Potatoes Lower Blood Lymphocyte Counts - in Pigs

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Spuds that like you -- in your summer salad

It has long been known that eating potatoes is good for bowel

health, but new research suggests that they may also have a

beneficial effect on the whole immune system. Especially if eaten

cold or in a potato salad, Anne Pichon reports in Chemistry &

Industry, the magazine of the SCI.

Spanish researchers found that growing pigs fed large quantities of

raw potato starch (RPS) had a healthier bowel. Not a surprise, but

they also found that RPS pigs had decreased levels of white blood

cells, such as leucocytes and lymphocytes in their blood. White

blood cells are produced as a result of inflammation or disease,

generally when the body is challenged.

The general down-regulation of leucocytes observed by the Spanish

researchers suggests an overall beneficial effect, a generally more

healthy body, according to immunology expert Lena Ohman at the

Department of Internal Medicine, Göteborg University, Sweden. A

reduction in leucocyte levels of about 15% was observed in the RPS

pigs. Lower lymphocyte levels are also indicative of reduced levels

of inflammation, but according to Ohman, the observed reduction in

both lymphocyte density and lymphocyte apoptosis by the Spanish

researchers is surprising.

Pigs were fed RPS over 14 weeks in what is the longest study of it

kind on the effect of starch on bowel health (Journal of the Science

of Food and Agriculture doi:10.1002/jsfa.2835). Study leader José

Francisco Pérez at the Universitat Autònoma de Barcelona, Spain,

said: `The use of raw potato starch in this experiment is designed

to simulate the effects of a diet high in resistant starch' says

Pérez.

Humans do not eat raw potatoes, but they do eat a lot of foods that

contain resistant starch, such as cold boiled potatoes, legumes,

grains, green bananas, pasta and cereals About 10% of the starch

eaten by human is resistant starch - starch that is not digested in

the small intestine and so is shunted into the large intestine where

it ferments.

Starch consumption is thought to reduce the risk of large bowel

cancer and may also have an effect on irritable bowel syndrome

(IBS). Ohman's team previously found that the overall lymphocyte

levels do not vary for IBS patients, but that lymphocytes are

transferred from the peripheral blood to the gut, which support the

hypothesis of IBS being at least partially an inflammatory disorder.

She says the decrease in lymphocytes observed by the Spanish is

therefore interesting, and a diet of resistant starch may be worth

trying in IBS patients.

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