunteers: A Randomized Crossover Trial

This open-label, randomized, controlled, crossover trial assessed the effect of daily virgin coconut oil (VCO) consumption on plasma lipoproteins levels and adverse events. The study population was 35 healthy Thai volunteers, aged 18-25. At entry, participants were randomly allocated to receive either (i) 15 mL VCO or (ii) 15 mL 2% carboxymethylcellulose (CMC) solution (as control), twice daily, for 8 weeks. After 8 weeks, participants had an 8-week washout period and then crossed over to take the alternative regimen for 8 weeks. Plasma lipoproteins levels were measured in participants at baseline, week-8, week-16, and week-24 follow-up visits. Results. Of 32 volunteers with complete follow-up (16 males and 16 females), daily VCO intake significantly increased high-density lipoprotein cholesterol by 5.72 mg/dL (p = 0.001) compared to the control regimen. However, there was no difference in the change in total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels between the two regimens. Mild diarrhea was reported by some volunteers when taking VCO, but no serious adverse events were reported. Conclusion. Daily consumption of 30 mL VCO in young healthy adults significantly increased high-density lipoprotein cholesterol. No major safety issues of taking VCO daily for 8 weeks were reported.

Associations between long chain polyunsaturated fatty acids and cardiovascular lipid risk factors in youth with type 1 diabetes: SEARCH Nutrition Ancillary Study

PURPOSE

In this longitudinal study we explored the relationships between plasma n-3 and n-6 polyunsaturated fatty acids (PUFAs) and Δ5 and Δ6 desaturase activities (D5D and D6D, respectively) and fasting lipids in youth with type 1 diabetes (T1D).

METHODS

Incident cases of T1D in youth <20years of age who were seen for a baseline study visit (N=914) and a 1-year follow-up visit (N=416) were included. Fasting blood samples were obtained at each visit and plasma phospholipid n-6 PUFAs were measured, which included linoleic acid (LA), dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA); n-3 PUFAs included α-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Estimated D5D and D6D were calculated as FA product-to-precursor ratios, where D5D=AA/DGLA and D6D=DGLA/LA. To examine the longitudinal relationships between long chain PUFAs, desaturase activities and fasting plasma lipids in youth with T1D mixed effects models were used for each individual PUFAs, D5D and D6D, adjusted for demographics, clinic site, diabetes duration, insulin regimen, insulin dose/kg, HbA1c, insulin sensitivity score, and body mass index with random effects to account for the repeated measurements.

FINDINGS

Favorable lipid associations were found between LA and low-density lipoprotein (LDL) cholesterol (β=-0.58, p<0.05); AA, plasma triglycerides (TG) (β=-0.04, p<0.05) and TG/high-density lipoprotein (HDL)-C ratio (β=-0.04, p<0.05); and D5D, plasma TG (β=-0.2, p<0.05) and TG/HDL-cholesterol ratio (β=-0.23, p<0.05). Findings were mixed for the n-3 PUFAs and DGLA: ALA was positively associated with plasma TG (β=0.33, p<0.05) and HDL cholesterol (β=9.86, p<0.05); EPA was positively associated with total cholesterol (β=8.17, p<0.05), LDL cholesterol (β=5.74, p<0.01) and HDL cholesterol (β=2.27, p<0.01); and DGLA was positively associated with TG/HDL-cholesterol ratio (β=0.05, P<0.05).

CONCLUSION

Findings suggest that the most abundant PUFA, LA as well as its metabolic bi-product AA, may be important targets for CVD lipid risk factor reduction in youth with T1D.

[Effects of an obesogenic diet enriched in sardine by-products on pro-atherogenic markers in Wistar rats]

AIM OF THE STUDY

The effects of an obesogenic diet enriched in sardine by-products (Sardina pilchardus) on blood pressure, glycemic control and some cardiovascular risk factors, in particular pro-atherogenic were studied on an experimental model.

MATERIALS AND METHODS

Male rats (n=12) weighing 200±10g were subjected to an adjustment phase of 10 days in an obesogenic diet containing 30% sheep fat. After this period, the rats were divided into two homogeneous groups. The first group (HF-SBp) consumes the obesogenic diet supplemented with 30% of by-products flour (F-SBp), and the second (HF) continuous to consume the obesogenic diet and serve as control.

RESULTS

At day 30, in HF-SBp versus HF group: a reduction was noted in diastolic (-11%) and systolic (-10%) pressure, glycemia (-19%), glycated hemoglobin percent (-43%), serum total lipids concentration (-22%), triacylglycerols (-37%), total cholesterol (-29%) and unesterified cholesterol (-30%), cholesteryl esters (-30%), cholesterol of very low density lipoprotein (-37%) and low density (-37%) was noted. Inversely, high-density lipoprotein cholesterol and LCAT activity were enhanced by 19% and 77%, respectively. However, the atherogenicity index and membrane fluidity were reduced (P<0.05).

CONCLUSION

Sardine by-products probably by their bioactive compounds properties seem to have antihypertensive, antidiabetic, hypolipidemic and antiatherogenic properties that could prevent and/or attenuate some metabolic disorders associated with obesity.

Omega 3 fatty acids promote macrophage reverse cholesterol transport in hamster fed high fat diet

The aim of this study was to investigate macrophage reverse cholesterol transport (RCT) in hamster, a CETP-expressing species, fed omega 3 fatty acids (ω3PUFA) supplemented high fat diet (HFD). Three groups of hamsters (n = 6/group) were studied for 20 weeks: 1) control diet: Control, 2) HFD group: HF and 3) HFD group supplemented with ω3PUFA (EPA and DHA): HFω3. In vivo macrophage-to-feces RCT was assessed after an intraperitoneal injection of (3)H-cholesterol-labelled hamster primary macrophages. Compared to Control, HF presented significant (p<0.05) increase in body weight, plasma TG (p<0.01) and cholesterol (p<0.001) with an increase in VLDL TG and in VLDL and LDL cholesterol (p<0.001). Compared to HF, HFω3 presented significant decrease in body weight. HFω3 showed less plasma TG (p<0.001) and cholesterol (p<0.001) related to a decrease in VLDL TG and HDL cholesterol respectively and higher LCAT activity (p<0.05) compared to HF. HFω3 showed a higher fecal bile acid excretion (p<0.05) compared to Control and HF groups and higher fecal cholesterol excretion (p<0.05) compared to HF. This increase was related to higher gene expression of ABCG5, ABCA1 and SR-B1 in HFω3 compared to Control and HF groups (<0.05) and in ABCG1 and CYP7A1 compared to HF group (p<0.05). A higher plasma efflux capacity was also measured in HFω3 using (3)H- cholesterol labeled Fu5AH cells. In conclusion, EPA and DHA supplementation improved macrophage to feces reverse cholesterol transport in hamster fed HFD. This change was related to the higher cholesterol and fecal bile acids excretion and to the activation of major genes involved in RCT.

Short chain saturated fatty acids decrease circulating cholesterol and increase tissue PUFA content in the rat

This study investigates the effect of various dietary saturated fatty acid (SFA) profiles on plasma lipid parameters and tissue fatty acid composition in rats. The experiment was designed to monitor polyunsaturated fatty acids (PUFA) levels, while examining different amounts and types of SFA. Four isocaloric diets were prepared, containing 10-11 mol% of fatty acids (FA) as linoleic acid (LNA) and 2.5 mol% as α-linolenic acid (ALA), leading to an identical and well-balanced LNA/ALA ratio. The initial rapeseed oil/corn oil mixture providing ALA and LNA was enriched with olive oil to prepare the olive oil diet. The butterfat diet was supplemented with butterfat, containing short-chain SFA (C4:0-C10:0, 17 mol% of FA), lauric acid (C12:0, 3.2 mol%), myristic acid (C14:0, 10.5 mol%) and palmitic acid (C16:0, 14.5 mol%). The saturates diet was supplemented with trilaurin, trimyristin and tripalmitin to obtain the same level of lauric, myristic and palmitic acids as the butterfat diet, without the short-chain SFA. The trimyristin diet was enriched with trimyristin only. The results showed that the butterfat diet contributed to specific effects, compared to the olive oil diet and the saturates and trimyristin diets: a decrease in plasma total, LDL- and HDL-cholesterol, higher tissue storage of ALA and LNA, and a higher level of (n-3) highly unsaturated fatty acids in some tissues. This study supports the hypothesis that in diets with identical well-balanced LNA/ALA ratios, short chain SFA may decrease circulating cholesterol and increase tissue polyunsaturated fatty acid content in the rat.

Saturated fatty acids: simple molecular structures with complex cellular functions

PURPOSE OF REVIEW

This review summarizes recent findings on the biological functions of saturated fatty acids. Some of these findings suggest that saturated fatty acids may have important and specific regulatory roles in the cells. Until now these roles have largely been outweighed by the negative impact of dietary saturated fatty acids on atherosclerosis biomarkers. Elucidated biochemical mechanisms like protein acylation (N-myristoylation, S-palmitoylation) and putative physiological roles are described.

RECENT FINDINGS

The review will focus on the following topics: new aspects on the metabolism of saturated fatty acids; recent reports on the biochemical functions of saturated fatty acids; current investigations on the physiological roles (elucidated and putative) of saturated fatty acids; and a discussion of the nutritional dietary recommendations (amounts and types) of saturated fatty acids.

SUMMARY

Dietary saturated fatty acids are usually associated with negative consequences for human health. Experimental results on the relationship between doses, physiological effects, specificities and functions of individual saturated fatty acids are, however, conflicting. In this context, this review describes emerging recent evidence that some saturated fatty acids have important and specific biological roles. Such data are needed to allow a balanced view in terms of potential nutritional benefits of saturated fatty acids, and, if necessary, reassessment of the current nutritional dietary recommendations.