Category: Dementia

A study finds a link between levels of one vitamin in the brain and how well people maintain their cognitive abilities.

Higher levels of vitamin D in the brain are associated with better cognitive performance and a slower decline in thinking abilities as people age.

Research has repeatedly linked sufficient vitamin D levels with a lower risk of dementia (1, 2, 3).

One study has estimated that maintaining adequate vitamin D could potentially prevent nearly one in five cases of dementia (Navale et al., 2022).

The evidence, however, is not consistent, as other research has found no association (also: Owusu et al., 2018).

The latest study approached the question differently by examining vitamin D directly in the brain, an area that has received relatively little research.

Professor Sarah Booth, one of the study’s authors, said the findings highlight the need to understand how nutrients and diet may help the ageing brain withstand diseases such as Alzheimer’s and other forms of dementia.

Vitamin D markers

The researchers followed 290 older adults and examined their brain tissue after death to determine how much vitamin D was present.

Dr Kyla Shea, the study’s first author, explained that previous research has generally relied on people’s diets or measurements of vitamin D in their blood when investigating its relationship with cognitive function.

The researchers therefore wanted to establish whether vitamin D is actually found in the human brain and, if so, whether brain concentrations are related to changes in cognition over time.

The results showed that participants with greater concentrations of vitamin D in their brains tended to have better cognitive function.

There was no corresponding association between brain vitamin D levels and the physical changes in the brain typically associated with Alzheimer’s disease.

As a result, the researchers cannot yet say exactly why vitamin D might be associated with better cognitive health.

Dr Shea noted that dementia involves multiple biological processes, many of which are still poorly understood. Vitamin D may therefore be connected with other aspects of brain health that were not examined in this study and could be investigated in future research.

How much vitamin D?

The findings do not mean that people should start taking large doses of vitamin D to protect against dementia.

Current recommendations are 600 IU of vitamin D per day for adults under 70 and 800 IU for those aged over 70.

Dr Shea said the study establishes that vitamin D is present in the brain at meaningful levels and that greater amounts are associated with less cognitive decline.

However, she stressed that more research is needed to determine which changes in the brain are associated with vitamin D before treatments or other interventions can be developed.

The study was published in the journal Alzheimer’s & Dementia (Shea et al., 2022).

The common drink contains compounds called phenylindanes that may help protect against dementia.

Drinking coffee may help protect against both Alzheimer’s and Parkinson’s.

The study examined compounds in coffee called phenylindanes that may help protect against dementia.

Higher levels of phenylindanes typically make coffee taste more bitter.

Dr Donald Weaver, study co-author, said:

“Coffee consumption does seem to have some correlation to a decreased risk of developing Alzheimer’s disease and Parkinson’s disease.

But we wanted to investigate why that is — which compounds are involved and how they may impact age-related cognitive decline.”

The study examined how phenylindanes interact with two proteins linked to the development of Alzheimer’s and Parkinson’s.

The results showed that phenylindanes inhibit both beta amyloid and tau proteins.

The researchers also compared dark roast, light roast and decaffeinated coffees.

Dark roasts contained the highest levels of phenylindanes.

Caffeine, though, made no difference, explained Dr Ross Mancini, the study’s first author:

“The caffeinated and de-caffeinated dark roast both had identical potencies in our initial experimental tests.

So we observed early on that its protective effect could not be due to caffeine.”

Dr Weaver said it is a major advantage that coffee is a natural crop:

“Mother Nature is a much better chemist than we are and Mother Nature is able to make these compounds.

If you have a complicated compound, it’s nicer to grow it in a crop, harvest the crop, grind the crop out and extract it than try to make it.”

Dr Weaver said much more work will be needed before any therapies can be developed:

“What this study does is take the epidemiological evidence and try to refine it and to demonstrate that there are indeed components within coffee that are beneficial to warding off cognitive decline.

It’s interesting but are we suggesting that coffee is a cure?

Absolutely not.”

Related

• 12 Proven Ways To Prevent Memory Loss As You Age (P)

The study was published in the journal Frontiers in Neuroscience (Mancini et al., 2018).

Several studies point to the same link between everyday drinks and long-term brain health.

Drinking tea or coffee may reduce the risk of stroke and dementia by around one-third.

Dementia is a decline in brain function that commonly occurs with ageing and can affect overall health.

Symptoms include memory loss, problems with language and changes in mood.

A stroke occurs when blood flow to part of the brain is interrupted, potentially causing brain damage.

Alzheimer’s is the most common form of dementia.

The benefits of tea may come from the flavonoids it contains.

Flavonoids are antioxidants and part of the polyphenol class found in plants that are known to have several health benefits and to help prevent various diseases.

Other research has found that tea, berries and apples may all help reduce the risk of dementia.

That study found that older people who ate more flavonoid-rich foods had up to a fourfold lower risk of dementia.

Drinking tea has also been linked to better overall brain health.

People who drank tea at least four times a week for 25 years had better-connected brains, regardless of whether they preferred oolong, black or green tea.

Regular tea drinkers also tend to have better-organised brain networks.

Moderate consumption linked to lower risk

Chinese researchers used data from over 350,000 people in the Biobank project.

The Biobank is a long-term project that tracks the health and well-being of volunteers in the UK.

Health data for participants was tracked over at least 10 years, including their intake of tea and coffee.

The results showed that people drinking 2-3 cups of coffee or 3-5 cups of tea per day had the lowest risk of stroke or dementia.

This amount of tea lowered the risk of stroke by 32 percent and dementia by 28 percent.

The study’s authors write:

“Our findings suggested that moderate consumption of coffee and tea separately or in combination were associated with lower risk of stroke and dementia.”

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• 8 Everyday Eating Habits That Reduce Dementia Risk (P)
• 12 Proven Ways To Prevent Memory Loss As You Age (P)

The study was published in the journal PLoS Medicine (Zhang et al., 2021).

Inadequate daily intake of this vitamin-like compound can lead to an enlarged heart, liver damage, weight gain as well as Alzheimer’s disease.

A deficiency in choline is linked to an increased Alzheimer’s risk.

While the liver naturally produces small amounts of the vitamin-like nutrient choline, it cannot manufacture enough to meet the body’s daily needs.

Choline is found in a range of foods, including egg yolks, beef, fish, chicken, wheat germ, soya beans, dairy products, peanuts, and almonds.

Choline is well known for its effect in treating memory disorders such as Alzheimer’s disease and dementia.

The US Institute of Medicine sets the minimum daily choline requirement at 550 mg for men and 425 mg for women.

Pregnant and breastfeeding women require at least 450 mg and 550 mg of choline per day respectively, due to the crucial role of this nutrient in infant development.

Despite these daily requirements, national dietary surveys have found that less than 10 percent of Americans are meeting the recommendations.

Essential for brain health

Choline is not only essential for brain health but also influences liver function, shortfalls in this nutrient can cause cell damage and irregularities in fat metabolism.

A study examined how choline deficiency can adversely affect the brain, liver, and heart.

The research team found that dietary choline deficiency in mice led to weight gain, reduced glucose metabolism, enlargement of the heart, neurological alterations, and liver damage.

Choline deficiency also led to elevated levels of tau tangles and beta-amyloid plaques, two key features of Alzheimer’s disease.

Amyloid plaques are clustered proteins between the nerve cells and tau tangles are abnormal accumulations of tau proteins inside neurons.

Dr Ramon Velazquez, the study’s senior author, highlighted that human choline deficiency presents a double-edged problem:

“It’s a twofold problem.

First, people don’t reach the adequate daily intake of choline established by the Institute of Medicine in 1998.

And secondly, there is vast literature showing that the recommended daily intake amounts are not optimal for brain-related functions.”

Beyond the brain

The study found a link between choline deficiency and a range of neurological and physical changes.

Adequate levels of choline, on the other hand, may improve overall health and protect the nervous system.

For example, elevated levels of homocysteine have been found to be neurotoxic and associated with neurodegenerative diseases but choline can reduce homocysteine levels.

Furthermore, choline helps synthesise acetylcholine — a vital neurotransmitter responsible for learning, memory, and attention.

These findings support other studies concerning the influence of dietary choline on human health.

The findings may encourage people, particularly vegans and those following plant-based diets, to pay closer attention to their choline intake.

The authors also explored proteins in the hippocampus, one of the brain areas wracked by Alzheimer’s.

Inadequate choline status appeared to affect hippocampal networks associated with postsynaptic membrane regulation and microtubule function — two areas that are vital for normal brain function.

In addition, blood plasma samples revealed that choline deficiency altered several liver-produced proteins that play important roles in metabolism.

Dr Velazquez said:

“Our work provides further support that dietary choline should be consumed on a daily basis given the need throughout the body.”

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The study was published in the journal Aging Cell (Dave et al., 2023).