Omega-3 vetzuren en groenten en fruit tegen dementie.*
Uit een Franse studie onder ruim 8.000 mensen van 65 jaar en ouder die 4 jaar lang werden gevolgd blijkt dat zowel voeding rijk aan
omega-3 vetzuren als voeding dagelijks met voldoende groenten en fruit de kans op
dementie met tot wel 30% kan verminderen. Voeding rijk aan
omega-6 vetzuren daarentegen doet de kans op dementie weer verhogen.
Fish, fruit and veggies may lower dementia risk
People who eat plenty of fruits, vegetables and fish may have a lower risk of developing dementia than those who are partial to steak and eggs, researchers reported.
In a study of more than 8,000 older adults, French researchers found that those whose diets were rich in omega-3 fatty acids had a lower risk of developing dementia over the next four years than those with diets low in omega-3.
Omega-3 fats are polyunsaturated fatty acids found largely in oily fish, like salmon and mackerel, as well as certain vegetable oils, including canola, flaxseed and walnut oils.
Conversely, the researchers found an elevated dementia risk among people with diets high in omega-6 fatty acids -- polyunsaturated fats found in meat, eggs and a variety of cooking oils, such as safflower, corn and soybean oils.
Fats were not the only dietary component that mattered, though, lead investigator Dr. Pascale Barberger-Gateau, of INSERM U593 and the University Victor Segalen, Bordeaux, and colleagues note. The researchers also found that people who ate fruits and vegetables everyday were 28 percent less likely to develop dementia than those who ate these foods less often.
"We showed that both fruits and vegetables, on the one hand, and fish consumption, on the other hand, had an independent protective effect (on) dementia risk," Barberger-Gateau explained.
What's more, the findings highlight the potential consequences of eating a lot of omega-6 fats without "counterbalancing" them with omega-3s. Research has long shown that the typical Western diet contains a far higher amount of omega-6 fat than the omega-3 variety.
The current findings, published in the journal Neurology, are based on 8,085 men and women older than 65 who were followed for four years. At the outset, participants were screened to rule out dementia, and completed detailed questionnaires on their diets, health and lifestyle habits.
While both fish intake and overall omega-3 intake, along with fruit and vegetable consumption, were generally linked to dementia risk, there was one exception. People who were genetically predisposed to Alzheimer's disease did not appear to benefit from omega-3 fats.
A particular variant of a gene called apolipoprotein E is linked to higher Alzheimer's risk; study participants who carried this variant did not show a reduced dementia risk from high fish intake. However, the researchers point out, the majority of the population does not carry this gene variant.
According to Barberger-Gateau, there's reason to believe that omega-3 fats, fruits and vegetables all directly influence dementia risk. Omega-3 fats are part of the outer membrane of brain cells, she noted, and they also have anti-inflammatory effects. Chronic low-level inflammation throughout the body is believed to contribute to many diseases, including dementia.
In contrast to omega-3s, omega-6 fats have been shown to promote inflammation.
As for fruits and vegetables, Barberger-Gateau said, they contain antioxidants -- like vitamin C, vitamin A precursors and substances called flavonoids -- that may help shield brain cells from damage.
"Our results give strong support to the general recommendations for a healthy diet," the researcher said -- which includes getting at least five servings of fruits and vegetables per day, eating fish at least once a week and choosing oils like canola, flaxseed and walnut.
The results cannot, however, speak to the issue of fish oil or antioxidant supplements, Barberger-Gateau stressed. These supplements have not yet been shown to offer any protection from dementia, she
said.
SOURCE: Neurology. (November 2007)
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