Changes in plasma triacylglycerol concentrations after sequential lunch and dinner in healthy subjects.

OBJECTIVES: The present study examines the kinetic of plasma triacylglycerol (TAG) after sequential ingestion of lunch and dinner as well as the contribution of dietary fat ingested at lunch to subsequent post-dinner TAG composition. METHOD: Six healthy subjects were included. After standardized breakfast (7: 30AM), 2 mixed meals with fat loads composed of 44 g olive oil (rich in oleic acid) at lunch (12PM) and 44 g sunflower oil (rich in linoleic acid) at dinner (7PM) were ingested. [1-13C] palmitate was added in lunch only. Plasma TAG and chylomicron-TAG (CMTAG) levels were measured sequentially after meals. [1-13C] palmitate enrichment and concentrations of oleic acid and linoleic acid were measured in all lipid fractions. RESULT: Post-dinner plasma TAG peak was delayed as compared to lunch (3 hours vs 1 hour, p=0.002) whereas the magnitude of the postprandial peaks was not significantly different between lunch and dinner (2.4+/-0.3 vs 2.0+/-0.4 mmol/L, p=0.85). [1-13C] palmitate enrichment was maximal 5 hours after lunch in all lipid fractions and decreased slowly thereafter. After dinner ingestion, the rate of decline of [1-13C] palmitate enrichment plateaued during the first 60 minutes. Oleic acid increased slightly and immediately after dinner and remained the predominant fatty acid in all lipid fractions during the first hour after dinner. A delayed peak of plasma and CM-TAG was observed after dinner as compared to lunch without difference in the magnitude of peaks. CONCLUSION: The contribution of dietary fat ingested at lunch to post-dinner lipemia is confirmed despite the relatively long lasting interval between the 2 meals (7 h) and the absence of any early peak of plasma TAG after dinner.

Blood lipid concentrations of docosahexaenoic and arachidonic acids at birth determine their relative postnatal changes in term infants fed breast milk or formula.

BACKGROUND: Factors other than dietary fatty acids could be involved in the variability observed in blood docosahexaenoate (22:6n-3) and arachidonate (20:4n-6) status in formula-fed infants. OBJECTIVE: We considered the 22:6n-3 and 20:4n-6 status at birth to be one of these factors and studied its influence on postnatal changes in term infants fed 4 different diets. DESIGN: The blood phospholipid composition was determined at birth and on day 42 of feeding in 83 term infants fed breast milk, nonsupplemented formula, or 2 different 22:6n-3-supplemented formulas. Relations between 22:6n-3 and 20:4n-6 status at birth and their relative postnatal changes, calculated by the difference between status at the end of the feeding period (6 wk of age) and at birth, were assessed. RESULTS: Postnatal changes in the plasma and erythrocyte phospholipids 22:6n-3 and 20:4n-6 were negatively related to their respective concentrations at birth (P < 0.01) and the slopes of the regression lines were not significantly affected by the type of milk ingested. Adjusted mean values for phospholipid 22:6n-3 in nonsupplemented-formula-fed infants and for 20:4n-6 in formula-fed infants decreased significantly more than they did in the other infant groups (P < 0.02). The status at birth and the type of milk ingested explained 33-64% and 7-47%, respectively, of the variability in postnatal changes. CONCLUSIONS: The status of 22:6n-3 and 20:4n-6 at birth in term infants is one of the major determinants of postnatal changes in these fatty acids. This finding indicates that research is required to characterize environmental, genetic, or both factors, which, in addition to maternal diet, could influence fatty acid status at birth.

Effect of two types of fish oil supplementation on plasma and erythrocyte phospholipids in formula-fed term infants.

We studied the effect of docosahexaenoic acid (DHA) supplementation of infant formulas on fatty acid composition of blood phospholipids in term infants. Two fish oil supplemented formulas containing 0.45 wt% DHA and high (0.35%) or low (0.10%) eicosapentaenoic acid (EPA) were fed for 42 days and compared with a standard formula and breast milk. Infants fed supplemented formulas and breast milk had similar time-dependent changes for DHA from birth to day 42, i.e., slight decreases in plasma phospholipids and erythrocyte phosphatidylcholine and no change in erythrocyte phosphatidylethanolamine. Low-EPA formula prevented EPA accumulation but did not limit the significant decrease in arachidonic acid (AA) noted in infants fed high-EPA formula. These results suggest that term infant formulas should be supplemented with DHA-rich EPA, low fish oil and AA to achieve a fatty acid status in formula-fed infants similar to that of breast-fed infants.

Long-term supplementation of culture medium with essential fatty acids alters alpha-linolenic acid uptake in Caco-2 clone TC7.

We investigated the influence of four different culture media: 20% fetal bovine serum (FBS), 5% FBS, 5% FBS supplemented with 10 mg x L(-1) linoleic acid (18:2(n-6)) or alpha-linolenic acid (18:3(n-3)) on alpha-linolenic acid apical uptake in clone TC7 of human intestinal Caco-2 cell line. Neither cellular viability nor cell monolayer integrity and permeability were altered by the four culture conditions. Our results show that the different culture media led to changes in alpha-linolenic acid maximal rate of uptake (Vmax) but did not alter the apparent transport constant (Km). Reducing FBS concentration from 20% to 5% increased significantly the rate of alpha-linolenic acid uptake, which was further increased by supplementation of the medium with 18:2(n-6) or 18:3(n-3). Supplementation with essential fatty acids led to a marked enrichment of brush-border membrane phospholipids in polyunsaturated fatty acids of the corresponding series and decreased significantly the levels of monounsaturated fatty acids. Saturated fatty acids, unsaturation index, and cholesterol/fatty acid ratios were unchanged. No clear relation could be established between the changes in membrane lipid composition and the alterations of alpha-linolenic acid uptake. These results indicate a weak influence of membrane lipid composition in the modulation of the uptake. Therefore, the increase of uptake following long-term supplementation of TC7 cells with essential fatty acids could be attributed to an increase of the expression of membrane protein(s) involved in the apical uptake of long-chain fatty acids. This remains to be established.

Analysis, separation, and bioassay of pyrrolizidine alkaloids from comfrey (Symphytum officinale).

Pyrrolizidine alkaloids have been linked to liver and lung cancers and a range of other deleterious effects. As with many natural toxicants, major problems arise in determining the effects of the different members of the class and the importance of various forms of ingestion. In this study we have investigated the levels of pyrrolizidine alkaloids in comfrey (Symphytum officinale), determined the levels in different parts of the plant and in herbal remedies, separated the alkaloids into two main groups--the principal parent alkaloids and the corresponding N-oxides--and, finally, carried out a simple bioassay based upon the mutagenic capability of the separated compounds in a human cell line. We conclude that the part of the plant ingested is important in terms of alkaloid challenge and that the effect of two of the major groups of alkaloids individually is different from that of alkaloids in the whole plant extract.

Triacylglycerol structure of human colostrum and mature milk.

Because triacylglycerol (TAG) structure influences the metabolic fate of its component fatty acids, we have examined human colostrum and mature milk TAG with particular attention to the location of the very long chain polyunsaturated fatty acid on the glycerol backbone. The analysis was based on the formation of various diacylglycerol species from human milk TAG upon chemical (Grignard degradation) or enzymatic degradation. The structure of the TAG was subsequently deduced from data obtained by gas chromatographic analysis of the fatty acid methyl esters in the diacylglycerol subfractions. The highly specific TAG structure observed was identical in mature milk and colostrum. The three major fatty acids (oleic, palmitic and linoleic acids) each showed a specific preference for a particular position within milk TAG: oleic acid for the sn-1 position, palmitic acid for the sn-2 position and linoleic acid for the sn-3 position. Linoleic and alpha-linolenic acids exhibited the same pattern of distribution and they were both found primarily in the sn-3 (50%) and sn-1 (30%) positions. Their longer chain analogs, arachidonic and docosahexaenoic acids, were located in the sn-2 and sn-3 positions. These results show that polyunsaturated fatty acids are distributed within the TAG molecule of human milk in a highly specific fashion, and that in the first month of lactation the maturation of the mammary gland does not affect the milk TAG structure.

Essential fatty acid composition of human colostrum triglycerides: its relationship with adipose tissue composition.

The relationships between essential fatty acid (EFA) composition of colostrum and white adipose tissue (WAT) were examined on day 5 after delivery in 69 healthy women. Fatty acid composition was assessed by capillary gas chromatography, and 33 fatty acids were detected in colostrum and in WAT. Total polyunsaturated fatty acid (PUFA) content was similar in colostrum and in WAT (15.7 +/- 3.1% and 16.1 +/- 3.8%, respectively), but long-chain PUFA content was higher in colostrum than in WAT (2.9 +/- 0.6% and 1 +/- 0.2%, respectively; P less than 0.001). The concentrations of linoleic acid were significantly correlated between colostrum and WAT (r = 0.77, P less than 0.0001). No correlation was found for alpha-linolenic acid. The relationships between long-chain PUFA composition of colostrum and WAT suggested that individual factors along with tissue specificity of the mammary gland are involved in either the capacity of desaturating and chain-elongating pathways and/or incorporation of long-chain PUFAs into colostrum.

[Changes in nutritional status at the initial phase of treatment of cancers and malignant hemopathies]. / Modifications de l'état nutritionnel à la phase initiale du traitement des cancers et des hémopathies malignes.

Changes in nutritional status at the initial phase of treatment of cancers and malignant blood diseases were evaluated in 32 male patients (mean age 58 +/- 18 years) examined during three 4-day stays in hospital (T0, T1, T2) at 2 months' interval. On the first day of each stay the following parameters were measured: food intake (kcal/day), weight (kg), squared height (m), fat mass (kg) obtained by measuring 4 skin folds and using Durnin's tables, brachial muscle area (cm2) and total skeletal muscle mass (kg) calculated from Heymsfield's equations. On the third and fourth days, after 48 hours of meat-free and fish-free diet, 3-methylhistidine (mmol/g creatininuria) and creatinine (mg) were measured in urine, and the urinary creatinine/height ratio (mg/cm/day) was calculated. Full anthropomorphic measurements were performed on 19/32 patients and complete measurements of 3-methylhistidine and the urinary creatinine/height ratio in 9/32 patients. Subsequent examinations revealed a decrease in brachial muscle area, total skeletal muscle mass and urinary creatinine/height ratio which, together with an increase in baseline 3-methylhistidine, confirmed the loss of muscle mass. Mean losses of muscle and fat were 6 p. 100 between T1 and T0 and 7 p. 100 between T2 and T0 for the muscle mass, and 9 p. 100 between T2 and T0 for the fat mass. These losses of body mass occurred very early, with significant differences between T1 and T0 and between T2 and T0. They suggest that protein-calorie malnutrition develops at a very early stage in patients treated for cancer or malignant blood disease.