According to a latest study the elderly with low levels of vitamin B12 in their blood may be more likely to develop problems with their thinking skills and have more brain shrinkage. The study points to a link between low B12 and early cognitive decline, a condition that often leads to dementia. Previous research has found that those people with high levels of vitamin B12 in their blood have lower levels of an amino acid called homocysteine, which some studies have linked to an increased risk of Alzheimer's disease, memory loss, and stroke.
For this study researchers looked at 121 people over the age of 65 in Chicago. Researchers analyzed their blood for levels of vitamin B12 and B12-related metabolites that can indicate a B12 deficiency. The participants also took tests measuring their memory and other cognitive skills.
After an average of four-and-a-half years, the researchers had the participants do the cognitive tests again. They also took MRI scans of the participants' brains to measure their total brain volume and look for other signs of brain damage.
They found that having high levels of four of five markers for vitamin B12 deficiency was associated with having lower scores on the cognitive tests and smaller total brain volume. On the cognitive tests, the scores ranged from -2.18 to 1.42, with an average of 0.23. For each increase of one micromole per liter of homocysteine, the cognitive scores decreased by 0.03 points. Interestingly, the concentrations of all vitamin B12 – related markers were linked with better cognitive test scores and higher total brain volume - but not the blood levels of vitamin B12 itself.
The results appear in the journal Neurology.
Study co-author Dr. Martha Clare Morris, of Rush University Medical Center, said low vitamin B12 can be difficult to detect in older people when looking only at blood levels of the vitamin. “Looking for vitamin B12 in blood not a good marker…We need to have better clinical measures to identify people who have marginal or low vitamin B status,” she said. She said doctors should be testing instead for homocysteine levels. She also said there wasn't enough evidence yet to recommend that all seniors take the vitamin in supplement form.
Geriatrician Dr Howard Dombrower - who works at Markham Stoffville Hospital – added, “It's normal for a geriatrician family doctor to prescribe B12 in memory decline if it is low. We might want to consider testing for these other products as well, like homocysteine…We might be missing a lot of people who do have B12 deficiencies. Even though their serums looks normal their bodies would still be deficient, and we would only know that by measuring these other chemicals.”
A Study published last year from the United Kingdom found that giving supplements to older patients with signs of cognitive impairments appeared to slow brain shrinkage, and also appeared to steady cognitive decline. Researchers are hoping to start more testing next year.
But Morris said doctors are not advocating that seniors start taking B vitamins to prevent dementia. “It's too early to say whether increasing vitamin B12 levels in older people through diet or supplements could prevent these problems, but it is an interesting question to explore,” she noted.
Vitamin B12 is found only in animal foods and other foods, such as cereal, that have been fortified with it. It's found in rich supply in organ meats, such as liver, as well as oysters, and found in smaller amounts in meat, poultry, fish, milk products and eggs.
“As we get older our stomachs produce less of the acid that breaks down the vitamin to make it available for absorption,” Rush University associate professor of clinical nutrition Christine Tangney, explained. “Older people also take more drugs that inhibit absorption, such as [the diabetes drug] metformin.” Older people tend to have trouble absorbing the vitamin from food, because of changes to their digestion as they age. Those with celiac disease, Crohn's disease or diabetes also have trouble absorbing it.
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