Limitations Of Current Evidence And Future Aims
There are several limitations of the current evidence base regarding vitamin D and its potential association with cognitive decline, dementia and AD. There is a lack of uniformity in the operationalization of vitamin D concentrations in observational studies, with a variety of different cut-points used to investigate the association with cognitive and neuroimaging outcomes. This is perhaps unsurprising considering there is an ongoing debate surrounding what the optimal vitamin D concentrations are for general health. In the US the Institute of Medicine recommends serum 25D concentrations of 50 nmol/L as sufficient whereas the Endocrine Society recommends concentrations 75 nmol/L. There is a need to standardise clinically relevant 25D cut-points in order to aid the interpretation of the research literature.
Evaluating The Epidemiologic Evidence
Even while there is a general impression of strong epidemiologic evidence to support associations between the B-vitamins and cognitive decline, in actuality, the evidence is weak. The impression may be driven by the numerous cross-sectional and case-control studies that relate dietary or biochemical levels of the B-vitamins to cognition or disease status. A primary limitation of these types of studies is that one cannot determine whether the observed association is a cause or effect of the disease. For example, both serum and dietary intake levels of folate have been reported to decline with prolonged institutionalization , and duration of dementia . In addition, studies that use a one-time cognitive assessment cannot separate attained or lifetime cognitive ability from cognitive decline due to age or disease. Confounding bias is highly likely in these types of studies because cognitive ability is related to many factors, including education, socio-economic status, and healthy lifestyle behaviors. Depression may be another source of confounding in these studies, as it is a common condition in persons with dementia , and has been associated with folate deficiency .
What To Do About Your Vitamin D Level
It’s a good idea to get your vitamin D level checked by your doctor annually. If your levels are low, they might recommend a supplement. According to the National Institutes of Health, adults are advised to get at least 600 IU of vitamin D each day, between food and supplements . The NIH notes that the safe upper limit of vitamin D for adults is 4,000 IU a day.
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/8causes Of B12 Deficiency
There are two major causes of B12 deficiency- pernicious anaemia and diet.
In the first case, your immune system destroys healthy cells in your stomach, preventing your body from absorbing the vitamin from the supplement and food you take.
The second one is caused due to insufficient intake of Vitamin B12 through the diet. It can be because you are not eating enough Vitamin B12 rich food or you are a vegan or a vegetarian.
Can Vitamin Deficiency Lead To Dementia
Vitamin deficiency can lead to a greater likelihood of developing dementia.
Food is key to life.
It provides essential nutrients for fueling human bodies.
Some foods are rich in nutrients.
Others are relatively negligible.
According to a recent Detroit News 4 article titled Study shows connection between vitamin deficiency and dementia, diets low in certain vitamins and minerals can increase the risk of developing dementia.
A study conducted by researchers in Israel and the United States found those who were deficient in folate had a 68 percent greater risk of receiving a dementia diagnosis.
There was also a found to be a three times greater risk of death from any cause.
The study was conducted on 27,000 individuals ages 60 to 70.
These findings about vitamin deficiency make sense.
Folate is also known as vitamin B9.
Although you likely have heard of its importance in fetal development during pregnancy to reduce the likelihood of birth defects like spina bifida, it has many other functions in the human body.
Did you know this vitamin is necessary in the production of healthy red blood cells?
Well, it is.
Because folate is a part of protein metabolisms, it helps build DNA and RNA.
It also helps to rid the body of homocysteine.
This amino acid can negatively impact the body if concentrations get too high.
The recent research suggests folate is also related to nerve and brain health.
Even so, vitamin deficiency of folate has been known to have other negative health effects.
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Vitamin D And Cognitive Decline: Neuroimaging Studies
Based on the available evidence from epidemiological studies it is plausible that vitamin D deficiency could be linked with pathological changes in the brain associated with neurodegenerative and cerebrovascular disorders . Furthermore, investigating the association between vitamin D concentrations and neuroimaging abnormalities could provide an insight into the potential mechanisms underlying the association with dementia-related disorders.
As reviewed above, two animal studies have examined the effect of vitamin D deficiency on the structural development of the brain. Compared to control rats born to vitamin D3 sufficient mothers, rats born to vitamin D3 deficient mothers had a 30% increase in hemisphere length, which suggests defected cortex development during embryogenesis . Moreover, vitamin D3 deficient pups had a 200% increase in lateral ventricle volume, which is indicative of atrophy in the surrounding regions. In a similar study, rats with transient vitamin D3 deficiency during early development demonstrated enlarged lateral ventricular volume in adulthood compared to control rats .
Table 2: Overview of cross-sectional neuroimaging studies investigating the association between vitamin D and neuroimaging outcomes in elderly adults
/8vitamin B12 Deficiency Similar To Dementia
Vitamin B12, also known as cobalamin, is a water-soluble vitamin required for the formation of the blood and the functioning of the nerve system. The problem with this vitamin is that our body cannot produce it, so it has to depend on food sources and supplements for it. The deficiency of the B12 vitamin is common among vegetarians and vegans as this mineral is not found in plant-based food products. Studies suggest that up to 80- 90 per cent of vegans and vegetarians are vitamin B12 deficient. This disorder impacts the human body in several ways. Right from causing vitamin deficiency anaemia to underpins the central nervous system. Many times symptoms of Vitamin B12 deficiency is confused with dementia due to overlapping signs. This leads to wrong or delayed treatment. Here are four signs of dementia similar to that of B12 deficiency.
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Reaction To The Study
Dr. Scott Kaiser is a geriatrician and director of Geriatric Cognitive Health for the Pacific Neuroscience Institute at Providence Saint Johns Health Center in Santa Monica, California.
He says that while the study showed an association, more research is needed to confirm causation on whether low vitamin D levels do in fact raise the risk of dementia.
This is a very interesting study and it adds to a very important area of inquiry between vitamin D and dementia risk. But at the end of the day, its still an association and kind of fodder for more study needed, Kaiser told Healthline.
However, if other studies confirm the link between vitamin D deficiency and dementia, Kaiser says that could be useful in lowering the risk of dementia.
I love that the authors suggest that addressing vitamin D deficiency could be an important strategy, in terms of population-level prevention, he said. Its worth investigating further if it might make sense to identify people who are at high risk, identify people who are vitamin D deficient and focus on providing getting adequate vitamin D levels, whether its through more sunlight, through dietary sources or through supplementation in those high risk groups.
What Are The Effects Of Low B12
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The Effects Of Less Investigated Vitamins And Quasi
Less is known about the effects of other vitamins on MCI and AD risk, but results from initial studies suggest the possibility that vitamin B-1 , vitamin B-3 , vitamin K, and other essential nutrients such as inositol, choline, and carnitine may also contribute to the prevention of dementia.
Thiamine-dependent enzymes play a critical role in glycolysis and the Krebs cycle, and deficiencies in the activity of these enzymes may contribute to reduced glucose metabolism, as evident in the brain of patients with dementia . Preclinical models of thiamine deficiency and human thiamine deficiency exhibit memory deficits, neuritic plaques, and hyperphosphorylation of tau . In addition, dietary supplementation with benfotiamine, a more bioavailable analog of thiamine, enhanced the spatial memory of APP/PSEN1 mutant mice and reduced amyloid plaque and phosphorylated tau in their brains . Furthermore, a recent case-control study of humans showed that blood thiamine diphosphate concentration was significantly reduced in patients with AD relative to controls and had an AUROC of 77.4%, sensitivity of 78.1%, and specificity of 77.2% . A subsequent study reported that thiamine phophatases are increased in the blood of patients with AD, which may explain the low thiamine diphosphate concentration in AD .
Treatments For Dementia From Nutritional Deficiencies
Fortunately, dementia that stems from nutritional deficiencies is both reversible and preventable. By maintaining a healthy, balanced diet rich with B vitamins and sufficient hydration, you can prevent the onset of dementia from nutritional deficiencies.
If dementia has already set in, treatments designed to restore the nutritional balance of the body, can correct the cerebral damage and restore the mind to its original state.
Highly treatable, dementia caused from a lack of nutrients is one of the mildest forms of dementia. By keeping your diet rich in B vitamins with fruits, vegetables and whole grains, you can successfully avoid this disorder.
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Other Potential Biologic Mechanisms Of Folate
Data are limited on potential mechanisms of folate effects on dementia other than homocysteine concentration. One possibility is that folate deficiency may decrease acetylcholine, a neurotransmitter that is reduced in Alzheimers disease. Folic acid is involved in the metabolic pathway for acetycholine synthesis. At least one animal model, however, did not find evidence of dietary folate effects on acetylcholine metabolism . Another possibility is that folate deficiency increases oxidative stress, but again, data on the antioxidant effects of folate are limited .
How The Study Was Conducted
Researchers from the University of Australia analyzed health data from more than 290,000 people in the UK Biobank, comparing vitamin D levels with brain imaging that measured the size of gray matter, white matter, and the hippocampus, the part of the brain responsible for executive functions like memory.
The scientists found that participants who had a genetically higher level of vitamin D had a decreased dementia risk, with the odds of dementia decreasing with higher concentrations of the vitamin, up to 50 nmol/L, after which the benefits were less marked.
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Can A Mild B12 Deficiency Be Corrected
With the help of a normal multivitamin, a slight B12 deficiency can be remedied. A vitamin B12 shortage may be avoided in a large number of persons. If you follow a strict vegetarian or vegan diet, it is critical that you consume breads, cereals, and other grains that have been fortified with vitamin B12, or that you take a daily vitamin B12 supplement.
Can Vitamin D Supplementation Slow Cognitive Decline
The researcher, however, noted that the study did not necessarily prove that the two have anything in common. The authors acknowledged that it is still not clear whether vitamin D supplementation can slow down cognitive decline.
UC Davis researchers will be conducting yet another study that will determine whether high doses of vitamin D can help in the prevention of memory loss.
This is after they got a financial boost from the National Institutes of Health to the tune of $4.7 million.
The researchers are embarking on a 5-year journey from 2018 where they will be testing the use of supplements in various populations.
They want to get first-hand information on whether supplementation can help prevent cognitive decline in seniors and whether the association is stronger in Latinos and African-Americans.
The leader of this research professor of neurology John Olichney is on record saying that vitamin D deficiency normally affects the elderly because the skin does not effectively synthesize the vitamin as people grow older.
He states that the problem is more rampant in persons who have darker skin.
The study will follow 180 participants in the East Bay and Sacramento regions.
We have to wait for the results of this study to get a better picture of the relationship between vitamin D and dementia.
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Associations Of Vitamins With Mci And Ad Deduced From Epidemiological Studies Interventions And Brain Imaging
A more direct approach to investigate the association between micronutrients and MCI and AD is to study the correlation with brain atrophy, metabolic function , and accumulation of amyloid, which can be measured with brain MRI, fluorodeoxyglucose standardized uptake value ratio, and PIB-PET, respectively .
High blood folate concentration in combination with low serum vitamin B-12 concentration is associated with a higher risk for cognitive impairment. The graphs show results from a study performed in Australia and a study performed in the United States . Data were adapted from references and with permission.
Results of a meta-analysis of 106 investigations showing statistically significant reductions in the concentration of 6 key vitamins in plasma of patients with AD relative to healthy controls . The meta-analysis only included studies that used established criteria for identifying AD cases and cognitively intact controls. Data were adapted from reference with permission. AD, Alzheimer disease.
Folate Deficiency And Dementia
For this reason, a research team examined the association between folate deficiency and increased risk of dementia, as well as likelihood of dying from any cause.
They analysed 27,188 medical records of adults aged 60 to 75 with no history of dementia and followed them for 10 years.
Nearly 13 percent of participants were low in folate, a serum level below 4.4 ng/ml.
The results showed that folate deficient people were at a greater risk of dementia and more likely to die from any cause.
After eliminating factors such as taking folic acid supplements, vitamin B12 deficiency, diabetes, cognitive decline, depression, and smoking, folate deficiency increased the risk of dementia by 68 percent and tripled the odds of dying from any cause.
The authors explain that folate deficiency can elevate the levels of an amino acid called homocysteine.
High levels of homocysteine can damage blood vessels and so reduce blood flow to the brain, leading to vascular dementia.
The process causes oxidative damage to DNA and makes brain cells age quickly and die.
The authors concluded:
Serum concentrations of folate may function as a biomarker used to modify the risks of dementia and mortality in old age.
The implications for public health policy appear to be to reliably monitor serum concentrations of folate in older adults and treat deficiency for preventative measures and/or as part of implemented therapeutic strategies while regularly reviewing patients clinical outcomes.
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Which Vitamin Combinations Might Provide An Effective Metabolic Tune
It is essential to understand the biology of brain aging and the metabolic pathways involved, before attempting to work out which vitamin combination might be required to optimize metabolic function in a manner that decelerates brain aging and the pathologies that lead to MCI and AD . Which metabolic pathways matter most can be thoroughly understood by examining 1) genetic risk factors, 2) changes in gene expression in the brain with age and with MCI or AD, 3) using bioinformatics, to identify which metabolic pathways are affected by such genetic changes, and 4) metabolic imbalances that indicate where metabolic blocks may be occurring. Once the metabolic pathways are identified, it becomes possible to establish which vitamins might be required as cofactors and substrates in these pathways and therefore reasonably have a putative role in preventing MCI and AD. These could then be considered as legitimate candidates for a metabolic tune-up to prevent brain aging and dementia. The aim would be to intervene with the appropriate vitamin intake combination well before the symptoms of MCI emerge current evidence indicates AD-related brain pathology and atrophy commence several years before the onset of MCI .
Data Extraction And Assessment Of Study Quality
Pre-designed, standardized data extraction forms were developed to capture pertinent information from each included study. The collected information included: the first authors name, year of publication, country, study design, mean age, follow-up duration, gender, adjusted factors, assessment method for serum 25D, sample size, and reported risk estimates and 95% CIs for dementia and AD across different categories of serum 25D. If a study did not provide enough information to extract the corresponding data, the authors were contacted to try and obtain the required additional information. Two authors independently extracted the data from each study and compared the data for consistency. Risk of bias was assessed using the Cochrane risk of bias tool and NOS. Any discrepancies were resolved by group discussion to reach consensus.
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About This Vitamin D And Dementia Research News
Higher vitamin D status has been suggested to have beneficial effects on the brain.
To investigate the association between 25-hydroxyvitamin D , neuroimaging features, and the risk of dementia and stroke.
We used prospective data from the UK Biobank to examine the association between 25D concentrations with neuroimaging outcomes and the risk of dementia and stroke . Observational analyses were adjusted for age, sex, ethnicity, month, center, and socioeconomic, lifestyle, sun behavior, and illness-related factors. Nonlinear Mendelian randomization analyses were used to test for underlying causality for neuroimaging outcomes and dementia and stroke .
Associations between 25D and total, gray matter, white matter, and hippocampal volumes were nonlinear, with lower volumes both for low and high concentrations . 25D had an inverse association with white matter hyperintensity volume . Vitamin D deficiency was associated with an increased risk of dementia and stroke, with the strongest associations for those with 25D < 25 nmol/L .
Nonlinear MR analyses confirmed the threshold effect of 25D on dementia, with the risk predicted to be 54% higher for participants at 25 nmol/L compared with 50 nmol/L. 25D was not associated with neuroimaging outcomes or the risk of stroke in MR analyses. Potential impact fraction suggests 17% of dementia could be prevented by increasing 25D to 50 nmol/L.