Lotte Lauritzen

Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review

The effects of both the amount and quality of dietary fat have been studied intensively during the past decades. Previously, low-fat diets were recommended without much attention to the quality of fat, whereas there is general emphasis on the quality of fat in current guidelines. The objective of this systematic review (SR) was to assess the evidence of an effect of the amount and type of dietary fat on body weight (BW), risk factors, and risk of non-communicable diseases, that is, type 2 diabetes (T2DM), cardiovascular diseases (CVD), and cancer in healthy subjects or subjects at risk for these diseases. This work was performed in the process of updating the fourth edition of the Nordic Nutrition Recommendations from 2004. The literature search was performed in October 2010 covering articles published since January 2000. A complementary search was done in February 2012 covering literature until December 2011. Two authors independently selected articles for inclusion from a total of about 16,000 abstracts according to predefined criteria. Randomized controlled trials (RCT) and prospective cohort studies (PCS) were included as well as nested case–control studies. A few retrospective case–control studies were also included when limited or no data were available from other study types. Altogether 607 articles were quality graded and the observed effects in these papers were summarized. Convincing evidence was found that partial replacement of saturated fat (SFA) with polyunsaturated fat (PUFA) or monounsaturated fat (MUFA) lowers fasting serum/plasma total and LDL cholesterol concentrations. The evidence was probable for a decreasing effect of fish oil on concentration of serum/plasma total triglycerides as compared with MUFA. Beneficial effect of MUFA both on insulin sensitivity and fasting plasma/serum insulin concentration was considered as probable in comparisons of MUFA and carbohydrates versus SFA, whereas no effect was found on fasting glucose concentration in these comparisons. There was probable evidence for a moderate direct association between total fat intake and BW. Furthermore, there was convincing evidence that partial replacement of SFA with PUFA decreases the risk of CVD, especially in men. This finding was supported by an association with biomarkers of PUFA intake; the evidence of a beneficial effect of dietary total PUFA, n-6 PUFA, and linoleic acid (LA) on CVD mortality was limited suggestive. Evidence for a direct association between total fat intake and risk of T2DM was inconclusive, whereas there was limited-suggestive evidence from biomarker studies that LA is inversely associated with the risk of T2DM. However, there was limited-suggestive evidence in biomarker studies that odd-chain SFA found in milk fat and fish may be inversely related to T2DM, but these associations have not been supported by controlled studies. The evidence for an association between dietary n-3 PUFA and T2DM was inconclusive. Evidence for effects of fat on major types of cancer was inconclusive regarding both the amount and quality of dietary fat, except for prostate cancer where there was limited-suggestive evidence for an inverse association with intake of ALA and for ovarian cancer for which there was limited-suggestive evidence for a positive association with intake of SFA. This SR reviewed a large number of studies focusing on several different health outcomes. The time period covered by the search may not have allowed obtaining the full picture of the evidence in all areas covered by this SR. However, several SRs and meta-analyses that covered studies published before year 2000 were evaluated, which adds confidence to the results. Many of the investigated questions remain unresolved, mainly because of few studies on certain outcomes, conflicting results from studies, and lack of high quality–controlled studies. There is thus an evident need of highly controlled RCT and PCS with sufficient number of subjects and long enough duration, specifically regarding the effects of the amount and quality of dietary fat on insulin sensitivity, T2DM, low-grade inflammation, and blood pressure. New metabolic and other potential risk markers and utilization of new methodology in the area of lipid metabolism may provide new insight.

Choice of foods and ingredients for moderately malnourished children 6 months to 5 years of age.

There is consensus on how to treat severe malnutrition, but there is no agreement on the most cost-effective way to treat infants and young children with moderate malnutrition who consume cereal-dominated diets. The aim of this review is to give an overview of the nutritional qualities of relevant foods and ingredients in relation to the nutritional needs of children with moderate malnutrition and to identify research needs. The following general aspects are covered: energy density, macronutrient content and quality, minerals and vitamins, bioactive substances, antinutritional factors, and food processing. The nutritional values of the main food groups—cereals, legumes, pulses, roots, vegetables, fruits, and animal foods—are discussed. The special beneficial qualities of animal-source foods, which contain high levels of minerals important for growth, high-quality protein, and no antinutrients or fibers, are emphasized. In cereal-dominated diets, the plant foods should be processed to reduce the contents of antinutrients and fibers. Provision of a high fat content to increase energy density is emphasized; however, the content of micronutrients should also be increased to maintain nutrient density. The source of fat should be selected to supply optimal amounts of polyunsaturated fatty acids (PUFAs), especially n-3 fatty acids. Among multiple research needs, the following are highlighted: to identify the minimum quantity of animal foods needed to support acceptable child growth and development, to examine the nutritional gains of reducing contents of antinutrients and fibers in cereal- and legume-based diets, and to examine the role of fat quality, especially PUFA content and ratios, in children with moderate malnutrition.

Maternal fish oil supplementation in lactation: Effect on visual acuity and n−3 fatty acid content of infant erythrocytes

Studies on formula-fed infants indicate a beneficial effect of dietary DHA on visual acuity. Cross-sectional studies have shown an association between breast-milk DHA levels and visual acuity in breast-fed infants. The objective in this study was to evaluate the biochemical and functional effects of fish oil (FO) supplements in lactating mothers. In this double-blinded randomized trial, Danish mothers with habitual fish intake below the 50th percentile of the Danish National Birth Cohort were randomized to microencapsulated FO [1.3 g/d long-chain n−3 FA (n−3 LCPUFA)] or olive oil (OO). The intervention started within a week after delivery and lasted 4 mon. Mothers with habitual high fish intake and their infants were included as a reference group. Ninety-seven infants completed the trial (44 OO-group, 53 FO-group) and 47 reference infants were followed up. The primary outcome measures were: DHA content of milk samples (0, 2, and 4 mon postnatal) and of infant red blood cell (RBC) membranes (4 mon postnatal), and infant visual acuity (measured by swept visual evoked potential at 2 and 4 mon of age). FO supplementation gave rise to a threefold increase in the DHA content of the 4-mon milk samples (P<0.001). DHA in infant RBC reflected milk contents (r=0.564, P<0.001) and was increased by almost 50% (P<0.001). Infant visual acuity was not significantly different in the randomized groups but was positively associated at 4 mon with infant RBC-DHA (P=0.004, multiple regression). We concluded that maternal FO supplementation during lactation did not enhance visual acuity of the infants who completed the intervention. However, the results showed that infants with higher RBC levels of n−3 LCPUFA had a better visual acuity at 4 mon of age, suggesting that n−3 LCPUFA may influence visual maturation.

Glutamate stimulates the formation of N-acylphosphatidylethanolamine and N-acylphosphatidylethanolamine in cortical neurons in culture

Abstract The formation of anandamide N-armarachidonoylethanolamine, N-acylethanolamine, and N-acylphosphatidylethanolamine was studied in primary cultures of rat cortical neurons. The cells were incubated for 22 h with [14C]ethanolamine, [U-14C]arachidonic acid, [3H]arachidonic acid, [32P]phosphate, [14C]stearic acid, or [3H]myristic acid. The lipids from the cells and media were separated by thin layer chromatography. [14C]Ethanolamine labelling revealed two compounds (I and II), which on different thin layer chromatography systems migrated as N-acylethanolamine (0.06-0.55% of total radioactivity) and N-acylphosphatidylethanolamine (0.66-6.49% of total radioactivity), respectively. Compound II was also labelled with [32P]phosphate, and radioactive fatty acids. Treatment of compound II with phospholipase D (Streptomyces chromofuscus) resulted in two compounds, one comigrating as phosphatidic acid and the other as N-acylethanolamine. Compound I could be labelled with [14C]stearic acid and [3H]myristic acid, but not with [3H]- or [I4C]arachidonic acid. Exogenous [3H]anandamide was metabolised with a t 1 2 of 2.6 h. The labelling of the two compounds identified as N-acylethanolamine and N-acylphosphatidylethanolamine were more pronounced the older the culture. The neurotoxic amino acid, glutamate, stimulated within 2 h dose-dependently (ED50 = 40 μM) the formation of both compounds. It is suggested that N-acylethanol amine and N-acylphosphatidylethanolamine are formed in relation to the cytotoxicity induced by glutamate, and that these compounds may be markers of neurotoxicity. We could not detect any formation of anandamide using radioactive arachidonic acid.

Fish oil supplementation of lactating mothers affects cytokine production in 2 1/2-year-old children

Abstractn−3 PUFA influence immune functioning and may affect the cytokine phenotype during development. To examine whether maternal fish oil supplementation during lactation could modify later immune responses in children, 122 lactating Danish mothers with a fish intake below the population median were randomized to groups supplemented for the first 4 mon of lactation with 4.5 g/d of fish oil (equivalent to 1.5 g/d of n−3 long-chain PUFA) or olive oil. Fifty-three mothers with a fish intake in the highest quartile of the population were also included. The FA composition of erythrocyte membranes was measured at 4 mon and at 2 1/2 yr. Plasma immunoglobulin E (IgE) levels and cytokine production in lipopolysaccharide-stimulated whole-blood cultures were determined at 2 1/2 yr. Erythrocyte n−3 PUFA at 4 mon were higher in infants from the fish oil group compared with the olive oil group (P<0.001) but were no longer different at 2 1/2 yr. The median production of lipopolysaccharide-induced interferon γ(IFN-γ) in the fish oil group was fourfold higher than that in the olive oil group (P=0.034), whereas interleukin-10 (IL-10) production was similar. The IFN-γ/IL-10 ratio was twofold higher in the fish oil group (P=0.019) and was positively correlated with 20∶5n−3/20∶4n−6 in erythrocytes at 4 mon (P=0.050). The percentages of atopic children and plasma IgE were not different in the two groups, but the study was not designed to look at atopy. Cytokine responses and erythrocyte FA composition in children of mothers with a high fish intake were intermediate in comparison with those in the randomized groups. Fish oil supplementation during lactation resulted in increased in vitro IFN-γ production in the children 2 yr after the supplementation was given, which may reflect a faster maturation of the immune system.

Whole-blood culture is a valid low-cost method to measure monocytic cytokines - A comparison of cytokine production in cultures of human whole-blood, mononuclear cells and monocytes

Whole-blood and peripheral blood mononuclear cell (PBMC) cultures are used as non-validated surrogate measures of monocytic cytokine production. The aim of this investigation was to compare ex vivo cytokine production from human whole-blood and PBMC with that from isolated monocytes. We also assessed the intra- and inter-individual variation in cytokine production. In 64 healthy men (age 19-40 years) IL-6, TNF and IL-10 were measured by enzyme-linked immunosorbent assay in supernatants from whole-blood, PBMC and monocytes cultured 24 h with lipopolysaccharide (LPS) or UV-killed L. acidophilus. Cytokines produced from whole-blood was found to be more strongly correlated with monocytic cytokines than cytokines from PBMC, particularly after LPS-stimulation: r=0.57, P<0.001 versus r=0.33, P=0.01 for IL-6 and r=0.43, P<0.001 versus r=0.30, P=0.02 for TNF-alpha. Adjustment for a preceding 8-week dietary fatty acid-intervention did not change any of the associations. Based on measurements at three time-points 8 weeks apart the intra-individual variation was > or = 50% smaller than the inter-individual variation (P<0.05) in most whole-blood cytokine responses and LPS-stimulated IL-6 from PBMC. We conclude that whole-blood cultures are well-suited low-cost proxy-measures of monocytic cytokine production. Moreover, large inter-individual variation in cytokine production was demonstrated whereas the individual responses in whole-blood were reproducible even over long time-periods.

Characterization of Glutamate‐Induced Formation of N‐Acylphosphatidylethanolamine and N‐Acylethanolamine in Cultured Neocortical Neurons

Abstract: Glutamate‐induced formation of N‐acylethanolamine (NAE) and N‐acylphosphatidylethanolamine (NAPE) was studied in primary cultures of mouse neocortical neurons prelabeled with [14C]ethanolamine. The formation of these two lipids was dependent on the maturity of the cell culture; i.e., no glutamate‐induced formation was seen in 2‐day‐old cultures, whereas glutamate induced a pronounced formation in 6‐day‐old cultures. The calcium ionophore A23187 (2 µM) stimulated, within 2 h, formation of NAPE in 2‐day‐old cultures (fourfold) as well as in 6‐day‐old cultures (eightfold). Glutamate exerted its effect via NMDA receptors as seen by the inhibitory action of the NMDA‐selective receptor antagonists d‐(−)‐2‐amino‐5‐phosphonovalerate and N‐(1‐(2‐thienyl)‐cyclohexyl)piperidine and the lack of effect of the α‐amino‐3‐hydroxy‐5‐methylisoxazole‐4‐propionic acid (AMPA)/kainate‐receptor antagonist 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX). In 6‐day‐old cultures, exposure to NMDA (100 µM for 24 h) induced a linear increase in the formation of NAPE and NAE as well as a 40–50% neuronal death, as measured by a decrease in cellular formazan formation [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay]. The increase in NAPE and NAE could be detected earlier than the neuronal death. Neither cyclic AMP, cyclic GMP, nitric oxide, protein kinase C, nor peroxidation appears to be involved in the formation of NAPE and NAE, as assessed by the use of different pharmacological agents. Exposure to 5 mM NaN3 for 8 h resulted in a >80% decrease in the cellular MTT staining and a pronounced linear increase in the formation of NAE and NAPE (reaching 25–30% of total labeling). [14C]Anandamide was also formed in [14C]arachidonic acid‐labeled neurons exposed to NaN3. No NAPE formation was detected in A23187‐stimulated mouse astrocytes, rat Leydig cells and cardiomyocytes, and several other cells. These results suggest that the glutamate‐induced formation of NAPE and NAE was mediated by the NMDA receptor and the formation of these lipids may be associated with neuronal death.

CELL SWELLING ACTIVATES PHOSPHOLIPASE A2 IN EHRLICH ASCITES TUMOR CELLS

Abstract. Ehrlich ascites tumor cells, loaded with 3H-labeled arachidonic acid and 14C-labeled stearic acid for two hours, were washed and transferred to either isotonic or hypotonic media containing BSA to scavenge the labeled fatty acids released from the cells. During the first two minutes of hypo-osmotic exposure the rate of 3H-labeled arachidonic acid release is 3.3 times higher than that observed at normal osmolality. Cell swelling also causes an increase in the production of 14C-stearic acid-labeled lysophosphatidylcholine. This indicates that a phospholipase A2 is activated by cell swelling in the Ehrlich cells. Within the same time frame there is no swelling-induced increase in 14C-labeled stearic acid release nor in the synthesis of phosphatidyl 14C-butanol in the presence of 14C-butanol. Furthermore, U7312, an inhibitor of phospholipase C, does not affect the swelling induced release of 14C-labeled arachidonic acid. Taken together these results exclude involvement of phospholipase A1, C and D in the swelling-induced liberation of arachidonic acid. The swelling-induced release of 3H-labeled arachidonic acid from Ehrlich cells as well as the volume regulatory response are inhibited after preincubation with GDPβS or with AACOCF3, an inhibitor of the 85 kDa, cytosolic phospholipase A2. Based on these results we propose that cell swelling activates a phospholipase A2—perhaps the cytosolic 85 kDa type—by a partly G-protein coupled process, and that this activation is essential for the subsequent volume regulatory response.

FORMATION OF N-ACYL-PHOSPHATIDYLETHANOLAMINES AND N-ACETYLETHANOLAMINES: PROPOSED ROLE IN NEUROTOXICITY

The formation of N-acyl-phosphatidylethanolamine (NAPE) and N-acylethanolamine (NAE), including anandamide, in mammals in relation to neurotoxicity is discussed. Data on the characterization of the NAPE-forming N-acyltransferase, the NAPE-hydrolyzing phospholipase D, and the NAE-hydrolyzing amidase are reviewed. We suggest that NAPE and NAE, including anandamide, are formed in neurons in response to the high intracellular calcium concentrations that occur in injured neurons, e.g. due to glutamate excitotoxicity. NAPE may have functions of its own besides being a precursor for NAE. The formation of both of these lipids may serve as a cytoprotective response, whether mediated by physical interactions with membranes or enzymes, or mediated by activation of cannabinoid receptors. This suggestion implies that NAPE and NAE may have pathophysiological roles in the brain. Whether these lipids also have physiological roles is uncertain.

Fluctuations in Human Milk Long-Chain PUFA Levels in Relation to Dietary Fish Intake

Within the Danish population, milk DHA (22∶6n−3) levels vary by more than a factor of 10. This paper deals with fluctuations in the milk content of 22∶6n−3 and other long-chain PUFA (LCPUFA) and the acute effects of fish meals and fish oil supplements on milk levels of LCPUFA. Twelve fish-eating mothers with 4-mon-old infants provided one blood and one adipose tissue sample, and seven consecutive morning hindmilk samples with dietary records from the previous days. Another 12 lactating women were given fish oil (2–8 g) for breakfast and delivered 6–12 milk samples during the following 24 h. The mean milk 22∶6n−3 content of the fish-eating mothers was 0.57±0.28 FA% (=percentage of total area of FAME peaks in GLC) and the day-to-day variation (SD/mean) within the individual was 35±17%. Mean milk 22∶6n−3 content on mornings with no fish the day before was 0.42±0.15 FA%; this was increased by 82±17% (n=9, P=0.05) if the mother had eaten fatty fish. Fish oil resulted in a twofold increase in milk 22∶6n−3 levels, which peaked after 10 h and lasted for 24 h. The EPA content of milk was also increased by fish meals and fish oil supplements, but these had no effect on the level of arachidonic acid. The study showed that diurnal and day-to-day fluctuations in levels of milk n−3 LCPUFA are large, which makes it difficult to assess the 22∶6n−3 intake of breast-fed infants from a single milk sample. In studies of the functional outcome of dietary 22∶6n−3 in breast-fed infants it is suggested also to use a measure of maternal 22∶6n−3 status.