**3. DHA and inflammation**

Inflammation is part of the body's normal response to injury or infection. However, when it is uncontrolled or inappropriate, it can damage the body's own tissues, contributing to a wide variety of chronic and acute disorders. Inflammation is characterised by the production of inflammatory cytokines, ARA-derived eicosanoids (prostaglandins, thromboxanes, leukotrienes), reactive oxygen species (ROS), and molecular adhesion [81, 101].

The term *cytokine* encompasses a group of families of low molecular weight molecules that are structurally related and comprise more than 200 members. They are characterised by their ability to alter the functional activity of cells and tissues [102]. They are involved in the immunoregulatory and effector mechanisms of the innate and adaptive immune system. They are also involved in angiogenesis and have been found to play a key role in neuro-immune and neuroendocrine processes. Their pleiotropism makes their functional classification difficult, but they can be divided according to their most significant function into the following groups [103, 104]: adaptive immune mediators, innate immune mediators, haemopoiesis mediators, and pro-inflammatory and immunosuppressive cytokines.

In disease states, fish oil has been shown to act as an anti-inflammatory agent. Omega-3 fatty acids regulate the production of ARA-derived eicosanoids [81]. EPA competes with ARA to stimulate the production of series three prostaglandins and series five leukotrienes that have a lesser inflammatory action than ARA-derived eicosanoids. Supplementation with DHA leads to changes in the metabolism of ARA and in the balance of eicosanoids synthesised from omega-3 and omega-6 fatty acids. Thus it can affect the functions regulated by these eicosanoids [42].

Although fatty acids can modify the quantity and type of eicosanoids produced, they can also modify inflammation via eicosanoid-independent mechanisms that include acting on receptors, intracellular signalling pathways, and transcription factor activity [51]. They are able to reduce levels of C-reactive protein (CRP), cytokines [81], chemokines, and other inflammatory biomarkers. In addition, they produce the lipid mediators known as resolvins and protectins, which have anti-inflammatory and immunomodulatory effects [27–30, 43, 81]. Other antiinflammatory actions of omega-3 LCPUFAs include a reduction in major histocompatibility complex (MHC) class II antigen presentation, reduction in reactive T cells, and reduction in Th1 cytokine production.

Omega-3 LCPUFAs could be said to act directly on inflammation by replacing arachidonic acid as a substrate for eicosanoid synthesis and indirectly by altering the expression of inflammatory genes via activation of transcription factors [101], among other mechanisms. The pathways are complex and much remains to be determined. It is thought that the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)

**43**

*Cytokines and Maternal Omega-3 LCPUFAs Supplementation*

[32]; such mechanisms are yet to be fully determined.

plasma, placenta, and umbilical cord blood [111].

and transforming growth factor beta (TGF-β) [113].

**4. DHA in pregnancy and lactation**

transcription factor plays a key role in the anti-inflammatory effects of DHA and EPA. Via Nrf2-dependent signalling, DHA can inhibit pro-inflammatory mediators such as nitric oxide synthase and cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines such as IL-6, interleukin-1 (IL-1), and tumour necrosis factor-α (TNF-α) [33]. Other studies suggest that omega-3 LCPUFAs are natural ligands of peroxisome proliferator-activated receptor gamma (PPAR-γ), a transcription factor that regulates the expression of genes involved in cellular proliferation, inflammation, and metabolism of fatty acids and lipoproteins. Activation of PPAR-γ can inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling and expression of inflammatory genes [105]. Despite the available data, little is known about the cellular and molecular mechanisms by which omega-3 LCPUFAs exert their beneficial effect in the prevention of inflammatory and immune diseases

Essential fatty acids and those derived from LA (the omega-6 group) and ALA (the omega-3 group) play an important role during pregnancy. They have been associated with prolonged pregnancy, delay of spontaneous labour and reduction in recurrent premature labour in animal and human studies, improving neonatal outcomes [106]. In vulnerable states such as pregnancy and lactation, a high intake of omega-3 LCPUFAs is recommended as maternal levels of DHA decrease during pregnancy [1] and continue to decrease if the lactation period is long [107]. Maternal DHA levels have also been observed to decrease further in multiple pregnancies and are lower in multiparous than in primiparous women [108] and when the time between pregnancies is short. This could be explained by the high demand for these fatty acids during pregnancy as the foetus receives them preferentially via the placenta [109]. The foetus' DHA status depends exclusively on this transfer and in turn its supply in the mother's diet [110]. Indeed, omega-3 PUFA supplementation in pregnancy has been associated with increased DHA concentrations in the

Lactation is another period in which DHA consumption is beneficial for both the mother and child. Breast milk contains DHA, as well as omega-6 and other omega-3 LCPUFAs, which make up 2% of the total fatty acid content. It also contains components that play a specific immunological role such as cytokines, growth factors, leucocytes, immunoglobulins, lysosomes, and proteins such as lactoferrin. The presence of cytokines in breast milk helps the neonatal immune system develop and confers protection to the infant who does not yet have a network of mature cytokines [112]. Even at femtomolar concentrations, they can regulate the actions and properties of immune cells. A wide range of both pro-inflammatory and antiinflammatory cytokines has been detected via numerous methods in breast milk throughout the different stages of lactation and includes IL-1 beta (β), IL-6, TNF-α,

The fatty acids present in breast milk also appear to play an important role in the maturation and function of the immune system. Exclusive breastfeeding for the first few months of life has been demonstrated to protect not only against various types of infection (respiratory, gastrointestinal, urinary, otitis media, and necrotising enterocolitis) [114, 115] but also against allergic diseases. For this reason, and others, breast milk is the ideal foodstuff for the newborn [116] as it provides the nutrients necessary for optimal growth and development. The composition of polyunsaturated fatty acids in breast milk is determined partly by the dietary PUFA content. There is a correlation between breast milk DHA levels and blood levels.

*DOI: http://dx.doi.org/10.5772/intechopen.86402*

*Cytokines and Maternal Omega-3 LCPUFAs Supplementation DOI: http://dx.doi.org/10.5772/intechopen.86402*

*Maternal and Child Health Matters Around the World*

oncological processes [97].

**3. DHA and inflammation**

(ROS), and molecular adhesion [81, 101].

and pro-inflammatory and immunosuppressive cytokines.

cells, and reduction in Th1 cytokine production.

cancer [96], with an observed reduction in inflammatory markers such as interleukin-6 (IL-6) in patients taking omega-3 fatty acid supplements, although these benefits are dependent on the duration, dose, and route of supplementation and the specific type of oncological treatment received. Its effects in leukaemia, lymphoma, neuroblastoma, glioblastoma, and lung, cervical, pancreatic, bladder, and ovarian cancer [97] have also been studied. The proposed mechanisms by which LCPUFAs act as adjuvants in cancer-specific treatments relate to their antitumour properties: they are anti-inflammatory [98], antiproliferative, pro-apoptotic, anti-invasive, and antimetastatic [99] and have epigenetic-regulatory effects [100]. Further studies are required to establish the therapeutic recommendations for EPA and DHA in

Inflammation is part of the body's normal response to injury or infection. However, when it is uncontrolled or inappropriate, it can damage the body's own tissues, contributing to a wide variety of chronic and acute disorders. Inflammation

The term *cytokine* encompasses a group of families of low molecular weight molecules that are structurally related and comprise more than 200 members. They are characterised by their ability to alter the functional activity of cells and tissues [102]. They are involved in the immunoregulatory and effector mechanisms of the innate and adaptive immune system. They are also involved in angiogenesis and have been found to play a key role in neuro-immune and neuroendocrine processes. Their pleiotropism makes their functional classification difficult, but they can be divided according to their most significant function into the following groups [103, 104]: adaptive immune mediators, innate immune mediators, haemopoiesis mediators,

In disease states, fish oil has been shown to act as an anti-inflammatory agent. Omega-3 fatty acids regulate the production of ARA-derived eicosanoids [81]. EPA competes with ARA to stimulate the production of series three prostaglandins and series five leukotrienes that have a lesser inflammatory action than ARA-derived eicosanoids. Supplementation with DHA leads to changes in the metabolism of ARA and in the balance of eicosanoids synthesised from omega-3 and omega-6 fatty acids. Thus it can affect the functions regulated by these eicosanoids [42].

Although fatty acids can modify the quantity and type of eicosanoids produced, they can also modify inflammation via eicosanoid-independent mechanisms that include acting on receptors, intracellular signalling pathways, and transcription factor activity [51]. They are able to reduce levels of C-reactive protein (CRP), cytokines [81], chemokines, and other inflammatory biomarkers. In addition, they produce the lipid mediators known as resolvins and protectins, which have anti-inflammatory and immunomodulatory effects [27–30, 43, 81]. Other antiinflammatory actions of omega-3 LCPUFAs include a reduction in major histocompatibility complex (MHC) class II antigen presentation, reduction in reactive T

Omega-3 LCPUFAs could be said to act directly on inflammation by replacing arachidonic acid as a substrate for eicosanoid synthesis and indirectly by altering the expression of inflammatory genes via activation of transcription factors [101], among other mechanisms. The pathways are complex and much remains to be determined. It is thought that the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)

is characterised by the production of inflammatory cytokines, ARA-derived eicosanoids (prostaglandins, thromboxanes, leukotrienes), reactive oxygen species

**42**

transcription factor plays a key role in the anti-inflammatory effects of DHA and EPA. Via Nrf2-dependent signalling, DHA can inhibit pro-inflammatory mediators such as nitric oxide synthase and cyclooxygenase-2 (COX-2) and pro-inflammatory cytokines such as IL-6, interleukin-1 (IL-1), and tumour necrosis factor-α (TNF-α) [33]. Other studies suggest that omega-3 LCPUFAs are natural ligands of peroxisome proliferator-activated receptor gamma (PPAR-γ), a transcription factor that regulates the expression of genes involved in cellular proliferation, inflammation, and metabolism of fatty acids and lipoproteins. Activation of PPAR-γ can inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signalling and expression of inflammatory genes [105]. Despite the available data, little is known about the cellular and molecular mechanisms by which omega-3 LCPUFAs exert their beneficial effect in the prevention of inflammatory and immune diseases [32]; such mechanisms are yet to be fully determined.

### **4. DHA in pregnancy and lactation**

Essential fatty acids and those derived from LA (the omega-6 group) and ALA (the omega-3 group) play an important role during pregnancy. They have been associated with prolonged pregnancy, delay of spontaneous labour and reduction in recurrent premature labour in animal and human studies, improving neonatal outcomes [106]. In vulnerable states such as pregnancy and lactation, a high intake of omega-3 LCPUFAs is recommended as maternal levels of DHA decrease during pregnancy [1] and continue to decrease if the lactation period is long [107]. Maternal DHA levels have also been observed to decrease further in multiple pregnancies and are lower in multiparous than in primiparous women [108] and when the time between pregnancies is short. This could be explained by the high demand for these fatty acids during pregnancy as the foetus receives them preferentially via the placenta [109]. The foetus' DHA status depends exclusively on this transfer and in turn its supply in the mother's diet [110]. Indeed, omega-3 PUFA supplementation in pregnancy has been associated with increased DHA concentrations in the plasma, placenta, and umbilical cord blood [111].

Lactation is another period in which DHA consumption is beneficial for both the mother and child. Breast milk contains DHA, as well as omega-6 and other omega-3 LCPUFAs, which make up 2% of the total fatty acid content. It also contains components that play a specific immunological role such as cytokines, growth factors, leucocytes, immunoglobulins, lysosomes, and proteins such as lactoferrin. The presence of cytokines in breast milk helps the neonatal immune system develop and confers protection to the infant who does not yet have a network of mature cytokines [112]. Even at femtomolar concentrations, they can regulate the actions and properties of immune cells. A wide range of both pro-inflammatory and antiinflammatory cytokines has been detected via numerous methods in breast milk throughout the different stages of lactation and includes IL-1 beta (β), IL-6, TNF-α, and transforming growth factor beta (TGF-β) [113].

The fatty acids present in breast milk also appear to play an important role in the maturation and function of the immune system. Exclusive breastfeeding for the first few months of life has been demonstrated to protect not only against various types of infection (respiratory, gastrointestinal, urinary, otitis media, and necrotising enterocolitis) [114, 115] but also against allergic diseases. For this reason, and others, breast milk is the ideal foodstuff for the newborn [116] as it provides the nutrients necessary for optimal growth and development. The composition of polyunsaturated fatty acids in breast milk is determined partly by the dietary PUFA content. There is a correlation between breast milk DHA levels and blood levels.

Likewise, there is a correlation between breast milk DHA levels and infant plasma levels [117, 118]. Other studies on supplementation have found a positive association between fish oil supplementation and a reduced plasma ω6/ω3 ratio in maternal plasma and in umbilical cord blood [119].

A dietary supply comprising mainly omega-6 fatty acids, as occurs in Western diets, can significantly inhibit the endogenous synthesis of omega-3 fatty acids, especially EPA and DHA given the enzymatic competition between their precursors. This becomes particularly relevant in the developing foetus and newborn, especially in premature or small-for-gestational-age babies [9]. Due to the limited capacity for synthesising these fatty acids [58], neonates are exclusively dependent on their placental transfer during pregnancy and their supply from breast milk. Therefore, a limited intake of omega-3 fatty acids in pregnancy or lactation can be associated with insufficient DHA levels for optimal neurological and immunological development in the foetus and newborn. In these states, a preventative nutritional intervention becomes particularly relevant as the fat that the mother consumes during pregnancy and lactation will greatly influence both foetal development and the lipid composition of breast milk and in turn the newborn's nutrition during the first stages of life [76, 120].

### **5. Patients and methods**

We studied whether supplementing maternal diet with omega-3 LCPUFAs during the last trimester of pregnancy and the breastfeeding period influenced the levels of inflammatory cytokines in mother and child. Our study included a group of healthy infants born to term to 46 mothers, who had been enrolled in a registered, doubleblind controlled randomised trial, from week 28 of pregnancy to the fourth month of lactation. Mothers were recruited in the Services of Gynecology of the Mother and Child Hospital of Granada, Spain (Hospital Materno-Infantil de Granada), and the Mother and Child University Hospital of Las Palmas de Gran Canaria, Spain (Complejo Hospitalario Universitario Insular Materno-Infantil de Canarias), between June 2009 and August 2010. Our sample was taken from an earlier larger study designed to assess the effects of omega-3 LCPUFA supplementation on the fatty acid profile of mothers and newborns [121]. The earlier study was registered on www.clinicaltrials.gov under identification code NCT01947426. The experimental groups were fish oil (FO) group (*n* = 24) which received 400 ml of fish oil-enriched drink [320 mg DHA + 72 mg EPA] per day and control (CT) group (*n* = 22) which received 400 ml of a non-supplemented drink per day. The dairy drinks were not commercially available products but specifically prepared for the study. The dietary supplementation started on week 28 of pregnancy and finished on the fourth month of lactation. We determined in mother and children plasma the concentrations of the following cytokines: GM-CSF, IL-2, IL-4, IL-6, IL-10, INF-γ, and TNF-α using MILLIPLEX® Human Cytokine/Chemokine kit in conjunction with a Luminex 200® system (Austin, TX, USA) and xPONENT® software package. The fatty acid profiles of maternal and children compartments were analysed in an earlier study [121], and DHA levels in mother and children plasma and erythrocyte membranes, as well as in breast milk, were used to evaluate correlation with cytokine levels.

### **6. Omega-3 fatty acids and cytokines during pregnancy**

Supplementation with omega-3 LCPUFAs during pregnancy affects the pattern of fatty acids in maternal plasma and umbilical cord blood [122–124].

**45**

*Cytokines and Maternal Omega-3 LCPUFAs Supplementation*

supplementation during pregnancy [34–36, 126, 129, 130].

A high intake of omega-3 fatty acids has been demonstrated to reduce the production of eicosanoids, cytokines, ROS and expression of adhesion molecules. Cell culture studies [33] have reported that EPA and DHA can inhibit the production of pro-inflammatory cytokines, such as TNF-α, IL-1, and IL-6, and in vitro studies have demonstrated that they can also reduce the expression of cell adhesion molecules and recently also in endothelial cells of the umbilical cord. These effects are supported by similar studies on dietary supplementation in animal and human models. In animal models, a reduction in the inflammatory response, expression of remodelling enzymes, and functional improvement has been demonstrated in offspring exposed to stressful situations whose mothers received DHA during pregnancy [34, 35]. In humans, some studies have revealed a decrease in cytokine levels, as a measure of systemic inflammatory response, after 8 weeks of fish oil supplementation [23]. During pregnancy, it has been demonstrated that intake of omega-3 long-chain fatty acids can modify cytokine levels and maturation of helper T (Th) cells [32]. Comparative studies in breastfed children whose mothers received EPA and DHA supplements from week 22 of pregnancy showed that this dietary intervention confers a reduction in Th1 cytokines such as IFN-gamma and IL-1 in the plasma and a reduction in the Th2 cytokines IL-14 and IL-13 in the umbilical cord blood [37]. In our study, in which mothers received supplements from week 28 of pregnancy and throughout breastfeeding, we found that levels of IL-6, TNF-α, IL-4, and IL-10 could be altered [26]. Maternal plasmatic levels of IL-10 and IL-4 were higher in the supplemental group (FO) than in the control group (CT). On the other hand, plasmatic IL-6 levels were higher both in mothers and children of the

Supplementation increases DHA levels not only in these compartments but also in

Inflammation is considered one of the main causes of complications during pregnancy and of prematurity and neonatal morbidity [10–15]. Indeed, pregnancy may be considered a mild, controlled, systemic inflammatory state. Cytokines TNF-α and IL-1 are heavily involved in the inflammatory processes associated with pregnancy and labour [10, 12, 13], although an increase in inflammatory biomarkers such as IL-8, hepatocyte growth factor and monocyte chemotactic protein during pregnancy have also been demonstrated. There is also a progressive increase in vascular biomarkers, such as E-Selectin, vascular adhesion molecule 1, intercellular adhesion molecule (ICAM) 1, and plasminogen activator-inhibitor 1 [126]. Other studies have suggested that an abnormal response from cytokines and other molecules such as leptin may be involved in the pathophysiology of pregnancy-related complications such as preeclampsia. An association has been demonstrated between TNF-α, IL-6, IL-8, IL-10, and leptin, indicating that a rise in these markers could be used as a marker of inflammatory dysfunction and endothelial dysfunction in preeclampsia [103]. In women with a diagnosis of preeclampsia, increased levels of inflammatory cytokines such as IL-6 have even been found in breast milk [104]. Significant changes can also take place during pregnancy that affect lipid and carbohydrate metabolic pathways and vascular function. Adipose tissue acts as both a store of energy during pregnancy and a metabolically active tissue [126]. Adipocytes and their stroma are a rich source of cytokines and inflammatory mediators such as TNF-α and adiponectin, which increase and decrease insulin resistance, respectively [127]. The increased insulin resistance and the changes that occur in the maternal lipid profile during pregnancy could play an important role in endothelial dysfunction [128]. The role of adipokines, cytokines, and vascular homeostasis biomarkers in the regulation of metabolic changes during pregnancy remains to be fully established. There are a few studies, some of which are in animal models, that have investigated the effect on inflammation of omega-3 LCPUFA

breast milk and in the infant's plasma if they are breastfed [121, 125].

*DOI: http://dx.doi.org/10.5772/intechopen.86402*

#### *Cytokines and Maternal Omega-3 LCPUFAs Supplementation DOI: http://dx.doi.org/10.5772/intechopen.86402*

*Maternal and Child Health Matters Around the World*

plasma and in umbilical cord blood [119].

tion during the first stages of life [76, 120].

to evaluate correlation with cytokine levels.

**6. Omega-3 fatty acids and cytokines during pregnancy**

Supplementation with omega-3 LCPUFAs during pregnancy affects the pattern of fatty acids in maternal plasma and umbilical cord blood [122–124].

**5. Patients and methods**

Likewise, there is a correlation between breast milk DHA levels and infant plasma levels [117, 118]. Other studies on supplementation have found a positive association between fish oil supplementation and a reduced plasma ω6/ω3 ratio in maternal

A dietary supply comprising mainly omega-6 fatty acids, as occurs in Western diets, can significantly inhibit the endogenous synthesis of omega-3 fatty acids, especially EPA and DHA given the enzymatic competition between their precursors. This becomes particularly relevant in the developing foetus and newborn, especially in premature or small-for-gestational-age babies [9]. Due to the limited capacity for synthesising these fatty acids [58], neonates are exclusively dependent on their placental transfer during pregnancy and their supply from breast milk. Therefore, a limited intake of omega-3 fatty acids in pregnancy or lactation can be associated with insufficient DHA levels for optimal neurological and immunological development in the foetus and newborn. In these states, a preventative nutritional intervention becomes particularly relevant as the fat that the mother consumes during pregnancy and lactation will greatly influence both foetal development and the lipid composition of breast milk and in turn the newborn's nutri-

We studied whether supplementing maternal diet with omega-3 LCPUFAs during the last trimester of pregnancy and the breastfeeding period influenced the levels of inflammatory cytokines in mother and child. Our study included a group of healthy infants born to term to 46 mothers, who had been enrolled in a registered, doubleblind controlled randomised trial, from week 28 of pregnancy to the fourth month of lactation. Mothers were recruited in the Services of Gynecology of the Mother and Child Hospital of Granada, Spain (Hospital Materno-Infantil de Granada), and the Mother and Child University Hospital of Las Palmas de Gran Canaria, Spain (Complejo Hospitalario Universitario Insular Materno-Infantil de Canarias), between June 2009 and August 2010. Our sample was taken from an earlier larger study designed to assess the effects of omega-3 LCPUFA supplementation on the fatty acid profile of mothers and newborns [121]. The earlier study was registered on www.clinicaltrials.gov under identification code NCT01947426. The experimental groups were fish oil (FO) group (*n* = 24) which received 400 ml of fish oil-enriched drink [320 mg DHA + 72 mg EPA] per day and control (CT) group (*n* = 22) which received 400 ml of a non-supplemented drink per day. The dairy drinks were not commercially available products but specifically prepared for the study. The dietary supplementation started on week 28 of pregnancy and finished on the fourth month of lactation. We determined in mother and children plasma the concentrations of the following cytokines: GM-CSF, IL-2, IL-4, IL-6, IL-10, INF-γ, and TNF-α using MILLIPLEX® Human Cytokine/Chemokine kit in conjunction with a Luminex 200® system (Austin, TX, USA) and xPONENT® software package. The fatty acid profiles of maternal and children compartments were analysed in an earlier study [121], and DHA levels in mother and children plasma and erythrocyte membranes, as well as in breast milk, were used

**44**

Supplementation increases DHA levels not only in these compartments but also in breast milk and in the infant's plasma if they are breastfed [121, 125].

Inflammation is considered one of the main causes of complications during pregnancy and of prematurity and neonatal morbidity [10–15]. Indeed, pregnancy may be considered a mild, controlled, systemic inflammatory state. Cytokines TNF-α and IL-1 are heavily involved in the inflammatory processes associated with pregnancy and labour [10, 12, 13], although an increase in inflammatory biomarkers such as IL-8, hepatocyte growth factor and monocyte chemotactic protein during pregnancy have also been demonstrated. There is also a progressive increase in vascular biomarkers, such as E-Selectin, vascular adhesion molecule 1, intercellular adhesion molecule (ICAM) 1, and plasminogen activator-inhibitor 1 [126]. Other studies have suggested that an abnormal response from cytokines and other molecules such as leptin may be involved in the pathophysiology of pregnancy-related complications such as preeclampsia. An association has been demonstrated between TNF-α, IL-6, IL-8, IL-10, and leptin, indicating that a rise in these markers could be used as a marker of inflammatory dysfunction and endothelial dysfunction in preeclampsia [103]. In women with a diagnosis of preeclampsia, increased levels of inflammatory cytokines such as IL-6 have even been found in breast milk [104].

Significant changes can also take place during pregnancy that affect lipid and carbohydrate metabolic pathways and vascular function. Adipose tissue acts as both a store of energy during pregnancy and a metabolically active tissue [126]. Adipocytes and their stroma are a rich source of cytokines and inflammatory mediators such as TNF-α and adiponectin, which increase and decrease insulin resistance, respectively [127]. The increased insulin resistance and the changes that occur in the maternal lipid profile during pregnancy could play an important role in endothelial dysfunction [128]. The role of adipokines, cytokines, and vascular homeostasis biomarkers in the regulation of metabolic changes during pregnancy remains to be fully established. There are a few studies, some of which are in animal models, that have investigated the effect on inflammation of omega-3 LCPUFA supplementation during pregnancy [34–36, 126, 129, 130].

A high intake of omega-3 fatty acids has been demonstrated to reduce the production of eicosanoids, cytokines, ROS and expression of adhesion molecules. Cell culture studies [33] have reported that EPA and DHA can inhibit the production of pro-inflammatory cytokines, such as TNF-α, IL-1, and IL-6, and in vitro studies have demonstrated that they can also reduce the expression of cell adhesion molecules and recently also in endothelial cells of the umbilical cord. These effects are supported by similar studies on dietary supplementation in animal and human models. In animal models, a reduction in the inflammatory response, expression of remodelling enzymes, and functional improvement has been demonstrated in offspring exposed to stressful situations whose mothers received DHA during pregnancy [34, 35]. In humans, some studies have revealed a decrease in cytokine levels, as a measure of systemic inflammatory response, after 8 weeks of fish oil supplementation [23]. During pregnancy, it has been demonstrated that intake of omega-3 long-chain fatty acids can modify cytokine levels and maturation of helper T (Th) cells [32]. Comparative studies in breastfed children whose mothers received EPA and DHA supplements from week 22 of pregnancy showed that this dietary intervention confers a reduction in Th1 cytokines such as IFN-gamma and IL-1 in the plasma and a reduction in the Th2 cytokines IL-14 and IL-13 in the umbilical cord blood [37]. In our study, in which mothers received supplements from week 28 of pregnancy and throughout breastfeeding, we found that levels of IL-6, TNF-α, IL-4, and IL-10 could be altered [26]. Maternal plasmatic levels of IL-10 and IL-4 were higher in the supplemental group (FO) than in the control group (CT). On the other hand, plasmatic IL-6 levels were higher both in mothers and children of the

CT group. Additionally, TNF-α was higher in CT children [26]. In a study on depression in pregnant women, it was also observed that prenatal EPA supplementation in particular reduced maternal levels of IL-6, Il-15, and TNF-α [131]. Clinically, these findings could translate to an increased anti-inflammatory "environment" provided by omega-3 LCPUFAs. TNF-α and IL-6 are pro-inflammatory, and IL-10, although it has both effects [131, 132], is considered the principal regulator of T cells and may act as an anti-inflammatory mediator of omega-3 LCPUFAs [133]. However, some studies have found no correlation between DHA and different cytokines: a study by Hawkes et al. [129] found that women receiving supplementation during pregnancy with a combination of 600 mg DHA plus 140 mg EPA daily for 4 weeks had an increase in omega-3 LCPUFA levels in the cells studied. DHA levels increased in a dose-dependent manner in the plasma and breast milk, which highlights the benefits of this dietary intervention. However, no significant differences were found between groups in the production of cytokines, either in breast milk cells or in peripheral blood. In addition to the dose, the duration of supplementation could be the key.

There has been some investigation into the clinical effect that supplementation may have on infants [133–136]. It has been observed that increased dietary intake of salmon during pregnancy increases levels of omega-3 LCPUFAs in umbilical cord plasma and affects cytokine production in neonates, with lower levels of IL-2, IL-4, IL-5, IL-10, and TNF-α in response to various stimuli [133]. Reduced IL-10 production has also been observed in vitro following stimulation with cat allergens in an atopic population [134]. Increased DHA and EPA in mother and child results in lower levels of PGE-2, a pro-inflammatory eicosanoid and inducer of IL-10 production, which could explain the reduced secretion of IL-10 in these individuals. This concept is also supported by Warstedt et al. [136] who suggested that reduced maternal levels of PGE-2 after omega-3 LCPUFA supplementation could contribute to a foetal immune system less prone to developing inflammatory disease such as allergies, since eicosanoids, cytokines, and chemokines are closely associated with the immune response. However, although results have been promising, it is still unclear whether or not omega-3 LCPUFAs affect the development of atopy [4].

Changes in fatty acid levels have been demonstrated to affect cytokine levels. A positive association has been observed between DHA and IL-10 such that at higher concentrations of DHA, IL-10 secretion is increased [26, 131]. Likewise, DHA has been negatively associated with IL-6, which could translate to an increased antiinflammatory effect [26, 137]. These findings will need to be confirmed in future studies to clarify the uncertainties regarding the various mechanisms by which omega-3 LCPUFAs can affect inflammatory cytokines [137].

#### **7. Conclusions**

DHA supplementation during the third trimester of pregnancy and during breastfeeding can affect cytokine production, increasing anti-inflammatory cytokine levels and decreasing pro-inflammatory cytokine levels. These effects may translate to a lower risk of pregnancy-related complications and childhood disease, but much remains to be investigated in these fields.

#### **Acknowledgements**

We thank all the members of our team who have participated in this work: Julio Ochoa, Federico Lara Villoslada, Naroa Kajarabille, Pedro Saavedra-Santana, Jose

**47**

*Cytokines and Maternal Omega-3 LCPUFAs Supplementation*

The authors declare no conflict of interest.

Antonio Hurtado, Manuela Peña, Javier Diaz-Castro, Irma Sebastian-Garcia, Elisabet Machin-Martin, Magdalena Villanueva, Octavio Ramirez-Garcia, and NUGELA group. The authors have no financial relationships relevant to this chapter to disclose.

and Luis Peña-Quintana2,3,4\*

1 Primary Health Care "El Calero", Servicio Canario de Salud, Las Palmas, Spain

Hospitalario Universitario Insular Materno-Infantil de Canarias, Las Palmas, Spain

3 Department of Clinical Sciences, University of Las Palmas de Gran Canaria, Spain

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

2 Unit of Pediatric Gastroenterology, Hepatology and Nutrition, Complejo

\*Address all correspondence to: luis.pena@ulpgc.es

provided the original work is properly cited.

*DOI: http://dx.doi.org/10.5772/intechopen.86402*

**Conflict of interest**

**Author details**

4 CIBER OBN, Spain

Yessica Rodriguez-Santana1

Antonio Hurtado, Manuela Peña, Javier Diaz-Castro, Irma Sebastian-Garcia, Elisabet Machin-Martin, Magdalena Villanueva, Octavio Ramirez-Garcia, and NUGELA group. The authors have no financial relationships relevant to this chapter to disclose.
