Category: Nutrition

Over 1 billion people worldwide have a vitamin D deficiency.

Difficulties with memory and learning are signs of vitamin D deficiency, research finds.

Vitamin D deficiency is even linked to disorders such as depression and schizophrenia.

Deficiency in the vitamin affects critical structures in the hippocampus, an area of the brain important in memory and learning.

Dr Thomas Burne, study co-author, said:

“Over a billion people worldwide are affected by vitamin D deficiency, and there is a well-established link between vitamin D deficiency and impaired cognition.

Unfortunately, exactly how vitamin D influences brain structure and function is not well understood, so it has remained unclear why deficiency causes problems.”

For the study, researchers removed vitamin D from the diets of mice for 20 weeks.

The mice clearly showed problems with learning and memory compared to a control group, who were fed sufficient levels of vitamin D.

The researchers found that vitamin D is important in keeping perineuronal nets in the hippocampus stable.

Dr Burne explained:

“These nets form a strong, supportive mesh around certain neurons, and in doing so they stabilise the contacts these cells make with other neurons.

As neurons in the hippocampus lose their supportive perineuronal nets, they have trouble maintaining connections, and this ultimately leads to a loss of cognitive function.”

The hippocampus is a particularly active part of the brain, which may be why it is affected by vitamin D deficiency early on, said Dr Burne:

“It’s like the canary in the coalmine—it might fail first because its high energy requirement makes it more sensitive to the depletion of essential nutrients like vitamin D.

Intriguingly, the right side of the hippocampus was more affected by vitamin D deficiency than the left side.”

The damage to these perineuronal nets may help to explain the memory problems that are a symptom of schizophrenia.

Dr Burne said:

“The next step is to test this new hypothesis on the link between vitamin D deficiency, perineuronal nets and cognition.

We are also particularly excited to have discovered these nets can change in adult mice.

I’m hoping that because they’re dynamic there is a chance that we can rebuild them, and that could set the stage for new treatments.”

The study was published in the journal Brain Structure and Function (Al-Amin et al., 2019).

Vitamin B12 deficiency is relatively common, especially in the elderly.

Problems with thinking and memory can be signs of vitamin B12 deficiency.

Low levels of vitamin B12, along with other vital nutrients, are linked to brain shrinkage.

Deficiencies in these critical micronutrients may also be important in the development of neurodegenerative diseases like Alzheimer’s.

Research has looked at nutrients in the ‘Mediterranean diet’, which is linked to better brain aging.

It found that people had better cognitive functioning when they had higher levels of important nutrients, including vitamin B12, omega-3 and omega-6 fatty acids, folate and others.

The study included 116 seniors who were given tests of their IQ, memory and thinking skills.

Scans also assessed the efficiency of their brains.

Professor Aron Barbey, study co-author, said:

“Efficiency has to do with how information is communicated within the network.

We looked at ‘local efficiency’ – how well information is shared within a spatially confined set of brain regions – and also ‘global efficiency,’ which reflects how many steps are required to transfer information from any one region to any other region in the network.

If your network is more efficiently configured, then it should be easier, on average, to access relevant information and the task should take you less time.”

The results showed that people performed better in the tests if their blood was higher in levels of these nutrients:

• omega-3 and omega-6 fatty acids,
• carotenoids,
• lycopene,
• riboflavin,
• folate,
• vitamin B12
• and vitamin D.

Professor Barbey explained the results:

“Our study suggests that diet and nutrition moderate the association between network efficiency and cognitive performance.

This means that the strength of the association between functional brain network efficiency and cognitive performance is associated with the level of the nutrients.”

Other potential signs of vitamin B12 deficiency include feeling tired, experiencing muscle weakness and being constipated.

Good sources of vitamin B12 include fish, poultry, eggs and low-fat milk.

Fortified breakfast cereals also contain vitamin B12.

The study was published in the journal Neuroimage (Zwilling et al., 2019).