DHA acts against Alzheimer’s, stroke, epilepsy, and other brain and retinal diseases
Frontier Voice of Nutrition Remarks (January 04, 2012)
Nalin Siriwardhana, PhD, interviewed Boyd Professor Nicolas G. Bazan, M.D., Ph.D., the Director of the Louisiana State University Health Sciences Center (LSUHSC) Neuroscience Center of Excellence, New Orleans
Docosahexaenoic acid (DHA) is an omega-3 fatty acid that offers promising benefits against several brain and eye (retinal and corneal) diseases, including Alzheimer’s, Parkinson’s, and age-related macular degeneration (a disease associated with aging that gradually impairs sharp central vision). DHA is necessary for healthy vision, memory, brain development, and successful aging. Those benefits are in addition to the well-known cardioprotection effects of this essential fatty acid called DHA.
Recent scientific studies provide clear evidence to encourage the intake of DHA. The major dietary sources of DHA are cold water, fatty fish such as salmon, tuna, sardines, and shellfish. Fish oil capsules contain both Eicosapentaenoic acid (EPA) and DHA, while vegetarian capsules from algae contain DHA but no EPA.
The nervous system protection effects of DHA are closely associated with a molecule produced from DHA called neuroprotectin D1 (NPD1). Nutrition Remarks interviewed Prof. Bazan G. Nicolas, the discoverer of NPD1. His prolific research began over 40 years ago with the discovery in 1970 that the brain rapidly releases essential fatty acids when confronted with stroke -like conditions as well as in seizures, as in epilepsy. This finding became a Citation Classic and the process is known as the “Bazan effect”. A simplified version of the conversation between Nutrition Remarks and Dr. Basan is as follows.
Question from Nutrition Remarks: Why do we need DHA or omega-3 fats?
Answer from Dr. Bazan: Omega-3 fatty acids are required to maintain different aspects of our health. Omega-3 fats are essential because our bodies cannot produce them due to lack of the required enzymes. Therefore, we need to take omega-3 from dietary sources such as fish and fish oil supplements. Specifically, DHA is necessary for our vision, brain development, memory, nervous system function and protection, homeostasis (sustaining internal stability or balance of functions), and successful aging, etc.
Question: What makes our nervous system become vulnerable to disease?
Answer: Several factors contribute to nervous system diseases, including genetic factors, nutrition deficiencies of omega-3 fatty acids and antioxidants, and unhealthy behaviors that include excessive alcohol consumption and drug addictions. Also, chronic inflammation and oxidative stress play a significant role in nervous system diseases.
Question: Why is DHA important for a healthy nervous system?
Answer: DHA is required for the development, maintenance, and proper functioning of a healthy nervous system. Low levels or deficiency of DHA has been reported in several nervous system diseases including Alzheimer’s disease.
Question: According to published technical explanations including yours, excessive and unhealthy oxidative stress and inflammation in the nervous system can cause detrimental health consequences. What are the common short-term and long-term mechanisms?
Answer: Over-activation of the brain’s immune cells (primarily the microglial cells) or the arrival of white cells (polymorphonuclear leukocytes) enhances oxidative stress to an unhealthy level, setting in motion an inflammatory response that causes damage and eventually nerve cell death. Thus, inflammatory mediators and harmful reactive oxygen and nitrogen radicals become abundant and cause damage to the nervous system over a long period of time. This also includes imbalances in calcium homeostasis and impairments in the cell mitochondria, and the effects can even be extended to unfavorable cardiovascular conditions. Oxidative stress and inflammation in the nervous can lead to
Question: How does DHA act against oxidative stress and inflammation in the nervous system?
Answer: An early nervous system response to oxidative stress, likely also in other organs, is the synthesis of protective molecules called docosanoids. Docosanoids are potent protective mediators derived from DHA available from cell phospholipids. The first identified docosanoid, NPD1, counteracts inflammation and oxidative stress, is anti-apoptotic (prevents cell death), and aims to restore homeostasis. Therefore it is important to maintain enough DHA in our body to fight against unhealthy inflammation and oxidative stress in the nervous system. Maintaining enough DHA not only protects us from nervous system disorders but also from other disease conditions including cardiovascular disease and some cancers.
Question: What would be the ideal level of DHA that we need to maintain in our body, and how often do we need to eat fish or take omega-3 supplements?
Answer: The American Heart Association recommends eating at least two servings/meals a week. Each serving is 3.5 ounces cooked, or about ¾ cup of flaked fish. However, we need more scientific investigation to decide the exact amounts that we need to eat or take as supplements to maintain a healthy nervous system. In general, we need to eat at least the recommended levels as most of us do not have enough DHA in our body.
At present, due to growing interest, there are several upcoming and ongoing clinical trials on omega 3-fats.
Nicolas G. Bazan, M.D., Ph.D., is a professor of ophthalmology, biochemistry and molecular biology, neurology and neuroscience at School of Medicine, Louisiana State University Health Sciences Center, and founding director of LSU’s Neuroscience Center of Excellence. He is the occupant of the Ernest C. and Ivette C. Villere Chair for Retinal Degeneration Research and the Chair of the LSUHSC Research Council/Translational Research Initiative. Other leadership responsibilities of Dr Bazan includes Senat Member of the German DZNE, a member of an NIH Study Section and the Chair of the Board of Governors of AFER (ARVO Foundation for Eye Research) He and his colleagues discover NPD1 and several other fundamental mechanisms through which essential fatty acids DHA and arachidonic acid regulate cell function and participate in the initiation and early progression of diseases. Through his research on synaptic signaling pathways he hopes to develop ways to reduce or prevent the irreversible brain damage caused by stroke, epilepsy, and neurodegenerative disease, as well as retinitis pigmentosa and age-related macular degeneration.
More about Dr. Bazan’s work and related links
The authors acknowledge the following:
Dr. Bazan acknowledges the support of NINDS, NEI, former NCRR, RPB, National Foundation Fighting Blindness, Arnold and Mabel Beckman Initiative for Macular Degeneration Research and the EENT Foundation.
Written by Nalin Siriwardhana, PhD
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