Parkinson’s disease is a brain condition where cells that produce a neurotransmitter called dopamine are lost in a particular area of our brain. Once 80% of these cells are lost those symptoms that we associate with Parkinson’s disease such as movement disorder and tremor become more apparent.
It’s also a common disorder affecting 2% of those over the age of 65 and 4-5% of those aged 85 years and older.

What hasn’t been known though, is what causes these special brain cells to die. Treatment for Parkinson’s has been targeted at replacing the dopamine that the brain can no longer adequately produce, but this does not address what has caused the loss of these brain cells in the first place.

Researchers have now discovered that a particular brain toxin, which occurs naturally in the brain, may be the missing link.

The brain toxin concerned is called DOPAL. It causes another brain protein, found throughout the brain, called alpha-synuclein, to form clumps. This clumping leads to more DOPAL being produced and this is then linked to causing dopamine producing cells to die.

Hopefully this will provide another small piece in the giant neuroscience jigsaw to help us understand better what causes Parkinson’s disease.

Ref:
W. Michael Panneton, V. B. Kumar, Qi Gan, William J. Burke, James E. Galvin. The Neurotoxicity of DOPAL: Behavioral and Stereological Evidence for Its Role in Parkinson Disease Pathogenesis. PLoS ONE, 2010; 5 (12): e15251 DOI: 10.1371/journal.pone.0015251

Berries are loaded with powerful antioxidants and blueberries in particular have exceptionally high levels of flavonoids. The deep blue colour of blueberries comes from the anthocyanin they contain and it is this sub-group of flavonoids, which have been found in other research to be beneficial in terms of helping us to maintain our memory and cognitive function.

Enjoying blueberries and the other deeply pigmented red berries and stone fruit has been recommended for a while, as being a useful to help protect us against dementia.
New research from Harvard now indicates that regularly eating berries may also lower your relative risk of developing Parkinson’s disease.

Parkinson’s disease is a neurodegenerative disease primarily affecting motor function but is also associated with a 30% incidence of dementia.

In this study, the researchers used a dietary questionnaire for 49,281 men and 80,336 women. They then analysed the association between amount of flavonoid intake from food and the risk of developing Parkinson’s disease.
They also analysed the consumption of five major food sources known to be high in flavonoid content i.e. berries, apples, red wine, tea, oranges and orange juice. The participants were followed over 20 to 22 years.

What were the findings?

In the male group it was found that those in the top 20% tier of flavonoid consumption were 40% less likely to develop Parkinson’s than those in the bottom 20% tier of consumption.

Interestingly in the ladies group, no such relationship between flavonoid consumption and risk of Parkinson’s was demonstrated.

However, in examining the effect of the different subgroup of flavonoids, it was found that regular consumption of anthocyanin from berries was associated with a lower risk of Parkinson’s disease in both men and women.

The message: eat more berries

This is the first human study to look at the link of flavonoids, (especially anthocyanin) in food and the risk of developing Parkinson’s disease. The findings suggest that men and women who regularly eat berries may have a lower risk of developing Parkinson’s disease. It also appears that men can to continue to further reduce their risk by eating a greater proportion of other flavonoid rich foods in general, including apples and oranges, tea, red wine (in moderation) and chocolate.

Ref:
Xiang Gao, MD, PhD Harvard School of Public health. American Academy of Neurology (2011, Feb17)

A little ray of sunshine for Parkinson’s disease may lie with Vitamin D.

Vitamin D is the vitamin we obtain through the action of ultraviolet light on our skin. Most of the vitamin D produced is then bound in the blood and only a tiny fraction remains free and able to bind to specific vitamin D receptors now known to be located in a number of target organs in the body including the brain.

Not only that, but the area of the brain with the highest density of Vitamin D receptors is in the Substantia Nigra. This is where highly specialized cells produce Dopamine, the brain neurotransmitter vital for regulating our mood, concentration, motivation and voluntary movement.
In Parkinson’s disease many of these highly specialized cells die and the loss of Dopamine manifests itself in the form of tremor, rigidity of movement, slowness of gait and cognitive decline. Plus, thirty percent of people with Parkinson’s disease develop dementia.
It is the second most common neurodegenerative disease in Australia and remains one of the most poorly understood.

So where does Vitamin D fit in with Parkinson’s disease?

The answer to that is not yet certain, but a recently published study has linked having a higher level of Vitamin D with up to a 65% reduction in the risk of developing Parkinson’s.

These results were in a long prospective study by Paul Knekt in Finland. He showed that in a group of 3173 people aged 50 to 79, followed up over a 29 year period, those with a higher level of Vitamin D had a 65% lower risk of developing Parkinson’s compared to those with the lowest levels.

However it should be noted that all of the subjects in this study actually had lower levels of vitamin D than is recommended. This may reflect the fact that Finland is not a country associated with a lot of sun exposure for its residents. So the suggestion is that having a lower level of Vitamin D may be a predisposing factor to an increased risk of Parkinson’s disease. There is no suggestion that having a low level is in fact a cause. The study remains a starting point to determine whether giving Vitamin D as a supplement would be useful.

One of the problems recognized is that Vitamin D deficiency is widespread, even in a sunny country such as Australia. It has been reported that half to two thirds of teenagers and adults in the US have lower than desirable levels. Because it is very difficult to get sufficient Vitamin D through our diet, having adequate sun exposure is essential to help us achieve and maintain a healthy level.

How much time do we need in the sun?

Five to fifteen minutes of sunlight exposure to the face and upper arms, four to six times a week is thought to be sufficient to prevent deficiency.
Those particularly at risk of deficiency here in Australia include the elderly living in residential care and dark skinned women, especially those who are veiled. The use of sunscreen (essential to protect us from skin cancer) unfortunately prevents the synthesis of Vitamin D in the skin. Application of Factor 8 will prevent up to 95% of Vit D conversion, so a short exposure without sunscreen is recommended and outside the high-risk times of 10 am to 3 pm.

Can we get Vitamin D from our food?

We can derive a limited amount of Vitamin D from food sources. However in cases of deficiency taking a supplement would be recommended.

Vitamin D2 can be found in:

Fatty fish such as mackerel, salmon and herring
Fortified margarines
Cod liver oil
Liver
Eggs

The role of Vitamin D in the brain

The association of Vitamin D and Parkinson’s disease is intriguing and as yet not fully explained. It is believed that Vitamin D acts as a hormone rather than a vitamin, in addition to its role in bone metabolism.

Current thinking is that it may exert a neuroprotective effect through its antioxidant properties, calcium regulation of nerve cells, enhanced nerve conduction, detoxification and immunomodulation.

A UK study looked at Vitamin D levels of a group of 858 Italian men and women over the age of 65 years. Of those with dementia, 50% were vitamin D deficient. Moreover, those with the greatest deficiency had a 60% increased risk of suffering cognitive decline over the 6-year follow up period.

The role of Vitamin D relating to Alzheimer’s disease was looked at in a 2008 study where 100 people with Parkinson’s disease were compared to 100 subjects with Alzheimer’s disease and 100 healthy controls. Here the fraction of patients with the lowest levels of Vitamin D was most marked in the Parkinson’s group (23%) compared to the Alzheimer’s group (16%) and healthy group (10%) indicating support for the notion that Vitamin D plays a role in affording some neuroprotection.

Meanwhile it remains prudent to ensure that we obtain adequate sun exposure to keep our Vitamin D levels up. So go on, it’s time to enjoy some time in the sun.

References:
Emory University (2008, October 17). Lack Of Vitamin D Linked To Parkinson’s Disease.
Archives of Neurology [2010] 67 (7) : 808-811 (Knekt P, Kilkkinen A, Rissanen H, Marniemi J, Sääksjärvi K, Heliövaara M.)