Vegetables are alive with bacteria

Posted on Tue, 27 Oct 15

Plants are bustling with billions of bacteria, and while historically we thought of these microbes being linked to food poisoning; that view is changing and they may actually be good for you.

Diets rich in plant foods are undoubtedly associated with robust health benefits, but a neglected nutritional property of traditional, plant-rich diets is that they are teeming with microsocopic bacteria.

Recent analysis has revealed that all plants harbor their own “plant microbiome,” which raises the possibility that these bacteria may have important health effects. Exposure to bacteria through more traditional or rural lifestyles, time spent in nature, fermented foods and probiotics has received a lot of attention lately because of links to reductions in diseases as diverse as autoimmunity and psychiatric illness, but the effect of exposure to plant micorbial communities has not been explored yet, simply because we did not know they were there.

In the British Journal of Nutrition, Leena von Hertzen from Helsinki University Central Hospital draws attention to this recently discovered area pointing out “every plant studied has been found to harbor endophytic bacteria, the ‘plant microbiota.’”

“Spoiled vegetables and contaminated berries have been reported as a source of food-borne infections, but hardly any attention has been devoted to the ‘friendly’ plant bacteria, which may play a pivotal role as an everyday source of microbial exposure, particularly in urban environments,” she says.

“The endophytic communities are diverse and abundant. For example, the number of bacteria within surface-sterilized salad leaves was up to 490 million in a typical serving of 85 g salad. The total number of bacteria (endo- and ectophytes together) was about 100-fold more, 4.7 billion bacteria, that are consumed in a salad serving.”

It is possible that prolonged food storage, low intake of fruits and vegetables, and sterilization - all of which can reduce exposure to plant microbes in modern diets - could be impacting our health in ways we do not yet appreciate.

Reference:

von Hertzen L. Plant microbiota: implications for human health. Br J Nutr. 2015 Nov;114(9):1531-2.