Introduction
Long-chain omega-3 fatty acids (n-3 FAs) are polyunsaturated fatty acids linked to overall health, including improvements in physical and mental performance [1]. The nutritionally essential fatty acid "alpha-linolenic" (ALA, 18:3 n-3) has a relatively low conversion rate (0.2 to 21%) to the "physiologically essential" fatty acids derived from its metabolism, in particular, eicosapentaenoic acid (EPA, 20:5 n−3) and docosahexaenoic acid (DHA, 22:6 n−3) [2]. This low conversion rate does not allow the human body to obtain the necessary amounts of EPA and DHA related to their functional benefits and therefore to ensure the necessary incorporation of EPA and DHA into tissue membrane phospholipids as well as their adequate levels in the blood, they must be ingested from the diet [3].
The availability of EPA and DHA in the body affects the lipid content of the membranes of different tissues (for example, skeletal muscle, cardiac, or the nervous system) and therefore their functionality in these organs that are so important for health [4]. However, there are no consensus recommendations on the intake of n-3 fatty acids, except for ALA (e.g., women need 1,1 g/day and men 1,6 g/day) [5]. Different governmental agencies and health-promoting organizations indicate a consumption of 1,4 to 2,5 g/day of n-3 fatty acids with an amount of EPA+DHA representing between 140 and 650 mg/day [2], the total recommended average daily intake of n-3 fatty acids being ~500 mg for the adult population.
Adequate dietary intake of n-3 fatty acids has been associated with functional improvement, mainly impacting (i) the central nervous system, (ii) the cardiovascular system, (iii) systemic inflammation, and (iv) skeletal muscle efficiency [6].
In particular, EPA has been granted benefits for reducing systemic inflammation and promoting recovery by enhancing muscle blood flow. DHA is abundant in the retina, testes, sperm, and brain, being one of the main structural components of the neuronal cell membrane [1]. Additionally, regular physical activity can induce changes in muscle phospholipids by increasing the proportion of DHA content and, consequently, favoring a higher content of n-3 fatty acids in the cell membranes of trained athletes compared to the sedentary population.
ALA is abundant in various vegetable oils, such as chia, perilla, and flaxseed oil, and to a lesser extent in walnut oil. EPA and DHA are found in seafood, algae, crustaceans, salmon, or hake, although to a much lesser extent in dairy products and meat (the animals' diet influences the content of n–3 fatty acids). Both dietary intake from common sources (fish) or supplements, as well as physical training, can change the status of n−3 fatty acids in the human body [1]. However, it should be considered that the usual process of food production, as well as the environmental conditions that impact the growth and development of many species of fish or livestock, are alarmingly influencing the natural concentration of AG n−3, causing a notable decrease in its content in marketed foods (for example, fish or eggs) [7].
Effects of supplementation with n-3 fatty acids on health and performance in physically active people.
Due to the anti-inflammatory effects, additional intake in the form of supplements with n-3 fatty acids would help improve post-training recovery, attenuate exercise-induced muscle damage, or reduce the severity of muscle soreness that usually occurs after (12 to 72 hours) following intense and prolonged exercise [6].
Supplementation with EPA and DHA has been associated with more efficient muscle protein synthesis (hypertrophy) and reduction of post-exercise inflammation in both young and older people [8]. Recent research advocates supplementation with n-3 fatty acids, particularly DHA, to reduce the severity of traumatic brain injury in athletes exposed to frequent impacts as occurs in many team sports (American Football, Rugby, etc.) and to promote mood, sleep quality, memory, cognition, and reaction time in physically active individuals [1].
The available scientific evidence seems to support the increase of dietary intake of n-3 fatty acids both through regular foods such as fatty fish or even dietary supplements, as a pragmatic strategy to improve cognitive activity and physical performance, as well as to mitigate exercise-induced inflammation and optimize post-exercise recovery [1]. However, it is worth noting that the positive effects of fish oil supplementation could be achieved through foods such as salmon, sardines, flaxseed oil, etc. [6].
Supplementation protocols and quality of marketed products
To induce detectable increases in n-3 fatty acids in cell membranes and promote health, a minimum period of two weeks of regular supplementation consuming 3 to 5 g/day of fish oil (providing more than 60%, ideally 85-90% of EPA+DHA) would be necessary [9]. However, longer periods, from four to twelve months, would be required to increase the content of EPA and DHA in red blood cell membranes [10]. The sum of EPA and DHA expressed as a percentage of total fatty acid content in erythrocytes represents the Omega 3 index, which has been identified as a marker associated with many health indicators in the general population [10].
To promote the incorporation of n-3 fatty acids at the muscle level, support functional capacity, and especially muscle growth, an intake of 4 g/day of fish oil supplements providing 1,86 g of EPA and 1,50 g of DHA (EPA-DHA ratio ~1,25) is necessary. This intake is approximately equivalent to an n-3 fatty acid content found in 200 to 400 g of fatty freshwater fish (e.g., salmon, herring, and sardines) [8].
To improve cognitive aspects and mitigate traumatic brain injury, depression, and anxiety, it has been suggested that supplements provide a higher proportion of DHA compared to EPA, in a range from 1 (equal amounts) up to 0,12 (8 times more DHA) [3].
High-quality fish oil supplements should include more than 60% up to 85-90% of n-3 fatty acids with an arachidonic acid to EPA content ratio below 0,04. Additionally, the inclusion of vitamin E (tocopherol) is highly recommended to reduce the oxidation of n-3 fatty acids, ensure product stability, and extend its shelf life [6].
To improve the bioavailability of n-3 fatty acids, fish oil supplements in capsule form are recommended due to their greater resistance to the action of gastric acids [3].
In summary, supplementation with n-3 fatty acids should be continued for at least two weeks, ideally from 4 to 12 weeks, ingesting 3 to 5 g/day of high-quality fish oil with high proportions of EPA and DHA. The intake protocol could consist of two daily doses of 1,5 to 2,5 g each (e.g., the first in the morning, before breakfast, and the second in the evening, before dinner).
Adverse effects of fish oil supplementation
Supplementation with fish oil appears to be safe for physically active people, with the main concern related to the purity of the products. Reports have been published of fish oil supplements containing high amounts of heavy metals and high concentrations of saturated fats at the expense of the amount indicated on the labels of EPA and DHA [11].
The scientific opinion of the European Food Safety Authority states the following: "As long as the oxidative stability of n–3 fatty acids is guaranteed, long-term intake of EPA+DHA supplements up to approximately 5 g/day does not appear to increase the risk of spontaneous bleeding episodes or hemorrhagic complications, nor does it affect glucose homeostasis, immune function, or lipid peroxidation."
However, a daily intake of fish oil exceeding the maximum indicated amount (> 5 g/day) should not be consumed by physically active healthy individuals without proper professional supervision [6,12].
Practical tips
Before suggesting fish oil supplements, it is advisable to carry out a thorough analysis of the diet and the blood fatty acid profile that indicates the level of n-3 fatty acids (Omega 3 index).
Those people who follow a vegan diet could be at high risk of ingesting insufficient EPA and DHA. In cases where it is not possible to modify food choices, the integration of high-quality fish oil supplements into the habitual diet should be considered. Periodic monitoring of the fatty acid profile is necessary to regularly adjust the composition of the diet and supplementation protocols.
Author
Dr. Fernando Naclerio
Professor in Strength Training and Sports Nutrition
Director of the Center for Physical Activity and Rehabilitation
Life Development Institute
Faculty of Human Sciences
University of Greenwich, United Kingdom.
f.j.naclerio@gre.ac.uk
OMEGA-3 PRO (120 PEARLS)
Omega-3 Athlete (90 Softgels)
References
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