STOCKHOLM, SWEDEN. There is substantial evidence that Alzheimer’s patients have significantly lower blood levels of DHA (docosahexaenoic acid), a main component of fish oil, than do normal controls. Epidemiological studies have also shown that regular fish consumption is associated with a substantially reduced risk of developing Alzheimer’s disease (AD) and dementia. Researchers at the Karolinska Institute report that supplementation with DHA-rich fish oil, while not effective in the treatment of moderate existing AD, does slow down the progression of milder forms of the disease.
Their clinical trial involved 174 patients with mild to moderate AD. The patients had a score between 15 and 30 on the Mini-Mental State Examination (a higher score indicates milder disease) and were treated with an acetylcholine esterase inhibitor (Donepezil, Galantamine or Rivastigmine) throughout the study. Participants were randomized to receive four 1-gram capsules of placebo oil (corn oil) daily or four 1-gram fish oil capsules daily for a 6-month period. The fish oil capsules provided 1.7 grams/day of DHA and 0.6 grams/day of EPA.
At the end of the 6-month period all patients were switched to receive the fish oil capsules for a further 6 months. As expected, the level of DHA and EPA in blood plasma phospholipids rose substantially during fish oil supplementation – by a factor of 2.4 for DHA and a factor of 3.6 for EPA. There was no statistically significant difference in Mini-Mental State Examination (MMSE) score or the score on the cognitive part of the Alzheimer Disease Assessment Scale between the placebo group and the fish oil supplemented group after 6 and 12 months. However, in a sub-group (32 patients) with a MMSE score greater than 27 points (very mild disease) the researchers did observe a significantly slower disease progression in the fish oil group than in the placebo group. The average decline in MMSE score in the placebo group over the first 6 months was 2.5 points versus only 0.5 points in the fish oil group. The decline over the next 6 months, when both groups received fish oil capsules, averaged 0.6 points indicating that the slowing of progression persists with continuing supplementation.
It was also noteworthy that fish oil supplemented patients experienced no decline at all in the MMSE scale on sub-items – “delayed word recall” and “attention”. The fish oil supplement was well-tolerated and safe. The researchers speculate that fish oils may act beneficially in very mild AD through their anti-inflammatory effect. Recent research has shown that there may be a critical period, 2 or more years before the onset of dementia, during which inflammation is pronounced in brains of patients with mild to moderate AD.
Freund-Levi, Y, et al. Omega-3 fatty acid treatment in 174 patients with mild to moderate Alzheimer disease. Archives of Neurology, Vol. 63, October 2006, pp. 1402-08