A micronutrient supplement modulates homocysteine levels regardless of vitamin B biostatus in elderly subjects

Elevated homocysteine (Hcy) levels (≥15 μmol/L) in the elderly are frequently associated with a higher risk of cardiovascular disease and cognitive decline. Several studies have already shown an Hcy-lowering effect of B vitamin supplementation in cohorts deficient in these nutrients. The aim of this randomized, double-blinded 12-week intervention study was to investigate whether Hcy levels in healthy elderly subjects (75.4±4.5 years, n=133) could be lowered with a micronutrient supplement (i.e., 400 μg folic acid, 100 μg cobalamin). Difference in mean initial Hcy levels between intervention (17.6±7.1 μmol/L, n=65) and placebo group (18.9±6.1 μmol/L, n=68) was not significant. The prevalence of cobalamin and folate deficiency in the total study population was low: 27% had serum-cobalamin levels ≤150 pmol/L, 12% holo-transcobalamin (Holo-TC) levels ≤50 pmol/L, 13% low cobalamin status using the aggregated cobalamin marker 4cB12 and 10% red blood cell (RBC) folate ≤570 nmol/L. Nevertheless, the treated subjects still showed improved cobalamin and folate biostatus (serum cobalamin Δt12-t0: 63±48 pmol/L; Holo-TC Δt12-t0: 17±19 pmol/L; RBC folate Δt12-t0: 326±253 nmol/L) and Hcy levels (Δt12-t0: -3.6±5.7 μmol/L). The effects were statistically significant compared to the placebo group with p=0.005 (serum cobalamin), p=0.021 (Holo-TC), p=0.014 (RBC-folate) and p<0.001 (Hcy). The Hcy-lowering effect was dependent on the initial Hcy levels (p<0.001). Our findings suggest that elevated Hcy levels in elderly subjects can be lowered regardless of the initial cobalamin and folate biostatus.

Identification and prediction of association patterns between nutrient intake and anemia using machine learning techniques: results from a cross-sectional study with university female students from Palestine

PURPOSE

This study utilized data mining and machine learning (ML) techniques to identify new patterns and classifications of the associations between nutrient intake and anemia among university students.

METHODS

We employed K-means clustering analysis algorithm and Decision Tree (DT) technique to identify the association between anemia and vitamin and mineral intakes. We normalized and balanced the data based on anemia weighted clusters for improving ML models' accuracy. In addition, t-tests and Analysis of Variance (ANOVA) were performed to identify significant differences between the clusters. We evaluated the models on a balanced dataset of 755 female participants from the Hebron district in Palestine.

RESULTS

Our study found that 34.8% of the participants were anemic. The intake of various micronutrients (i.e., folate, Vit A, B5, B6, B12, C, E, Ca, Fe, and Mg) was below RDA/AI values, which indicated an overall unbalanced malnutrition in the present cohort. Anemia was significantly associated with intakes of energy, protein, fat, Vit B1, B5, B6, C, Mg, Cu and Zn. On the other hand, intakes of protein, Vit B2, B5, B6, C, E, choline, folate, phosphorus, Mn and Zn were significantly lower in anemic than in non-anemic subjects. DT classification models for vitamins and minerals (accuracy rate: 82.1%) identified an inverse association between intakes of Vit B2, B3, B5, B6, B12, E, folate, Zn, Mg, Fe and Mn and prevalence of anemia.

CONCLUSIONS

Besides the nutrients commonly known to be linked to anemia-like folate, Vit B6, C, B12, or Fe-the cluster analyses in the present cohort of young female university students have also found choline, Vit E, B2, Zn, Mg, Mn, and phosphorus as additional nutrients that might relate to the development of anemia. Further research is needed to elucidate if the intake of these nutrients might influence the risk of anemia.

Nutritional status of flexitarians compared to vegans and omnivores - a cross-sectional pilot study

BACKGROUND

In the Western world, there has been a notable rise in the popularity of plant-based, meat-reduced flexitarian diets. Nevertheless, there is insufficient data on the nutritional status of individuals following this dietary pattern. The aim of this study was to investigate the intake and endogenous status of various nutrients in a healthy German adult study population consisting of flexitarians (FXs), vegans (Vs) and omnivores (OMNs).

METHODS

In this cross-sectional study, dietary intake of 94 non-smoking adults (32 FXs, 33 Vs, 29 OMNs) between 25 and 45 years of age was assessed using 3-day dietary records. In addition, blood samples were collected to determine different endogenous nutrient status markers.

RESULTS

32%, 82% and 24% of the FXs, Vs, and OMNs respectively reported using dietary supplements. In the FXs, intake of total energy as well as macronutrients and most micronutrients were within the reference range. FXs had higher intakes of fiber, retinol-equ., ascorbic acid, folate-equ., tocopherol-equ., calcium, and magnesium compared to OMNs. However, cobalamin intake in FXs (2.12 µg/d) was below the reference (4 µg/d). Based on 4cB12, 13% of FXs showed a cobalamin undersupply [< -0.5 to -2.5] compared to 10% of OMNs, and 9% of Vs. The median 25(OH)D serum concentrations in FXs, Vs and OMNs were 46.6, 55.6, and 59.6 nmol/L. The prevalence of an insufficient/deficient vitamin-D status [< 49.9 nmol 25(OH)D/L] was highest in FXs (53%), followed by Vs (34%) and OMNs (27%). In FXs and Vs, the supplement takers had better cobalamin and vitamin-D status than non-supplement takers. Anemia and depleted iron stores were found only occasionally in all groups. In women, the prevalence of pre-latent iron deficiency and iron deficiency was highest in FXs (67%) compared to Vs (61%) and OMNs (54%).

CONCLUSION

Our findings indicated that all three diets delivered sufficient amounts of most macro- and micronutrients. However, deficiencies in cobalamin, vitamin-D, and iron status were common across all diets. Further studies are needed to investigate the nutrient supply status and health consequences of meat-reduced plant-based diets. The study was registered in the German Clinical Trial Register (number: DRKS 00019887, data: 08.01.2020).

Folate, vitamin B12 and vitamin D status in healthy and active home-dwelling people over 70 years

BACKGROUND

Ageing is characterised by physiological changes that can affect the nutrient availability and requirements. In particular, the status of vitamin D, cobalamin and folate has often been found to be critical in older people living in residential care. However, there is a lack of studies investigating the status of these nutrients in healthy and active home-dwelling elderly people.

METHODS

The aim of this cross-sectional study was to assess the status of vitamin D based on serum concentrations of 25-hydroxycholecalciferol [25-(OH)D], cobalamin based on serum concentrations of holotranscobalamin (holoTC) and folate based on red blood cell (RBC) folate in unsupplemented, healthy and active German home-dwelling subjects ≥ 70 years of age (n = 134, mean ± SD: 75.8 ± 4.5 years). Dietary intake was assessed by 3-day food recalls. The study was conducted between March and November of 2021 (during the COVID-19 pandemic).

RESULTS

The mean 25-(OH)D concentration was high at 85.1 ± 26.0 nmol/L, while the majority of women (92%) and men (94%) had 25-(OH)D concentrations ≥ 50 nmol/L. Less than 10% of men and women had 25-(OH)D concentrations < 50 nmol/L. The mean holoTC concentration was 88.9 ± 33.7 pmol/L (94.8 ± 34.6 pmol/L in women and 73.6 ± 25.6 in men). Only 8% of the women were cobalamin deficient (< 50 pmol/L holoTC) compared to 22% of the men. The mean RBC folate concentration was 831 ± 244 nmol/L, while the prevalence of folate deficiency was 10%. Linear regression analysis showed that only folate equivalent intake was associated with the relevant nutrient status marker.

CONCLUSION

Our findings suggest that healthy, independently living older people with high levels of education, physical activity, and health awareness are not necessarily at higher risk of vitamin D, folate and cobalamin deficiency. Further studies are needed to verify these findings and to identify lifestyle and dietary patterns that can predict adequate nutrient status for healthy ageing.

TRIAL REGISTRATION

This study is officially recorded in the German Clinical Trials Register (DRKS00021302).

Very low Omega-3 Index in young healthy students from Palestine

Oily fish is rich in long-chain omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which have been associated with several health benefits. However, fish consumption is generally low in many countries, including the Middle East, resulting in low omega-3 blood levels. In Palestine, no data on the omega-3 blood status is available. The aim of this cross-sectional study was to assess the omega-3 status and related factors in young healthy subjects from Palestine. Omega-3 status was assessed using the Omega-3 Index-defined as the sum of EPA + DHA in relation to the total fatty acid content of erythrocytes. A total of 149 subjects, 50 males and 99 females (age range: 18-24 years), were included in the study. In addition to the Omega-3 Index, data on anthropometrics, physical activity, smoking status, fish intake, dietary supplement intake, blood lipid profile, and whole erythrocyte fatty acid pattern were collected. The mean (SD) Omega-3 Index was 2.56 (0.57)%, with 97.9% of subjects having an index below 4%. The majority of participants (91.8%) consumed less than two portions of fish per week, and only 4% reported taking omega-3 supplements, mostly irregularly. Our findings show that young Palestinian students have an alarmingly low omega-3 status. Further studies are needed to investigate whether the omega-3 status is also low in the general Palestinian population.

Equal bioavailability of omega-3 PUFA from Calanus oil, fish oil and krill oil: A 12-week randomized parallel study

The bioavailability of long-chain omega-3 polyunsaturated fatty acids (n3 PUFA) can be affected by the form in which they are bound. An alternative source of n3 PUFA is Calanus finmarchicus oil (CO), which, unlike fish oil (FO) and krill oil (KO), contains fatty acids primarily bound as wax esters. Recent studies have shown that n3 PUFA from CO are bioavailable to humans, but CO has not been compared to other marine oils such as FO or KO. Therefore, the aim of this study was to investigate the influence of 12 weeks supplementation with CO, FO and KO on the long-term n3 PUFA status in healthy volunteers. The Omega-3 Index (O3I), defined as red blood cell EPA + DHA content as a percentage of total identified fatty acids, was used as a measure to assess n3 PUFA status. Sixty-two participants (mean ± standard deviation [SD] age: 29.7 ± 8.43 years) completed the randomized parallel group study (CO group: n = 21, 4 capsules/day, EPA + DHA dose: 242 mg/day; FO group: n = 22, 1 capsule/day, EPA + DHA dose: 248 mg/day; KO group: n = 19, 2 capsules/day, EPA + DHA dose: 286 mg/day). At baseline, the three groups showed comparable (mean ± SD) O3I values (CO: 5.13 ± 1.12%, FO: 4.90 ± 0.57%, KO: 4.87 ± 0.77%). The post-interventional (mean ± SD) O3I increase was comparable between the three groups (CO: 1.09 ± 0.55%; FO: 1.0 ± 0.53%; KO: 1.15 ± 0.65%, all p < 0.001). The study confirms that CO can increase the n3 PUFA status comparable to FO and KO and is therefore an alternative marine source of bioavailable n3 PUFA, especially with regard to sustainability.

Assessment of the vitamin D status and its determinants in young healthy students from Palestine

The global prevalence of vitamin D deficiency is high. Poor vitamin D status, especially in women, has been reported in several countries in the Middle East despite adequate year-round sunlight for vitamin D synthesis. However, data on vitamin D status in Palestine are scarce. The aim of this cross-sectional study was to evaluate vitamin D status based on serum concentrations of 25-hydroxycholecalciferol [25-(OH)D] among young healthy Palestinian students (18-27 years) and to assess associations between 25-(OH)D concentrations and several predictors. The mean 25-(OH)D concentration of women (n 151) was 27⋅2 ± 14⋅5 nmol/l, with the majority having insufficient (31⋅1 %) or deficient (<60 %) 25-(OH)D status. Only 7 % of women achieved sufficient or optimal 25-(OH)D status. In contrast, men (n 52) had a mean 25-(OH)D concentration of 58⋅3 ± 14⋅5 nmol/l, with none classified as deficient, and most obtaining sufficient (55⋅8 %) or even optimal 25-(OH)D status (11⋅5 %). Among women, 98 % wore a hijab and 74 % regularly used sunscreen. Daily dietary vitamin D intake (3-d 24-h recalls) was 45⋅1 ± 36⋅1 IU in the total group (no sex differences). After adjustment, multiple linear regression models showed significant associations between 25-(OH)D concentrations and the use of supplements (B = 0⋅069; P = 0⋅020) and dietary vitamin D (B = 0⋅001; P = 0⋅028). In gender-stratified analysis, the association between supplement use and 25-(OH)D concentrations was significant in women (B = 0⋅076; P = 0⋅040). The vitamin D status of women in the present cohort is critical and appears to be mainly due to wearing a hijab, regular use of sunscreen and low dietary vitamin D intake. The vitamin D status of the women should be improved by taking vitamin D containing supplements or fortified foods.

Red blood cell fatty acid patterns from 7 countries: Focus on the Omega-3 index

Red blood cell (RBC) fatty acid (FA) patterns are becoming recognized as long-term biomarkers of tissue FA composition, but different analytical methods have complicated inter-study and international comparisons. Here we report RBC FA data, with a focus on the Omega-3 Index (EPA + DHA in% of total FAs in RBC), from samples of seven countries (USA, Canada, Italy, Spain, Germany, South Korea, and Japan) including 167,347 individuals (93% of all samples were from the US). FA data were generated by a uniform methodology from a variety of interventional and observational studies and from clinical laboratories. The cohorts differed in size, demographics, health status, and year of collection. Only the Canadian cohort was a formal, representative population-based survey. The mean Omega-3 Index of each country was categorized as desirable (>8%), moderate (>6% to 8%), low (>4% to 6%), or very low (≤4%). Only cohorts from Alaska (treated separately from the US), South Korea and Japan showed a desirable Omega-3 Index. The Spanish cohort had a moderate Omega-3 Index, while cohorts from the US, Canada, Italy, and Germany were all classified as low. This study is limited by the use of cohorts of convenience and small sample sizes in some countries. Countries undertaking national health status studies should utilize a uniform method to measure Omega-3 FA levels.

Marine Oil from C. finmarchicus Enhances Glucose Homeostasis and Liver Insulin Resistance in Obese Prediabetic Individuals

The intermediate state between normal glucose tolerance and overt type 2 diabetes mellitus is associated with micro- and macrovascular diseases, requiring safe and cost-effective treatment measures interventions. A novel source of LC n-3 FAs is Calanus finmarchicus Oil, which showed promising effects on glucose homeostasis in preclinical studies due to anti-obesity effects and/or anti-inflammatory properties. In total, 43 obese patients (BMI: 31.7 ± 5.2 kg/m²) were allocated in the following two groups: (1) Calanus oil group (2 g CO/day) and (2) placebo group (2 g paraffin oil/day). Markers of glucose metabolism, body composition and energy intake were measured at the beginning (t0), after 12 weeks (t₁₂) and 16 weeks (t₁₆). Overall, parameters reflecting abnormal glucose homeostasis and insulin resistance in the liver, including fasting insulin (−2.9 mU/L ± 4.10, p < 0.05), HOMA-IR (−0.9 ± 1.28, p < 0.05) and hepatic insulin resistance index (−1.06 ± 1.72 × 10⁶, p < 0.05) significantly enhanced after a 12-week CO-intervention, while no differences were observed in HbA1c, AUC_0–2h Glucose, AUC_0–2h Insulin, 2 h plasma glucose and muscle insulin sensitivity index. Our results indicate that Calanus oil causes beneficial effects on glucose metabolism and insulin resistance in obese patients, with clinical relevance to be verified in further studies. In addition, the possible active compounds and their mechanisms of action should be elucidated.

Effects of Exercise Combined with a Healthy Diet or Calanus finmarchicus Oil Supplementation on Body Composition and Metabolic Markers-A Pilot Study

Aging is accompanied by a progressive decline in muscle mass and an increase in fat mass, which are detrimental changes associated with the development of health conditions such as type-2 diabetes mellitus or chronic low-grade inflammation. Although both exercise as well as nutritional interventions are known to be beneficial in counteracting those age-related changes, data to which extent untrained elderly people may benefit is still sparse. Therefore, a randomized, controlled, 12-week interventional trial was conducted in which 134 healthy untrained participants (96 women and 38 men, age 59.4 ± 5.6 years, body mass index (BMI) 28.4 ± 5.8 kg/m²) were allocated to one of four study groups: (1) control group with no intervention (CON); (2) 2×/week aerobic and resistance training only (EX); (3) exercise routine combined with dietary counseling in accordance with the guidelines of the German Nutrition Society (EXDC); (4) exercise routine combined with intake of 2 g/day oil from Calanus finmarchicus (EXCO). Body composition (bioelectrical impedance analysis), as well as markers of glucose metabolism and blood lipids, were analyzed at the beginning and the end of the study. The highest decreases in body fat were observed within the EXCO group (−1.70 ± 2.45 kg, p < 0.001), and the EXDC (−1.41 ± 2.13 kg, p = 0.008) group. Markers of glucose metabolism and blood lipids remained unchanged in all groups. Taken together results of this pilot study suggest that a combination of moderate exercise and intake of oil from Calanus finmarchicus or a healthy diet may promote fat loss in elderly untrained overweight participants.

Characterization, dietary habits and nutritional intake of omnivorous, lacto-ovo vegetarian and vegan runners - a pilot study

BACKGROUND

The number of people preferring plant-based nutrition is growing continuously in the western world. Vegetarianism and veganism are also becoming increasingly popular among individuals participating in sport. However, whether recreationally active vegetarian and vegan populations can meet their nutritional needs is not clear.

METHODS

The purpose of this cross-sectional study was to compare the nutrient intake of omnivorous (OMN, n = 27), lacto-ovo vegetarian (LOV, n = 25) and vegan (VEG, n = 27) recreational runners (two to five training sessions per week) with intake recommendations of the German, Austrian and Swiss Nutrition Societies (Deutsche, Österreichische und Schweizerische Gesellschaften für Ernährung, D-A-CH) for the general population. Lifestyle factors and supplement intake were examined via questionnaires; dietary habits and nutrient intake were determined based on 3-day dietary records.

RESULTS

More than half of each group did not reach the recommended energy intake (OMN: 10.4, 8.70-12.1; LOV: 9.67, 8.55-10.8; VEG: 10.2, 9.12-11.3 MJ). Carbohydrate intake was slightly below the recommendations of > 50 EN% in OMN (46.7, 43.6-49.8 EN%), while LOV (49.4, 45.5-53.3 EN%) and VEG (55.2, 51.4-59.0 EN%) consumed adequate amounts (p = 0.003). The recommended protein intake of 0.8 g/kg body weight (D-A-CH) was exceeded in all three groups (OMN: 1.50, 1.27-1.66; LOV: 1.34, 1.09-1.56; VEG: 1.25; 1.07-1.42 g/kg BW; p = 0.047). Only VEG (26.3, 22.7-29.8 EN%) did not achieve the recommended fat intake of 30 EN%. The supply of micronutrients, such as vitamin D and cobalamin, was dependent on supplement intake. Additionally, female OMN and LOV achieved the recommended daily intake of 15 mg iron only after supplementation, while VEG consumed adequate amounts solely via food.

CONCLUSION

All three groups were sufficiently supplied with most nutrients despite the exceptions mentioned above. The VEG group even showed advantages in nutrient intake (e.g. carbohydrates, fiber and iron) in comparison to the other groups. However, the demand for energy and several macro- and micronutrients might be higher for athletes. Thus, it is also necessary to analyze the endogenous status of nutrients to evaluate the influence of a vegetarian and vegan diet on the nutrient supply of athletes.

TRIAL REGISTRATION

German Clinical Trial Register (DRKS00012377), registered on April 28, 2017.

Effects of a low and a high dietary LA/ALA ratio on long-chain PUFA concentrations in red blood cells

There is a debate about the optimal dietary ratio of LA and ALA to promote an efficient conversion of ALA to EPA and DHA, which have implications for human health.

Effects of a 12-week high-α-linolenic acid intervention on EPA and DHA concentrations in red blood cells and plasma oxylipin pattern in subjects with a low EPA and DHA status

The essential omega-3 fatty acid alpha-linolenic acid (ALA, 18:3n3) can be converted into EPA and DHA.

Intestinal Absorption and Factors Influencing Bioavailability of Magnesium-An Update

Background:

Information on the bioavailability of the essential mineral Mg2+ is sparse.

Objective/Method:

Evaluation of the present knowledge on factors influencing the bioavailability and intestinal absorption of Mg2+.

Results:

Mg2+ is absorbed via a paracellular passive and a transcellular active pathway that involves TRPM6/7 channel proteins. The bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors. Dietary factors impairing Mg2+ up-take include high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate, whereas proteins, medium-chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose) enhance Mg2+ uptake. The Mg2+ dose is a major factor controlling the amount of Mg2+ absorbed. In principle, the relative Mg2+ uptake is higher when the mineral is in-gested in multiple low doses throughout the day compared to a single, large intake of Mg2+. The type of Mg2+ salt appears less relevant than is often thought. Some studies demonstrated a slightly higher bioavailability of organic Mg2+ salts compared to inorganic compounds under standardized conditions, whereas other studies did not.

Conclusion:

Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form produces the highest bioavailability. The Mg2+ intake dose combined with the endogenous Mg2+ status is more important. Because Mg2+ cannot be stored but only retained for current needs, a higher absorption is usually followed by a higher excretion of the mineral.

Feasibility and first results of a group program to increase the frequency of cognitively stimulating leisure activities in people with mild cognitive impairment (AKTIVA-MCI)

AKTIVA-MCI is a program for patients with mild cognitive impairment (MCI) that aims to enhance participation in cognitively stimulating leisure activities. Participation in cognitively stimulating activities seems to be a potential strategy for people with MCI delaying cognitive decline for a while. In total, 35 MCI patients were enrolled in the pilot study of whom 29 completed the whole program (16 female, 71.1±7.5 years; Mini Mental Status Examination score: 28±2.2). Daily activity protocols were used to measure the frequency of participation in cognitively stimulating activities during the program (12 sessions). Additional standardized psychometric tests and questionnaires were used to assess cognition, mood, and subjective memory decline. Analyses of the daily activity protocols showed that during the intervention participants increased the frequency of several cognitively stimulating leisure activities. Comparison of pre-post data indicates no changes in cognitive status, mood, and subjective memory decline. These findings indicate that the program is suitable for patients with MCI.

Effect of DHA supplementation on oxylipin levels in plasma and immune cell stimulated blood

INTRODUCTION

EPA and DHA cause different physiological effects, which are in many cases mediated via their oxidative metabolites (oxylipins). However, metabolism studies investigating the effect of either EPA or DHA on comprehensive oxylipin patterns are lacking.

MATERIAL AND METHODS

The short and long term (1, 3, 6, and 12 week) effect of 1076mg/d DHA (free of EPA) on free (unesterified) oxylipin concentrations in plasma and lipopolysacharid (LPS) stimulated blood of 12 healthy men (mean age 25.1 ± 1.5 years) was investigated.

RESULTS

After DHA supplementation, plasma levels of all DHA-oxylipins (HDHAs, EpDPEs, DiHDPEs) significantly increased (up to 600%) in a time-dependent fashion. Oxylipins of EPA and arachidonic acid (AA) were also affected. Whereas a slight increase in several EPA-derived hydroxy-FAs (including the RvE1 precursor 18-HEPE) and dihydroxy-FAs was observed after DHA supplementation, a trend to a slight decline in AA-derived oxylipin levels was found. In LPS stimulated blood, it is shown that DHA supplementation significantly reduces the ability of immune cells to form AA-derived COX (TXB2 and PGB2) and 12-LOX (12-HETE) eicosanoids. While no increase in EPA COX metabolites was found, n-3 PUFA 12-LOX metabolites of EPA (12-HEPE) and DHA (14-HDHA) were highly induced.

CONCLUSION

We demonstrated that DHA supplementation causes a time-dependent shift in the entire oxylipin profile suggesting a cross-linked metabolism of PUFAs and subsequent formation of oxygenated lipid mediators.

Low long chain omega-3 fatty acid status in middle-aged women

INTRODUCTION

Long-chain (LC) omega-3 fatty acids (n-3 PUFAs) have beneficial effects on cardiovascular health and cognitive decline. Several studies have shown that the LC n-3 PUFA status in women in western countries is low. The aim of this study was to assess the LC n-3 PUFA status in middle-aged German women and to identify variables that might affect the status.

MATERIAL AND METHODS

From the nationwide and cross-sectional German VitaMinFemin study, fatty acid levels in the erythrocyte membrane (% of total erythrocyte fatty acids) were ascertained for 446 women (40-60 years).

RESULTS

The average omega-3 index (% of eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) of the total study population was 5.49±1.17%. A total of 62.8% of women had a low omega-3 index (>4-6%). The omega-3 index was affected by age and smoking, with slightly higher values in women ≥50 years (p=0.032) and non-smokers (p=0.002). Women taking hormonal contraceptives showed a lower EPA level (p<0.001), a lower ratio of EPA/alpha-linoleic acid (p<0.001) and a higher ratio of DHA/EPA (p<0.001) than women without hormonal contraception.

CONCLUSION

The low LC n-3 PUFA status in middle-aged German women (40-60 years) is related to an increased risk of cardiovascular diseases and possibly other diseases and should therefore be improved. Further studies are needed to determine the influence of estrogen on the effect on LC n-3 PUFA status.

Lipid Class Specific Quantitative Analysis of n-3 Polyunsaturated Fatty Acids in Food Supplements

Supplementation products containing n-3 PUFA from marine sources serve a large market. Although the amount of eicosapentaenoic acid and docosahexaenoic acid in the products is provided by the manufacturer, no or little information is available on their lipid pattern. Therefore, we quantitatively analyzed the fatty acid pattern in the lipid fractions triglycerides, phospholipids, ethyl esters, and free fatty acids in supplementation products by means of solid phase extraction and gas chromatography. Twelve products from the European and U.S. markets containing fish, krill, algal, or plant oil were analyzed. Total n-3 PUFA content ranged from 68 g/100 g fat (fish oil) to 42 g/100 g fat (algal oil) to 17 g/100 g fat (krill oil). On the basis of the n-3 PUFA containing lipid class, the supplements can be separated dominantly in ethyl ester, re-esterified triglyceride, triglyceride, and phospholipid containing products. Algae-based products contained natural triglycerides, krill oils a complex mixture of phospholipids, triglycerides, and free fatty acids, and fish oil products either ethyl esters, re-esterified triglycerides, or triglycerides. Even products of the same class and source showed distinct differences in their lipid pattern. A specification of the lipid composition of n-3 PUFA products would allow distinguishing the different (qualities of) supplements.

Impact of Omega-3 Fatty Acid Supplementation on Memory Functions in Healthy Older Adults

As the process of Alzheimer's disease (AD) begins years before disease onset, searching for prevention strategies is of major medical and economic importance. Nutritional supplementation with long-chain polyunsaturated omega-3 fatty acids (LC-n3-FA) may exert beneficial effects on brain structure and function. However, experimental evidence in older adults without clinical dementia is inconsistent, possibly due to low sensitivity of previously employed test batteries for detecting subtle improvements in cognition in healthy individuals. Here we used LOCATO, recently described as a robust and sensitive tool for assessing object-location memory (OLM) in older adults, to evaluate the impact of LC-n3-FA supplementation on learning and memory formation. In a double-blind placebo-controlled proof-of-concept study, 44 (20 female) cognitively healthy individuals aged 50-75 years received either LC-n3-FA (2,200 mg/day, n = 22) or placebo (n = 22) for 26 weeks. Before and after intervention, memory performance in the OLM-task (primary) was tested. As secondary outcome parameters, performance in Rey Auditory Verbal Learning Test (AVLT), dietary habits, omega-3-index, and other blood-derived parameters were assessed. Omega-3 index increased significantly in the LC-n3-FA group compared with the placebo group. Moreover, recall of object locations was significantly better after LC-n3-FA supplementation compared with placebo. Performance in the AVLT was not significantly affected by LC-n3-FA. This double-blind placebo-controlled proof-of-concept study provides further experimental evidence that LC-n3-FA exert positive effects on memory functions in healthy older adults. Our findings suggest novel strategies to maintain cognitive functions into old age.

Effects of docosahexaenoic acid supplementation on PUFA levels in red blood cells and plasma

INTRODUCTION

Polyunsaturated fatty acids (PUFA) are metabolized in a complex network of elongation, desaturation and beta oxidation.

MATERIAL AND METHODS

The short (1 and 3 wk), and long term (6 and 12 wk) effect of 1076mg/d docosahexaenoic acid (DHA, free of eicosapentaenoic acid (EPA)) on (absolute) PUFA concentrations in plasma and red blood cells (RBC) of 12 healthy men (mean age 25.1±1.5 years) was investigated.

RESULTS

RBC DHA concentrations significantly (p<0.001) increased from 28±1.6µg/mL to 38±2.0µg/mL (wk 1), 52±3.3µg/mL (wk 3), 68±2.6µg/mL (wk 6), and 79±3.5µg/mL (wk 12). Arachidonic acid (AA) concentrations declined in response to DHA treatment, while the effect was more pronounced in plasma (wk 0: 183±9.9µg/mL, wk 12: 139±8.0µg/mL, -24%, p<0.001) compared to RBC (wk 0: 130±3.7µg/mL, wk 12: 108±4.0µg/mL, -16%, p=0.001). Furthermore, an increase of EPA concentrations in plasma (wk 0: 15±1.5µg/mL, wk 1:19±1.6µg/mL, wk 3: 27±2.3µg/mL, wk 6: 23±1.2µg/mL, wk 12: 25±1.7µg/mL, p<0.001) and RBC (wk 0: 4.7±0.33µg/mL, wk 1: 6.7±1.3µg/mL, wk 3: 8.0±0.66µg/mL, wk 6: 6.9±0.44µg/mL, wk 12: 6.7±0.45µg/mL, n.s.) was observed suggesting a retroconversion of DHA to EPA.

CONCLUSION

Based on PUFA concentrations we showed that DHA supplementation results in increased EPA levels, whereas it is not known if this impacts the formation of EPA-derived lipid mediators. Furthermore, shifts in the entire PUFA pattern after supplementation of EPA or DHA should be taken into account when discussing differential physiological effects of EPA and DHA.

Impact of leptin on memory function and hippocampal structure in mild cognitive impairment

Metabolic changes have been suggested to contribute to dementia and its precursor mild cognitive impairment (MCI), yet previous results particularly for the "satiety hormone" leptin are mixed. Therefore, we aimed to determine if MCI patients show systematic differences in leptin, independent of sex, adipose mass, age, and glucose and lipid metabolism, and whether leptin levels correlated with memory performance and hippocampal integrity. Forty MCI patients (20 females, aged 67 years ± 7 SD) were compared to 40 healthy controls (HC) that were pair-wise matched for sex, age, and body fat. Memory performance was assessed using the auditory verbal learning test. Volume and microstructure of the hippocampus were determined using 3T-neuroimaging. Fasting serum markers of leptin, glucose and lipid metabolism, and other confounding factors were assayed. MCI patients, compared with HC, showed lower serum leptin, independent of sex, age, and body fat (P < 0.001). Glucose and lipid markers did not attenuate these results. Moreover, MCI patients exhibited poorer memory and lower volume and microstructural integrity within hippocampal subfields. While leptin and memory were not significantly correlated, mediation analyses indicated that lower leptin contributed to poorer memory through its negative effect on right hippocampus volume and left hippocampus microstructure. We demonstrated that MCI is associated with lower serum leptin independent of sex, age, body fat, glucose, and lipid metabolism. Our data further suggest that inefficient leptin signaling could partly contribute to decreases in memory performance through changes in hippocampus structure, a hypothesis that should now be verified in longitudinal studies. Hum Brain Mapp 37:4539-4549, 2016. © 2016 Wiley Periodicals, Inc.

Low daily dose of 3 mg monacolin K from RYR reduces the concentration of LDL-C in a randomized, placebo-controlled intervention

Hypercholesterolemia and elevated homocysteine concentrations are associated with cardiovascular risk. Previous studies have demonstrated a cholesterol-lowering effect of red yeast rice (RYR) supplements which contained 5 to 10 mg of monacolin K. We hypothesized that the intake of a low monacolin K dose may likewise reduce low-density lipoprotein-cholesterol (LDL-C) and other plasma lipids. In secondary analyses, we tested the homocysteine lowering effect of folic acid, which was also included in the study preparation. Therefore, we conducted a randomized, double-blind, and placebo-controlled intervention study. One hundred forty-two nonstatin-treated participants with hypercholesterolemia (LDL-C ≥ 4.14 ≤ 5.69 mmol/L) were randomized to the supplement group with RYR or the placebo group. Participants of the supplement group consumed 3 mg monacolin K and 200 μg folic acid per day. A significant (P < .001) reduction of LDL-C (-14.8%), total cholesterol (-11.2%), and homocysteine (-12.5%) was determined in the supplement group after 12 weeks. A total of 51% of the participants treated with RYR achieved the limit of LDL-C <4.14 mmol/L advised and 26% reached the threshold level of homocysteine <10 μmol/L. No significant changes were exhibited within the placebo group. Other parameters remained unchanged and no intolerances or serious adverse events were observed. In conclusion, we demonstrated that a low dose of daily 3 mg monacolin K from RYR reduces the concentration of LDL-C; a risk factor for cardiovascular diseases.

Higher omega-3 index and DHA status in pregnant women compared to lactating women - Results from a German nation-wide cross-sectional study

INTRODUCTION

During pregnancy and lactation, there is a high need of long-chain (LC) omega-3 fatty acids (n-3 PUFA), especially docosahexaenoic acid (DHA), for fetus and infant. Also, a low LC n-3 PUFA status during pregnancy is associated with postpartum depression. The aim of this cross-sectional study was to analyze the LC n-3 PUFA status in German women during pregnancy and lactation.

MATERIAL AND METHODS

As a part of a nationwide cross-sectional study in which the nutrient status of women in different stages of life was determined, 213 pregnant (≥27th week of gestation) and 127 lactating women between 18 and 44 years were evaluated regarding their LC n-3 PUFA status by measuring the omega-3 index (relative eicosapentaenoic acid (EPA) and DHA concentration in erythrocyte fatty acid).

RESULTS

The mean omega-3 index of the total study population was 6.23±1.48%. Pregnant women showed significant (p≤0.001) higher omega-3 index values (6.40±1.31%) and DHA concentrations (5.91±1.23%) than lactating women (omega-3 index: 5.50±1.34%; DHA: 4.79±1.27%). Woman with LC n-3 PUFA supplementation showed higher omega-3 index values (7.73±1.28%) vs. women without supplementation (6.04±1.39%, p≤0.001). Week of pregnancy, month of lactation as well as smoking were negatively associated with the omega-3 index.

CONCLUSION

Comprehensive data on the long-term LC n-3 PUFA status of German women during pregnancy and lactation are presented. To evaluate an optimal maternal omega-3 index in view of the fetal and infant development further studies are needed.

Vitamin B-12 concentration, memory performance, and hippocampal structure in patients with mild cognitive impairment

BACKGROUND

Low-normal concentrations of vitamin B-12 (VitB12) may be associated with worse cognition. However, previous evidence has been mixed, and the underlying mechanisms remain unclear.

OBJECTIVE

We determined whether serum VitB12 concentrations within the normal range were linked to memory functions and related neuronal structures in patients with mild cognitive impairment (MCI).

DESIGN

In a cross-sectional design, we assessed 100 amnestic MCI patients (52 women; age range: 50-80 y) with low- and high-normal VitB12 concentration (median split: 304 pmol/L) for memory functions with the use of the Auditory Verbal Learning Test. MRI was performed at 3 tesla (n= 86) for the estimation of the volume and microstructure of the hippocampus and its subfields as indicated by the mean diffusivity on diffusion-weighted images. With the use of a mediation analysis, we examined whether the relation between VitB12 and memory performance was partially explained by volume or microstructure.

RESULTS

MCI patients with low-normal VitB12 showed a significantly poorer learning ability (P= 0.014) and recognition performance (P= 0.008) than did patients with high-normal VitB12. Also, the microstructure integrity of the hippocampus was lower in patients with low-normal VitB12, mainly in the cornu ammonis 4 and dentate gyrus region (P= 0.029), which partially mediated the effect of VitB12 on memory performance (32-48%). Adjustments for age, sex, education, apolipoprotein E e4 status, and total homocysteine, folate, and creatinine did not attenuate the effects.

CONCLUSIONS

Low VitB12 concentrations within the normal range are associated with poorer memory performance, which is an effect that is partially mediated by the reduced microstructural integrity of the hippocampus. Future interventional trials are needed to assess whether supplementation of VitB12 may improve cognition in MCI patients even in the absence of clinically manifested VitB12 deficiency. This trial was registered at clinicaltrials.gov as NCT01219244.

Influence of weight reduction on blood levels of C-reactive protein, tumor necrosis factor-α, interleukin-6, and oxylipins in obese subjects

INTRODUCTION

Obesity is associated with inflammation and weight reduction has been shown to influence the inflammatory process. Besides classic inflammatory markers, oxidized polyunsaturated fatty acid (PUFA) metabolites (oxylipins) are potent mediators of inflammation. Little is known about endogenous levels of oxylipins, e.g. hydroxy, epoxy and dihydroxy FA in obese subjects with persistent low-grade inflammation. We aimed to evaluate levels of inflammatory markers and blood oxylipins in obese subjects before and after weight reduction.

SUBJECTS AND METHODS

In the present study, 42 obese (BMI 32.7 ± 0.22 kg/m(2)) men and women were classified in groups according to high-sensitivity C-reactive protein (hsCRP) levels (no inflammation<1mg/L; low-grade inflammation ≥ 3 mg/L). Subjects underwent an intervention for eight weeks, which consisted of two phases: (1) week 1 and 2: total replacement of three meals by a formula diet and (2) six week partial formula diet (replacement of 1-2 meals). Blood samples were taken prior and post intervention for analysis of plasma protein levels of hsCRP, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Plasma Levels of free (unesterified) hydroxy, epoxy, and dihydroxy FAs as well as several prostanoids were analyzed in plasma by means of LC-MS-based targeted metabolomics.

RESULTS

At baseline subjects with low-grade inflammation (hsCRP 8.95 ± 1.39 mg/L) showed significant higher levels of IL-6 (22.7 ± 1.15 ng/L) and TNF-α (17.4 ± 0.75 ng/L) compared to subjects with no inflammation (hsCRP: 0.69 ± 0.05 mg/L; IL-6: 15.9 ± 1.18 ng/L; TNF-α: 14.6 ± 0.80 ng/L). In both group's body weight was significantly reduced (p<0.001) after intervention (no inflammation group: -7.19 ± 0.86 kg, -7.3 ± 0.89%, p<0.001; low-grade inflammation group: -6.78 ± 0.87 kg, -6.7 ± 0.81%, p<0.001). Moreover, we observed significant decreases in levels of hsCRP (4.66 ± 0.64 mg/L; p=0.006), IL-6 (6.81 ± 1.15 ng/L; p<0.001) and TNF-α (6.09 ± 0.47 ng/L; p<0.001) in subjects with low-grade inflammation. Of 60 quantified oxylipins, 11 linoleic acid (LA)-, 1 dihomo-γ-linolenic acid (DGLA)-, 7 alpha linolenic acid (ALA)-, 15 arachidonic acid (AA)-, 8 eicosapentaenoic acid (EPA)- and 18 docosahexaenoic acid (DHA)-metabolites could be detected in plasma. For most oxylipins no differences were found between the low and high hsCRP groups before and after weight reduction. Interestingly, in subjects with low- grade inflammation several AA-derived oxylipins (5-, 8-, 12-hydroxyeicosatetraenoic acids (HETE)) were significantly higher compared to subjects with no inflammation before weight reduction and significantly reduced after weight reduction.

CONCLUSION

Even moderate weight loss in obese subjects correlates to a significant improvement in the inflammatory state, by reducing hsCRP, IL-6, TNF-α and few oxylipins. The biological consequences of these changes remain to be further investigated.

Genetic Variants of the FADS Gene Cluster Are Associated with Erythrocyte Membrane LC PUFA Levels in Patients with Mild Cognitive Impairment

BACKGROUND

Long-chain (> 20 C-atoms) polyunsaturated fatty acids (LC PUFAs) of both the omega-6 (n-6) and omega-3 (n-3) series are important for the functional integrity of brain and thereby cognition, memory and mood. Clinical studies observed associations between altered LC PUFA levels and neurodegenerative diseases such as Alzheimer´s disease and its prodromal stage, mild cognitive impairment (MCI).

METHODS

The present study examined the LC PUFA status of MCI patients with specific view on the relative LC n-3 PUFA levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocyte membranes (omega-3 index). 12 single nucleotide polymorphisms (SNPs) of the FADS1, FADS2, and FADS3 gene clusters were genotyped in 111 MCI patients and evaluated associations with PUFA levels in erythrocyte membranes (primary outcome). In addition, the associations between FADS SNPs and LC PUFA levels with serum lipid levels as well as depressive symptoms were examined (secondary outcomes).

RESULTS

Minor allele carrier of rs174546, rs174548 (FADS1), rs3834458, rs1535, rs174574, rs174575, rs174576, and rs174578 (FADS2) showed significant higher n-6 and n-3 precursor PUFA levels (linoleic acid, and alpha-linolenic acid, respectively) and lower arachidonic acid (AA) levels in erythrocyte membranes compared to the major allele carriers. Differences in EPA and DHA levels were not significant. Minor allele carriers of rs174574, rs174576 and rs174578 (FADS2) and rs174455 (FADS3) exhibited significant higher triglyceride levels, whereas minor allele carriers for rs174449 and rs174455 (FADS3) exhibited significant higher total- and LDL-cholesterol levels compared to the more common variant. The mean omega-3 index of the study cohort was 6.19 ± 1.55 %. In more than 85 % of the patients, the omega-3 index was below 8 % and in 23 % below 5 %. Moreover, it was shown that a low DHA status and omega-3 index was associated with depressive symptoms (Beck's depression-inventory).

DISCUSSION AND CONCLUSION

These findings indicate an association between several FADS genotypes for higher n-6 and n-3 precursor PUFA and lower AA levels in erythrocyte membranes in minor compared to major allele carriers. To what extent FADS genotypes and a lower conversion of LA and ALA to biologically important LC PUFAs such as AA, EPA and DHA contributes to cognitive decline should be investigated in further trials. Nevertheless, the omega-3 index in this cohort of MCI patients can be classified as insufficient.

Glycemic index and microstructure analysis of a newly developed fiber enriched cookie

A diet with a high glycemic index (GI) is associated with an elevated risk for obesity or type 2 diabetes.

Effect of omega-3 polyunsaturated fatty acids on the cytoskeleton: an open-label intervention study

Background

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) show beneficial effects on cardiovascular health and cognitive functions, but the underlying molecular mechanisms are not completely understood. Because of the fact that cytoskeleton dynamics affect almost every cellular process, the regulation of cytoskeletal dynamics could be a new pathway by which n-3 PUFAs exert their effects on cellular level.

Methods

A 12-week open-label intervention study with 12 healthy men was conducted to determine the effects of 2.7 g/d n-3 PUFA on changes in mRNA expression of cytoskeleton-associated genes by quantitative real-time PCR in whole blood. Furthermore, the actin content in red blood cells was analyzed by immunofluorescence imaging.

Results

N-3 PUFA supplementation resulted in a significant down-regulation of cytoskeleton-associated genes, in particular three GTPases (RAC1, RHOA, CDC42), three kinases (ROCK1, PAK2, LIMK), two Wiskott-Aldrich syndrome proteins (WASL, WASF2) as well as actin related protein 2/3 complex (ARPC2, ARPC3) and cofilin (CFL1). Variability in F-actin content between subjects was high; reduced actin content was only reduced within group evaluation.

Conclusions

Reduced cytoskeleton-associated gene expression after n-3 PUFA supplementation suggests that regulation of cytoskeleton dynamics might be an additional way by which n-3 PUFAs exert their cellular effects. Concerning F-actin, this analysis did not reveal unmistakable results impeding a generalized conclusion.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-511X-14-4) contains supplementary material, which is available to authorized users.

Associations between Omega-3 Index increase and triacylglyceride decrease in subjects with hypertriglyceridemia in response to six month of EPA and DHA supplementation

INTRODUCTION

Ingestion of long-chain n-3 PUFA effectively decreases serum triacylglycerol (TAG) levels and increases the Omega-3 Index, defined as the % of EPA and DHA in erythrocyte fatty acids. However, it remains unclear whether there is a relationship between the Omega-3 Index increase (ΔO3I increase) and the TAG level decrease (ΔTAG). We hypothesized that TAG reduction is strongly depended on Omega-3 Index increase.

SUBJECTS AND METHODS

Secondary analyses of data from a former double-blind placebo-controlled trial in which 150 dyslipidemic statin-treated subjects were randomized to four capsules of fish oil daily either as re-esterified TAG or ethyl esters in identical doses (1.01 g EPA+0.67 g DHA) or corn oil as a placebo for a period of six month.

RESULTS

108 subjects fulfilled the criteria of the current study protocol and were included in the analyses. A weak but significant negative correlation between ΔO3I and ΔTAG was observed (r=-0.211, p<0.05). However, the relation between ΔO3I and serum ΔTAG was not linear (coefficients of determination R(2): 0.044). After sub-grouping the study population into Omega-3 Index response groups, the group with a mean ΔO3I of>4% after six months of n-3 PUFA treatment demonstrated the greatest TAG reduction.

DISCUSSION AND CONCLUSIONS

A weak association between Omega-3 Index increase and TAG level decrease was found. This may be explained by highly fluctuating TAG levels, a large inter-individual difference in response of the Omega-3 Index, a cohort of subjects with only slightly elevated TAG levels and high Omega-3 Index values at baseline, and possibly to insufficient statistical power. Since there was no strong association between Omega-3 Index increase and the TAG level decrease, we conclude that changes in serum TAG levels are not a viable substitute for the Omega-3 Index to monitor treatment with EPA and DHA.

Increase of EPA-derived hydroxy, epoxy and dihydroxy fatty acid levels in human plasma after a single dose of long-chain omega-3 PUFA

INTRODUCTION

Several supplementation studies with long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) describe an increase of EPA-derived hydroxy, epoxy and dihydroxy fatty acids in blood, while changes in levels of other LC n-3 and n-6 PUFA-derived oxylipins were minor. In order to investigate the kinetics of changes in oxylipin levels in response to LC n-3 PUFA ingestion, we conducted a single dose treatment study with healthy subjects.

SUBJECTS AND METHODS

In the present kinetic study, we compared patterns of hydroxy, epoxy and dihydroxy fatty acids in plasma of 6 healthy men before and after 6, 8, 24, and 48h of fish oil (1008mg EPA and 672mg DHA) ingestion. Levels of EPA- as well as other LC PUFA-derived hydroxy, epoxy and dihydroxy fatty acids were analyzed in plasma by LC-MS. Additionally, levels of these oxylipins were compared with their parent PUFA levels in plasma phospholipids.

RESULTS

All EPA-derived oxylipin levels were significantly increased 6h after LC n-3 PUFA ingestion and gradually drop thereafter reaching the baseline levels about 48h after treatment. The relative increase in EPA plasma phospholipid levels highly correlated with the increase of plasma EPA-derived oxylipin levels at different time points. In contrast, plasma levels of arachidonic acid- and DHA-derived oxylipins as well as parent PUFA levels in plasma phospholipids were hardly changed.

DISCUSSION AND CONCLUSIONS

Our findings demonstrate that a single dose of LC n-3 PUFAs can rapidly induce a shift in the EPA oxylipin profile of healthy subjects within a few hours. Taking the high biological activity of the EPA-derived epoxy fatty acids into account, even short-term treatment with LC n-3 PUFAs may cause systemic effects, which warrant further investigation.

Modulation of blood oxylipin levels by long-chain omega-3 fatty acid supplementation in hyper- and normolipidemic men

INTRODUCTION

Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFA) such as EPA and DHA have been shown to possess beneficial health effects, and it is believed that many of their effects are mediated by their oxygenated products (oxylipins). Recently, we have shown that serum levels of several hydroxy, epoxy, and dihydroxy FAs are dependent on the individual status of the parent FAs in a cohort of normo- and hyperlipidemic subjects. So far, the effect of an increased dietary LC n-3 PUFA intake on hydroxy, epoxy, and dihydroxy FA levels has not been investigated in subjects with mild combined hyperlipidemia.

SUBJECTS AND METHODS

In the present study, we compared oxylipin patterns of 10 hyperlipidemic (cholesterol >200mg/dl; triglyceride >150mg/ml) and 10 normolipidemic men in response to twelve weeks of LC n-3 PUFA intake (1.14g DHA and 1.56g EPA). Levels of 44 free hydroxy, epoxy and dihydroxy FAs were analyzed in serum by LC-MS. Additionally, oxylipin levels were compared with their parent PUFA levels in erythrocyte membranes; a biomarker for the individual PUFA status.

RESULTS

Differences in the oxylipin pattern between normo- and hyperlipidemic subjects were minor before and after treatment. In all subjects, levels of EPA-derived oxylipins (170-4800pM) were considerably elevated after LC n-3 PUFA intake (150-1400%), the increase of DHA-derived oxylipins (360-3900pM) was less pronounced (30-130%). The relative change of EPA in erythrocyte membranes is strongly correlated (r≥0.5; p<0.05) with the relative change of corresponding epoxy and dihydroxy FA serum levels. The effect on arachidonic acid (AA)-derived oxylipin levels (140-27,100pM) was inconsistent.

DISCUSSION AND CONCLUSIONS

The dietary LC PUFA composition has a direct influence on the endogenous oxylipin profile, including several highly biological active EPA- and DHA-derived lipid mediators. The shift in oxylipin pattern appears to be dependent on the initial LC PUFA status particularly for EPA. The finding that also levels of other oxylipins derived from ALA, LA or AA are modified by LC n-3 PUFA intake might suggest that at least some of the effects of EPA and DHA could be mediated by a shift in the entire oxylipin profile.

Comparison of free serum oxylipin concentrations in hyper- vs. normolipidemic men

Oxylipins, the oxidation products of unsaturated fatty acids (FA), are potent endogenous mediators being involved in the regulation of various biological processes such as inflammation, pain and blood coagulation. Compared to oxylipins derived from arachidonic acid (AA) by cyclooxygenase action, i.e. prostanoides, only limited information is available about the endogenous levels of hydroxy-, epoxy- and dihydroxy-FA of linoleic acid (LA), AA, α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in humans. Particularly, it is unknown how metabolic disorders affect endogenous oxylipin levels in humans. Therefore, in the present study we compared the serum concentrations of 44 oxylipins in 20 normolipidemic with 20 hyperlipidemic (total cholesterol >200 mg/dl; LDL-C>130 mg/dl; TG>150 mg/dl) men (age 29-51 y). The serum concentration varied strongly among subjects. For most hydroxy-, epoxy- and dihydroxy-FA the concentrations were comparable to those in plasma reported in earlier studies. Despite the significant change in blood lipid levels the hyperlipidemic group showed only minor differences in oxylipin levels. The hyperlipidemic subjects had a slightly higher serum concentration of 8,9-DiHETrE, 5-HEPE, 10,11-DiHDPE, and a lower concentration of 12,13-DiHOME, 12-HETE, 9,10-DiHODE, and 12,13-DiHODE compared to normolipidemic subjects. Overall the hydroxy-, epoxy- and dihydroxy-FA levels were not changed suggesting that mild combined hyperlipidemia has no apparent effect on the concentration of circulating oxylipins. By contrast, serum levels of several hydroxy-, epoxy-, and dihydroxy-FA are dependent on the individual status of the parent FA. Particularly, a strong correlation between the EPA content in the erythrocyte membrane and the serum concentration of EPA derived oxylipins was observed. Given that the synthesis of EPA from other n-3 FA in humans is low; this suggests that oxylipin levels can be directly influenced by the diet.

Bioavailability of long-chain omega-3 fatty acids

Supplements have reached a prominent role in improving the supply of long-chain omega-3 fatty acids, such as Eicosapentaenoic acid (EPA 20:5n-3) and Docosahexaenoic acid (DHA 22:6n-3). Similar to other nutrients, the availability of omega-3 fatty acids is highly variable and determined by numerous factors. However, the question of omega-3 fatty acids bioavailability has long been disregarded, which may have contributed to the neutral or negative results concerning their effects in several studies. This review provides an overview of the influence of chemical binding form (free fatty acids bound in ethylesters, triacylglycerides or phospholipids), matrix effects (capsule ingestion with concomitant intake of food, fat content in food) or galenic form (i.e. microencapsulation, emulsification) on the bioavailability of omega-3 fatty acids. There is a need to systematically investigate the bioavailability of omega-3 fatty acids formulations, which might be a key to designing more effective studies in the future.

Long-chain omega-3 fatty acids improve brain function and structure in older adults

Higher intake of seafish or oil rich in long-chain omega-3 polyunsaturated fatty acids (LC-n3-FA) may be beneficial for the aging brain. We tested in a prospective interventional design whether high levels of supplementary LC-n3-FA would improve cognition, and addressed potential mechanisms underlying the effects. Sixty-five healthy subjects (50-75 years, 30 females) successfully completed 26 weeks of either fish oil (2.2 g/day LC-n3-FA) or placebo intake. Before and after the intervention period, cognitive performance, structural neuroimaging, vascular markers, and blood parameters were assayed. We found a significant increase in executive functions after LC-n3-FA compared with placebo (P = 0.023). In parallel, LC-n3-FA exerted beneficial effects on white matter microstructural integrity and gray matter volume in frontal, temporal, parietal, and limbic areas primarily of the left hemisphere, and on carotid intima media thickness and diastolic blood pressure. Improvements in executive functions correlated positively with changes in omega-3-index and peripheral brain-derived neurotrophic factor, and negatively with changes in peripheral fasting insulin. This double-blind randomized interventional study provides first-time evidence that LC-n3-FA exert positive effects on brain functions in healthy older adults, and elucidates underlying mechanisms. Our findings suggest novel strategies to maintain cognitive functions into old age.

Regulation of lipid metabolism-related gene expression in whole blood cells of normo- and dyslipidemic men after fish oil supplementation

Background

Beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs) on the lipid levels of dyslipidemic subjects are widely described in the literature. However, the underlying molecular mechanisms are largely unknown. The aim of this study was to investigate the effects of n-3 PUFAs on the expression of lipid metabolism-related genes in normo- and dyslipidemic men to unveil potential genes and pathways affecting lipid metabolism.

Methods

Ten normo- and ten dyslipidemic men were supplemented for twelve weeks with six fish oil capsules per day, providing 1.14 g docosahexaenoic acid and 1.56 g eicosapentaenoic acid. The gene expression levels were determined by whole genome microarray analysis and quantitative real-time polymerase chain reaction.

Results

Several transcription factors (peroxisome proliferator-activated receptor α (PPARα), retinoid X receptor (RXR) α, RXRγ, hepatic nuclear factor (HNF) 6, and HNF1ß) as well as other genes related to triacylglycerol (TG) synthesis or high-density lipoprotein (HDL-C) and cholesterol metabolism (phospholipids transfer protein, ATP-binding cassette sub-family G member 5, 2-acylglycerol O-acyltransferase (MOGAT) 3, MOGAT2, diacylglycerol O-acyltransferase 1, sterol O-acyltransferase 1, apolipoprotein CII, and low-density lipoprotein receptor) were regulated after n-3 PUFA supplementation, especially in dyslipidemic men.

Conclusion

Gene expression analyses revealed several possible molecular pathways by which n-3 PUFAs lower the TG level and increase the HDL-C and low-density lipoprotein level, whereupon the regulation of PPARα appear to play a central role.

Trial registration

ClinicalTrials.gov (ID: NCT01089231)

Transcriptome-based identification of antioxidative gene expression after fish oil supplementation in normo- and dyslipidemic men

Background

The beneficial effects of omega-3 polyunsaturated fatty acids (n-3 PUFAs), especially in dyslipidemic subjects with a high risk of cardiovascular disease, are widely described in the literature. A lot of effects of n-3 PUFAs and their oxidized metabolites are triggered by regulating the expression of genes. Currently, it is uncertain if the administration of n-3 PUFAs results in different expression changes of genes related to antioxidative mechanisms in normo- and dyslipidemic subjects, which may partly explain their cardioprotective effects. The aim of this study was to investigate the effects of n-3 PUFA supplementation on expression changes of genes involved in oxidative processes.

Methods

Ten normo- and ten dyslipidemic men were supplemented for twelve weeks with fish oil capsules, providing 1.14 g docosahexaenoic acid and 1.56 g eicosapentaenoic acid. Gene expression levels were determined by whole genome microarray analysis and quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Using microarrays, we discovered an increased expression of antioxidative enzymes and a decreased expression of pro-oxidative and tissue enzymes, such as cytochrome P450 enzymes and matrix metalloproteinases, in both normo- and dyslipidemic men. An up-regulation of catalase and heme oxigenase 2 in both normo- and dyslipidemic subjects and an up-regulation of cytochrome P450 enzyme 1A2 only in dyslipidemic subjects could be observed by qRT-PCR analysis.

Conclusions

Supplementation of normo- and dyslipidemic subjects with n-3 PUFAs changed the expression of genes related to oxidative processes, which may suggest antioxidative and potential cardioprotective effects of n-3 PUFAs. Further studies combining genetic and metabolic endpoints are needed to verify the regulative effects of n-3 PUFAs in antioxidative gene expression to better understand their beneficial effects in health and disease prevention.

Trial registration

ClinicalTrials.gov (ID: NCT01089231)

Moderate doses of EPA and DHA from re-esterified triacylglycerols but not from ethyl-esters lower fasting serum triacylglycerols in statin-treated dyslipidemic subjects: Results from a six month randomized controlled trial

Recently, in a supplementation study over six months, it has been demonstrated that re-esterified omega-3 fatty acid triacylglycerols (n3-FA-rTAGs) led to a higher increase in omega-3-index compared to identical doses of n3-FA ethyl-esters (n3-FA-EEs), suggesting a better long-term bioavailability. The aim of this study was to examine whether differences occur between the two forms in affecting fasting serum lipid levels. 150 dyslipidemic statin-treated participants were randomized to corn oil as a placebo or fish oil either as rTAG or EE in identical doses (1.01g EPA+0.67g DHA). No changes in total cholesterol, HDL or LDL levels were observed. In the rTAG-group, but not in the EE-group, fasting serum TAG levels were significantly reduced from baseline after three and six months. There was no significant difference between the two n3-FA-groups. However, serum TAG levels were significantly lowered after six months in the rTAG-group compared to the placebo-group in contrast to the EE-group.

Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations--a comparative bioavailability study of fish oil vs. krill oil

BACKGROUND

Bioavailability of omega-3 fatty acids (FA) depends on their chemical form. Superior bioavailability has been suggested for phospholipid (PL) bound omega-3 FA in krill oil, but identical doses of different chemical forms have not been compared.

METHODS

In a double-blinded crossover trial, we compared the uptake of three EPA+DHA formulations derived from fish oil (re-esterified triacylglycerides [rTAG], ethyl-esters [EE]) and krill oil (mainly PL). Changes of the FA compositions in plasma PL were used as a proxy for bioavailability. Twelve healthy young men (mean age 31 y) were randomized to 1680 mg EPA+DHA given either as rTAG, EE or krill oil. FA levels in plasma PL were analyzed pre-dose and 2, 4, 6, 8, 24, 48, and 72 h after capsule ingestion. Additionally, the proportion of free EPA and DHA in the applied supplements was analyzed.

RESULTS

The highest incorporation of EPA+DHA into plasma PL was provoked by krill oil (mean AUC0-72 h: 80.03 ± 34.71%*h), followed by fish oil rTAG (mean AUC0-72 h: 59.78 ± 36.75%*h) and EE (mean AUC0-72 h: 47.53 ± 38.42%*h). Due to high standard deviation values, there were no significant differences for DHA and the sum of EPA+DHA levels between the three treatments. However, a trend (p = 0.057) was observed for the differences in EPA bioavailability. Statistical pair-wise group comparison's revealed a trend (p = 0.086) between rTAG and krill oil. FA analysis of the supplements showed that the krill oil sample contained 22% of the total EPA amount as free EPA and 21% of the total DHA amount as free DHA, while the two fish oil samples did not contain any free FA.

CONCLUSION

Further studies with a larger sample size carried out over a longer period are needed to substantiate our findings and to determine differences in EPA+DHA bioavailability between three common chemical forms of LC n-3 FA (rTAG, EE and krill oil). The unexpected high content of free EPA and DHA in krill oil, which might have a significant influence on the availability of EPA+DHA from krill oil, should be investigated in more depth and taken into consideration in future trials.

Enhanced increase of omega-3 index in response to long-term n-3 fatty acid supplementation from triacylglycerides versus ethyl esters

BACKGROUND

There is a debate currently about whether different chemical forms of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are absorbed in an identical way. The objective of this study was to investigate the response of the omega-3 index, the percentage of EPA+DHA in red blood cell membranes, to supplementation with two different omega-3 fatty acid (n-3 FA) formulations in humans.

DESIGN

The study was conducted as a double-blinded placebo-controlled trial. A total of 150 volunteers was randomly assigned to one of the three groups: (1) fish oil concentrate with EPA+DHA (1.01 g+0.67 g) given as reesterified triacylglycerides (rTAG group); (2) corn oil (placebo group) or (3) fish oil concentrate with EPA+DHA (1.01 g+0.67 g) given as ethyl ester (EE group). Volunteers consumed four gelatine-coated soft capsules daily over a period of six months. The omega-3 index was determined at baseline (t(0)) after three months (t(3)) and at the end of the intervention period (t(6)).

RESULTS

The omega-3 index increased significantly in both groups treated with n-3 FAs from baseline to t(3) and t(6) (P<0.001). The omega-3 index increased to a greater extent in the rTAG group than in the EE group (t(3): 186 versus 161% (P<0.001); t(6): 197 versus 171% (P<0.01)).

CONCLUSION

A six-month supplementation of identical doses of EPA+DHA led to a faster and higher increase in the omega-3 index when consumed as triacylglycerides than when consumed as ethyl esters.

Significance of long-chain polyunsaturated fatty acids (PUFAs) for the development and behaviour of children

omega-6 and omega-3 polyunsaturated fatty acids (PUFAs) play a central role in the normal development and functioning of the brain and central nervous system. Long-chain PUFAs (LC-PUFAs) such as eicosapentaenoic acid (EPA, C20:5omega-3), docosahexaenoic acid (DHA, C22:6omega-3) and arachidonic acid (AA, C20:4omega-6), in particular, are involved in numerous neuronal processes, ranging from effects on membrane fluidity to gene expression regulation. Deficiencies and imbalances of these nutrients, not only during the developmental phase but throughout the whole life span, have significant effects on brain function. Numerous observational studies have shown a link between childhood developmental disorders and omega-6:omega-3 fatty acid imbalances. For instance, neurocognitive disorders such as attention-deficit hyperactivity disorder (ADHD), dyslexia, dyspraxia and autism spectrum disorders are often associated with a relative lack of omega-3 fatty acids. In addition to a high omega-6 fatty acid intake and, in many cases, an insufficient supply of omega-3 fatty acids among the population, evidence is increasing to suggest that PUFA metabolism can be impaired in individuals with ADHD. In this context, PUFA imbalances are being discussed as potential risk factors for neurodevelopmental disorders. Another focus is whether the nutritive PUFA requirements-especially long-chain omega-3 fatty acid requirements-are higher among some individuals. Meanwhile, several controlled studies investigated the clinical benefits of LC-PUFA supplementation in affected children and adolescents, with occasionally conflicting results.