Potatoes for diabetics

Thursday, February 16, 2012

by SUSAN MANN

Ontario’s potato industry is becoming more involved in the uptake of new varieties through Agriculture and Agri-Food Canada’s process to funnel new releases to the marketplace through its Accelerated Release program.

Vanessa Currie, University of Guelph research technician with the plant agriculture department, says that increased involvement indicates the success and importance of the program.

She doesn’t know yet how many provincial growers will sign up this year to test any of the 13 new varieties released Wednesday by the federal government’s Potato Research Centre in Fredericton, New Brunswick. Among the varieties available are: a low glycemic index one that has potential health benefits for diabetics and diet conscious consumers, a red fleshed potato, a high starch potato for industrial starch use, plus ones for the chip and French fry industries and for the fresh market.

The low glycemic index potato has a moderate index number of 65 when served hot and very low, 34, when served cold. On the federal agriculture department’s website, the potato is described as small to medium sized, with average yields, average to good appearance and white skin.

By way of comparison, some other vegetable’s glycemic index numbers are: 15 for cauliflower, tomatoes and celery and 39 for cooked carrots.

People digest low glycemic index foods more slowly. Lower glycemic foods are more desirable because they don’t cause a big spike of insulin in the body the way high glycemic foods, such as jellybeans with an index number of 80, do.

Fredericton-based potato breeder Benoit Bizimunga says anything with a glycemic index number above 70 is considered to be high, while between 69 and 56 it’s moderate and below 55 is classified as low. Recent research shows that healthy, low glycemic index diets have a variety of benefits, including more sustainable weight loss and improved diabetes management.

Bizimunga says the glycemic index number depends on how the food is prepared and consumed, which means the accompanying ingredients. One of the reasons why the low glycemic index potato’s number is higher when it’s served hot compared to cold is the structure of the starch in the potato changes when it’s heated in a pan of water and then cooled.

Usually the glycemic index of potatoes is higher than 70, but it depends on the variety, he says.

To get the low glycemic index number, people would have to eat the low glycemic potato cold in a salad but “even hot it’s one of the lowest because most of them will be 70, which is going to be high,” he explains, noting the hot version of the low glycemic potato’s number is in the moderate range and that’s good news.

Bizimungu says it will be about five more years before the low glycemic potato is available for consumers to buy in grocery stores.

Currie says the low glycemic potato has already been tested quite extensively, including at the University of Guelph.

The next step for the low glycemic potato and other varieties released Wednesday is field testing on Canadian farms. Through the federal agriculture department’s Accelerated Release program, potato industry entrepreneurs of every size can register for an opportunity to evaluate the new varieties first hand in their fields. Participants pay $100 per selection and receive a limited quantity of the breeder’s seed plus non-exclusive rights to conduct their own field performance and quality evaluation trials for two years. After that, participants can submit cash bids to procure a further three-year period of exclusive testing.

Alliston-area potato farmer Chris Kowalski says he grew 25 acres of a low glycemic variety a few years ago for one year. He says of the variety he grew it was never proven but they were touted as low glycemic.

It’s feasible to grow low glycemic index potatoes commercially “but the biggest problem is if you give it to 10 different scientists they’ll come up with 10 different results for the glycemic index number,” he explains, noting the number changes depending on how the potato is prepared.

Of the variety he grew, the yield was similar to other potatoes and “disease pressure wasn’t any different,” he notes. Kowalski says they were a type of russet potato and he combined them with other russets and sold them as russets. But Kowalski says he’d be willing to try growing the newly released low glycemic potato.

The Potato Research Centre releases up to 10 new potato varieties annually.

Prince Edward Island is still Canada’s main potato growing region with 86,000 acres of the country’s 361,100 acres last year. Manitoba was second with 73,000 acres. Ontario had 37,700 acres. BF