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Fear of Alzheimer's disease is rampant. But there is berry good evidence that a particular food significantly decreases the risk of Alzheimer's disease and other forms of dementia.
Dementia and other neurological disorders such as Alzheimer's and Parkinson's disease have become increasingly worrisome over the past few decades for many of us. This is especially the case among those of us in industrialized countries – those regions that maintain the 'perfect storm' of rampant toxic pollutants and the Western diet.
Increasingly, research is finding that instead of dementia-related diseases being the result of just bad luck or genetics - as many will have it - what we do and in particular, what we eat, will effect our risk of Alzheimer's and other dementias dramatically. In other words, what we put into our mouths – combined with what pollutants we are exposed to – relate directly to the health of our brains later in life.
Berry good evidence
A team of international researchers, which included scientists from the U.S. National Institutes of Health, Washington State University, India's Annamalai University and Oman's Sultan Qaboos University College of Medicine and Health Sciences, investigated the evidence relating berries and Alzheimer's disease and other forms of dementia.
They found all the berries, in fact, significantly reduced the risk of various forms of dementia.
The researchers found that strawberries – containing caffeic acid, ellagic acid, anthocyanins, catechins and gallic acid – decreased cyclooxidation and increased neurological health.
They found that bilberries and their anthocyanin, flavonol, lutein and zeaxanthin content provides antioxidant protection against damage to arteries and neurons.
They found clear evidence that blackcurrants, with their high content of polyphenols, provide protection against the formation of the beta-amyloid fibrils that have been found in the brains of dementia-ridden folks.
They also found that blackberries also provide polyphenols together with other antioxidants that reduce oxidation and increase glutathione levels, helping detox the blood and liver.
And blueberries' flavanols, anthocyanins and cinnamate content were found to be associated with increased memory and learning, as well as reduced radical oxidation species that harm brain cells.
Fruit in the diet reduces dementia
The evidence is clear that berries - and fruit in general - decrease the risk of dementia. A study published last year from China's Tianjin Medical University investigated 1,324 elderly persons from three regions. The researchers found that the incidence of Alzheimer's, vascular dementia and other forms of dementia was increased over five times (that's over 500%) among those who lacked fruit in their diets.
Fruits and veggies proven to decrease dementia risk
Another study, of 2,235 men between 45 and 60 years old from the UK's Cardiff University and the University of South Wales, found that higher fruit and vegetable intake significantly decreased the risk of dementia. They also found that regular exercise and low alcohol intake reduced the risk of all types of dementia.
Diets with greater content of fruits and veggies also proven to decrease dementia risk
As I have written about before, the evidence is clear that a diet that contains more plant-based foods in general has been shown to reduce dementia risk. This has been shown in a number of studies showing that the Mediterranean diet – a diet notably higher in plant-based foods – decreases the risk of Alzheimer's disease.
This was evidenced by a large review from researchers from the Mayo Clinic in Rochester, New York. The scientists conducted a large systematic meta-study on the evidence. They found five studies that met their strict quality criteria.
These five studies were from France, Australia and the U.S. Combined they included 7,537 human subjects, who ranged from 62 years old to 80 years old.
The test subjects were followed for between two and eight years among the studies.
The results of the meta-analysis was that those whose diets more correlated with the Mediterranean diet – meaning more plant-based foods and healthy fats – had a 33% reduced risk of Alzheimer's disease.
The antioxidant denominator
While certainly fats are an essential element – because saturated fats are more easily oxidized and thus add to ones oxidative stress potential – the higher levels of antioxidants provided by the increased amount of fruits and veggies. This was underscored in the discussion portion of the Mayo Clinic researchers' paper:
"Higher adherence to Mediterranean diet has been shown to be associated with low level of C-reactive protein and lower interleukin levels. Therefore a possible underlying mechanism for the neuroprotective effects of the Mediterranean diet could be due to its vascular properties and its ability to reduce inflammation, and oxidative stress, which are also associated with the pathophysiology of the degenerative disease."
Indeed, the Mediterranean diet and in general, diets higher in fruits and vegetables have been found to reduce inflammation and oxidative stress particularly because they contain more antioxidants: These foods neutralize the oxidation that takes place among the body's fats and toxins – becoming what are called reactive oxidative species or ROS as mentioned.
And as a considerable amount of dementia research has illustrated, the oxidative stress caused by reactive oxidative species is directly related to the neuron damage and amyloid fibrils associated with Alzheimer's disease.
Back to the berries
This returns us to our berry discussion because guess what: Berries contain some of the highest levels of antioxidants among foods. And antioxidants are called "antioxidant" because they specifically neutralize reactive oxidative species.
For example, according to research from USDA Agricultural Research Service scientists, berries hold six of the positions among the top twelve common foods in the U.S. in terms of their antioxidant potential.
Small red beans holds the top spot, at 13,727 antioxidant capacity per serving size (in units of micromoles of Trolox equivalents) but wild blueberries rank number two and commercial blueberries rank number five with 13,427 and 9,019, respectively.
Meanwhile, cranberries rank number six, blackberries rank number eight, raspberries rank number ten and strawberries rank number eleven of the greatest antioxidant foods among common U.S. foods.
This means that if our diet includes good portions of berries every day, we will be guaranteed to have some of the highest levels of antioxidants available.
By the way, rounding out the top twelve most antioxidant foods - besides the small red beans at the number one spot - we find red kidney beans at the number three spot, pinto beans at the number four spot, artichoke hearts at the number seven spot, prunes at the number nine spot and red delicious apples at the number twelve position. So include these other plant-based foods with your berries and you are maximizing your body's antioxidant potential - and reducing your risk of Alzheimer's disease and other forms of dementia.
Subash S, Essa MM, Al-Adawi S, Memon MA, Manivasagam T, Akbar M. Neuroprotective effects of berry fruits on neurodegenerative diseases. Neural Regen Res. 2014 Aug 15;9(16):1557-66. doi: 10.4103/1673-5374.139483.
Wei CJ, Cheng Y, Zhang Y, Sun F, Zhang WS, Zhang MY. Risk factors for dementia in highly educated elderly people in Tianjin, China. Clin Neurol Neurosurg. 2014 Jul;122:4-8. doi: 10.1016/j.clineuro.2014.04.004.
Elwood P, Galante J, Pickering J, Palmer S, Bayer A, Ben-Shlomo Y, Longley M, Gallacher J. Healthy lifestyles reduce the incidence of chronic diseases and dementia: evidence from the Caerphilly cohort study. PLoS One. 2013 Dec 9;8(12):e81877.
Wu X, Beecher GR, Holden JM, Haytowitz DB, Gebhardt SE, Prior RL. Lipophilic and hydrophilic antioxidant capacities of common foods in the United States. J Agric Food Chem. 2004 Jun 16;52(12):4026-37.