COLOURS of FRUITS and VEGETABLES
and 10-YEAR INCIDENCE of STROKE*
This is the title of a paper published in Stroke - Journal of the American Heart Association, in September 2011, by Dutch scientists.
Background and Purpose
Earlier studies have already shown a strong association between a high consumption of fruits and vegetables and a lower risk of stroke. This paper presents the first research to investigate links between specific fruit and vegetable colour groups and stroke.
The authors state that “the colour of the edible portion of fruits and vegetables reflect the presence of pigmented bioactive compounds (eg carotenoids, anthocyanidins, and flavonoids).” However which fruit and vegetable colour groups contribute most to the beneficial association of fruits and vegetables with stroke incidence was unknown. Hence this study by the Dutch research team led by Linda M. Oude Griep.
That the different coloured fruits and vegetables have different phytochemicals (plant chemicals) is well known. In my January 2010 newsletter Phytochemicals, the section Phytochemicals and Colour describes this in detail.
The study was a prospective, population-based cohort study and included 20,069 men and women aged 20 to 65 years (average 41 years) who were free from cardiovascular disease at baseline. These participants completed “a validated, 178-item food frequency questionnaire. Hazard ratios (HR) were calculated for stroke incidence ….adjusting for age, sex, lifestyle, and dietary factors.”
During 10 years of follow-up, 233 incident cases of stroke were documented.
The questionnaire documented consumption of fruits and vegetables that were classified into four colour groups:
· Green - including dark leafy vegetables, cabbages and lettuces
· Orange/yellow - mostly citrus fruits
· Red/purple - such as beetroot (beets)
· White - apples and pears (55%), bananas, cauliflower, chicory, cucumber and onion.
[Note that the ‘colour’ refers to the flesh of the fruit or vegetable: for example, a red apple is a white fruit, the skin only is red, the rest of it is white.]
The median consumption of these four colour groups of fruits and vegetables was 62 g/d (grams per day) green, 87 g/d orange/yellow, 57 g/d red/purple, and 118 g/d white.
“Green, orange/yellow, and red/purple fruits and vegetables were not related to the incidence of stroke. Higher intake of white fruits and vegetables was inversely associated with incident stroke.”
The risk of stroke incidence was 52% lower for people with a high intake of white fruits and vegetables compared to people with a low intake.
“Each 25-g/d [grams per day] increase in white fruit and vegetable consumption was associated with a 9% lower risk of stroke.” An average apple is about 100-150 grams.
Conclusion of the Authors
“High intake of white fruits and vegetables may protect against stroke.”
If there was a prescription drug, without side effects of any kind, that could slash the risk of stroke by 52%, (and there isn’t one), it would be a best seller, even eclipsing the sale of statin drugs!
There is a large volume of published evidence (in peer reviewed journals) showing that natural substances in food can help prevent and heal a wide variety of illnesses. This recent study shows that eating an abundance of certain foods (white fruits and vegetables) can help protect against stroke.
This does not mean that other fruits and vegetable colour groups aren’t worth eating. To the contrary. This present study only looks at one disease state, namely stroke. To give but one example of the protective effect of other coloured fruits and vegetables on disease: red fruits and vegetables are high in lycopene, phytoene, phytofluene and vitamin E, where lycopene, in particular, has been well documented to be protective against prostate disease.
It is also a possibility that the observed reduction in stroke might further be due to a generally healthier lifestyle of individuals consuming a diet rich in fruits and vegetables.
*Copyright 2012: The Huntly Centre.
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