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.

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.

Source: Society of Chemical Industry

Related stories:

How sweet it is: 'Revolutionary' process points to sugar-fueled cars
Chemists are describing development of a “revolutionary” process for converting plant sugars into hydrogen, which could be used to cheaply and efficiently power vehicles equipped with hydrogen fuel cells without producing any pollutants.
Defining gene's role may lead to prevention of dangerous corn toxin
Discovery that a specific gene is integral to both fungal invasion of corn and development of a potentially deadly toxin in the kernels may lead to ways to control the pathogen and the poison.
US rush to produce corn-based ethanol will worsen 'dead zone' in Gulf of Mexico
The U.S. government’s rush to produce corn-based ethanol as a fuel alternative will worsen pollution in the Gulf of Mexico, increasing a “Dead Zone” that kills fish and aquatic life, according to University of British Columbia researcher Simon Donner.
When the chips are down -- soak them
Good news for chips lovers everywhere – new research in SCI’s Journal of the Science of Food and Agriculture shows that pre-soaking potatoes in water before frying can reduce levels of acrylamide.
Policies key as ethanol 'revolution' links agriculture, energy sectors
The recent boom in production of ethanol from corn grain has tightly linked the agriculture and energy sectors in an unprecedented fashion.
Carrot cake study on sugar in type 2 diabetes
Patients with type 2 diabetes are often advised to cut out sucrose (table sugar) all together. However, in recent years this traditional advice has been questioned by some researchers who suggest that moderate amounts of sugar can be safely consumed as part of the diet of patients with diabetes. Now a new study has been published that is consistent with this revised approach. It showed that patients who increased their daily sugar intake (in the form of carrot cake) but maintained a stable body weight, showed no adverse changes in their blood glucose.
Too much fructose could leave dieters sugar shocked
Here’s one tip for how to eat at the holidays: Don’t take your cues from Santa. The sugary cookies and fat-laden fruitcakes the mythical North Pole resident eats are a no-no. But you don’t have to go no-carb to stay fit at the holidays, either, University of Florida researchers say.
Waistline growth on high-carb diets linked to liver gene
Experts have been warning for years that foods loaded with high-fructose corn syrup and other processed carbohydrates are making us fatter. Now, a University of Wisconsin-Madison study has uncovered the genetic basis for why this is so.

News discussion:

General Science news