Vitamin D is important at every age. Low levels have been associated to heart disease, stroke, high blood pressure, and more severe asthma to name but a few conditions. In people over the age of about 65 having sufficient vitamin D levels in the body is really important to protect against fractures. Many individuals in the UK have insufficient levels of vitamin D which is worrying for a number of health reasons. A new piece of research (1) has linked insufficient vitamin D levels in older individuals with depression and poor mood. Low vitamin D levels are particularly prevalent in older people so the research is particularly relevant to this age group.
I have written about vitamin D being linked to poor mood as well as SAD (seasonal affective disorder) and brain function in the past and this research (1) adds to the accumulating evidence for the importance of vitamin D for good mental health.
The researchers of this current study (1) examined the relationship between blood serum vitamin D levels and depressive symptoms in a group of over 500 women and 400 men aged 65 and older who were followed for 6 years. At the start of the study vitamin D and depressive symptoms were assessed, these were then measured again after 3 years and then again after 6 years. A special scale, known as the Center for Epidemiological Studies-Depression Scale (CES-D), was used to assess depression and depressed mood was defined as CES-D of 16 or higher.
The results(1) showed that women with vitamin D levels less than 50 nmol/liter compared with those with higher levels experienced increases in depression scores after 3 and 6 years. Women with low vitamin D, who were not depressed at the start of the study, also had significantly higher risk of developing depressive mood over the follow-up, in fact they were twice as likely to become depressed over the following 6 years compared to women with sufficient vitamin D levels. Men with vitamin D levels below 50 nmol/litre compared with those with higher levels also experienced increases in depression scores but the results were not significant. Men with low Vitamin D also tended to have a higher risk of developing depressed mood over the 6 year period.
The authors conclude (1) “Our findings suggest that hypovitaminosis D [low vitamin D levels] is a risk factor for the development of depressive symptoms in older persons. The strength of the prospective association is higher in women than in men. Understanding the potential causal pathway between Vit- D deficiency and depression requires further research”
The study does not prove that low vitamin D levels cause depression but the association is interesting when added to the previous evidence that I mentioned at the start of the post. It is interesting to note that at the start of the study around 75% of the women and 50% of the men had vitamin D levels which were below 50nmol/litre, a level which is beginning to be recognised as insufficient. I think that many UK individuals would find their vitamin D levels were below 50nmol/litre if they were tested by their doctors. The authors suggest that preventing vitamin D deficiency in the elderly may become a future a strategy to prevent the development of depressive mood and that normalisation of vitamin D levels may be part of any depression treatment plans in older patients in the future. More evidence and larger trials are currently needed.
As I have said in all of my posts on vitamin D if you rarely get out into the sunlight you may wish to consider taking a vitamin D supplement. Only small amounts of vitamin D are found in food sources such as oily fish (mackerel, salmon and sardines) and egg yolks. 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. For most people over 18 a supplement containing up to 2000 iu/day can be considered. However, you may wish to get your levels tested at the doctors prior to commencing supplementation, vitamin D is a fat soluble vitamin and it is possible to take too much. When looking for vitamin D supplements two forms are generally available. Cholecalciferol, known as vitamin D3, and ergocalciferol or vitamin D2. Cholecalciferol is generally taken to be the more potent, easily absorbed and preferred form of vitamin D
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(1) Milaneschi Y et al. 2010. Serum 25-Hydroxyvitamin D and Depressive Symptoms in Older Women and Men. Journal of Clinical Endocrinology & Metabolism , published online on May 5, 2010 doi:10.1210/jc.2010-0347
Written by Ani Kowal
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