Dr's Casebook: Wiggling worms may give us a clue to slow Alzheimer’s disease
Dr Keith Souter writes: While many studies are showing that keeping physically and mentally active helps, relatively few studies demonstrate a direct link with diet. But new research on worms suggests that there may be a link between low levels of vitamin B12 and Alzheimer’s disease.
In Alzheimer’s disease, the commonest type of dementia, there is shrinkage of the brain, the development of neurofibrillary tangles and amyloid plaques. This build-up of amyloid slows everything down in the brain. And this is where we come to the research on worms. A very specific nematode called C. elegans lives in soil and feeds on bacteria. Each one is a thin, translucent creature only about a millimetre in length.
Of note is that amyloid has the same deleterious effect on them as it does on us.
Scientists have found that when these worms develop the equivalent of Alzheimer’s they lose their wiggle. It has been conclusively shown that this is because amyloid paralyses their nervous system.
Over several years scientists studied amyloid effects on these worms in petri dishes. All were fed the bacterium E.coli. However, different strains of E.coli had different levels of vitamin B12 than others, so they could compare vitamin B12 deficient worms with those with healthy levels.
They found that when vitamin B12 was given to the amyloid worms that were vitamin B12 deficient, paralysis and loss of their wiggle occurred much more slowly. This suggested that B12 was beneficial in slowing the disease, even though it did not reduce the level of amyloid in their nervous system.
They discovered that vitamin B12 relies on a specific enzyme called methionine synthase to work. Without it, B12 has no effect. They also found giving the vitamin to worms with healthy levels did not help. They noted that vitamin B12 had no effect on the amyloid levels, merely on the tendency to paralyse and lose the wiggle.
This does not mean that people should start taking vitamin B12 supplements. It suggests that dietary modification may be important in affecting the beginning of Alzheimer’s disease and possibly other neurological conditions. This research on wiggling worms may have opened up important possibilities.