Previously I have investigated how healthy lifestyle and diet can impact brain function and have also looked at the importance of vegetables and fruits for a well working brain.  A very recently published preliminary small study (1) has found that blueberries may be particularly useful to memory.

The authors of the study wrote in their report (1) that there was an urgent need to develop ways to prevent dementia and protect the aging brain.  They decided to look at blueberries since laboratory studies have indicated that compounds found in these berries, mainly a group of flavonoids, or plant chemicals (phytochemicals), called anthocyanins, may be associated with improved neurone function in the brain and possibly with protection against neurodegeneration.  The anthocyanins found in blueberries, and other berries and fruits, have antioxidant and anti-inflammatory properties.

This current study (1) investigated the consumption of wild blueberry juice and memory function.  After twelve weeks individuals consuming the blueberry juice had improved memory as well as a trend toward reduced depressive symptoms when compared to a control group of individuals who did not consume blueberry juice.  The authors concluded that “The findings of this preliminary study suggest that moderate-term blueberry supplementation can confer neurocognitive [brain/memory] benefit and establish a basis for more comprehensive human trials to study preventive potential and neuronal mechanisms” "These preliminary memory findings are encouraging and suggest that consistent supplementation with blueberries may offer an approach to forestall or mitigate neurodegeneration,"

This study only looked at blueberries.  However, I would suggest that eating a wide variety of vegetables and fruits daily is important since they contain a huge array of vitamins, minerals and bioflavonoids (bioactive plant chemicals).  Many of the vitamins and bioflavonoids found in these foods act as antioxidants in the body and this may be one way that that prevent disease.  Antioxidants protect the body from attack by destructive molecules known as ‘free radicals’, they protect against something called ‘oxidative stress’ in the body.

A previous study(2) found that:
“Healthy subjects of any age with a high daily intake of fruits and vegetables have higher antioxidant levels, lower levels of biomarkers of oxidative stress, and better cognitive performance than healthy subjects of any age consuming low amounts of fruits and vegetables. Modification of nutritional habits aimed at increasing intake of fruits and vegetables should be encouraged to lower prevalence of cognitive impairment in later life”. 

As mentioned in my previous posts regarding memory and brain function, linked in the first paragraph, people who live healthily over many years tend to be less likely to experience mental decline in later life.  The exciting point about most of the research is that unhealthy behaviours can be modified.  At any age we can make the choice to be a little healthier.  We can add some physical activities into the day – whether that be walking for an extra 15-30minutes a day, taking the stairs instead of the lift or doing a weekly exercise or dance class.  It is also possible to look at the diet and see if there is a way to add extra portions of vegetables and fruits into our daily meals.

Nutritional supplements can never be viewed as an alternative to healthy eating and living.  However, if you feel your diet consistently falls short of vegetables and fruits you may wish to consider taking a food-state multi-vitamin and mineral supplement which tends to provide bioflavonoids in addition to the nutrients and is easy for the body to absorb.  Another vital nutrient for the brain is Omega 3 fatty acids.   For those of you who do not eat oil fish regularly (at least twice per week) you may want to consider taking a daily fish oil supplement in order to provide omega 3 fatty acids to the body (a supplement to provide around 250-350mg of EPA and 250-350mg DHA).  For vegetarians and vegans flaxseed oil can provide the shorter chain omega 3 fatty acid, alpha linolenic acid, (a supplement providing 1000mg alpha-linolenic acid daily) can be considered.  Vegetarian EPA and DHA supplements produced from algae are also becoming increasingly available and may be worth investigating.

(1) D. Shidler et al.  2010.  Blueberry Supplementation Improves Memory in Older Adults.  J. Agric. Food Chem.  Publication Date (Web): January 4, 2010.  DOI: 10.1021/jf9029332
(2) Polidori MC et al. 2009.  High fruit and vegetable intake is positively correlated with antioxidant status and cognitive performance in healthy subjects. J Alzheimers Dis. 17:4
Written by Ani Kowal

Exercise and healthy eating are great ways to vitalise life.  This month two new studies (1,2) published in the Archives of Neurology add to the evidence which suggests that regular exercise can help prevent the problems that often occur in thinking and memory that can come with age and also may help to turn back the clock on brain aging.

The first study(1) was set up to examine the effects of exercise on cognition (mental function) and other factors associated with Alzheimer’s disease in older adults suffering with mild cognitive impairments. 

Mild cognitive impairment typically means the individual will have some memory difficulties such as forgetting names or forgetting where things have been placed.  Around 10-15% of individuals with this kind of mild cognitive impairment will go on to develop dementia – this is in contrast to about 1-2% of the general population.

The study(1) was small but well designed.  Participants were assigned to either a high-intensity aerobic exercise or stretching group (the control group).  The exercise group were under the supervision of a fitness trainer and exercised at 75% to 85% of heart rate for 45 to 60 minutes, 4 days per week for 6 months.  The exercise was done using a treadmill or an exercise bike. The control group carried out supervised stretching activities according to the same schedule but maintained their heart rate at or below 50%.  At the start of the study and then at 3 months and 6 months blood was collected and cognitive tests were taken. 

The results(1) at 6 months found that there were sex-specific positive effects, in women,  on cognition as well as various blood-results (mainly related to blood sugar and stress hormones).  6 months of intense aerobic exercise was found to improve cognitive abilities of attention and concentration, organization, planning, and multi-tasking.  In the stretching ‘control group’ cognitive function test scores continued to decline.  Women seemed to benefit a little more from the exercise than men – the reason is not entirely known although in women the exercise also seemed to improve the cells sensitivity to the hormone insulin, men did not show the same improvement in insulin sensitivity.

This is a preliminary study into exercise and brain function and it may well be that the brain can benefit from lower intensity aerobic exercise – current research is underway to find out how much exercise is deemed to be ‘enough’ to benefit the brain.
 

The other study (2) showed that engaging in moderate physical activity such as brisk walking, swimming, or yoga in midlife or later could cut the risk of developing mild thinking problems.  The study involved over 1300 people without dementia who completed a Physical Exercise Questionnaire.  The frequency of physical exercise among 198 individuals with mild cognitive decline was compared to 1126 with normal cognition.  The results showed that, in both men and women, any frequency of moderate exercise performed in midlife or late life was associated with a reduced risk of having mild cognitive impairment.  Specifically moderate exercise in midlife was associated with a 39% reduced likelihood of developing mild cognitive impairment, and moderate exercise in late life was associated with a 32% reduced likelihood of mental decline.

These two studies support the growing body of evidence showing the benefits of a physically active lifestyle on the brain.  In conjunction with good nutrition I believe that there really are tangible ways to keep the brain healthy.  Please read my previous posts relating to brain health.

(1)Baker LD et al.  2010.  Effects of aerobic exercise on mild cognitive impairment: a controlled trial. Arch Neurol.  67(1):71-9.
(2) Geda YE et al.  2010.  Physical exercise, aging, and mild cognitive impairment: a population-based study. Arch Neurol.  67(1):80-6.
Written by Ani Kowal

Back in August I wrote about how diet can impact the brain and behaviour in children.  Nutrition for the brain is something I am very interested in and those of you who follow this blog will see that there is a lot of scientific evidence to show that what we eat can make a difference to mood and feelings as well as brain structure and function.

A very recent review study (1) has concluded that multi-nutrient supplementation may be associated with a small but significant increase in a measure of intelligence and academic performance in healthy schoolchildren.  The authors of the study do state however that “more research is required, however, before public health recommendations can be given” (1).

The researchers undertook the study because “Although multiple micronutrient interventions have been shown to benefit children's intellectual development, a thorough evaluation of the totality of evidence is currently lacking to direct public health policy” (1).  The aim of the research was to review the present literature on the effects of multiple-nutrient supplements on cognitive (mental/intellectual) performance in school aged children (children aged up to 18).  The researchers looked at data from trials published between 1970 and 2008 – quite a huge body of work!  As stated above, they found that multi-nutrient supplements seemed to have a small but significant positive effect on academic performance. 

The important aspect of these kinds of research studies, in my opinion, is that they show that nutrition does impact the brain, thinking, mood and therefore perhaps academic performance.  Limitations of such studies include the quality of the supplement, the quantity and also the actual diet of the child.  If you read the post from August you will see that overall diet quality is very important to the brain.  A good supply of daily vegetables, fruits, unrefined and unprocessed foods and healthy omega 3 fats as well as a protein supply with each meal is a great way to look after body and mind.  Regular exercise is also crucial for mood. 

In terms of supplements, they can never replace a healthy diet.  If you are considering supplements I would suggest a good quality multivitamin-mineral supplement, I like food-state supplements as they are made from ‘food’ and not chemicals and are easily absorbed into the body.  In addition to this I think that a daily omega 3 fatty acid supplement is definitely worth considering – these fats really are essential for the brain.  The most effective of the omega 3 fatty acids for brain function seem to be the long chain omega 3 fats EPA and DHA which are found in oily fish such as salmon, trout, mackerel and sardines.  These can be purchased as an oil or in capsule form.  Many of the oils are made easy for children to take as they are flavoured and have no fishy taste or smell.  For vegetarians and vegans flaxseed oil can be taken – this is a shorter chain omega 3 fat and not as effective, since the body has to work hard to convert it into the longer chain structure – however, it is certainly worth taking.  This kind of fat can be found in good amounts in walnuts and flaxseeds.  Vegan EPA and DHA is now being produced from algae, it is expensive but available to buy from some retailers and online.

(1)Eilander A et al.  2010.  Multiple micronutrient supplementation for improving cognitive performance in children: systematic review of randomized controlled trials.  American Journal of Clinical Nutrition.  91: 115-130
Written by Ani Kowal

Messages are constantly being published to encourage us to eat plenty of vegetables and fruits and I certainly write about the importance of these foods often.  Vegetables and fruits provide the body with an array of vitamins, minerals and bioflavonoids (bioactive plant chemicals) which are associated with the prevention of many diseases.  Some of the vitamins and bioflavonoids act as antioxidants in the body and this may be one way that that prevent disease.  Antioxidants are another topic that I often write about, they protect the body from attack by destructive molecules known as ‘free radicals’.

A newly published study (1) has found that eating a diet rich in vegetables and fruits may be associated with a reduced risk of ‘cognitive impairment’, mental impairment, later in life.

193 healthy people aged 45-102 years old were included in the study.  Each participant took part in cognitive testing and also gave blood which was assessed for antioxidant status.  Each person also completed a specific food frequency questionnaire which assessed their daily intake of vegetable and fruits.  The participants were scored to have either a high intake or a low intake.  94 subjects in the high-intake score group had significantly higher cognitive test scores and higher levels of antioxidant nutrients in their blood compared to 99 subjects who had low intake of vegetables and fruits.  In addition to this the cognitive scores were directly correlated with blood levels of specific antioxidant nutrients (1).

The authors of the study conclude (1) “Healthy subjects of any age with a high daily intake of fruits and vegetables have higher antioxidant levels, lower levels of biomarkers of oxidative stress, and better cognitive performance than healthy subjects of any age consuming low amounts of fruits and vegetables. Modification of nutritional habits aimed at increasing intake of fruits and vegetables should be encouraged to lower prevalence of cognitive impairment in later life”. 

This follows on well from the piece I posted on Monday which discussed recent evidence that lifestyle may impact cognition later in life.  The High Intake group in this study was consuming around 400g of vegetables and fruits daily which is a very achievable amount.  The low intake group, by contrast were eating less that 100g of these foods daily.  Integrating at least 5 portions of vegetables and fruits into the daily diet is highly recommended. 

Dr. M. Cristina Polidori, currently at the Department of Geriatrics, Marienhospital Herne, Ruhr-University of Bochum, Germany, explained in a press release (2): “It is known that there is a strong association between fruit and vegetable intake and the natural antioxidant defenses of the body against free radicals. It is also known that bad nutritional habits increase the risk of developing cognitive impairment with and without dementia. With this work we show a multiple link between fruit and vegetable intake, antioxidant defenses and cognitive performance, in the absence of disease and independent of age. Among other lifestyle habits, it is recommended to improve nutrition in general and fruit and vegetable intake in particular at any age, beginning as early as possible. This may increase our chances to remain free of dementia in advanced age.”

Further, much larger, studies are planned that will include patients with Alzheimer’s disease at different stages and patients with mild cognitive impairment without dementia.  I will be following developments with interest.  As my many previous posts have shown, a good diet and lifestyle really can impact our health, both in the present and the future.  As I mentioned last week, even small changes can add up over time to create a bigger impact. 

(1)Polidori MC et al.  High fruit and vegetable intake is positively correlated with antioxidant status and cognitive performance in healthy subjects. J Alzheimers Dis. 17:4
(2)Science daily press release.  http://www.sciencedaily.com/releases/2009/09/090909064910.htm.  IOS Press BV (2009, September 10). High Fruit And Vegetable Intake Linked To Antioxidant Status And Cognitive Performance In Healthy Subjects. ScienceDaily. Retrieved September 11, 2009, from http://www.sciencedaily.com¬ /releases/2009/09/090909064910.htm
Written by Ani Kowal

Recently I wrote about healthy living as a means of reducing the risk of developing chronic disease as well as being a possible way of protecting against Alzheimer’s disease

A study based on a UK population (1) has added further evidence for the effect that diet and lifestyle can have on mental/brain (cognitive) function.   The researchers were looking at the health behaviours of over 5000 men and women who were civil service office workers in London UK.  They assessed the health of the workers over a period of about 17 years when the workers were at three different stages of life: early midlife, around 44 years old, midlife, around 56 years old and late-midlife, when they were around 61 years old.  A score, of 0 to 4, was given for the number of unhealthy behaviours the individuals participated in.  Smoking, low physical activity and low fruit and vegetables consumption were among the unhealthy behaviours being assessed.  Poor thinking skills (known as executive function) and poor memory in late-midlife were the outcomes being measured and analysed.

Compared with those who had no unhealthy behaviours, those with 3–4 unhealthy behaviours over the study period were nearly three times more likely to have poorer thinking skills. A similar association was observed for memory – the men and women who had the most number of unhealthy behaviours were about twice as likely to have declining memory.  The risk of poor thinking skills and poor memory was greater the more times the participants reported unhealthy behaviours over the 3 age phases that were assessed (1).  

Current smokers were more likely to show the lowest memory, verbal, and math-related thinking and reasoning skills at each age that was assessed.  Similar findings were also noted among those who ate fewer versus more than 2 servings of fruits and vegetables each day.   Men and women who reported lower levels of physical activity during midlife and late-midlife also showed greater risk for cognitive deficit (1).

The authors conclude (1) that “This study suggests that both the number of unhealthy behaviours and their duration are associated with subsequent cognitive function in later life.”

The research only shows associations, it’s not a study that proves that healthy living can prevent mental decline but it indicates that people who live healthily over many years tend to be less likely to experience mental decline in later life.  The exciting point about this research is that all of these unhealthy behaviours can be modified.  At any age we can make the choice to be a little healthier.  With a bit of planning we can add some physical activities into the day – whether that be walking for an extra 15-30minutes a day, taking the stairs instead of the lift or doing a weekly exercise or dance class.  It is also possible to look at the diet and see if there is a way to add extra portions of vegetables and fruits into our daily meals for example adding a piece of fruit to our breakfast, eating fruit as a snack, having a large mixed salad with lunch and including at least two portions of vegetables with our evening meal.  Reaching the minimum 5 portions a day needn’t be too challenging.  Making changes gradually can help the process seem less overwhelming and it all adds up to make a difference in the long-run. 

As I have previously mentioned, nutritional supplements can never be viewed as an alternative to healthy eating and living.  However, if you feel your diet consistently falls short of vegetables and fruits you may wish to consider taking a food-state multi-vitamin and mineral supplement which tends to provide bioflavonoids in addition to the nutrients and is easy for the body to absorb.  For those of you who do not eat oil fish regularly (at least twice per week) you may want to consider taking a daily fish oil supplement in order to provide omega 3 fatty acids to the body (a supplement to provide around 250-350mg of EPA and 250-350mg DHA).  For vegetarians and vegans flaxseed oil can provide the shorter chain omega 3 fatty acid, alpha linolenic acid, (a supplement providing 1000mg alpha-linolenic acid daily can be considered).  Vegetarian EPA and DHA supplements produced from algae are also becoming increasingly available.

(1) Séverine Sabia S et al.  2009.  Health Behaviors From Early to Late Midlife as Predictors of Cognitive Function.  The Whitehall II Study.   American Journal of Epidemiology.  170(4):428-437
Written by Ani Kowal

Children everywhere are starting to get ready to go back to school after their long summer holidays.  Nutrition and diet can impact the body and health in many ways, the most apparent concerns for parents of school aged children are immune health and brain function/behaviour.

In July I wrote about probiotics and prevention/treatment of childhood colds and last year I wrote about boosting immune health in children going back to school.  Today I wanted to have another look at behaviour and the brain.  Previously I have written about ADHD, particularly with regards the importance of omega 3 fatty acids for brain function.  The brain is a highly complex organ.  In infancy and childhood the brain is growing rapidly and it requires a lot of energy.  There is a mounting body of evidence to suggest that diet can influence the development and functioning of the brain (1).  This influence may well start with the diet of the mother during pregnancy and then in the infant in early life, however later in childhood nutritional intervention may well make a difference to brain function and cannot be discounted.

There is increasing evidence that the missing of breakfast has negative behavioural and attention consequences later in the morning and it is also thought that meals of a low rather than high glycaemic load are beneficial with regards child behaviour.  There are also findings of an association between a tendency to develop low blood sugar (glucose) and aggression in children(2). 

Glycaemic index and glycaemic load are terms used to characterise foods and diets based on their effects on blood glucose levels.  Foods that release sugar quickly into the bloodstream have what is known as a high Glycaemic Index (GI), meals that favour a spike in blood sugar levels are said to have a high Glycaemic Load (GL).  White bread, potatoes, processed/refined carbohydrates have a high glycaemic index i.e. they tend to cause a rapid surge in blood sugar.  Vegetables, whole-grain high-fibre carbohydrates, create a more gradual change in blood sugar levels and are considered to have a low glycaemic index.  For the classification of more food examples please visit the website 'The Glycemic Index', there you will find a database where you can search for specific foods and find out more about GI and health.

Certain nutrients have greater effects on brain development than do others and hence may have more of an impact on childhood behaviour and brain function. The important nutrients include protein (which is so important for proper growth in childhood), certain fats (especially omega 3 fats), iron, zinc, copper, iodine, selenium, vitamin A, choline, and folate (3).  There is evidence that sub-clinical deficiencies of vitamins and minerals may influence anti-social behaviour and intelligence but the evidence is still controversial(4).The B vitamins, Folate and B12 (cobalamin), are vital for the brain.  Deficiencies have negative consequences on the developing brain, and behaviour, during infancy; and deficits of both vitamins are associated with a greater risk of depression during adulthood (5).  Recently vitamin D has also received attention with regards brain functioning.  As you can see a myriad of nutrients are important for the brain and they probably work and act synergistically, this makes clinical trials difficult to carry out.  However, there have been three well-designed studies which have reported that vitamin/mineral supplementation in children can reduce anti-social behaviour (2).

It is difficult to conclusively say which vitamins/minerals are most important and whether or not supplementation can help children – this is because behaviour is difficult to standardise and measure in a trial-setting.  Also psychological and environmental influences will be having an effect.  Needless to say our bodies are complex, we require various nutrients in correct proportions in order to stay optimally healthy.  Many children in the UK fall short of achieving recommended 5 portions of fruit and vegetable daily which is worrying for health and many children do not eat oily fish (the best source of omega 3 fatty acids) at all.  If you are concerned that your child is not eating a consistently healthy diet you may wish to consider a food-state multivitamin and mineral supplement that has been formulated specifically for children together with an omega 3 fatty acid supplement – easy to take liquid fish oils are now available for children which are naturally flavoured (usually lemon or orange).  Flaxseed oil and omega 3 supplements produced from algae are available for vegetarian/vegan children.

A UK based study concludes: “Whilst the importance of diet in educational attainment remains under investigation, the evidence for promotion of lower-fat, -salt and -sugar diets, high in fruits, vegetables and complex carbohydrates, as well as promotion of physical activity remains unequivocal in terms of health outcomes for all schoolchildren”(6)

(1)Benton D.  2008.  Eur J Nutr.  The influence of children's diet on their cognition and behavior. Eur J Nutr.  47 Suppl 3:25-37.
(2) Benton D.  2007.  The impact of diet on anti-social, violent and criminal behaviour. Neurosci Biobehav Rev. 31(5):752-74.
(3)Georgieff MK.  2007.  Nutrition and the developing brain: nutrient priorities and measurement.  Am J Clin Nutr.  85(2):614S-620S.
(4)Benton D.  2008.  Micronutrient status, cognition and behavioral problems in childhood.  Eur J Nutr. 47 Suppl 3:38-50.
(5)Black MM.  2008.  Effects of vitamin B12 and folate deficiency on brain development in children.  Food Nutr Bull.  29(2 Suppl):S126-31.
(6)Ells LJ et al.  2008.  A systematic review of the effect of dietary exposure that could be achieved through normal dietary intake on learning and performance of school-aged children of relevance to UK schools. Br J Nutr.  100(5):927-36.

Written by Ani Kowal

Following my last post I was interested to read a well researched review paper (1) that looks into the link between vitamin D deficiency and the development of dementia.  The report is published in the May issue of the Journal of Alzheimer’s disease and is written my William B Grant PhD of the Sunlight, Nutrition and Health Research Centre (SUNARC).  SUNARC is an organization devoted to research and education relating to the prevention of chronic disease through changes in diet and lifestyle.  I have previously mentioned SUNARC when reporting on the importance of Vitamin D for health.

Previously I highlighted the link between vitamin D and the brain when I wrote about the potential use of the sunlight vitamin for helping sufferers of SAD (seasonal affective disorder) and also possible link between low vitamin D levels in those suffering from depression and mood disorders.

William Grant, the author of the paper, begins by highlighting the rise in individuals who are suffering with dementia in the Western world.  The condition deserves attention since the number of people living into old age is increasing and it is a worthwhile aim to help individuals achieve lasting health as they age so they may live life to the full.  There are several risk factors for the development of Alzheimer's disease and vascular dementia. Based on an increasing number of studies linking these risk factors with Vitamin D deficiency, the article(1) suggests that further investigation of possible direct or indirect linkages between Vitamin D and these dementias is certainly needed.  Diet and lifestyle are being increasingly researched in relation to their links with dementia prevention and vitamin D is gaining attention for its role in many condition from heart disease, diabetes, bone health, cancer, infections, chronic fatigue and more.

Low blood serum levels of vitamin D have been associated(1) with increased risk for several diseases which are also considered risk factors for the development of dementia  or are often reported to precede the incidence of dementia e.g. cardiovascular diseases, diabetes mellitus, depression, dental caries, osteoporosis, and periodontal disease.  These studies are only observational studies,nproviding medical researchers with links between vitamin D and dementia.  As yet there no randomised controlled trials to draw evidence from.

The way that vitamin D may be working to protect the brain is via several mechanisms.  It seems to be able to act by protecting the neurones in the brain (brain nerve cells), it may also be protecting the blood vessels in the brain and having an effect by protecting against excess calcium entry into the brain.  Vitamin D also seems to act as an anti-inflammatory – an important factor since dementia is often linked to inflammation in the brain and body (1).  There is also plenty of evidence to suggest an important role for vitamin D in brain development and function.

Writing in the article, Dr. Grant states, "To date, the evidence includes observational studies supporting a beneficial role of vitamin D in reducing the risk of diseases linked to dementia such as vascular and metabolic diseases, as well as an understanding of the role of vitamin D in reducing the risk of several mechanisms that lead to dementia." “However, until RCTs are performed, the hypothesis cannot be considered a fact”

A recent analysis(2) found that there is a global widespread insufficiency of vitamin D and there is evidence from the National Diet and Nutrition Surveys (NDNS) which suggests that in the UK deficiency of this vital nutrient is a real problem (3,4,5,6).  The problem is made worse in the older generations, as we age our bodies find it increasingly difficult to manufacture vitamin D.  In the UK many of us do not get enough sunlight exposure to generate decent levels of vitamin D in our bodies, especially in the autumn and winter months when we cover our bodies up and don’t get out during the daylight hours very often. 

Only small amounts of vitamin D are found in food sources such as oily fish (mackerel, salmon and sardines) and egg yolks.  As many of us in the UK are falling short of recommended vitamin D levels, if you rarely get out into the sun, you may wish to consider a vitamin D supplement which provides around 12mcg/day (around 500iu a day).  Such a supplement may be particularly useful during the autumn and winter months.

For more interesting information about the benefits of vitamin D and sunlight for health please visit the SUNARC website, the information there is well presented and backed up by significant amounts of good evidence.

(1)Grant, WB.  2009. Does Vitamin D Reduce the Risk of Dementia?  Journal of Alzheimer's Disease 17:151-159.
(2)Hagenau T et al.  2008.  Global vitamin D levels in relation to age, gender, skin pigmentation and latitude: an ecologic meta-regression analysis.  Osteoporosis International May [E publication ahead of print]
(3) Finch S et at.  1998.  National Diet and Nutrition Survey of People aged 65 Years and Over.  London: H. M. Sationery Office.
(4) Gregory L et al.  2000.  National Diet and Nutrition Survey of People aged 4-18 years. Vol 1.  Report of the Diet and Nutrition Survey.  London:  The Stationery Office
(5) Henderson L et al.  2002.  National Diet and Nutrition Survey: Adults Aged 19-64 years.  Vol 1: Types and Quantities of Foods Consumed.  London: The Stationery Office
(6) Hypponen E & Power C.  2007.  Hypovitaminosis D in British adults age 45y: nationwide cohort study of dietary and lifestyle predictors.  Am J Clin Nutr.  85:860-888.

Written by Ani Kowal

What we eat can certainly have an impact on the way our brains function.  Previously I have written about the importance of a healthy diet for brain function and also the links between the Mediterranean style diet and the brain. 

In both of these posts I write about how important oily fish seem to be for the efficient functioning of the brain (mental function is often referred to as cognition).  Previously I have concentrated on the fact that oily fish provide omega 3 fatty acids which are vital for the structure and function of the brain.  However, oily fish also provides a dietary source of Vitamin D.  This is important, since food sources of vitamin D are limited.  Oily fish such as mackerel, salmon, sardines and trout are the primary food source.  Egg yolks contain some vitamin D and some foods are fortified with this ‘sunshine’ vitamin.  Our main source of vitamin D is the manufacture in the body via the exposure of our skin to sunlight.  Recently, however, there has been a lot of concern that UV exposure in the UK may be insufficient to keep vitamin D levels high enough for optimal for health with many individuals in the UK are falling short of recommended levels.  More can be read on the importance of vitamin D in previous blog posts.

A very recently published study (1) has found a link between vitamin D levels in the body and brain function (cognitive performance).  Previous studies have found that an inadequacy in vitamin D could be linked to problems with brain function but so far results have been inconsistent.  This study (1), which was conducted by University of Manchester scientists, was set up in order to examine the association between blood serum vitamin D levels and cognitive performance in middle-aged and older men.  3,133 Eurpoean men aged 40-79 years were included in the research.  Cognitive (brain) function was tested via a number of different validated tests.  Blood serum vitamin D levels were measured as was physical activity, functional performance and mood/depression.

Higher levels of vitamin D were significantly associated with better cognitive function as measured by one of the tests, the Digit Symbol Substitution test (DSST).  This test is an internationally-recognised test that assesses an individual's memory, recognition capabilities and speed of information processing.  Reduced cognitive function was most pronounced in individuals with the lowest vitamin D levels.  This research provides valuable information, however further research is warranted to determine whether health vitamin D levels, or vitamin D supplementation, can play a role in preserving cognitive function in older adults (1).

Although the study is only an association study it has some key strengths: it was based on a large population sample and took into account potential confounding influences, such as depression and levels of physical activity.   Interestingly the association between increased vitamin D and faster information processing was more significant in men aged over 60 years, although the biological reasons for this remain unclear and requires further investigation.

The positive effects vitamin D appears to have on the brain need to be explored further but certainly raise questions about its potential benefit for those with or susceptible to dementia.  Dr Susanna Sorensen, Head of Research at The Alzheimer’s Society made a comment (2) on the research via the charity website:

“One in three people over 65 will die with dementia making research into this area vital. This study, including over 3,000 men from a number of European locations, shows that maintaining vitamin D levels could play a role in reducing the decline of brain function. 

However, further research is needed to determine whether or not vitamin D can help preserve brain function in older people or reduce risk of dementia. As vitamin D is readily available to most people, through exposure to sunshine or eating oily fish, it will be interesting to see the results of future studies.

In the meantime, current evidence tells us that a healthy lifestyle, including a balanced diet and exercise, is the best way of reducing your risk of dementia.”

Alzheimer's Society is the UK's leading care and research charity for people with dementia and those who care for them.  There are 700,000 people with dementia in the UK with numbers set to rise to one million by 2025.  Alzheimer's Society is a membership organisation, which works to improve the quality of life of people affected by dementia in England, Wales and Northern Ireland.  Please visit their website for more information.  You may also like to read the two posts I mentioned at the start of this piece which are about brain function.

If you rarely get out into the sunlight you may wish to consider taking a vitamin D supplement which provides around 12mcg of the nutrient per day (around 500iu).  Vitamin D supplements may be particularly useful during the autumn and winter months and for individuals who have darker skins or who don’t go outside regularly.

(1) Lee DM et al.  2009.  Association between 25-hydroxyvitamin D levels and cognitive performance in middle-aged and older European men.  J Neurol Neurosurg Psychiatry. Published Online First: 21 May 2009. doi:10.1136/jnnp.2008.165720
(2)Alzheimer's Society comment on research into impact of vitamin D on brain performance
Published Wednesday 20th May 2009 in Research news http://www.alzheimers.org.uk/site/scripts/news_article.php?newsID=469

Written by Ani Kowal