Solà Marsiñach and Cuenca Lipids in Health and Disease (2019) 18:145 https://doi.org/10.1186/s12944-019-1065-9 REVIEW Open Access The impact of sea buckthorn oil fatty acids on human health Marta Solà Marsiñach1* and Aleix Pellejero Cuenca2 Abstract The beneficial properties of fatty acids have been undervalued for several years. In contraposition, new studies reveal that fatty acids have an essential role for human health. The aim of the study is to demonstrate the clinical applications of fatty acids present in sea buckthorn oil. The composition of fatty acids found in sea buckthorn (Hippophae rhamnoides) oil is unique for this species, presenting a vast range of health benefits for humans and therefore it is highly valued by both biomedicine and the cosmetic industry. In this way, we will see the clinical effect of monounsaturated, polyunsaturated and saturated fatty acids that constitute sea buckthorn oil and how they contribute to the correct function of the organism. Despite there being studies that support the positive effects of sea buckthorn fatty acids, they are limited. Hence, most of the results obtained in this review are from studies of isolated fatty acids instead of fatty acids extracted from sea buckthorn oil. These facts permit to demonstrate the effect of sea buckthorn fatty acids separately but we lost the possibility of detecting a synergic effect of all of them. More studies are necessary to certify the clinical application of the fatty acids present in sea buckthorn oil as well as discovering possible synergies between them. Keywords: Fatty acids, Sea buckthorn, Omega-3, Omega-6, Clinical applications, Human health, Plant, Omega-7, Hippophae rhamnoides, Omega-9 Introduction As already mentioned, a number of studies have re- For several decades, the beneficial properties of fatty vealed that fatty acids are very diverse, each type of them acids have been largely ignored. In contrast, this paper having different effects over the organism. So far, the will review the contributions made by several re- fatty acids found to be most beneficial are those present- searchers who have shed light over the fact that the fatty ing an even number of carbons (4 to 30) and instaura- acid group is actually large and diverse, as well as greatly tions, which are mainly found in marine species. beneficial for human health. However, lately it has also been highlighted that some From a nutritional standpoint, fatty acids have an import- plants, such as sea buckthorn, also contain abundant ant role in several metabolic and structural functions. They and valuable fatty acids (especially in their seeds) with are indispensable compounds of the cell membranes, are high nutritional value, as well as useful for several clin- responsible for the transport of vitamins, and regulate the ical applications. In particular, sea buckthorn is a perfect concentration of lipids in plasma. Furthermore, fatty acids natural vegetable source to obtain a wide range of fatty produce a number of precursors such as eicosanoides, acids, especially essential and unsaturated fatty acids, decosanoides, steroid hormones and biliary acid, all of them both the most beneficial for human health. It is a plant fundamental for the adequate functioning of the metabol- that is composed of different bioactive compounds, ism. In addition, they are the most important energetic nu- which may also be found in other medicinal plants. The trient –it is currently recommended that at least 20% of the characteristic that makes sea buckthorn unique is the total energy intake should derive from lipids–. qualitative and quantitative composition of its fatty acids, particularly the presence of the fatty acid omega-7 group, higher than in any other plant. * Correspondence: [email protected] 1Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Crta. Sea buckthorn (Hippophae) is a hardy bush of the de Valls, s/n, 43007 Tarragona, Spain Elaegnaceae family classified into nine subspecies, from Full list of author information is available at the end of the article © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Solà Marsiñach and Cuenca Lipids in Health and Disease (2019) 18:145 Page 2 of 11 which Hipopphae rhamnoides L. subsp sinensis and Hip- Objectives pophae rhamnoides L. subsp rhamnoides are the most The aim of this review is to demonstrate the clinical ap- applied to commercial purposes [1]. It is a deciduous plication of fatty acids present in sea buckthorn oil. Sea spiny species distributed all over the temperate zone of buckthorn was the source selected to demonstrate these Asia and Europe, as well as over subtropical zones at positive effects due to its variety and unusual fatty acids high altitude [2]. Its products, particularly the oil ob- in its composition compared to other plants. In general, tained from the seed and the soft parts of the plant, con- the studies focused on the fatty acid from sea buckthorn tain an interesting composition of lipophilic compounds. oil are limited and, for this reason, in most cases it has In relation to the oil composition, sea buckthorn is char- been necessary to classify the different fatty acids pre- acterized by a unique mixture of bioactive components, sents in the oil composition and reveal their benefits being one of them the fatty acids. In general, the oil ob- separately Hence, the review will show the clinical appli- tained from seed is rich in omega-3 and omega-6 fatty cation of fatty acids that sea buckthorn oil composes in- acids, while in the pulp oils are predominantly fatty acids dependently of its origin. from the omega-7 group [3] (Table 1). Although the prevalence of fatty acids in the different parts is well Methods established, there could be variations depending on the Systematic searches were conducted using the PubMed subspecies, harvesting time and method of isolation [4]. database without any restriction in year of publication. Several mechanisms of oil extraction are used, solvent Keywords used include “sea buckthorn”, “sea buckthorn extraction using hexane and supercritical CO2 being the oil”, “palmitoleic acid”, “linoleic acid”, “linolenic acid”, most common in industrial and laboratory scale [5]. In “alpha-linolenic acid”, “oleic acid” and “gamma-linolenic any case, several studies of fatty acids contained in sea acid”. The criteria for inclusion were (1) in vivo and in buckthorn oil reveal that it may play an important role vitro clinical trials and reviews published in English and in very different aspects in relation to the human body, (2) research studies focused in any health benefits of the such as cardiovascular disorders, as a stimulator of the fatty acids of sea buckthorn oil. immune system, as well as promoting cognitive func- tions and bone health [6]. Moreover, it may be important Results to improve various skin conditions such as atopic The systematic searches were conducted from April to dermatitis [2], acne skin [7, 8] or psoriasis [9]. June 2018. The search flow is summarized in Fig. 1.The first search includes 87 records after the duplications were removed. After the screening, 33 articles were ex- cluded due to the fact that they did not focus on the Table 1 Fatty acid composition of oils from seeds, whole fatty acids of sea buckthorn oil [10] and that they were berries and pulp/peel of Sea buckthorn of different origins [4] written in Chinese [2]. The articles included (54) were Fatty acid Seed (%) Berry (%) Pulp/peel (%) reviews [11], in vitro trials [7] in vivo trials [12] and subsp. sinensis studies seeking to determine the qualitative and quanti- tative composition of sea buckthorn oil [8]. Palmitoleic acid 0 33.6 27.2 For the sake of clarity, the present review has been Linoleic acid 41 18.6 12 structured in three main parts, covering the three fatty Linolenic acid 26.6 11.2 7.1 acids found in sea buckthorn oil: firstly, monounsatu- Oleic acid 19.4 17.6 17.1 rated fatty acids omega-7 and omega-9 (palmitoleic acid, Palmitic acid 8.8 22.9 26.7 vaccenic acid and oleic acid), then, polyunsaturated fatty acids omega-3 and omega-6 (linoleic acid and linolenic Stearic acid 2.5 1.5 1.3 acid), and finally, the saturated fatty acids (stearic acid Vaccenic acid 2.2 6.7 8.1 and palmitic acid). Each of these subheadings explains in subsp. rhamnoides more detail the characteristics of the relevant fatty acid: Palmitoleic acid 0 26 32.8 its chemical structure, its proportion (%) in the oil and Linoleic acid 39 15.3 9 its effects over human health in order of significance. Linolenic acid 30.6 8.8 3.2 Monounsaturated fatty acids Oleic acid 17.2 17.2 17.3 Palmitoleic acid (PA) Palmitic acid 7.4 23.7 27.4 PA (16:1) is an omega-7 monounsaturated fatty acid very Stearic acid 3 1.2 0.7 uncommon within the plant kingdom. Consequently, it Vaccenic acid 2.8 7.7 9.1 is very difficult to introduce it in the human diet Means obtained from Yang (2002) [4] through vegetable food sources. Sea buckthorn is one of Solà Marsiñach and Cuenca Lipids in Health and Disease (2019) 18:145 Page 3 of 11 Fig.