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Omega-3s and Brain Health

 

OMEGA-3s AND BRAIN HEALTH

 

The information on this page is produced exclusively for healthcare professionals, and is not intended for consumers or patients. This publication is not intended as a substitute for medical therapy or as a manual for self-treatment. All readers should seek professional advice for any specific medical problem.

I. What are Essential Fatty Acids (EFAs)
II. Sources of Essential Fatty Acids
III. Balance of Omega-6 to Omega-3 is Key to Good Health
IV. Proven Benefits of Essential Fatty Acids
V. Dose
VI. Safety of EFA Supplementation

I. What are Essential Fatty Acids (EFAs)

The human body can manufacture most of the fats it needs, including cholesterol, saturated fatty acids, and unsaturated fatty acids. However, there are two families of fatty acids, the omega-6 and the omega-3 fatty acids, that are considered essential fatty acids. These fatty acids are essential because the parent omega-6 fatty acid, linoleic acid (LA), and the parent omega-3 fatty acid, alpha-linolenic acid (ALA), absolutely cannot be synthesized by the body and must be obtained from the diet or supplementation.

Omega-3 fatty acids are essential fatty acids that are necessary from conception through pregnancy, and continue to support normal growth and development of infants. Throughout life, omega-3 fats aid in the prevention and treatment of heart disease, diabetes, arthritis, inflammatory diseases, and cancer.1 Omega-3 fatty acids also play an important role in protecting the health of the brain, eyes, and nervous system.

Omega-6 fatty acids are abundant in nature, and responsible for the inflammatory immune response.

Over 8,000 published clinical trials have unequivocally established that omega-3 fatty acids are important in human nutrition. This clinical guide is intended to provide the healthcare practitioner with a basic understanding of omega-3 fatty acids and how to best utilize their powerful health-promoting qualities in the clinical setting.

 

II. Sources of Essential Fatty Acids

The primary source of omega-6 fatty acids in the human diet is linoleic acid (LA) from the oils of seeds and grains. Sunflower, safflower, soy, and corn oils are particularly rich in linoleic acid. Evening primrose oil, borage oil, and black currant oil are unique due to their relatively high content of the health-promoting omega-6 fatty acid, gamma-linolenic acid (GLA).

The primary dietary source of omega-3 fatty acids is alpha-linolenic acid (ALA) from seeds and seed oils that are derived from plants such as flax, walnuts, and canola. Fish and fish oils are the richest source of preformed long chain omega-3 fatty acids, Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA).

 

III. Balance of Omega-6 to Omega-3 is Key to Good Health

Humans have evolved consuming a diet that contained approximately equal amounts of omega-3 and omega-6 fatty acids. About 100 years ago, the industrial revolution introduced technology that allowed for the refining of vegetable and seed oils, which led to a dramatic increase in the consumption of omega-6 fatty acids among the industrialized countries. In addition, the introduction of animal feeds derived from grains rich in omega-6 fats has resulted in the production of meat, fish, and eggs high in omega-6 fats and virtually void of omega-3 fats.

Today, in Western diets, the ratio of omega-6 to omega-3 fatty acids ranges from 20:1–30:1 instead of the pre-industrial range of 1:1–2:1.5 A large body of scientific evidence has established that a high intake of omega-6 fatty acids shifts the physiological state to one that promotes thrombosis, vasoconstriction, inflammation, and poor cellular health. The physiologic changes that result from high intake of omega-6 fats has been implicated in pathophysiology of heart disease, diabetes, autoimmune and inflammatory diseases (rheumatoid arthritis, colitis ulcerosa, multiple sclerosis, lupus, asthma, etc.), depression, dementia, and other chronic diseases.
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IV. Proven Benefits of Essential Fatty Acids

1. General Health and Well-Being

A large body of scientific evidence suggests that aberrant inflammation underlies many common chronic diseases and is an obstacle to overall good health. The direct role of arachidonic acid-derived lipid mediators in promoting inflammation and EPA- and DHA-derived lipid mediators in regulating the resolution of inflammation has initiated much scientific interest in the influence of the omega-6:omega-3 ratio on human health.

In a population-based study involving 2,416 adolescents and adults living in New Zealand, there was a positive association between higher serum omega-3 concentration and physical well-being and self-reported mental well-being. (6) In addition, higher omega-3 intake is associated with:

  • Improved mood (7)
  • Healthy metabolism and body composition (8,9)
  • Bone strength (10)
  • Memory (11)
  • Respiratory function (12)
  • Skin health (13)
  • Eye health (14)
  • Attention and focus (15)
2. Cardiovascular Health

The most rigorous evidence supports using fish oil to benefit the hearts of healthy people, and those at high risk of, or who have, heart disease. Evidence from a multitude of large, well-conducted, controlled clinical trials demonstrate that omega-3 fats support cardiac health.

The evidence is so strong that the American Heart Association (AHA) considers increasing omega-3 fatty acids as a vital public health intervention, and encourages physicians to recommend their consumption. In fact, the AHA guidelines include recommendation for all Americans to consume omega-3–rich fish at least twice weekly. For individuals with documented heart disease, the AHA recommends 1 gram of EPA+DHA daily, and for patients with elevated triglycerides 2–4 grams of EPA+DHA daily.

Omega-3 fats have been shown to:

  • Improve heart rate and rhythm (16)
  • Reduce triglycerides (17)
  • Reduce blood pressure (18)
  • Lessen the effects of chronic inflammation on the heart and blood vessels (19)
  • Reduce the risk of angina, heart attack, and stroke (20)
  • Reduce risk for co-morbidies of cardiovascular disease, including insulin resistance and metabolic syndrome (21)
3. Cognitive Health

Research has shown that omega-3 fats are necessary to develop, maintain, and protect structures of the central nervous system from conception through pregnancy and infancy and, undoubtedly, throughout life. There is some debate with regard to the relative importance of EPA versus DHA, but there is an overall scientific consensus that both EPA and DHA contribute to cognitive health and development as well as mental well-being, behavior, learning, and mood.

Most evidence suggests that DHA is particularly important for development of the brain and nervous system in infants, protection and repair of brain and nervous tissue from age-associated damage, and improving mental function.

Research suggests that DHA plays an important role in:

  • Supporting fetal nervous system development in utero (22)
  • Improving cognitive function in infants, toddlers, and children (23)
  • Preventing dementia and Alzheimer’s in the aging population (24)
  • Improving cognitive performance in individuals 70+ years of age (25)

Published clinical trials suggest that EPA has a particular affinity for conditions associated with altered mood and behavior including:

  • Depression (26)
  • Bipolar disorder (27)
  • Schizophrenia (28)
  • ADHD (29)
4. Anti-inflammatory

Inflammation is a normal protective physiological mechanism, but several factors in the Western diet, including excess omega-6 fat intake, and a relative deficiency of omega-3 fats, result in long-term inflammation. Omega-3 fatty acids from fish oil have anti-inflammatory effects due to the competition of EPA with AA in the cyclooxygenase and lipoxygenase pathways. In addition, omega-3s contribute to the formation of resolvins and protectins, which aid in the removal of inflammatory cells, and restoration of tissue homeostasis once the need for inflammation is over.

Epidemiological evidence has demonstrated that EPA and DHA levels are decreased in patients who suffer from chronic pain and inflammation.(30) Randomized controlled trials have demonstrated reduced morning stiffness and joint tenderness with regular oral intake of fish oil.(31)

Pharmacological anti-inflammatory drugs are effective in reducing inflammation, but carry potentially dangerous side effects, rendering them impractical for long-term use. Several well-designed clinical trials have examined the use of fish oil on nonsteroidal anti-inflammatory drug (NSAIDS) use or steroid use in non-surgical back pain and rheumatoid arthritis. These trials show that fish oil consistently demonstrated a reduced requirement for anti-inflammatory drugs and improved clinical outcomes.(32) The anti-inflammatory benefits of fish oil are generally attained at a minimum dose of 3 grams of EPA+DHA and require 8–12 weeks of supplementation to realize these benefits.

Fish oil has been successfully used in a range of conditions related to chronic inflammation including:

  • Rheumatoid arthritis (33,34)
  • Ankylosing spondylitis (chronic inflammation and potential fusion of the spine and sacroiliac joints) (35)
  • Back pain (36)
5. Pregnancy, Infancy, and Breast-Feeding

DHA is a significant structural component of the brain, eyes, and nervous system, which all are rapidly developing throughout the last trimester of pregnancy and the early stages of life. The fetus is dependent on its mother for DHA intake, which must be sufficient to maintain her own healthy levels and meet fetal demands, especially during the period of rapid nervous system development (last trimester to age 2)

Research has shown that fish oil supplementation Improves DHA status of mothersand their breast milk, and infants. (37)

Higher DHA status has been correlated with:

  • Helping women to get pregnant (38)
  • Lowering the risk of premature births (39)
  • Reducing the risk of post-partum depression (40)

Research has also shown that getting enough DHA during pregnancy improves the health of offspring in several ways.

  • Studies show that DHA may improve behavior, attention, focus, and learning in children41
  • Reduce the risk of allergies (42)
  • Positively influences immune development (43)
  • Increase indices of intelligence in babies and children (44)
  • Lower brain DHA levels are also associated with cognitive deficits and increased behavioral indicators of anxiety, aggression, and depression in children (45)

In the US, Dietary Reference Intakes (DRI) for DHA during pregnancy have not been established. However, the world’s leading experts on lipids and human nutrition have concluded that during pregnancy and lactation women must ensure a minimum DHA intake of 300 mg daily. (46)

6. Ocular Health

Omega-3 fatty acids from fish oil help maintain healthy structure and function of ocular tissue. DHA is particularly important for the eyes, and attains its highest concentration anywhere in the body within the eye tissue.(47) Certain unique biochemical characteristics of DHA make it vital for the development, function, and maintenance of the highly active, light-receiving cells found in the eye.

Research has shown that DHA is necessary to develop, maintain, and protect visual structures from conception through pregnancy, infancy, and throughout life.

  • DHA supplemented during pregnancy plays a role in the maturation of the visual system, and DHA supplementation of infant formula supports visual acuity. (48)
  • Omega-3 fats support the body’s natural anti-inflammatory response, which can alleviate many ocular symptoms including dryness, pain, redness, and lack of tear production. (49)
  • Higher intake of omega-3 fats is also associated with decreased likelihood of having age-related macular degeneration and cataracts. (50)
  • Consistent evidence suggests that omega-3 fats act in a protective role against light, oxygen, and age-associated damage to the eyes. (51)

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V. Dose

Dosing is based on the amount of EPA+DHA in a product, and not on the total amount of fish oil. Supplements vary in potency and the percentage of EPA and DHA in the oil.

Experts recommend 500–1000 mg EPA+DHA per day to maintain health and avoid deficiency. Therapeutic doses of EPA+DHA range from 1 to 4 grams. To support the body’s anti-inflammatory response, clinical studies suggest a minimum of 3 grams of EPA and DHA with some studies using 10 grams or more.

The most well documented benefits of omega-3 fatty acids are for heart health, although omega-3s have shown proven benefits for a number of health conditions stemming from these fats’ anti-inflammatory properties. The American Heart Association’s recommendations on dosage follow.


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VI. Safety of EFA Supplementation

The US Food and Drug Administration (FDA) classified omega-3 fatty acids from fish oil as “generally recognized as safe” (GRAS).52 In fact, The FDA has ruled that up to 3 g of EPA+DHA is safe to be included in the food supply of Americans without fear of adverse events.53In addition, there are no known significant drug interactions with omega-3 fatty acids.54 When using higher amounts of EPA and DHA in the clinical setting, it is important to monitor the use, efficacy, safety, and potential interactions.

The hemodynamic effects of omega-3 fatty acids have led to theoretical concerns about increased risk for bleeding at higher doses (above 3 grams EPA+DHA), if taken with blood thinning medications, or before surgery. The theoretical risk of clinically significant bleeding has not been verified in a controlled setting. A 2007 expert opinion published in the American Journal of Cardiology concluded that omega-3 fatty acid supplements do not increase the risk for clinically significant bleeding, even in patients also being treated with antiplatelet or anti-thrombotic medication.55 The therapeutic use of omega-3 fatty acids perioperatively to improve surgical outcomes and reduce adverse events is also the subject of current clinical investigations.

Increasing EPA and DHA intake through fish consumption alone is associated with the risk of consuming excess environmental toxins. The US Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) have warned the public about the potential dangers of consuming too much fish because of the associated toxins.56 The introduction of high-quality fish oil supplements that have been processed to remove environmental contaminants allows for supplementation of high levels of EPA and DHA for preventive and therapeutic clinical use without the risk of toxicity. In studies that compare levels of mercury, organochlorines, and other environmental toxins commonly found in fish versus fish oil supplements have shown that fish oil does in fact provide the benefits of EPA and DHA without any associated environmental contaminants.57
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CONTENT COURTESY OF NORDIC NATURALS (www.nordicnaturals.com)

 

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