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The Role of Omega-3 Fatty Acids in Inflammation and Cardiovascular Health

M3 India Newsdesk Dec 26, 2024

Omega-3 fatty acids are well-recognised for their anti-inflammatory and cardioprotective properties. This article reviews the mechanisms through which omega-3s impact inflammation and cardiovascular health, examining clinical evidence and providing practical recommendations for patient guidance.


Cardiovascular diseases (CVD) are leading causes of mortality worldwide, with chronic inflammation playing a significant role in the development of CVD, atherosclerosis, and other metabolic conditions. Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have emerged as key nutrients in managing inflammation and reducing cardiovascular risk.

This article examines the biochemical pathways through which omega-3s exert their effects, along with clinical evidence supporting their role in cardiovascular health.


Omega-3 fatty acids: Overview and sources

Omega-3 fatty acids are essential polyunsaturated fatty acids (PUFAs) critical for various physiological processes. EPA and DHA, primarily found in marine sources, have been extensively studied for their health benefits. Another omega-3, alpha-linolenic acid (ALA), present in flaxseed, chia, and walnuts, serves as a precursor to EPA and DHA, although conversion rates are generally low (less than 10%).

  1. Dietary sources: EPA and DHA are abundant in fatty fish (salmon, sardines, and mackerel), while ALA is found in plant oils and seeds.
  2. Recommended intake: According to the National Institute of Nutrition (NIN) and the Indian Council of Medical Research (ICMR), the Recommended Dietary Allowance (RDA) for alpha-linolenic acid (ALA), for Men: 2 grams per day and for Women: 1.6 grams per day.

However, since conversion rates of ALA to EPA and DHA are low (often less than 10%), the NIN suggests that Indians should also consume sources of EPA and DHA directly, especially for those with higher cardiovascular risk. While NIN/ICMR does not specify EPA and DHA intake, 250–500 mg of combined EPA and DHA daily is considered beneficial based on current research for reducing inflammation and cardiovascular risks. This can be achieved by incorporating fatty fish such as mackerel (bangda), sardines (pedvey), or salmon twice a week, which aligns with the general guidance provided by international recommendations.


Biochemical mechanisms of omega-3 fatty acids in inflammation

Omega-3 fatty acids influence inflammation through various pathways:

  1. Membrane integration: EPA and DHA are incorporated into cell membranes, replacing omega-6 fatty acids like arachidonic acid (AA), thus reducing the production of pro-inflammatory eicosanoids.
  2. Eicosanoid production: EPA competes with AA for cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, leading to the formation of less inflammatory eicosanoids, such as prostaglandins and leukotrienes.
  3. Specialised pro-resolving mediators (SPMs): EPA and DHA are precursors to SPMs, including resolvins, protectins, and maresins, which actively resolve inflammation without compromising immune function.

Through these mechanisms, omega-3s help reduce chronic, low-grade inflammation, a major contributor to cardiovascular disease and other metabolic disorders.


Cardiovascular benefits of omega-3 fatty acids

  1. Anti-inflammatory effects

Omega-3 fatty acids inhibit pro-inflammatory cytokines, including TNF-α and IL-6, and reduce adhesion molecules, both of which are instrumental in atherosclerotic plaque formation. By mitigating inflammatory responses, omega-3s may help prevent the progression and rupture of atherosclerotic plaques.

  1. Lipid modulation

EPA and DHA are effective in lowering triglycerides by up to 30%, a substantial reduction with positive implications for cardiovascular health. Omega-3s achieve this through decreased hepatic triglyceride synthesis and increased β-oxidation of fats.

  1. Blood pressure regulation

Omega-3s have been associated with mild antihypertensive effects, likely due to their vasodilatory properties mediated by increased endothelial nitric oxide. They also reduce arterial stiffness, which is beneficial for patients with hypertension.

  1. Prevention of arrhythmias

Research indicates that omega-3s can modulate electrical activity in cardiac cells, reducing the risk of arrhythmias, especially ventricular fibrillation, which is a common cause of sudden cardiac death.


Evidence from clinical trials

Several randomised controlled trials (RCTs) and observational studies have supported the cardiovascular benefits of omega-3 fatty acids:

GISSI-prevenzione trial: A landmark study showing a significant reduction in sudden cardiac death among post-myocardial infarction patients who took omega-3 supplements.

REDUCE-IT trial: Demonstrated that high-dose EPA (icosapent ethyl) significantly reduced cardiovascular events in high-risk patients with elevated triglycerides despite statin therapy.

OMEGA trial: This trial revealed reductions in inflammation markers in patients with stable coronary heart disease after omega-3 supplementation.

The results from these studies reinforce the role of omega-3s in inflammation and cardiovascular health, especially for high-risk populations.


Clinical applications and dosage recommendations

For patients with established CVD or high cardiovascular risk, a therapeutic dose of 1-4 grams of EPA and DHA per day is often recommended. Such dosages have been linked to reductions in triglycerides and inflammatory markers, contributing to cardiovascular benefits. Clinicians should tailor recommendations based on each patient’s needs, lipid profiles, and potential contraindications.

Safety and considerations

Omega-3s are generally safe; however, high doses can increase bleeding risk, particularly in patients on anticoagulants. Monitoring and consultation with a specialist are essential to optimising individual dosages.


Omega-3 supplementation vs. dietary sources

  • Dietary sources: Emphasising whole-food sources of omega-3s is ideal for sustained cardiometabolic health. Recommended sources include:
  1. Fatty fish: Salmon, sardines, and mackerel, rich in EPA and DHA.
  2. Plant-based sources (for ALA): Flaxseeds, chia seeds, and walnuts, though ALA requires conversion to EPA and DHA.
  • Supplements: Omega-3 supplements (fish oil, krill oil, or algal oil for vegetarians) can serve as a practical alternative when dietary intake is insufficient. It is essential to select supplements based on purity, sustainability, and patient-specific needs.

Practical considerations and patient education

To maximise the benefits of omega-3 intake, clinicians should consider the following strategies for patient education:

  1. Counselling on food choices: Encourage a Mediterranean-style diet rich in omega-3s to enhance cardiovascular health.
  2. Setting realistic expectations: Inform patients that omega-3s work best when combined with other lifestyle modifications, including regular physical activity and balanced diets.
  3. Addressing myths: Educate patients about the differences between ALA, EPA, and DHA and the importance of dosage and formulation, as not all omega-3 supplements provide the same benefits.

Omega-3 fatty acids, particularly EPA and DHA, play a multifaceted role in reducing inflammation and promoting cardiovascular health. By incorporating these fats into cellular membranes and modifying eicosanoid production, omega-3s offer significant cardioprotective effects. For clinicians, promoting a diet rich in omega-3s, supplemented when necessary, provides an effective strategy for managing inflammation and reducing cardiovascular risks among patients.

 

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

The author of this article: Ms Rutambhara Nhawkar is a Clinical Dietician, M. Sc. (Clinical Nutrition & Dietetics),  Certified Diabetes Educator and a medical writer from Pune.

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