Diet rich in vegetables, legumes and nuts could lower early symptoms linked with Parkinson's disease: Study
Parkinson's disease is a movement disorder which causes tremors, stiffness and issues with walking, balance and coordination
People consuming a diet rich in vegetables, nuts, legumes are less likely to encounter some of the early symptoms associated with a devastating movement disorder called Parkinson's disease, a new study found. The signs, which include depression and constipation and sleep disorders, could appear 10 years before the disease strikes.
Parkinson's disease causes tremors, stiffness, and issues with walking, balance, and coordination. The condition affects a region in the brain that controls movements. It is common among people aged over 60. However, about 5 to 10% of adults develop the condition before the age of 50.
The study, however, does not prove that a healthy diet cuts the risk of early symptoms of Parkinson's disease -- but only shows a link. "It certainly provides yet another reason for getting more vegetables, nuts, and legumes in your diet," Dr. Samantha Molsberry, from Harvard University, says. "More research is needed to determine whether eating a healthy diet could delay or even prevent the development of Parkinson's disease among people who have these preceding symptoms already."
To confirm the link, scientists will have to run an experimental study that randomly assigns individuals to follow a specific diet pattern. They will then have to follow them for longer periods to study the effects. Such experiments are expensive, Molsberry tells MEA WorldWide (MEAWW).
When Molsberry and her colleagues previously investigated how diet patterns influence Parkinson's disease, they found that people who practiced healthy eating had a lower risk for movement disorder. The findings add weight to a previous study that found a connection between adherence to the Mediterranean diet and lower odds of the conditions, she notes.
The study followed 47,679 middle-aged adults, starting from the 1980s. Every four years, the team questioned participants on the degree of adherence to diets. In 2012, they were asked if they experienced two early symptoms: constipation and a sleep disorder, where people act out their dreams.
Then, from 2014 to 2015, Molsberry and her colleagues checked if 17,400 participants experienced five signs that precede the disease: loss of sense of smell, impaired color vision, excessive daytime sleepiness, body pain, and depression.
The researchers evaluated either the alternate Mediterranean diet -- which includes vegetables, fruits, legumes, nuts, fish, whole grains but not dairy, or the Alternative Healthy Eating Index. The latter is designed to cut the risk of chronic diseases such as cardiovascular diseases, diabetes, heart failure, some forms of cancer.
They compared the prevalence of early signs among the two groups -- those with high and low adherence to the diet. Their analysis showed that people sticking to the Mediterranean diet to a higher degree were 33% less likely to face three or more early signs of Parkinson's disease. Alternative Healthy Eating Index also showed similar results, the researchers said.
Take constipation, for instance, it affected 37% of women with lower adherence to the diets, compared to 32% who largely stuck to healthy eating. Similarly, it was reported in 22% of men with lower adherence and 12% in the other group.
Dr. Molsberry highlighted a few limitations in their study. Some of the participants, she says, may have had early symptoms before the study. This could have influenced them to opt for healthy eating. "Constipation would tend to cause increased consumption of fruits and vegetables because of their high fiber content," she explains, adding that it could lead to higher adherence to the two diet patterns.
However, experiencing one or more of these features does not necessarily indicate that people will eventually develop Parkinson's disease, she notes. Further, "because our cohort [group] participants are primarily white individuals with higher socioeconomic status living in the US, our results may not be directly applicable to other populations with different characteristics," she adds.
What explains the link between healthy eating and lower Parkinson's risk?
Dr. Molsberry believes many of these symptoms have some bearing on the development of early-stage Parkinson's disease. "The exact mechanisms by which diet patterns could influence the risk of Parkinson's disease remain unknown," she adds.
However, the gut and nerve cells supporting the digestive tract may be involved in the development of the disease, she says. Other studies have proposed a link between the aggregation of a protein called α-synuclein in the gut and the condition. One study suggested that targeting the protein clumps could slow down the disease.
There are some theories to explain the link. One of them suggests that a healthy diet could be preventing the break down of the nervous system or by protecting against the aggregation of the protein in the gut. "It is also possible that, because adherence to healthy dietary patterns is associated with consumption of foods high in antioxidants and anti-inflammatory compounds, diet pattern may instead, reduce risk of Parkinson's disease or prodromal [early signs of] Parkinson's disease features by preventing oxidative stress and neuroinflammation," she adds.
The study is published in Neurology.