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The evidence suggests that taking B vitamins won't fail to arrest cognitive decline in older people. B vitamins have taken another hit. A few weeks ago I told you how, contrary to expectations, a group of B vitamins did not show any signs of preventing coronary heart disease. Now a similar finding's been made about what's called cognitive decline in older people; a fall in thinking ability and memory that's associated with a slide to dementia. The B vitamins were being used to lower a substance in the blood called homocysteine, high levels of which have been linked to various diseases. The trouble is that conclusions about homocysteine as a risk factor have been based on studies observing whole populations. What's needed for proof though is a trial to reduce homocysteine levels intentionally and see what happens. This is easy and cheap to do with folic acid and vitamins B6 and B12. Unfortunately a trial of healthy elderly New Zealanders with high homocysteine levels failed to make a dent in cognitive decline. So something else appears to be at work and yet again vitamin supplements bite dust.
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