DNA methylation pattern in overweight women under an energy-restricted diet supplemented with fish oil

Epigenomic mechanisms of dietary prescriptions for obesity therapy

Dietary modification is a cornerstone and a primary goal for weight loss, whose effects may be related to epigenetic phenomena. In this literature review, a comprehensive search without time restriction was performed in PubMed/Medline, Cochrane, SciELO, and Scopus databases to identify epigenetic signatures related to obesity outcomes upon dietary advice. In this context, experimental studies and clinical trials have identified certain DNA methylation marks, miRNA expression profiles and histone modifications putatively associated with adiposity outcomes after different nutritional interventions. These include traditional dietary patterns, diets with different macronutrient compositions, and supplementation with fatty acids, amino acids and derivatives, methyl donors, vitamins and minerals, probiotics and prebiotics, and bioactive food compounds. Some of these epigenetic signatures have been mapped to genes involved in food intake control, adipogenesis, lipolysis, fatty acid oxidation, body fat deposition, and gut microbiota modulation. However, additional studies are still required to address dosage and follow-up variability, validation of epigenetic marks, genome-wide approaches, and appropriate statistical settings. Although more investigation is required, these insights may contribute to the characterization of epigenetic biomarkers of body weight regulation toward the prescription of tailored dietary strategies targeting the epigenome for a more precise obesity management and control.

The epigenetic impact of fatty acids as DNA methylation modulators

DNA methylation is a key epigenetic mechanism that regulates gene expression. Fatty acids, the building blocks of many essential lipids, play a crucial role in various biological events. Aberrant acetylation and methylation profiles are linked to a number of non-communicable diseases. Various fatty acids have been identified as potential 'epi-drugs' because of their ability to correct aberrant acetylation and methylation profiles in a number of non-communicable diseases, enhancing the value of their biochemical properties. This review summarizes the effects of selected saturated and unsaturated fatty acids and fatty-acid-rich food items on disease-associated DNA methylation profiles, aiming to justify the classification of fatty acids as DNA methylation modulators.

A Survey of Fatty Acid Content of the Male Reproductive System in Mice Supplemented With Arachidonic Acid

Paternal exposure to high-fat diets or individual fatty acids (FAs) including arachidonic acid (AA) modifies progeny traits by poorly understood mechanisms. Specific male reproductive system FAs may be involved in paternal inheritance, as they can modify a range of cellular components, including the epigenome. Our objective was to determine FAs in compartments of the male reproductive system that potentially affect ejaculate composition-right and left testicular interstitial fluid (TIF), vesicular gland fluid (VGF), and epididymal adipose tissue (EAT)-in mice exposed to AA or vehicle daily for 10 days (n = 9-10/group). Whole blood (WB) and interscapular brown adipose tissue (IBAT) FA profiles were used as reference. AA significantly affected only VGF FAs relative to vehicle, that is, increased and decreased levels of arachidic and docosahexaenoic acid, respectively, versus vehicle (0.28% ± 0.01% and 0.23% ± 0.03%, respectively, p = 0.049, and 2.42% ± 0.47% and 3.00% ± 0.58%, respectively, p = 0.041). AA affected distinct FAs in WB. Additionally, we uncovered AA-dependent and AA-independent FA laterality. Myristic acid was higher in AA-exposed left versus right TIF (0.68% ± 0.35% and 0.60% ± 0.11%, respectively, p = 0.004). Right TIF contained higher oleic and linoleic acid and lower stearic acid than left TIF (29.01% ± 3.07% and 24.00% ± 2.18%, respectively, p = 0.005; 9.14% ± 1.88% and 7.05% ± 1.36%, respectively, p = 0.005; and 21.90% ± 2.92% and 26.01% ± 2.46%, respectively, p = 0.036), irrespective of exposure to AA. The TIF oleic/stearic acid ratio suggested higher Stearoyl-CoA Desaturase 1 activity in the right versus the left testis (1.35 ± 0.32 and 1.00 ± 0.17, respectively, p = 1.0 × 10-4). Multitissue comparisons revealed that TIF and VGF FA profiles were distinct from WB, EAT, or IBAT counterparts, suggesting tissue-specific FA fingerprints. In conclusion, AA modulated selected VGF long-chain FAs that may impact on uterine inflammation and subsequent embryonic development. AA altered local FA synthesis or selective uptake, rather than eliciting passive uptake from WB. Additionally, we uncover a significant laterality of testis FAs that may result in asymmetric sperm cell phenotypes.

Epigenome-wide association study of dietary fatty acid intake

BACKGROUND

Dietary intake of n-3 polyunsaturated fatty acids (PUFA) may have a protective effect on the development of cardiovascular diseases, diabetes, depression and cancer, while a high intake of n-6 PUFA was often reported to be associated with inflammation-related traits. The effect of PUFAs on health outcomes might be mediated by DNA methylation (DNAm). The aim of our study is to identify the impact of PUFA intake on DNAm in the Cooperative Health Research in the Region of Augsburg (KORA) FF4 cohort and the Leiden Longevity Study (LLS).

RESULTS

DNA methylation levels were measured in whole blood from the population-based KORA FF4 study (N = 1354) and LLS (N = 448), using the Illumina MethylationEPIC BeadChip and Illumina HumanMethylation450 array, respectively. We assessed associations between DNAm and intake of eight and four PUFAs in KORA and LLS, respectively. Where possible, results were meta-analyzed. Below the Bonferroni correction threshold (p < 7.17 × 10-8), we identified two differentially methylated positions (DMPs) associated with PUFA intake in the KORA study. The DMP cg19937480, annotated to gene PRDX1, was positively associated with docosahexaenoic acid (DHA) in model 1 (beta: 2.00 × 10-5, 95%CI: 1.28 × 10-5-2.73 × 10-5, P value: 6.98 × 10-8), while cg05041783, annotated to gene MARK2, was positively associated with docosapentaenoic acid (DPA) in our fully adjusted model (beta: 9.80 × 10-5, 95%CI: 6.25 × 10-5-1.33 × 10-4, P value: 6.75 × 10-8). In the meta-analysis, we identified the CpG site (cg15951061), annotated to gene CDCA7L below Bonferroni correction (1.23 × 10-7) associated with eicosapentaenoic acid (EPA) intake in model 1 (beta: 2.00 × 10-5, 95% CI: 1.27 × 10-5-2.73 × 10-5, P value = 5.99 × 10-8) and we confirmed the association of cg19937480 with DHA in both models 1 and 2 (beta: 2.07 × 10-5, 95% CI: 1.31 × 10-5-2.83 × 10-5, P value = 1.00 × 10-7 and beta: 2.19 × 10-5, 95% CI: 1.41 × 10-5-2.97 × 10-5, P value = 5.91 × 10-8 respectively).

CONCLUSIONS

Our study identified three CpG sites associated with PUFA intake. The mechanisms of these sites remain largely unexplored, highlighting the novelty of our findings. Further research is essential to understand the links between CpG site methylation and PUFA outcomes.

Variability in the Clinical Effects of the Omega-3 Polyunsaturated Fatty Acids DHA and EPA in Cardiovascular Disease-Possible Causes and Future Considerations

Cardiovascular disease (CVD) that includes myocardial infarction and stroke, is the leading cause of mortality worldwide. Atherosclerosis, the primary underlying cause of CVD, can be controlled by pharmacological and dietary interventions, including n-3 polyunsaturated fatty acid (PUFA) supplementation. n-3 PUFA supplementation, primarily consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has shown promise in reducing atherosclerosis by modulating risk factors, including triglyceride levels and vascular inflammation. n-3 PUFAs act by replacing pro-inflammatory fatty acid types in cell membranes and plasma lipids, by regulating transcription factor activity, and by inducing epigenetic changes. EPA and DHA regulate cellular function through shared and differential molecular mechanisms. Large clinical studies on n-3 PUFAs have reported conflicting findings, causing confusion among the public and health professionals. In this review, we discuss important factors leading to these inconsistencies, in the context of atherosclerosis, including clinical study design and the differential effects of EPA and DHA on cell function. We propose steps to improve clinical and basic experimental study design in order to improve supplement composition optimization. Finally, we propose that understanding the factors underlying the poor response to n-3 PUFAs, and the development of molecular biomarkers for predicting response may help towards a more personalized treatment.

Research progress in the role and mechanism of Leucine in regulating animal growth and development

Leucine, a branched-chain amino acid, is essential in regulating animal growth and development. Recent research has uncovered the mechanisms underlying Leucine's anabolic effects on muscle and other tissues, including its ability to stimulate protein synthesis by activating the mTORC1 signaling pathway. The co-ingestion of carbohydrates and essential amino acids enhances Leucine's anabolic effects. Moreover, Leucine has been shown to benefit lipid metabolism, and insulin sensitivity, making it a promising strategy for preventing and treating metabolic diseases, including type 2 diabetes and obesity. While emerging evidence indicates that epigenetic mechanisms may mediate Leucine's effects on growth and development, more research is needed to elucidate its mechanisms of action fully. Specific studies have demonstrated that Leucine promotes muscle growth and metabolic health in animals and humans, making it a promising therapeutic agent. However, it is essential to note that Leucine supplementation may cause digestive issues or interact with certain medications, and More study is required to determine definitively optimal dosages. Therefore, it is important to understand how Leucine interacts with other nutrients, dietary factors, and lifestyle habits to maximize its benefits. Overall, Leucine's importance in human nutrition is far-reaching, and its potential to prevent muscle loss and enhance athletic performance warrants further investigation.

Epigenetic Biomarkers of Metabolic Responses to Lifestyle Interventions

Studies have examined the possible utility of epigenetic phenomena (DNA methylation changes, covalent histone modifications, and miRNA expression patterns) in predicting individual responses to different lifestyle programs. Nonetheless, most available evidence is focused on identifying epigenetic marks eventually associated with body composition and adiposity outcomes, whereas their roles in metabolic endings remain less explored. This document comprehensively reviewed the evidence regarding the use of epigenetic signatures as putative biomarkers of metabolic outcomes (glycemic, lipid, blood pressure, and inflammatory/oxidative stress features) in response to different lifestyle interventions in humans. Although more investigation is still necessary in order to translate this knowledge in clinical practice, these scientific insights are contributing to the design of advanced strategies for the precise management of cardiometabolic risk, gaining understanding on metabolic heterogeneity, allowing for the prediction of metabolic outcomes, and facilitating the design of epigenome-based nutritional strategies for a more customized approach for metabolic alterations treatment under the scope of precision nutrition.

Nutrition, DNA methylation and obesity across life stages and generations

Obesity is a complex multifactorial condition that often manifests in early life with a lifelong burden on metabolic health. Diet, including pre-pregnancy maternal diet, in utero nutrition and dietary patterns in early and late life, can shape obesity development. Growing evidence suggests that epigenetic modifications, specifically DNA methylation, might mediate or accompany these effects across life stages and generations. By reviewing human observational and intervention studies conducted over the past 10 years, this work provides a comprehensive overview of the evidence linking nutrition to DNA methylation and its association with obesity across different age periods, spanning from preconception to adulthood and identify future research directions in the field.

Omega-3 fatty acids and individual variability in plasma triglyceride response: A mini-review

Cardiovascular disease (CVD) is a leading cause of death worldwide. Supplementation with the marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with lower CVD risk. However, results from randomized controlled trials that examine the effect of omega-3 supplementation on CVD risk are inconsistent. This risk-reducing effect may be mediated by reducing inflammation, oxidative stress and serum triglyceride (TG) levels. However, not all individuals respond by reducing TG levels after omega-3 supplementation. This inter-individual variability in TG response to omega-3 supplementation is not fully understood. Hence, we aim to review the evidence for how interactions between omega-3 fatty acid supplementation and genetic variants, epigenetic and gene expression profiling, gut microbiota and habitual intake of omega-3 fatty acids can explain why the TG response differs between individuals. This may contribute to understanding the current controversies and play a role in defining future personalized guidelines to prevent CVD.

The role of dietary strategies in the modulation of hallmarks of aging

The hallmarks of aging constitute an interconnected network of basic mechanisms that modulate aging and can be modulated by lifestyle factors, including dietary strategies. This narrative review aimed to summarize the evidence on promoting dietary restriction or adherence to specific dietary patterns on hallmarks of aging. Studies with preclinical models or humans were considered. Dietary restriction (DR), usually operationalized as a reduction in caloric intake, is the main strategy applied to study the axis diet-hallmarks of aging. DR has been shown to modulate mainly genomic instability, loss of proteostasis, deregulating nutrient sensing, cellular senescence, and altered intercellular communication. Much less evidence exists on the role of dietary patterns, with most of the studies evaluating the Mediterranean Diet and other similar plant-based diets, and the ketogenic diet. Potential benefits are described in genomic instability, epigenetic alterations, loss of proteostasis, mitochondrial dysfunction, and altered intercellular communication. Given the predominant place of food in human life, it is imperative to determine the impact of nutritional strategies on the modulation of lifespan and healthspan, considering applicability, long-term adherence, and side effects.

Dietary omega-3 fatty acid intake impacts peripheral blood DNA methylation -anti-inflammatory effects and individual variability in a pilot study

Omega-3 or n-3 polyunsaturated fatty acids (PUFAs) are widely studied for health benefits that may relate to anti-inflammatory activity. However, mechanisms mediating an anti-inflammatory response to n-3 PUFA intake are not fully understood. Of interest is the emerging role of fatty acids to impact DNA methylation (DNAm) and thereby modulate mediating inflammatory processes. In this pilot study, we investigated the impact of n-3 PUFA intake on DNAm in inflammation-related signaling pathways in peripheral blood mononuclear cells (PBMCs) of women at high risk of breast cancer. PBMCs of women at high risk of breast cancer (n=10) were obtained at baseline and after 6 months of n-3 PUFA (5 g/d EPA+DHA dose arm) intake in a previously reported dose finding trial. DNA methylation of PBMCs was assayed by reduced representation bisulfite sequencing (RRBS) to obtain genome-wide methylation profiles at the single nucleotide level. We examined the impact of n-3 PUFA on genome-wide DNAm and focused upon a set of candidate genes associated with inflammation signaling pathways and breast cancer. We identified 24,842 differentially methylated CpGs (DMCs) in gene promoters of 5507 genes showing significant enrichment for hypermethylation in both the candidate gene and genome-wide analyses. Pathway analysis identified significantly hypermethylated signaling networks after n-3 PUFA treatment, such as the Toll-like Receptor inflammatory pathway. The DNAm pattern in individuals and the response to n-3 PUFA intake are heterogeneous. PBMC DNAm profiling suggests a mechanism whereby n-3 PUFAs may impact inflammatory cascades associated with disease processes including carcinogenesis.

Metabolic and Epigenetics Action Mechanisms of Antiobesity Medicinal Plants and Phytochemicals

Ever-growing research efforts are demonstrating the potential of medicinal plants and their phytochemicals to prevent and manage obesity, either individually or synergistically. Multiple combinations of phytochemicals can result in a synergistic activity that increases their beneficial effects at molecular, cellular, metabolic, and temporal levels, offering advantages over chemically synthesized drug-based treatments. Herbs and their derived compounds have the potential for controlling appetite, inhibiting pancreatic lipase activity, stimulating thermogenesis and lipid metabolism, increasing satiety, promoting lipolysis, regulating adipogenesis, and inducing apoptosis in adipocytes. Furthermore, targeting adipocyte life cycle using various dietary bioactives that affect different stages of adipocyte life cycle represents also an important target in the development of new antiobesity drugs. In this regard, different stages of adipocyte development that are targeted by antiobesity drugs can include preadipocytes, maturing preadipocytes, and mature adipocytes. Various herbal-derived active compounds, such as capsaicin, genistein, apigenin, luteolin, kaempferol, myricetin, quercetin, docosahexaenoic acid, quercetin, resveratrol, and ajoene, affect adipocytes during specific stages of development, resulting in either inhibition of adipogenesis or induction of apoptosis. Although numerous molecular targets that can be used for both treatment and prevention of obesity have been identified, targeted single cellular receptor or pathway has resulted in limited success. In this review, we discuss the state-of-the-art knowledge about antiobesity medicinal plants and their active compounds and their effects on several cellular, molecular, and metabolic pathways simultaneously with multiple phytochemicals through synergistic functioning which might be an appropriate approach to better management of obesity. In addition, epigenetic mechanisms (acetylation, methylation, miRNAs, ubiquitylation, phosphorylation, and chromatin packaging) of phytochemicals and their preventive and therapeutic perspective are explored in this review.

Omega-3 Polyunsaturated Fatty Acids Prevent Nonalcoholic Steatohepatitis (NASH) and Stimulate Adipogenesis

The increasing impact of obesity on global human health intensifies the importance of studies focusing on agents interfering with the metabolism and remodeling not only of the white adipose tissue (WAT) but also of the liver. In the present study, we have addressed the impact of n-3 PUFA in adipose cells' proliferation and adipogenesis, as well as in the hepatic lipid profile and morphology. Mice were induced to obesity by the consumption of a high-fat diet (HFD) for 16 weeks. At the 9th week, the treatment with fish oil (FO) was initiated and maintained until the end of the period. The FO treatment reduced the animals' body mass, plasma lipids, glucose, plasma transaminases, liver mass, triacylglycerol, and cholesterol liver content when compared to animals consuming only HFD. FO also decreased the inguinal (ing) WAT mass, reduced adipocyte volume, increased adipose cellularity (hyperplasia), and increased the proliferation of adipose-derived stromal cells (AdSCs) which corroborates the increment in the proliferation of 3T3-L1 pre-adipocytes or AdSCs treated in vitro with n-3 PUFA. After submitting the in vitro treated (n-3 PUFA) cells, 3T3-L1 and AdSCs, to an adipogenic cocktail, there was an increase in the mRNA expression of adipogenic transcriptional factors and other late adipocyte markers, as well as an increase in lipid accumulation when compared to not treated cells. Finally, the expression of browning-related genes was also higher in the n-3 PUFA treated group. We conclude that n-3 PUFA exerts an attenuating effect on body mass, dyslipidemia, and hepatic steatosis induced by HFD. FO treatment led to decreasing adiposity and adipocyte hypertrophy in ingWAT while increasing hyperplasia. Data suggest that FO treatment might induce recruitment (by increased proliferation and differentiation) of new adipocytes (white and/or beige) to the ingWAT, which is fundamental for the healthy expansion of WAT.

Dietary fish and ω-3 polyunsaturated fatty acids are associated with leukocyte ABCA1 DNA methylation levels

OBJECTIVES

A diet rich in fish and ω-3 polyunsaturated fatty acids (PUFAs) has been thought to reduce the risk for cardiovascular disease (CVD). The beneficial effects of fish oil and ω-3 PUFA on CVD can be mediated by epigenetic status of the genes associated with lipid metabolism and inflammation. The aim of this study was to investigate whether dietary fish and fatty acid (FA) intakes are associated with leukocyte ATP-binding cassette transporter A1 (ABCA1) DNA methylation levels in a Japanese population.

METHODS

This cross-sectional study included 298 adults (137 men and 161 women) without clinical history of CVD or cancer. The pyrosequencing method was used to measure leukocyte ABCA1 DNA methylation levels. Dietary fish and FA intakes were assessed based on the validated food frequency questionnaire.

RESULTS

Mean ABCA1 DNA methylation levels were significantly lower in the highest fish intake groups (≥5-6/wk) compared with the lowest intake group (≤1-2/wk; P = 0.004). In multivariable linear regression analyses, higher dietary intake of ω-3 PUFAs and ω-3 highly unsaturated fatty acids was significantly associated with decreased levels of ABCA1 DNA methylation (P = 0.001 and 0.005); whereas no significant associations were seen between intake of dietary saturated fatty acid, monounsaturated fatty acid, and ω-6 PUFAs and ABCA1 DNA methylation.

CONCLUSION

Higher dietary fish and ω-3 PUFA intake were associated with lower ABCA1 DNA levels in a Japanese population. The present results may bring potential insights on biological mechanisms underlying the protective effects of dietary fish and ω-3 PUFA intakes on CVD.

CD36 and GPR120 Methylation Associates with Orosensory Detection Thresholds for Fat and Bitter in Algerian Young Obese Children

Background: The spontaneous preference for dietary fat is regulated by two lingual lipid sensors (CD36 and GPR120) in humans and rodents. Our objective was to investigate whether obesity in children is associated with methylation of lipid sensor genes, and whether this alteration was implicated in altered gustatory perception of fat and bitter and increased preference of palatable foods. Methods: School children were recruited and classified according to their body mass index (BMI) z-score into two groups: obese and lean children. The detection of orosensory perception for oleic acid and 6-n-propylthiouracil was assessed by using a 3-alternative forced-choice test. After blood DNA extraction, methylation patterns were investigated by methylation-specific PCR. The children were also subjected to a food habit questionnaire. Results: Obese children showed higher lipid and bitter detection thresholds than lean children. Besides, more obese children presented higher methylation level of the CpG sites than lean participants. Interestingly, CD36 and GPR120 gene methylation was associated with high lipid detection thresholds in obese participants. The obese participants preferred highly palatable fat-rich food items, associated with CD36 and GPR120 gene methylation. Conclusion: Epigenetic changes in CD36 and GPR120 genes might contribute to low orosensory perception of fat and bitter taste, and might be, consequently, critically involved in obesity in children

Epigenetic contribution to obesity

Obesity is a worldwide epidemic and contributes to global morbidity and mortality mediated via the development of nonalcoholic fatty liver disease (NAFLD), type 2 diabetes (T2D), cardiovascular (CVD) and other diseases. It is a consequence of an elevated caloric intake, a sedentary lifestyle and a genetic as well as an epigenetic predisposition. This review summarizes changes in DNA methylation and microRNAs identified in blood cells and different tissues in obese human and rodent models. It includes information on epigenetic alterations which occur in response to fat-enriched diets, exercise and metabolic surgery and discusses the potential of interventions to reverse epigenetic modifications.

Epigenetic Regulation by Dietary Restriction: Part II

In the first part of our review, we extensively discuss the different variants of dietary restriction (DR) regimens, as well as its corresponding mechanism(s) and subsequent effects. We also provide a detailed analysis of the different epigenetic mechanisms based on current knowledge. We postulate that DR may represent an environmental intervention that can modulate the epigenomic profile of an individual. It is highly plausible that epigenetic regulation by DR may help explain the asymmetric manifestation of DR effects in different individuals. Additionally, epigenetic modifications via DR may lead to epigenetic programming, providing protection against age-associated diseases, which in turn could lead to reduced morbidity and increased lifespan. In the second part of the review, we summarize recent findings that highlight the epigenomic axis of DR, which provides a better understanding of the mechanisms by which its numerous health benefits are achieved.

Fatty acids, epigenetic mechanisms and chronic diseases: a systematic review

BACKGROUND

Chronic illnesses like obesity, type 2 diabetes (T2D) and cardiovascular diseases, are worldwide major causes of morbidity and mortality. These pathological conditions involve interactions between environmental, genetic, and epigenetic factors. Recent advances in nutriepigenomics are contributing to clarify the role of some nutritional factors, including dietary fatty acids in gene expression regulation. This systematic review assesses currently available information concerning the role of the different fatty acids on epigenetic mechanisms that affect the development of chronic diseases or induce protective effects on metabolic alterations.

METHODS

A targeted search was conducted in the PubMed/Medline databases using the keywords "fatty acids and epigenetic". The data were analyzed according to the PRISMA-P guidelines.

RESULTS

Consumption fatty acids like n-3 PUFA: EPA and DHA, and MUFA: oleic and palmitoleic acid was associated with an improvement of metabolic alterations. On the other hand, fatty acids that have been associated with the presence or development of obesity, T2D, pro-inflammatory profile, atherosclerosis and IR were n-6 PUFA, saturated fatty acids (stearic and palmitic), and trans fatty acids (elaidic), have been also linked with epigenetic changes.

CONCLUSIONS

Fatty acids can regulate gene expression by modifying epigenetic mechanisms and consequently result in positive or negative impacts on metabolic outcomes.

CD 36: Focus on Epigenetic and Post-Transcriptional Regulation

CD36 is a transmembrane protein involved in fatty acid translocation, scavenging for oxidized fatty acids acting as a receptor for adhesion molecules. It is expressed on macrophages, as well as other types of cells, such as endothelial and adipose cells. CD36 participates in muscle lipid uptake, adipose energy storage, and gut fat absorption. Recently, several preclinical and clinical studies demonstrated that upregulation of CD36 is a prerequisite for tumor metastasis. Cancer metastasis-related research emerged much later and has been less investigated, though it is equally or even more important. CD36 protein expression can be modified by epigenetic changes and post-transcriptional interference from non-coding RNAs. Some data indicate modulation of CD36 expression in specific cell types by epigenetic changes via DNA methylation patterns or histone tails, or through miRNA interference, but this is largely unexplored. The few papers addressing this topic refer mostly to lipid metabolism-related pathologies, whereas in cancer research, data are even more scarce. The aim of this review was to summarize major epigenetic and post-transcriptional mechanisms that impact CD36 expression in relation to various pathologies while highlighting the areas in need of further exploration.

Epigenetic Regulation of Metabolism and Inflammation by Calorie Restriction

Chronic caloric restriction (CR) without malnutrition is known to affect different cellular processes such as stem cell function, cell senescence, inflammation, and metabolism. Despite the differences in the implementation of CR, the reduction of calories produces a widespread beneficial effect in noncommunicable chronic diseases, which can be explained by improvements in immuno-metabolic adaptation. Cellular adaptation that occurs in response to dietary patterns can be explained by alterations in epigenetic mechanisms such as DNA methylation, histone modifications, and microRNA. In this review, we define these modifications and systematically summarize the current evidence related to CR and the epigenome. We then explain the significance of genome-wide epigenetic modifications in the context of disease development. Although substantial evidence exists for the widespread effect of CR on longevity, there is no consensus regarding the epigenetic regulations of the underlying cellular mechanisms that lead to improved health. We provide compelling evidence that CR produces long-lasting epigenetic effects that mediate expression of genes related to immuno-metabolic processes. Epigenetic reprogramming of the underlying chronic low-grade inflammation by CR can lead to immuno-metabolic adaptations that enhance quality of life, extend lifespan, and delay chronic disease onset.

Methylation profile of the ADRB3 gene and its association with lipid profile and nutritional status in adults

BACKGROUND

Defects in DNA methylation have been shown to be associated with metabolic diseases such as obesity, dyslipidemia, and hypercholesterolemia. To analyze the methylation profile of the ADRB3 gene and correlate it with lipid profile, lipid intake, and oxidative stress based on malondialdehyde (MDA) and total antioxidant capacity (TAC), homocysteine and folic acid levels, nutritional status, lifestyle, and socioeconomic variables in an adult population. A cross-sectional epidemiological study representative of the East and West regions of the municipality of João Pessoa, Paraíba state, Brazil, enrolled 265 adults of both genders. Demographic, lifestyle, and socioeconomic questionnaires and a 24-h recall questionnaire were applied by trained interviewers' home. Nutritional and biochemical evaluation (DNA methylation, lipid profile, MDA, TAC, homocysteine and folic acid levels) was performed.

RESULTS

DNA hypermethylation of the ADRB3 gene, analyzed in leukocytes, was present in 50% of subjects and was associated with a higher risk of being overweight (OR 3.28; p = 0.008) or obese (OR 3.06; p = 0.017), a higher waist-hip ratio in males (OR 1.17; p = 0.000), greater intake of trans fats (OR 1.94; p = 0.032), higher LDL (OR 2.64; p = 0.003) and triglycerides (OR 1.81; p = 0.031), and higher folic acid levels (OR 1.85; p = 0.022).

CONCLUSIONS

These results suggest that epigenetic changes in the ADRB3 gene locus may explain the development of obesity and non-communicable diseases associated with trans-fat intake, altered lipid profile, and elevated folic acid. Because of its persistence, DNA methylation may have an impact in adults, in association with the development of non-communicable diseases. This study is the first population-based study of the ADRB3 gene, and the data further support evaluation of ADRB3 DNA methylation as an effective biomarker.

Feasibility Outcomes of a Pilot Randomized Clinical Trial to Increase Cruciferous and Green Leafy Vegetable Intake in Posttreatment Head and Neck Cancer Survivors

BACKGROUND

Higher intakes of cruciferous vegetables (CVs) and green leafy vegetables (GLVs) in observational studies are associated with improvements in survival and cancer-related biomarkers in patients diagnosed with head and neck cancer (HNC). These results have yet to be corroborated in a randomized clinical trial (RCT).

OBJECTIVE

Determine the feasibility of implementing a 12-week RCT to increase CV and GLV intake in posttreatment HNC survivors.

DESIGN AND PARTICIPANTS

This was a two-arm RCT conducted among 24 posttreatment HNC survivors. Survivors were recruited from a southeastern, National Cancer Institute-designated Comprehensive Cancer Center between January 2015 and September 2016.

INTERVENTION

There were two groups: (1) an experimental group (n=12) receiving weekly 15- to 30-minute telephone dietary counseling from a registered dietitian nutritionist stressing 2.5 cups per week CVs and 3.5 cups per week GLVs, and (2) an attention control group (n=12) receiving weekly 15- to 30-minute telephone dietary counseling from a registered dietitian nutritionist focusing on general healthy eating for cancer survivors. Participants completed a baseline survey, three 24-hour dietary recalls, phlebotomy, and anthropometric measures prior to randomization and at the end of the 12-week study period. The experimental group also completed weekly vegetable record recalls.

MAIN OUTCOME MEASURES

Primary outcomes included feasibility, recruitment, retention, adherence, and safety. Secondary outcomes included inflammatory markers and carotenoids.

STATISTICAL ANALYSES PERFORMED

Descriptive statistics were generated for demographic, epidemiological, and clinical variables as well as the primary feasibility outcomes. Between- and within-group comparisons of mean serum cytokine and carotenoid levels were performed using appropriate statistical tests depending on their respective distributions for the purpose of generating preliminary effect sizes.

RESULTS

Overall, 350 incident HNC cases were screened for eligibility, and 98 were eligible for study participation. Reasons for ineligibility and exclusion included deceased (n=93); wrong or inactive telephone numbers, or unable to be reached, or lost to follow-up (n=93); not meeting inclusion criteria (n=39); and too ill to participate (n=27). Of the 98 eligible HNC cases, 24 agreed to participate, for an enrollment rate of 25%. The most common reason for nonparticipation was distance (n=48), as participants were asked to report for two on-site assignments. The retention rate was 96%. Mean intervention adherence rates for weekly goals were 67% CV, 74% GLV, and 71% overall. Completion rate of weekly counseling calls was 90%. The experimental group reported an overall mean increase of 5.5 cups GLV and 3.5 cups CV per week from baseline intake, respectively. No significant between- or within-arm differences were observed for inflammatory markers or carotenoids.

CONCLUSION

A posttreatment intervention aimed at increasing CV and GLV intake in HNC survivors is feasible. A larger RCT is needed to assess the efficacy of this intervention on disease outcomes.

Effects of dietary interventions on DNA methylation in adult humans: systematic review and meta-analysis

DNA methylation is a key component of the epigenetic machinery that is responsible for regulating gene expression and, therefore, cell function. Patterns of DNA methylation change during development and ageing, differ between cell types, are altered in multiple diseases and can be modulated by dietary factors. However, evidence about the effects of dietary factors on DNA methylation patterns in humans is fragmentary. This study was initiated to collate evidence for causal links between dietary factors and changes in DNA methylation patterns. We carried out a systematic review of dietary intervention studies in adult humans using Medline, EMBASE and Scopus. Out of 22 149 screened titles, sixty intervention studies were included, of which 65% were randomised (n 39). Most studies (53%) reported data from blood analyses, whereas 27% studied DNA methylation in colorectal mucosal biopsies. Folic acid was the most common intervention agent (33%). There was great heterogeneity in the methods used for assessing DNA methylation and in the genomic loci investigated. Meta-analysis of the effect of folic acid on global DNA methylation revealed strong evidence that supplementation caused hypermethylation in colorectal mucosa (P=0·009). Meta-regression analysis showed that the dose of supplementary folic acid was the only identified factor (P<0·001) showing a positive relationship. In summary, there is limited evidence from intervention studies of effects of dietary factors, other than folic acid, on DNA methylation patterns in humans. In addition, the application of multiple different assays and investigations of different genomic loci makes it difficult to compare, or to combine, data across studies.

Plasticity of lifelong calorie-restricted C57BL/6J mice in adapting to a medium-fat diet intervention at old age

Calorie restriction (CR) is a dietary regimen that supports healthy aging. In this study, we investigated the systemic and liver‐specific responses caused by a diet switch to a medium‐fat (MF) diet in 24‐month‐old lifelong, CR‐exposed mice. This study aimed to increase the knowledge base on dietary alterations of gerontological relevance. Nine‐week‐old C57BL/6J mice were exposed either to a control, CR, or MF diet. At the age of 24 months, a subset of mice of the CR group was transferred to ad libitumMF feeding (CR‐MF). The mice were sacrificed at the age of 28 months, and then, biochemical and molecular analyses were performed. Our results showed that, despite the long‐term exposure to the CR regimen, mice in the CR‐MF group displayed hyperphagia, rapid weight gain, and hepatic steatosis. However, no hepatic fibrosis/injury or alteration in CR‐improved survival was observed in the diet switch group. The liver transcriptomic profile of CR‐MF mice largely shifted to a profile similar to the MF‐fed animals but leaving ~22% of the 1,578 differentially regulated genes between the CR and MF diet groups comparable with the expression of the lifelong CR group. Therefore, although the diet switch was performed at an old age, the CR‐MF‐exposed mice showed plasticity in coping with the challenge of a MF diet without developing severe liver pathologies.

Role of genetic and environmental factors in DNA methylation of lipid metabolism

A number of recent studies revealed that DNA methylation plays a central role in the regulation of lipid metabolism. DNA methylation modifications are important regulators of transcriptional networks that do not affect the DNA sequence and can translate genetic variants and environmental factors into phenotypic traits. Therefore, elucidating the factors that underlie inter-individual DNA methylation variations gives us an opportunity to predict diseases and interfere with the establishment of aberrant DNA methylation early. In this review, we summarize the findings of DNA methylation-related studies focused on unravelling the potential role of genetic and environmental factors in DNA methylation and the regulatory effect of DNA methylation on gene expression in lipid metabolism.

DHA-rich n-3 fatty acid supplementation decreases DNA methylation in blood leukocytes: the OmegAD study

Background: Dietary fish oils, rich in long-chain n-3 (ω-3) fatty acids (FAs) [e.g., docosahexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3)], modulate inflammatory reactions through various mechanisms, including gene expression, which is measured as messenger RNA concentration. However, the effects of long-term treatment of humans with DHA and EPA on various epigenetic factors-such as DNA methylation, which controls messenger RNA generation-are poorly described.Objective: We wanted to determine the effects of 6 mo of dietary supplementation with an n-3 FA preparation rich in DHA on global DNA methylation of peripheral blood leukocytes (PBLs) and the relation to plasma EPA and DHA concentrations in Alzheimer disease (AD) patients.Design: In the present study, DNA methylation in four 5'-cytosine-phosphate-guanine-3' (CpG) sites of long interspersed nuclear element-1 repetitive sequences was assessed in a group of 63 patients (30 given the n-3 FA preparation and 33 given placebo) as an estimation of the global DNA methylation in blood cells. Patients originated from the randomized, double-blind, placebo-controlled OmegAD study, in which 174 AD patients received either 1.7 g DHA and 0.6 g EPA (the n-3 FA group) or placebo daily for 6 mo.Results: At 6 mo, the n-3 FA group displayed marked increases in DHA and EPA plasma concentrations (2.6- and 3.5-fold), as well as decreased methylation in 2 out of 4 CpG sites (P < 0.05 for all), respectively. This hypomethylation in CpG2 and CpG4 sites showed a reverse correlation to changes in plasma EPA concentration (r = -0.25, P = 0.045; and r = -0.26, P = 0.041, respectively), but not to changes in plasma DHA concentration, and were not related to apolipoprotein E-4 allele frequency.Conclusion: Supplementation with n-3 FA for 6 mo was associated with global DNA hypomethylation in PBLs. Our data may be of importance in measuring various effects of marine oils, including gene expression, in patients with AD and in other patients taking n-3 FA supplements. This trial was registered at clinicaltrials.gov as NCT00211159.

A systematic review of studies of DNA methylation in the context of a weight loss intervention

AIM

Obesity results from the interaction of genetic and environmental factors, which may involve epigenetic mechanisms such as DNA methylation (DNAm).

MATERIALS & METHODS

We have followed the PRISMA protocol to select studies that analyzed DNAm at baseline and end point of a weight loss intervention using either candidate-locus or genome-wide approaches.

RESULTS

Six genes displayed weight loss associated DNAm across four out of nine genome-wide studies. Weight loss is associated with significant but small changes in DNAm across the genome, and weight loss outcome is associated with individual differences in baseline DNAm at several genomic locations.

CONCLUSION

The identified weight loss associated DNAm markers, especially those showing reproducibility across different studies, warrant validation by further studies with robust design and adequate power.

Epigenetic changes in blood leukocytes following an omega-3 fatty acid supplementation

Background

Omega-3 polyunsaturated fatty acids (n-3 FAs) have several beneficial effects on cardiovascular (CV) disease risk factors. These effects on CV risk profile may be mediated by several factors, including epigenetic modifications. Our objective is to investigate, using genome-wide DNA methylation analyses, methylation changes following an n-3 FA supplementation in overweight and obese subjects and to identify specific biological pathways potentially altered by the supplementation.

Results

Blood leukocytes genome-wide DNA methylation profiles of 36 overweight and obese subjects before and after a 6-week supplementation with 3 g of n-3 FAs were compared using GenomeStudio software. After supplementation, 308 CpG sites, assigned to 231 genes, were differentially methylated (FDR-corrected Diffscore ≥│13│~ P ≤ 0.05). Using Ingenuity Pathway Analysis system, a total of 55 pathways were significantly overrepresented following supplementation. Among these pathways, 16 were related to inflammatory and immune response, lipid metabolism, type 2 diabetes, and cardiovascular signaling. Changes in methylation levels of CpG sites within AKT3, ATF1, HDAC4, and IGFBP5 were correlated with changes in plasma triglyceride and glucose levels as well as with changes in the ratio of total cholesterol/HDL-cholesterol following the supplementation.

Conclusions

These data provide key differences in blood leukocytes DNA methylation profiles of subjects following an n-3 FA supplementation, which brings new, potential insights on metabolic pathways underlying the effects of n-3 FAs on CV health.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-017-0345-3) contains supplementary material, which is available to authorized users.

Fish oil prevents changes induced by a high-fat diet on metabolism and adipokine secretion in mice subcutaneous and visceral adipocytes

KEY POINTS

Fish oil (FO), rich in omega-3 polyunsaturated fatty acids, has beneficial effects on changes induced by obesity and partially prevents associated comorbidities. The effects of FO on adipocytes from different adipose tissue depots in high-fat (HF) diet induced obese mice have not been uninvestigated. This is the first study to examine the effects of FO on changes in metabolism and adipokine production in adipocytes from s.c. (inguinal; ING) or visceral (retroperitoneal; RP) white adipose depots in a HF diet-induced obese mice. Unlike most studies performed previously, FO supplementation was initiated 4 weeks before the induction of obesity. HF diet caused marked changes in ING (glucose uptake and secretion of adiponectin, tumour necrosis factor-α and interleukin-6 in ING) and RP (lipolysis, de novo lipogenesis and secretion of pro-inflammatory cytokines) adipose depots. Previous and concomitant FO administration prevented the changes in ING and RP adipocytes induced by the HF diet.

ABSTRACT

In the present study, we investigated the effect of fish oil (FO) on metabolism and adipokine production by adipocytes from s.c. (inguinal; ING) and visceral (retroperitoneal; RP) white adipose depots in high-fat (HF) diet-induced obese mice. Mice were divided into CO (control diet), CO+FO, HF and HF+FO groups. The HF group presented higher body weight, glucose intolerance, insulin resistance, higher plasma total and low-density lipoprotein cholesterol levels, and greater weights of ING and RP adipose depots accompanied by hypertrophy of the adipocytes. FO exerted anti-obesogenic effects associated with beneficial effects on dyslipidaemia and insulin resistance in mice fed a HF diet (HF+FO group). HF raised RP adipocyte lipolysis and the production of pro-inflammatory cytokines and reduced de novo synthesis of fatty acids, whereas, in ING adipocytes, it decreased glucose uptake and adiponectin secretion but did not change lipolysis. Therefore, the adipose depots play different roles in HF diet-induced insulin resistance according to their location in the body. Concerning cytokine secretion, adipocytes per se in addition to white adopise tissue infiltrated leukocytes have to be considered in the aetiology of the comorbidities associated with obesity. Evidence is presented showing that previous and concomitant administration of FO can prevent changes in metabolism and the secretion of hormones and cytokines in ING and RP adipocytes induced by HF.

Methylation on the Circadian Gene BMAL1 Is Associated with the Effects of a Weight Loss Intervention on Serum Lipid Levels

The circadian clock system has been linked to the onset and development of obesity and some accompanying comorbidities. Epigenetic mechanisms, such as DNA methylation, are putatively involved in the regulation of the circadian clock system. The aim of this study was to investigate the influence of a weight loss intervention based on an energy-controlled Mediterranean dietary pattern in the methylation levels of 3 clock genes, BMAL1, CLOCK, and NR1D1, and the association between the methylation levels and changes induced in the serum lipid profile with the weight loss treatment. The study sample enrolled 61 women (body mass index = 28.6 ± 3.4 kg/m(2); age: 42.2 ± 11.4 years), who followed a nutritional program based on a Mediterranean dietary pattern. DNA was isolated from whole blood obtained at the beginning and end point. Methylation levels at different CpG sites of BMAL1, CLOCK, and NR1D1 were analyzed by Sequenom's MassArray. The energy-restricted intervention modified the methylation levels of different CpG sites in BMAL1 (CpGs 5, 6, 7, 9, 11, and 18) and NR1D1 (CpGs 1, 10, 17, 18, 19, and 22). Changes in cytosine methylation in the CpG 5 to 9 region of BMAL1 with the intervention positively correlated with the eveningness profile (p = 0.019). The baseline methylation of the CpG 5 to 9 region in BMAL1 positively correlated with energy (p = 0.047) and carbohydrate (p = 0.017) intake and negatively correlated with the effect of the weight loss intervention on total cholesterol (p = 0.032) and low-density lipoprotein cholesterol (p = 0.005). Similar significant and positive correlations were found between changes in methylation levels in the CpG 5 to 9 region of BMAL1 due to the intervention and changes in serum lipids (p < 0.05). This research describes apparently for the first time an association between changes in the methylation of the BMAL1 gene with the intervention and the effects of a weight loss intervention on blood lipids levels.

Associations between whole peripheral blood fatty acids and DNA methylation in humans

Fatty acids (FA) modify DNA methylation in vitro, but limited information is available on whether corresponding associations exist in vivo and reflect any short-term effect of the diet. Associations between global DNA methylation and FAs were sought in blood from lactating infants (LI; n = 49) and adult males (AMM; n = 12) equally distributed across the three conventional BMI classes. AMM provided multiple samples at 2-hour intervals during 8 hours after either a single Western diet-representative meal (post-prandial samples) or no meal (fasting samples). Lipid/glucose profile, HDAC4 promoter and PDK4 5’UTR methylation were determined in AMM. Multiple regression analysis revealed that global (in LI) and both global and PDK4-specific DNA methylation (in AMM) were positively associated with eicosapentaenoic and arachidonic acid. HDAC4 methylation was inversely associated with arachidonic acid post-prandially in AMM. Global DNA methylation did not show any defined within-day pattern that would suggest a short-term response to the diet. Nonetheless, global DNA methylation was higher in normal weight subjects both post-prandially and in fasting and coincided with higher polyunsaturated relative to monounsaturated and saturated FAs. We show for the first time strong associations of DNA methylation with specific FAs in two human cohorts of distinct age, diet and postnatal development stage.

Design, measurement and processing of region-specific DNA methylation assays: the mass spectrometry-based method EpiTYPER

EpiTYPER® is a mass spectrometry-based bisulfite sequencing method that enables region-specific DNA methylation analysis in a quantitative and high-throughput fashion. The technology targets genomic regions of 100–600 base pairs and results in the quantitative measurement of DNA methylation levels largely at single-nucleotide resolution. It is particularly suitable for larger scale efforts to study candidate regions or to validate regions from genome-wide DNA methylation studies. Here, we describe in detail how to design and perform EpiTYPER measurements and preprocess the data, providing details for high quality measurements not provided in the standard EpiTYPER protocol.

DNA Methylation Changes Induced by a High-Fat Diet and Fish Oil Supplementation in the Skeletal Muscle of Mice

BACKGROUND/AIMS

To investigate the global changes in DNA methylation and methylation of the promoter region of the peroxisome proliferator-activated receptor gamma transcript variant 2 (Pparg2) gene resulting from a high-fat diet (HFD) and/or fish oil supplementation.

METHODS

Fish oil, rich in omega-3 polyunsaturated fatty acids, or water was orally administered to male mice for 12 weeks. After the first 4 weeks, the animals were fed a control diet or an HFD until the end of the experimental protocol, when the epididymal fat, gastrocnemius muscle and liver were excised.

RESULTS

Pparg2 mRNA expression was upregulated by obesity and downregulated by fish oil supplementation in the liver. In the gastrocnemius muscle, diet-induced obesity increased global DNA methylation. Fish oil prevented the decrease in Pparg2 promoter methylation induced by obesity in the gastrocnemius muscle. Regardless of the diet given, fish oil supplementation increased Pparg2 promoter methylation at CpG-263 in muscle and adipose tissue.

CONCLUSION

HFD and fish oil modified global and Pparg2 promoter DNA methylation in a tissue-specific manner. Fish oil supplementation attenuated body weight gain, abolished the increase in Pparg2 expression in the liver and prevented the decrease in Pparg2 promoter methylation in the muscle induced by the HFD.

The effect of polyunsaturated fatty acids on obesity through epigenetic modifications

BACKGROUND AND PURPOSE

In recent years it has been demonstrated that polyunsaturated fatty acids (PUFA) have anti-inflammatory and as regulators of lipid metabolism. However, the epigenomic mechanisms involved in these processes are not known in depth. The aim of this review was to describe the scientific evidence supports that regular consumption of PUFA may reduce obesity and overweight by altering epigenetic marks.

MATERIAL AND METHODS

A search of recent publications was carried out in human clinical trials, as well as animal model and in vitro experiments.

RESULTS

Exist a possible therapeutic effect of PUFAs on the prevention and development of obesity due to their ability to reversively modify the methylation of the promoters of genes associated with lipid metabolism and to modulate the activity of certain microRNAs.

CONCLUSIONS

A better knowledge and understanding of the PUFAs role in epigenetic regulation of obesity is possible with the current published results. The PUFAs may modulate the promotor epigenetic marks in several adipogenic genes and regulate the expression of several miRNAs.

From inflammaging to healthy aging by dietary lifestyle choices: is epigenetics the key to personalized nutrition?

The progressively older population in developed countries is reflected in an increase in the number of people suffering from age-related chronic inflammatory diseases such as metabolic syndrome, diabetes, heart and lung diseases, cancer, osteoporosis, arthritis, and dementia. The heterogeneity in biological aging, chronological age, and aging-associated disorders in humans have been ascribed to different genetic and environmental factors (i.e., diet, pollution, stress) that are closely linked to socioeconomic factors. The common denominator of these factors is the inflammatory response. Chronic low-grade systemic inflammation during physiological aging and immunosenescence are intertwined in the pathogenesis of premature aging also defined as ‘inflammaging.’ The latter has been associated with frailty, morbidity, and mortality in elderly subjects. However, it is unknown to what extent inflammaging or longevity is controlled by epigenetic events in early life. Today, human diet is believed to have a major influence on both the development and prevention of age-related diseases. Most plant-derived dietary phytochemicals and macro- and micronutrients modulate oxidative stress and inflammatory signaling and regulate metabolic pathways and bioenergetics that can be translated into stable epigenetic patterns of gene expression. Therefore, diet interventions designed for healthy aging have become a hot topic in nutritional epigenomic research. Increasing evidence has revealed that complex interactions between food components and histone modifications, DNA methylation, non-coding RNA expression, and chromatin remodeling factors influence the inflammaging phenotype and as such may protect or predispose an individual to many age-related diseases. Remarkably, humans present a broad range of responses to similar dietary challenges due to both genetic and epigenetic modulations of the expression of target proteins and key genes involved in the metabolism and distribution of the dietary constituents. Here, we will summarize the epigenetic actions of dietary components, including phytochemicals, and macro- and micronutrients as well as metabolites, that can attenuate inflammaging. We will discuss the challenges facing personalized nutrition to translate highly variable interindividual epigenetic diet responses to potential individual health benefits/risks related to aging disease.

Repeated batch fermentation biotechnology for the biosynthesis of lipid and gamma-linolenic acid by Cunninghamella bainieri 2A1

The biosynthesis of biomedical products including lipid and gamma-linolenic acid (GLA) by Cunninghamella bainieri 2A1 was studied in repeated batch fermentation. Three key process variables, namely, glucose concentration, ammonium tartrate concentration, and harvesting time, were optimized using response surface methodology. Repeated batch fermentation was carried out by the cultivation of Cunninghamella bainieri 2A1 in nitrogen-limited medium with various nitrogen concentration (1-4 g/L) and glucose concentration (20-40 g/L) at three time intervals (12 h, 24 h, and 48 h). Experimental results showed that the highest lipid concentration of 6.2 g/L and the highest GLA concentration of 0.4 g/L were obtained in optimum conditions, where 20.2 g/L glucose, 2.12 g/L ammonium tartrate, and 48 h harvesting time were utilized. Statistical results showed that the interaction between glucose and ammonium tartrate concentration had highly significant effects on lipid and GLA biosynthesis (P < 0.01). Moreover, harvesting time had a significant interaction effect with glucose and ammonium tartrate concentration on lipid production (P < 0.05).