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Researchers from the University of Oxford have determined that B vitamin supplementation can slow and possibly reverse the progression of Alzheimer's symptoms along with cognitive impairment
The researchers – from Oxford's Nuffield Department of Clinical Neurosciences - conducted a clinical trial with 156 elderly patients who had mild cognitive impairment and a high risk of dementia and Alzheimer's disease. The researchers randomized the patients and for two years, gave one group a daily supplement with 800 micrograms of folic acid, 20 milligrams of vitamin B6, and 500 micrograms of vitamin B12. They gave a placebo supplement to the control group.
Before the trial and during the testing period, the researchers utilized magnetic resonance imaging (MRI) to measure the patients' atrophy levels of grey matter in their brains. Atrophying grey matter is a sign of the progression of Alzheimer's disease and other forms of dementia. Atrophy in the grey matter is shown as the amount of grey matter shrinks in the imaging tests.
While grey matter regions did shrink among both groups, the researchers found that those given the B vitamin supplements had about seven times less grey matter shrinkage than did the placebo group.
The researchers also found that those whose grey matter shrunk fastest had higher levels of homocysteine, and those with higher homocysteine levels received the greatest benefit from the B vitamin supplements. They summarized the effects thus:
B vitamins lower homocysteine, which directly leads to a decrease in grey matter atrophy, thereby slowing cognitive decline."
The researchers also conducted neuropsychological testing on the patients to correlate their grey matter losses with neuropsychological function. Their testing concluded that the B vitamins not only helped reduce grey matter losses, but also reduced the drop in neuropsychological scores among the supplement group.
In their conclusion the researchers stated:
Our results show that B-vitamin supplementation can slow the atrophy of specific brain regions that are a key component of the Alzheimer disease process and that are associated with cognitive decline."
Other Studies Confirm the Link Between B Vitamins, Homocysteine and Alzheimer's
However, other studies have linked B vitamins and high homocysteine levels with cognitive decline, Alzheimer's disease and dementia.
For example, in a study from Korea's Ewha Womans University, 321 elderly people were studied and tested for cognitive function, together with their levels of vitamin B12, folate and homocysteine.
After using multiple regression analysis, low folate levels were associated with low scores on naming tests, and low levels of vitamin B12 in the blood were related to low scores on word list memory. High homocysteine levels were also associated with low scores on word memory and construction recall testing.
The researchers stated in their conclusion:
These results suggest that plasma folate, vitamin B12, homocysteine and tissue factor pathway inhibitor are associated with cognitive function in cognitively impaired (Alzheimer's disease and Mild cognitive impairment) elderly and that the association was stronger in patients with Alzheimer's disease."
What is Homocysteine and why are High Levels so Bad?
Increased homocysteine levels have also been linked with cardiovascular disease – more specifically the progression of atherosclerosis or the hardening of the arteries. Thus, high homocysteine levels have been found among those who have suffered from strokes and heart attacks.
Elevated homocysteine levels are anything higher than 10-15 μmol/L depending upon the age and health of the patient. The Oxford researchers classified their high homocysteine patients as those with levels of 11 μmol.
Homocysteine and its two partners methionine and cysteine, is involved in the metabolic detoxification process called methylation. This transfers methyl groups from one molecule to another. When a methyl group is transferred to a oxidative toxin it speeds its discharge from the body. Higher levels of homocysteine are typically accompanied by higher levels of oxidative radicals and toxins in the liver and blood stream.
If not neutralized, these toxins cause oxidative damage to blood vessels and cells - including brain and nerve cells.
Various nutrients – including B vitamins as well as many other phytonutrients – are considered methyl donors: They donate methyl groups, which assists the body's detoxification and healing efforts. Healthy methylation also helps protect cellular DNA from mutation.
It should also be noted that folate - nature's form - may be a better form of the B9 vitamin than folic acid. Excessive folic acid supplementation has been linked with increased cancer risk. A 2009 study showed folic acid fortification increased colon cancer risk.
Food sources of folate include parsley, turnip and mustard greens, collard greens, romaine lettuce, spinach, asparagus, broccoli, cauliflower and beets. Lentils and brewer's yeast are also good sources. In supplements, the 5-methyltetrahydrofolate (5-MTHF) nutrient offers an option to synthesized folic acid.
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Morris MS. The role of B vitamins in preventing and treating cognitive impairment and decline. Adv Nutr. 2012 Nov 1;3(6):801-12.
Kim G, Kim H, Kim KN, Son JI, Kim SY, Tamura T, Chang N. Relationship of cognitive function with B vitamin status, homocysteine, and tissue factor pathway inhibitor in cognitively impaired elderly: a cross-sectional survey. J Alzheimers Dis. 2013;33(3):853-62.
Hirsch S, Sanchez H, Albala C, de la Maza MP, Barrera G, Leiva L, Bunout D. Colon cancer in Chile before and after the start of the flour fortification program with folic acid. Eur J Gastroenterol Hepatol. 2009 Apr;21(4):436-9.
Pietrzik K, Bailey L, Shane B. Folic acid and L-5-methyltetrahydrofolate: comparison of clinical pharmacokinetics and pharmacodynamics. Clin Pharmacokinet. 2010 Aug;49(8):535-48.
Originally published: 2013-08-08
Article updated: 2019-05-25