This week Public Health England (PHE) advised that everyone over the age of 4 needs vitamin D equivalent to an average intake of 10 micrograms a day. This is based on the conclusion of a Department of Health commissioned report by The Scientific Advisory Committee on Nutrition.
Vast amounts of research has gone into the role of vitamin D during the past few years with over 4000 studies in 2015 alone. It has been known for some time that vitamin D is essential for absorption of calcium and phosphorus, therefore bone and muscle health. More recently a link between vitamin D and mental health has been established. Also a link with the immune and nervous systems. Very recently it has been discovered that every cell in the body, including the brain has a vitamin D receptor and that vitamin D can up regulate and down regulate genes, what this means for human health is not yet known but clearly shows that vitamin D plays a larger role than previously thought. There are few studies looking at vitamin D and Parkinson’s however in southeastern United States, people with Parkinson’s have lower vitamin D blood levels than those without Parkinson’s and in Finland higher vitamin D levels have been associated with reduced risk of developing Parkinson’s by two-thirds. Further consideration for people with Parkinson’s is the impact of vitamin D deficiency, the symptoms of which include muscle pain and weakness and depression. Vitamin D is essential to calcium absorption and for people that have taken dairy out of their diet, due to the association with lower uric acid levels, calcium intake may be low. Vitamin D deficiency will exacerbate calcium deficiency.
Further it is now known that Vitamin D is a powerful antioxidant; antioxidants lower the risk and slow the progression of Parkinson’s. In spring and summer, the majority of the population get enough vitamin D through sunlight (D3) and a healthy, balanced diet. However due to the angle of the sun from October to March in the UK, vitamin D can not be synthesised and everyone is reliant on dietary sources. It is extremely difficult to meet the 10 micrograms recommendation from food alone, therefore PHE has advised that people should take a daily supplement containing 10 micrograms of vitamin D over winter. People whose skin has little or no exposure to the sun, such as those in institutions or who always cover their skin when outside, are advised to take a supplement throughout the year. Ethnic minority groups with dark skin, from African, Afro-Caribbean and South Asian backgrounds, may not synthesise enough vitamin D from sunlight in the summer and are also advised to take a supplement all year round.
Good food sources of vitamin D are oily fish, eggs and fortified foods such as cereal. The only vegan source of vitamin D is mushrooms, however this is D2 which is a less efficacious form. Future studies will look at how much more D2 needs to be consumed to match D3. Over the longer term we are likely to see more foods fortified with vitamin D. However until then as advised by PHE supplementation is necessary. Supplements are available in traditional tablet form and as a mouth spray. Both delivery methods have been found to be equally effective. However mouth sprays are absorbed through blood capillaries therefore bypassing the gut so may be more suitable for people with malabsorption conditions. Vitamin D is set to remain a hot topic of research over the coming years increasing knowledge on its role in human health, dosages required, delivery mechanisms and hopefully in Parkinson’s.