A high intake of monounsaturated and polyunsaturated fatty acids could lower the risk of developing Parkinson's disease, according to researchers in the Netherlands.
Both types of unsaturated fatty acids are contained within neuronal cell membranes and are known to have neuroprotective, antioxidant, and anti-inflammatory properties.
The researchers involved in the new study, published in Neurology (2005;64:2040-2045), wanted to build on this knowledge by determining whether a high intake of unsaturated fatty acids might be associated with a lower risk of Parkinson's disease.
Monounsaturated (MUFAs) fatty acids have been shown to help lower LDL (bad) cholesterol when substituted for saturated fat. Sources of MUFAs include olive, canola oils, avocados, peanuts, nuts and seeds.
One of the main forms of polyunsaturated fatty acids (PUFAs) is omega-3, commonly derived from fish, which have been shown to deliver considerable benefits for cardiovascular health and cognitive function. Omega-6 is also essential for human health, found in grains, most plant-based oils, poultry, and eggs.
However the modern diet is more heavily weighted towards omega-6 consumption than omega-3, an imbalance that has led to the growing popularity of the latter in fortified and functional foods and in supplement form.
The new study may give further weight to arguments in favor of the Mediterranean diet, which typically consists of foods rich in both MUFAs and PUFAs since it is based as it is on olive oil, nuts, fresh fish, fruits and vegetables. Three separate studies published this year have highlighted the heart health benefits of this diet, in lowering cholesterol levels, lowering the risk factors for heart disease and boosting longevity.
The new prospective population-based cohort study involved 5,289 people aged 55 or over, all of whom were free of dementia and Parkinson's disease at baseline.
At the start of the trial the participants underwent complete dietary assessment, and the incidence of Parkinson's disease was assessed through repeated in-person examination and continuous monitoring by computer linkage to medical records.
The mean duration of the study was six years, during which time 51 patients were diagnosed with Parkinson's. Higher intakes of total fat, MUFAs, and PUFAs were "significantly associated" with a lower risk of developing the disease, but no associations were found for dietary saturated fat, cholesterol, or trans-fat.
"These findings suggest that high intake of unsaturated fatty acids might protect against Parkinson's disease," concluded the researchers.
Parkinson's disease is a progressive neurological disorder that affects around 6.3 million people worldwide. One in ten cases are diagnosed before the age of 50.
The cause is not understood but it is thought to result from the combined effects of factors including aging, genetic predisposition, and environmental exposures. Symptoms include tremors, stiffness, slow movement and poor coordination and balance.
A study published in the Archives of Neurology (59, pp 1541-1550) in 2002 linking coenzyme-Q10 to a slowing of the progressive disability caused by Parkinson's is thought to have been at least partly responsible for a surge in consumer demand for CoQ10, usually sourced from Japan, in the past three years. Prices are high, however, and supply is short, so the new research may present a viable alternative method of prevention.
A meta-analysis published in this month's issue of the Lancet Neurology (issue 4, pp362-5) underlines evidence that diets rich in vitamin E could also protect against the development of Parkinson's disease.