Wednesday, November 3, 2010

Omega 3 - Not the Cure for Alzheimer's (Again)

Another quick one - into my email this morning came this link:

Another study of Alzheimer's Disease and Omega 3 fatty acids. (That link goes to JAMA "free" full text article published this week but I had to watch a Vytorin add for a minute).

400 some-odd elders with mild to moderate dementia were randomized to 2 grams of algal DHA daily or placebo for 18 months. They were followed with a bunch of neuropsych measures, and a subgroup was examined with serial spinal taps for CSF DHA (not surprisingly increased in the DHA group), and another subgroup was monitored via MRI for brain atrophy (no difference between treatment and control groups). So you can't say the researchers didn't give it their all.

Fish oil is cheap and sexy and biologically awesome, but it won't reverse the neuronal brain damage of full-blown dementia. Nor does it appear to slow it down (though some APOE4 negative DHA folks did better on some of the cognitive tests than the controls). I think it likely works far better (and makes more sense biologically) as a long-term preventative measure rather than as a treatment or cure. Fish eaters in epidemiological studies tend to eat fish for many years, or be in populations where eating fish is extremely common and lifelong, and dementia is less common than in non-fish eaters. Of course that's a correlation - but at least it is a biologically plausible one. Maybe we need a salmon clinical trial in lieu of a algal DHA one.

Adverse events was also interesting - how safe is fish oil with warfarin (a blood thinner)? These relatively high doses of DHA resulted in 3 people on warfarin having an INR (measure of blood-thinning) out of range once during the trial. One of the control group on warfarin had an INR out of range. Since anyone on warfarin ought to have INRs measured regularly, a consistent fish oil dose should not pose a problem, I would think.

If one is looking for a cure or significant improvement for Alzheimer's, I would bet more money on decreasing acute inflammation or improving energy efficiency in the brain via ketosis. This article was also linked to my email: New Drug may halt and even reverse the effects of Alzheimer's. The "new drug" is immune globulin with beta amyloid antibodies administered IV. I have to find the actual article to take a gander and won't have time until later - so more updates then. It would be interesting to see that immune globulin helps Alzheimer's when beta amyloid vaccine doesn't seem to do much at all (other than get rid of beta amyloid) - the dementia remains.

I don't know that there will be a longer term clinical trial of omega 3 fatty acids - such trials are expensive, and not sexy. We'll see.


  1. More nutritional reductionism... these researchers just cannot keep pulling a single nutrient out and hoping like hell you can overlay it on an SAD and undo a lifetime of damage. This sort of stuff should continue to scream to people that a)you can't eat crap and negate that with one magic nutrient, and b) waiting until someone has jumped, gone splat, and then attemtped to put them back together again is never a good idea. People have to get out of their heads that they can live it up now and science will hand them a quick fix later.

  2. I have the impression that this study was trying to look for slowing of the progression of the disease - asking 2 grams of fish oil in a vat of SAD to do the work is asking a lot.

  3. I really enjoy your blog Dr. Deans, regarding this study and a host of studies the past year or so regarding fish oil:

    1. has consideration been given to dosing, say comparing 2grams vs. 4 or even 6 if considered safe?

    2. frequency: daily doses vs. large single weekly doses as done in some Vitamin D studies with the elderly?

    3. fish oil variants, i suspect that "fish oil" is too broad a term considering the differences between standard fish oil, cod liver oil, Krill oil and fermented cod liver oil supplemented with butter oil(K2) we could be missing critical data by not comparing and investigating the differences in these products.

    4. krill oil was studied for its effects on premenstrual syndrome and dysmenorrhea, while successful to some extent one couldn't help but wonder what share of krill accounted for the benefit vs. the same experiment conducted with standard fish oil.

    5. if we accept that no food can be studied in isolation without some caveats, do studies that fail to show efficacy of fish oil for treating something such as Alzheimer's require more study with different co-factors (different diets, omega 3:6 ratio's drastically altered?)

    6. im concerned when such studies are treated by some in the scientific community (not you but other bloggers who are fearful of uncertainty and nuance)as open and shut cases to prove that there is no "miracle drug" or "cure all"

    thank you and keep on blogging, this site is a welcome addition to the blog-sphere

  4. J - very thoughtful comment - this study has the highest dose of DHA of any dementia study I can recall. There was a depression study that compared 1g, 2g, and 4g DHA (I'm almost 100% sure it was DHA but I'm having a devil of a time tracking down the original study. I'll have to look back at the references from another study to find it) and found benefit from 1g and 2g but no increased benefit from 4g a day. But who knows how much omega 6 was in the diets? At least the study I blogged about above checked percentages of fatty acids in the CSF and the omega 3 percentage increased 40% (off the top of my head - I could be wrong here) in the treatment group.

    I'm also concerned that this study (and all the other failures of omega 3 in full-blown dementia) will make doctors and scientists ignore omega 3.

    An additional concern is the rancidity of the pills - omega 3s don't keep very well.


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