Postprandial response of trans fatty acids in prepubertal obese children

Intake of n-3 LCPUFA and trans-fatty acids is unrelated to development in body mass index and body fat among children

BACKGROUND

The number of children and adolescents with obesity has increased worldwide. Some studies have found an increase in the intake of n-3 long-chain polyunsaturated fatty acid (LCPUFA) to be beneficial for weight and obesity status. The objectives of this study were to examine if intake of trans-fatty acids (TFA) and n-3 LCPUFA at school start was associated with weight and body fat development in the following 3 and 7 years, and if substituting other fats for n-3 LCPUFA in regression models influenced weight and body fat development.

METHODS

A total of 285 children (boys:130, girls:155) were included in this study. Weight, height and skinfold thickness (SF) of children were measured at age 6, 9 and 13 years by trained research personnel. Multivariate linear regression models were used to investigate the associations between n-3 LCPUFA or TFA intake and subsequent changes in body mass index (BMI) or SF. To investigate substitution effects, we constructed regression models including information on n-3 LCPUFA and all other energy given components of the diet, except for the nutrient to be substituted (all other fats and specific subgroups; saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and other polyunsaturated fatty acids (PUFAs)).

RESULTS

No significant associations were observed between intake of TFA or n-3 LCPUFA and changes in BMI and SF. Also, results from regression analysis showed substituting other fats for n-3 LCPUFA did not associate with BMI or SF development.

CONCLUSION

The lack of associations between n-3 LCPUFA and TFA and adiposity suggests that fat composition in the diet does not play a major role in obesity development among school-aged children.

Fatty Acids in Membranes as Homeostatic, Metabolic and Nutritional Biomarkers: Recent Advancements in Analytics and Diagnostics

Fatty acids, as structural components of membranes and inflammation/anti-inflammatory mediators, have well-known protective and regulatory effects. They are studied as biomarkers of pathological conditions, as well as saturated and unsaturated hydrophobic moieties in membrane phospholipids that contribute to homeostasis and physiological functions. Lifestyle, nutrition, metabolism and stress—with an excess of radical and oxidative processes—cause fatty acid changes that are examined in the human body using blood lipids. Fatty acid-based membrane lipidomics represents a powerful diagnostic tool for assessing the quantity and quality of fatty acid constituents and also for the follow-up of the membrane fatty acid remodeling that is associated with different physiological and pathological conditions. This review focuses on fatty acid biomarkers with two examples of recent lipidomic research and health applications: (i) monounsaturated fatty acids and the analytical challenge offered by hexadecenoic fatty acids (C16:1); and (ii) the cohort of 10 fatty acids in phospholipids of red blood cell membranes and its connections to metabolic and nutritional status in healthy and diseased subjects.

Hexadecenoic Fatty Acid Isomers in Human Blood Lipids and Their Relevance for the Interpretation of Lipidomic Profiles

Monounsaturated fatty acids (MUFA) are emerging health biomarkers, and in particular the ratio between palmitoleic acid (9cis-16:1) and palmitic acid (16:0) affords the delta-9 desaturase index that is increased in obesity. Recently, other positional and geometrical MUFA isomers belonging to the hexadecenoic family (C16 MUFA) were found in circulating lipids, such as sapienic acid (6cis-16:1), palmitelaidic acid (9trans-16:1) and 6trans-16:1. In this work we report: i) the identification of sapienic acid as component of human erythrocyte membrane phospholipids with significant increase in morbidly obese patients (n = 50) compared with age-matched lean controls (n = 50); and ii) the first comparison of erythrocyte membrane phospholipids (PL) and plasma cholesteryl esters (CE) in morbidly obese patients highlighting that some of their fatty acid levels have opposite trends: increases of both palmitic and sapienic acids with the decrease of linoleic acid (9cis,12cis-18:2, omega-6) in red blood cell (RBC) membrane PL were reversed in plasma CE, whereas the increase of palmitoleic acid was similar in both lipid species. Consequentially, desaturase enzymatic indexes gave different results, depending on the lipid class used for the fatty acid content. The fatty acid profile of morbidly obese subjects also showed significant increases of stearic acid (C18:0) and C20 omega-6, as well as decreases of oleic acid (9cis-18:1) and docosahexaenoic acid (C22:6 omega-3) as compared with lean healthy controls. Trans monounsaturated and polyunsaturated fatty acids were also measured and found significantly increased in both lipid classes of morbidly obese subjects. These results highlight the C16 MUFA isomers as emerging metabolic marker provided that the assignment of the double bond position and geometry is correctly performed, thus identifying the corresponding lipidomic pathway. Since RBC membrane PL and plasma CE have different fatty acid trends, caution must also be used in the choice of lipid species for the interpretation of lipidomic profiles.

Serum Trans Fatty Acids Are Not Associated with Weight Gain or Linear Growth in School-Age Children

BACKGROUND

Animal and human adult studies indicate that long-term intake of trans fatty acids (TFAs) may be associated with weight gain. High intake of fast foods and snacks, which are rich in TFAs, is linked to overweight status among school-age children. However, the specific effects of TFAs in this population are unknown.

OBJECTIVE

We examined whether serum TFAs, used as biomarkers of intake, are associated with faster weight gain and linear growth during school years.

METHODS

We quantified TFAs by GLC in serum samples of 668 children aged 5-12 y at the time of recruitment into an ongoing cohort study performed in Bogota (Colombia) since 2006. Serum proportions of trans palmitoleic acid (16:1t), trans oleic acid (18:1t), trans linoleic acid (18:2t), and total TFAs were used as biomarkers of intake. Anthropometric characteristics were measured periodically for a median of 30 mo. Body mass index-for-age z scores (BAZs) and height-for-age z scores (HAZs) were calculated with the use of the WHO reference. We estimated mean changes in BAZs and HAZs over follow-up according to quartiles of each TFA at baseline by using mixed-effects regression models with restricted cubic splines.

RESULTS

Proportions of trans palmitoleic acid, trans oleic acid, trans linoleic acid, and total TFAs (mean ± SD, % of total serum FAs), were 0.22 ± 0.06, 0.91 ± 0.37, 0.96 ± 0.27, and 2.10 ± 0.59, respectively. Serum TFAs were not associated with changes in BAZs and HAZs after adjusting for sex, baseline age, and socioeconomic status. In a subgroup analysis by sex, serum trans palmitoleic acid was positively associated with the estimated change in HAZs from ages 6 to 14 y in boys (with use of the first quartile as the reference, differences in HAZs for trans palmitoleic acid quartiles were 0.73, 0.53, and 0.70, P-trend = 0.03).

CONCLUSIONS

Proportions of serum TFAs, used as biomarkers of TFA intake, were not associated with weight gain in children aged 6-14 y in low- and middle-income populations in Bogota. The proportion of trans palmitoleic acid was positively associated with linear growth in boys. Longer follow-up and studies in diverse cohorts with wider ranges of TFA intake are warranted.

Lipid markers of "geometrical" radical stress: synthesis of monotrans cholesteryl ester isomers and detection in human plasma

Heteroatom-centered free radicals are able to transform cis unsaturated fatty acids to the thermodynamically more stable, but unnatural, trans configuration. The "geometrical" radical stress can be estimated in biological samples using trans fatty acid isomers as lipid markers. Regioselectivity is an important feature of the "geometrical" radical stress, because the supramolecular organization of the polyunsaturated fatty acid moieties of phospholipids can lead to preferential monotrans isomer formation. The regioisomer recognition is a crucial step, which is helped by appropriate molecular libraries available through radical-based synthetic methodologies. Cholesteryl linoleate and arachidonate esters are interesting targets for their biochemical connection with membrane phospholipid turnover and their well-known roles in cardiovascular health. The synthesis of monotrans isomers of PUFA cholesteryl esters was achieved by a thiyl radical-catalyzed cis-trans isomerization. Valuable NMR, IR, and Raman spectroscopic data have been collected for promising application in metabolomics and lipidomics. The identification of monotrans cholesteryl ester isomers was carried out in human plasma by GC, Raman, and IR analyses, demonstrating for the first time the presence of specific regiosiomers connected to free radical stress. This work helps to highlight the chemical biology approach for the access to molecular libraries applicable to biomarker development, and the cis-trans isomerization as a relevant process to be integrated in the puzzling scenario of free radical-mediated lipid modifications.

Factors associated with childhood obesity in Spain. The OBICE study: a case–control study based on sentinel networks

Objective

To estimate the association strength of dietary behaviour and sedentary habits in relation to childhood obesity in Spain.

Design

A matched case–control study was carried out using data collected by sentinel network paediatricians in general practices.

Setting

Five Spanish autonomous communities.

Subjects

Cases were 437 children (2–14 years old) with BMI >95th percentile according to Spanish reference tables. Controls were 751 children (2–14 years old; two paired per case) with BMI <84th percentile. Data were collected in two phases: individual (questionnaires filled in by sentinel paediatricians) and family (self-administered questionnaires filled in a family environment). Crude OR and adjusted OR (ORc and adj OR) for the given variables were calculated using a simple and multiple conditional logistic regression analysis.

Results

The factors with the greatest effect on obesity were family history of obesity: both parents (adj OR = 11·2), mother but not father (adj OR = 9·1), father but not mother (adj OR = 6·1), siblings (adj OR = 2·7); and eating between meals (adj OR = 2·5) and consumption of sweets and soft drinks >2 times/week (adj OR = 2·0). The highest protection effect was found for five meals per day (adj OR = 0·5), the regular consumption of breakfast (adj OR = 0·5) and for eating fruit for dessert (adj OR = 0·6). Factors related to sedentary habits did not appear as noteworthy.

Conclusions

We have determined the association between certain dietary behaviour and family history with childhood obesity in several Spanish regions.

Postprandial plasma adiponectin response is reduced in prepubertal premature pubarche girls

The association between premature pubarche (PP) and metabolic syndrome is controversial and not supported by some authors. The aim of this study was to determine insulin resistance syndrome, plasma adiponectin, and fatty acid profile in PP girls to discern potential confounder variables and markers of metabolic disturbances. We studied 22 prepubertal girls with a diagnosis of PP and 20 healthy controls who differed in body mass index (BMI) (19.33 +/- 0.71 vs 17.30 +/- 0.60). We evaluated insulin resistance syndrome components and postprandial response of adiponectin, nonesterified fatty acids, and fatty acid profile after consumption of a standardized breakfast. No lipid disturbances were detected in the PP group. High-density lipoprotein to low-density lipoprotein cholesterol ratio tended to be lower in PP girls (P = .052), but this effect disappeared when data were adjusted for both BMI and age (P = .480). Insulin levels tended to be higher at 2 hours in PP girls, who showed significantly higher C-peptide area under the curve. In contrast, adiponectin at 3 hours after the meal and postprandial adiponectin area under the curve were significantly lower. The PP girls showed significantly higher percentages of eicosapentaenoic acid in total plasma and plasma phospholipids. No differences were found in the postprandial fatty acid clearance rate. In conclusion, PP girls and controls differed in postprandial plasma adiponectin response and in postprandial plasma C-peptide response after both BMI and age adjustment. Cholesterol plasma disturbances were mainly attributable to their higher BMI, although n-3 polyunsaturated fatty acids were higher because of the PP.

Trans fatty acids and weight gain

Increasing rates of obesity have stimulated research into possible contributing factors, including specific dietary components such as trans fatty acids (TFAs). This review considers the evidence for an association between TFA intake and weight gain. It concludes that there is limited but consistent evidence from epidemiological studies, and from a primate model, that increased TFA consumption may result in a small additional weight gain. Data from a long-term study in a primate model suggest that TFA may have a greater adipogenic effect than cis monounsaturated fatty acids; however, there are currently inadequate mechanistic data to provide a comprehensive and plausible explanation for any such metabolic differences between the types of fatty acids.

Periodontitis is associated with altered plasma fatty acids and cardiovascular risk markers

BACKGROUND AND AIMS

In periodontitis it has been found that some perturbation exists in lipid biomarkers, such as increased serum total cholesterol and low-density lipoprotein cholesterol. Nevertheless, the relationship between fatty acids and periodontitis has been demonstrated only in a few studies and remains controversial. The aim of this investigation was to explore the effects of periodontitis on a cluster of traditional and novel cardiovascular risk factors such as plasma-lipids profile, types of plasma fatty acids, adhesion molecules and systemic inflammatory markers.

METHODS AND RESULTS

At a university dental school, 56 patients all over 35 years old were enrolled and invited to participate in the study. Total plasma fatty acids, saturated, n-6 polyunsaturated and monounsaturated fatty acids, peroxidability index, soluble VCAM, TNF-alpha, cholesterol, triacylglycerols, and VLDL-c were significantly higher in the periodontitis group compared to the non-periodontitis group.

CONCLUSIONS

This close association found between plasma triacylglycerols, LDL-c, saturated fatty acids, polyunsaturated fatty acids, total amount of fatty acids and coenzyme Q(10) with some periodontal data such as periodontal probing depth, recession of the gingival margin and clinical attachment level (Pearson correlation between 0.3 and 0.6), leads to the conclusion that there is an inter-relationship between periodontitis, plasma fatty acids profile and the increase in metabolic risk factors for cardiovascular diseases.

Changes in plasma fatty acid composition after intake of a standardised breakfast in prepubertal obese children

Obese patients typically show a pattern of dyslipidaemia and changes in plasma fatty acid composition reflecting abnormalities in lipoprotein metabolism and dietary habits. Animals and obese adults have been widely studied; however, contradictory results have been published in children. The objective was to assess changes in plasma fatty acid composition in total plasma lipids and plasma lipid fractions in obese prepubertal children compared with those of normal weight and to evaluate changes in postprandial plasma fatty acids during a 3 h period after intake of a standardised breakfast. The study was a case-control study with thirty-four obese and twenty normal-weight prepubertal children (Tanner 1). Anthropometric and metabolic variables and fatty acid concentrations were measured in plasma and its fractions. Liquid chromatography was used to separate lipid fractions and GLC to quantify fatty acids. Plasma total fatty acids (TFA), SFA, MUFA and PUFA concentrations were higher in obese than in control children. Except for 18 : 0, 18 : 3n-3, 20 : 4n-6 and n-3 PUFA, all fatty acids in TAG were also elevated in the obese group. Fatty acids 16 : 1n-7, 18 : 0, 18 : 1n-9, 20 : 2n-6, TFA and MUFA significantly decreased between the 2nd and 3rd hour in normal-weight v. obese children. The concentration of 16 : 1n-7 was positively and the proportion of 20 : 4n-6 inversely associated with a significant increase in risk of obesity. Obese prepubertal children show an altered plasma fatty acid profile and concentrations, mainly related to the TAG fatty acid profile, with a lower clearance of fatty acids v. normal-weight prepubertal children.

Development of insulin resistance and its relation to diet in the obese child

The incidence rate of obesity in youth has continued to increase worldwide and about 30% of obese children display insulin resistance (IR) and other metabolic abnormalities. The present study reviews the mechanisms for development of IR in the obese child and possible links between IR and dietary factors in childhood and adolescence. Although increased concentrations of plasma free fatty acids (FFA) and their counter part at intracellular level, long-chain acyl-coenzyme A (LC acyl-CoA), have been related to the early onset of IR in childhood obesity, a new endocrine paradigm states that adipose tissue secretes a wide variety of hormones and cytokines that regulate lipid energy metabolism. These hormonal changes precede any changes in metabolites such as FFA and glucose and appear to be associated with early IR in childhood. Excessive caloric intake increases IR in children; opposite, substantial reduction of overweight achieved by a hypocaloric diet decreases it. Elevated consumption of animal protein, particularly in early life, as well as diets rich in saturated, trans, and n-6 polyunsaturated fatty acids, and diets with a high carbohydrate to fat ratio, besides a high glycaemic and low-fiber diet also appear to exacerbate adiposity and IR.