The Bright Side of the Fish Oil Component - DHA

This news release from ScienceDaily directly contradicts the findings of just a a few weeks ago. In my earlier post I was addressing research which indicated DHA can induce a "Th 1 type mediated inflammatory response". In relation to Stroke the conventional wisdom quite literally screams that such a response is the very last thing one would want to treat stroke yet now we have a report asserting remarkable efficacy of DHA in ameliorating damage from stroke.

ScienceDaily (2010-11-08) -- A new study shows that a component of fish oil is a powerful therapeutic agent that can protect brain tissue in a model of stroke, even when treatment is delayed by five hours. These findings not only target a new stroke treatment approach, but also provide vital information about the length of the therapeutic window.

For those so interested you can download the full article at this link. Bit of surprise, Springerlink usually doesn't give stuff away and I suspect this is a website error so be quick!

The findings of this study are remarkable:

The volume of the area of destroyed tissue was reduced by an average of 40% when DHA was administered at 3 hours, 66% at 4 hours, and 59% at 5 hours. Further analysis showed it triggered production of Neuroprotectin D1 (NPD1), a naturally occurring neuroprotective molecule in the brain derived from DHA and discovered by Dr. Bazan. Not only did DHA treatment salvage brain tissue that would have died, its repair mechanisms rendered some areas indistinguishable from normal tissue by 7 days. Dr. Bazan's laboratory leads the field of medical research into understanding DHA's and NPD1's pro-survival properties. 

Impressive. Probably as efficacious as anything else out there. Certainly much better than the agents currently in use. Is this solely a function of DHA? I can't find this in my archives but I'm sure I've read, long ago, that intravenous infusion of monounsaturated fats can also confer remarkable protection against stroke damage.

The experimental structure is your standard middle cerebral artery occlusion model, where a main cerebral artery is blocked. It is very important to remember that there are two principle kinds of stroke: occlusive and hemorrhagic, the latter referring to bleeding in the brain.

As mentioned in this current, a prior study of theirs (full text at link) found that DHA was protective against ischemic stroke but with this important qualification:

Methods—Sprague-Dawley rats were anesthetized with isoflurane and subjected to 2 hour of MCAo. Animals were treated with either DHA (low doses 3.5 or 7 mg/kg; medium doses 16 or 35 mg/kg; and high dose 70 mg/kg) or an equivalent volume of saline intravenously 3 hours after MCAo onset. Neurologic status was evaluated during occlusion (60 minutes) and on days 1, 2, 3, and 7 after MCAo. Seven days after MCAo, brains were perfusion-fixed, and infarct areas and volumes were determined.  

Results—Only the low and medium doses of DHA significantly improved the neurologic score compared with vehicle-treated rats at 24 hours, 48 hours, 72 hours, and 7 days.

That qualification is very important. The current craze about omega 3's needs to be tempered with the realisation that more is not always better and is often downright dangerous. Keep the balance, don't believe the hype. Consider this hype from the news release:

DHA has potent anti-inflammatory effects. Since inflammation is at the root of many chronic diseases, DHA treatment has been widely demonstrated to have beneficial effects in patients with coronary heart disease, asthma, rheumatoid arthritis, osteoporosis, sepsis, cancer, dry eye disease, and age-related macular degeneration, but its potential benefit in stroke was not known.

DHA can help with the mentioned conditions but the statement is way over the top. For example, high levels of DHA may even damage the retina, there is data supporting this contention. I would argue that where benefit is being derived from DHA it is principally arising because of insufficient DHA in the diet. In particular situations increasing DHA intake will have value but a consistent habit of high relative intake of any fat or nutrient is generally not a good thing.

For example, I have concerns about high vitamin A and beta carotene intake. There is evidence that this can be risky and may promote cancer. Not sure, but the other puzzling thing about vitamin A is something I read by the questionable Dr. Mercola, who stated that he noted in one study Vitamin A impeded vitamin D. I checked the data but only could find one reference, not Dr. Mercola's reference, indicating that vitamin A does indeed impede vitamin D function.

At a personal level I cannot offer any solid advice. For some a "low" intake of nutrient A may be sufficient and even better than the recommended daily intake. For others a "high" intake may be required. We tend to fail to appreciate just how novel our individual physiologies are. I have read a number of doctors who have asserted that various lab results were completely incongruous with the patient's condition.

So don't be led into thinking that the BIG problems of nutrition and health have been addressed. Don't be beguiled by all the "health experts" out there. A few years ago a friend of mine, Trish, made a striking comment. She said to me that people need to learn to "listen" to their bodies. I was struck by that observation because I believe it is a very good attitude to adopt towards one's health. Sure, read the literature but always with a very critical eye, watch out for those promising signs and wonders, but in all that advice how often do you find the experts advising, "learn to listen to your body". It takes practice, when I was in active physical training I would spreadsheet a wide range of physiological variables, from sleep to resting pulse. If you want good advice on how to best manage your health, then listen to your body because it is wiser than those health experts.