On 15th October I wrote about the connection between B vitamins and healthy bones and I also mentioned how elevated homocysteine levels may be implicated in bone deterioration and heart disease.  Today I want to look at the link between elevated homocysteine levels, low vitamin B12 levels and cognitive (mental) decline.

To recap: Homocysteine is produced when the amino acid (the building blocks of protein) methionine is broken down in the body.  Normal levels of homocysteine are important to help build and maintain body tissues, however elevated concentrations in the blood can be harmful and have been associated with an increased risk of many disorders.  At normal levels homocystein can be converted in the body into a harmless substance called cystanthionine.  The conversion of homocysteine into this harmless substance depends upon various B vitamins  (B6, B12 and folic acid).  Having good levels of these B vitamins appears to be a very good way of preventing high homocysteine levels and low levels of B vitamins have been associated with raised homocysteine levels.

A new study (1) was recently published which showed that older adults who have vitamin B12 levels that are low, but still within the normal range, may exhibit a quicker rate of brain shrinkage (brain volume loss) as they age compared to those who have good levels.  The authors wanted to investigate the association between vitamin B12 status and brain volume loss in a population of adults aged 61-87 over a 5 year period.  The participants were free of cognitive impairment (they were free of dementia) at the start of the study.  Those with lower vitamin B12 levels at the start of the study experienced the greatest decrease in brain volume over the 5 year period.  This was only a small preliminary study involving 107 individuals, the authors suggest that low vitamin B12 status should be further investigated and that trials with vitamin B supplements would be useful.

A loss in brain volume has been linked to a faster rate of mental decline and progression to diseases such as Alzheimer’s disease and dementia.  Vitamin B12 is extremely important in order to keep nerve cells healthy.  The study mentioned above (1) suggests, but does not prove, that modifying vitamin B12 status could be important in protecting the brain and preventing cognitive decline.  The results of the study do suggest that it is important to keep our vitamin B12 levels higher than just the minimum.

A study last year (2) looked at the association between cognitive decline and vitamin B12.  The study included 1684 individuals who were followed for 10 years.  Mental state (cognition) was examined a minimum of 3 times over the 10 years as were serum vitamin B12 concentrations.  Analysis of the results found that reduced vitamin B12 status was associated to cognitive decline.  The investigators also found that a high homocysteine level was associated with a greater rate of cognitive decline.  Again the authors indicate the need for further studies and supplementation trials for the prevention of dementia.

A review (3) paper published this year discussed the importance of vitamin B12 for brain health throughout life from infancy to adulthood.  In childhood low vitamin B12 levels may be related to behavioural problems and in adults it seems to be related to social development, depression and cognitive problems.  It seems as though this nutrient really is vital throughout our lifespan. 

Many older adults in the UK have lowered vitamin B12 levels.  In the diet, B12 comes from meat, fish, dairy, other animal products, and fortified breakfast cereals. Strict vegetarians, who avoid meat, and vegans, who avoid all animal products, are also at risk of B12 deficiency.  Studies seem to suggest that anything in the stomach that affects the normal acidity and digestive processes, ranging from infections to acid reflux medications to aging, may also interfere with the absorption of vitamin B12. 

The vitamin B group work very well as a team and interact in many processess, if you decide to take a supplement it may well be worth considering a multi-B vitamin supplement rather than single B vitamin supplement, or a broad spectrum multi-nutrient supplement (I prefer food state supplements which appear to be more easily absorbed by the body).

(1) Vogiatzoglou A et al.  2008.  Vitamin B12 status and rate of brain volume loss in community-dwelling elderly.  Neurology.  71:826-832
(2)Clarke R et al.  2007.  Low vitamin B-12 status and risk of cognitive decline in older adults.  Am J Clin Nutr.  86:1384-1391
(3)Black MM.  2008.  Effects of vitamin B12 and folate deficiency on brain development in children.  Food Nutr Bull.  29:S126-131

Written by Ani Kowal

On the 22 October I mentioned the potential use of Vitamin D supplements for helping individuals suffering from the mood disorder SAD (seasonal affective disorder).  This year a number of papers have been published (1,2,3,4) which suggest that vitamin D could potentially be useful for the treatment of other mood disturbances and depressive episodes.

In 2007 a review paper was published (5) which suggested that vitamin D deficiency may play a role in depression and other mood and mental health disturbances, especially in the elderly where low vitamin D levels are commonly found.  The paper highlighted a number of trials that which showed that vitamin D supplementation appeared to be useful in the treatment of depression but expressed a need for further studies.

Vitamin D seems to be a hot topic this year and I have written about it a number of times in my blog posts.  Low vitamin D levels seem to be linked to cancer, heart disease, SAD, chronic fatigue syndrome, migraine headaches and various other diseases, not only bone conditions such as osteoporosis and osteoarthritis.  It is becoming glaringly obvious that this ‘sunshine vitamin’ is more important than we once thought. 

Two studies this year have linked low vitamin D status, as measured by low circulating blood levels of vitamin D, with depressive symptoms.  One study (1) was carried out in overweight and obese individuals and the other (3) in older adults (aged 65 – 95 years).  Both studies found that there was an association between depression status and severity with decreased serum (blood) vitamin D levels.  In the study with overweight/obese participants high-dose vitamin D supplementation led to significant improvements in depressive symptoms, compared to placebo, during the study.  The studies so not prove a causal relationship between low vitamin D and depression but they do add to the mounting evidence which suggests a very real link.  Further, larger studies will be needed to verify the information and investigate this exciting association further.

It is not currently known why vitamin D may be useful in treating mood disorders or why low levels may have a part to play in causing mood problems.  It may be that vitamin D has an effect on hormones linked to mood.  Studies are bound to unravel the mystery over the next few years!

A recent analysis(6) 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 (7,8,9,10).  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. 

Walking and exercise have also been linked to improved mood, so a lunchtime walk, in daylight, may bring added mood lifting benefits.  Only small amounts of vitamin D are found in food sources such as oily fish (mackerel, salmon and sardines) and eggs.  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.

You may also want to think about getting a daylight lamp for your work desk to help improve mood.  Some of these lamps produce light that the body can use for vitamin D production (check with the manufacturer of the lamp).

For more interesting information about the benefits of vitamin D and sunlight for health please visit the Sunlight Nutrition And Health Research Centre, the information there is well presented and backed up by significant amounts of good evidence.

(1)Jorde R et al.  2008.  Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial.  J Intern Med. Sep 10. [Epub ahead of print]
(2)Murphy PK & Wagner CL.  2008.  Vitamin D and mood disorders among women: an integrative review.  J Midwifery Womens Health.  53:440-446
(3)Hoogendijk WJ et al.  2008.  Depression is associated with decreased 25-hydroxyvitamin D and increased parathyroid hormone levels in older adults. Arch Gen Psychiatry. 65(5):508-12.
(4)Johnson MA et al.  2008.  Vitamin D deficiency and insufficiency in the Georgia Older Americans Nutrition Program.  J Nutr Elder.  27:29-46
(5)Berk M et al.  2007.  Vitamin D deficiency may play a role in depression.  Med Hypotheses.  69:1316-1319
(6)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]
(7) Finch S et at.  1998.  National Diet and Nutrition Survey of People aged 65 Years and Over.  London: H. M. Sationery Office.
(8) 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
(9) 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
(10) 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