Omega-3 in breast milk increases with increased Omega-3 intake (review of 22 studies) -Aug 2017

Are There Changes in the Fatty Acid Profile of Breast Milk with Supplementation of Omega-3 Sources? A Systematic Review

Existem mudangas no perfil de acidos graxos no leite materno com a suplementagao de fontes de omega 3? Uma revisao sistematica
Ginecol Obstet 2017;39:128-141. published online March 17, 2017, DOI http://dx.doi.org/10.1055/s-0037-1599094.
Yasmin Notarbartolo di Villarosa do Amaral1 Daniele Marano1 Leila Maria Lopes da Silva1 Aline Carnevale Lia Dias Guimaraes1 Maria Elisabeth Lopes Moreira1

 Download the PDF (study starts on page 46) from VitaminDWiki

Purpose To evaluate the effect of supplementation with omega-3 sources on the fatty acid composition of human milk.

Methods The review consisted of the search for articles published in PubMed, Biblioteca Virtual de Saude (Virtual Health LibraryVHL) and Web of Science databases using the following keywords: fatty acids, omega-3, human milk and supplementation; for this purpose, we have used the program of research to integrate the services for the maintenance of autonomy (PRISMA) checklist. The following selection criteria were used: articles in English, Portuguese, Spanish or Italian, published between 2000 and 2015, and about studies performed in humans. We found 710 articles that met the established criteria; however, only 22 of them were selected to be part of this study.

Results All studies found a positive relationship between the consumption of omega- 3 sources and their concentration in human milk. The differences in the findings are due to the distinct methods used, such as the specific time of the omega-3 supplementation, the type of omega-3 source offered, as well as the sample size.

Conclusion Although the studies were different in several methodological aspects, it was possible to observe the importance of omega-3 supplementation during gestation and/or the puerperium.

Discussion - from the PDF

The omega-3 and omega-6 polyunsaturated fatty acids consumed through dietary triglycerides are digested in the small intestines and can then be absorbed, transported into the bloodstream and taken up between tissues throughout the body (including brain, retina and heart).8 Essential dietary fatty acids in the form of linoleic acids (LAs) and a - linolenic acids (ALAs) are activated in the forms known as keto- acyl-CoA, and then used for the conversion of long chain polyunsaturated fatty acids and other polyunsaturated products, such as those derived from the series of desaturation and elongation reactions that are particularly active in the liver and, to a lesser extent, in other tissues.8

Linoleic and ALA fatty acids need to be ingested through food, since the human body does not have enzymes to synthesize them. Some vegetables synthesize them and are, therefore, an abundant source of these fatty acids, as well as the products derived from these vegetables. Omega-3 fatty acids (DHA and EPA) can be synthesized by the human body to a certain level, albeit a very limited one. The consumption of omega-3 sources through dietcan be done by ingesting fish or fish oils, and foods enriched or fortified with these important fatty acids.9

Although ALA in humans is converted to EPA and DHA, the exact percentage of this conversion is unknown, but it is estimated to be low (5% EPA and 0.5% DHA).10,11 Due to their enzymatic immaturity, children and especially neonates cannot convert all the DHA required for their development from ALA.12 Therefore, feeding in the gestational period is of great importance as it determines the type of fatty acid that will accumulate in the fetal tissue. The essential fatty acids are transferred through the placenta, and in the third gestational trimester are deposited in the brain and retina of the fetus. It should be noted that the fetus withdraws a total of 50 to 75mg of polyunsaturated fatty acids from the mother, most of them being DHA.13-16

Numerous studies have been conducted to evaluate the effects of the supplementation of omega-3 and its metabolites in pregnancy and puerperium on the composition of HM. This is due to the synthesis of DHA probably occurring minimally in the mammary gland6,17,18 as well as due to the role that this polyunsaturated fatty acid plays on visual acuity, cognition and in the formation of the nervous tissue of the newborn.19

Although supplementation appears to be the most reliable medium for increasing omega-3 levels in HM, there are numerous differences among the studies evaluated in relation to the following parameters: sample size, study design, timing of omega-3 supplementation (gestation and/or lactation), type of supplementation (fish oil, in natura fish consumption), and amount and type of omega-3 offered (EPA and/or DHA).

Regarding the diversity of the countries where the studies selected for this systematic review were performed, it is worth noting that the consumption of omega-3 rich foods in Western countries is well below that of other countries.20
In the United States, the intake of omega-3 and its metabolites (DHA and EPA) was estimated at 1.6 and 0.1-0.2 g/day respectively, and the dietary ratio between omega-6 and omega-3 was « 9.8:1.21 A study with Canadian pregnant women showed that the average daily intake of omega-3 and DHA was 1.45 and 0.082 g/day respectively.22 Populations living in coastal countries, such as Japan and Norway, where fish are widely consumed, have a higher dietary intake of omega-3 (>1 g/day), and consequently, high concentrations of DHA in their breast milk.20,23,24 Although there is no official dietary recommendation for EPA and DHA in the US, several expert groups suggest a DHA intake of at least 200 mg/day, which may reach 1,000 mg DHA/day for pregnant and lactating women, and 1.4-2.7 g of omega-3, and suggest the omega-6/omega-3 ratio of « 2-5:1.21,25

Corroborating the above recommendations, the consensus published by Koletzko et al 26 states that an average intake of at least 200 mg of DHA per day is advisable; it also states that consumption of up to 1 g of DHA or 2 to 7 g of omega-3 per day is safe. This amount can be achieved by consuming one to two servings of fish per week, including fatty fish such as herring, mackerel and salmon. However, it is known that the consumption of fish can contribute significantly to the exposure to contaminants such as methylmercury, which is particularly toxic to the developing brain and possibly harmful to infant growth. To decrease the amounts of methylmercury in the body, one should reduce the intake of contaminated foods during the pregestational and gestational periods. The fish with the highest levels of methylmercury are predatory fish such as marlin, pike, swordfish and shark. However, after an extensive literature review, the consensus points out that the beneficial effects of regular consumption of fish sources of DHA during pregnancy appear to overcome the potential drawbacks of the increased intake of contaminants.

Regarding the period of supplementation, the selected studies presented different time periods (pregnant and/or nursing) when omega-3 supplementation was performed and measured, which may partially justify the differences in the results we found. On this issue, in their randomized clinical trial, Boris et al 27 evaluated two hypotheses, namely:

• 1) whether omega-3 supplementation during pregnancy increased omega-3 levels at the beginning of breastfeeding; and
• 2) whether the continuation of supplementation after delivery was necessary to sustain the long-term increase in omega-3 levels.

There was a marked drop in omega-3 levels in the group that stopped supplementation during the puerperium. Such a decrease in the concentration of DHA in breast milk as lactation progresses is corroborated by numerous studies.4,28,29 On the other hand, the group that received fish oil during gestation and lactation showed levels of omega-3 three times higher, and double the levels of DHA.27 It is worth mentioning that polyunsaturated fatty acids are deposited in the brain during the last gestational trimester, and that this process continues after delivery. Furthermore, the neurological development continues during the first years of life.27 The results found by Ribeiro et al 30 also demonstrated that supplementation with fish oil limited to pregnancy was not as effective as supplementation during pregnancy and lactation. Therefore, supplementation during pregnancy and lactation is recommended by numerous studies.20,30,31

Important issues to take into account in these studies are the type of omega-3 source and the quantity that was supplied. It was observed that most of the selected studies used fish oil to increase the consumption of omega-3; however, some studies have used the supply of fresh food, fortified drinks and food education techniques. The use of fish oil has benefits, but it can lead to low compliance due to its adverse effects, such as fish flavor eructation, digestive discomfort and night sweats.5,32 The randomized double blind clinical trial conducted by Dun- stan et al20 aimed to evaluate the effects of fish oil supplementation during pregnancy on the composition of HM and on the development of the infant in the first year of life. The concentration of fatty acids in the milk was analyzed on the third day, sixth week and sixth month after delivery. It was observed that women who received fish oil had a higher concentration of EPA and DHA in the milk on the third day and the sixth week after delivery.

Regarding the consumption of fish, the study by Henderson et al33 demonstrated that ingesting 100-120 g of sardines 2 to 3 times a week resulted in increased levels of fatty acids without the need for fish oil. Harris et al 34 disagreed with this, and have observed that in order to increase 0.5 to 1 g of DHA in breast milk, it is necessary to consume 350 - 750 g of 1% fat or 75-150 g of 10% fish fat. In the study by Patin et al,35 it was observed that the levels of DHA in HM increased with the ingestion of 300 g of sardines per week, with 5% fat, without the need to use fish oil supplementation. This study recommended the consumption of fish two to three times per week during gestation.

Gaete and Atalah1 conducted a prospective study with 26 pregnant women, which consisted of an educational feeding strategy to recommend individual consumption of different preparations based on marine foods. A guide with information on the importance of maternal lactation to the newborn, and on the importance of fish consumption by the mother to increase DHA levels was also distributed. The strategy of food education is considered an important intervention to raise awareness about the need for fish consumption during the gestational and puerperal period.

The study by Atalah et al 5 aimed to evaluate the effects of the introduction of omega-3 fortified milk beverages (DHA and EPA) during gestation on the composition of HM and red blood cells. One-hundred and seventy-five women from the intervention group and 177 from the control group were evaluated in the clinical trial. The pregnant women were evaluated at three moments of the pregnancy and once after delivery to evaluate the consumption near the date of the interview. The evaluation of milk composition was performed in only 16 women, and a 50% increase in omega-3 in breast milk was observed. However, there was no statistical difference between the evaluated groups in relation to the amount of EPA and DHA, probably due to the small sample size.

Regarding the type of omega-3 offered, seven studies offered DHA and EPA, seven offered DHA only, and three offered DHA, arachidonic acid (ARA) and EPA. It was observed that the amount of DHA was always higher than that of EPA, probably because of its important role on the nervous system, cognition and vision. It is worth noting that there is no consensus regarding the optimal levels of DHA consumption at different stages of life. However, most technical groups recommend around 200 to 500 mg/day in the adult population, and, during gestation, it is recommended to consume fish between two to three times per week.5

There are numerous factors that contribute to the variability of EPA and DHA content in breast milk, such as

• lactation stage,
• gestational age, and
• maternal nutritional status.

What is verified is that certain selected studies 20,27,30,36 did not control the analyses for important confounding factors, such as food consumption. Therefore, estimates of association may be compromised by the fact that certain studies did not quantify follow-up losses, but also because they did not control important confounding factors.

All selected articles showed the importance of supplementation of omega-3 in different forms (capsules, dairy drinks, strategy for feeding education, consumption of fish) on the nutritional composition of HM in the gestational and/ or puerperal periods. However, four studies1,5,27,37 did not reach statistical significance. This can be partially explained by the sample size, which can reduce the strength of the study to elucidate possible associations, possible adhesion reduction in relation to the intake of supplements and the food education practices employed, as well as the follow-up losses, which may cause a decrease in the validity of the results.

Short URL = https://is.gd/O3Breast