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Toward healthier oats

POGA’s executive director Shawna Mathieson (with son Andrew) says higher levels of avenanthramides could give people even more reasons to eat oats. Photo by Shawna Mathieson, POGA.

Oats have a lot of things going for them when it comes to human health, and one of those things is a group of bioactive compounds called avenanthramides. So a three-year project at the University of Saskatchewan is laying the foundation to help breeders develop oat varieties with higher avenanthramide levels.

“Oats are a very unique crop. They are a cereal crop, but they are very different from most cereal crops, such as corn, rice and wheat. First of all, oats have a high oil content, which is not usual in cereal grains. For example, rice has about two per cent oil, but oats may have up to 18 per cent. The high oil content gives high energy, which is very good for feed,” explains Xiao Qiu, a professor in the university’s department of food and bioproduct sciences who is leading the avenanthramide project.

“Second, oats contain beta-glucan, a type of water-soluble dietary fibre with important health benefits.” The health effects of beta-glucan have been examined in many studies, and the two best-documented benefits are that it lowers cholesterol, which helps reduce the risk of heart disease, and that it reduces glycemic response after a meal, which helps control or prevent diabetes.

“And third, oats have avenanthramides, a type of polyphenol. Polyphenols are a big group of compounds that have many different types of functions, but avenanthramides are a unique type of polyphenol. They have very high antioxidant activity compared with some other polyphenols, and antioxidants are good for protection against cardiovascular disease and many other things. Avenanthramides also have strong anti-skin-irritation and anti-allergic activity. As well, [some research indicates] avenanthramides have high anti-proliferative activity; cancer cells grow very fast, so these kinds of compounds could inhibit cancer growth.” Although more research needs to be done to confirm the human health benefits of consuming avenanthramides, results so far suggest they may provide a variety of important benefits such as contributing to a reduced risk of colon cancer and a reduced risk of heart disease.

Avenanthramides are found only in oats, not other cereals. In fact, the “avena” in “avenanthramide” comes from the scientific name for oats, Avena sativa. The oat plant uses avenanthramides to help defend itself against pathogens.

Qiu notes that avenanthramides are being used commercially in skin lotions, creams and other personal care products. For example, Aveeno is a company whose name comes from its use of oats and oat extracts in its personal care products. “The basic functional compounds in Aveeno’s products are avenanthramides because of their very high antioxidant and anti-irritation activity.” Also, an Alberta-based company called Ceapro extracts avenanthramides from oats and sells the extract to companies for use in such products.

Qiu’s research program investigates the biosynthesis of bioactive compounds in plants and microbes, and includes studies of oat oil, beta-glucan and avenanthramides. His current avenanthramide project started in January 2015 and is funded by Saskatchewan’s Agriculture Development Fund and the Prairie Oat Growers Association (POGA).

Qiu and his research team have already completed this project’s first objective, which was to survey avenanthramide levels in oat germplasm. “If we want to increase the avenanthramide content in oats, we have to know which germplasm samples have higher levels. If the level is high in a sample, then an oat breeder could potentially use it as a parent for crossbreeding,” he says.

The researchers obtained germplasm samples from the university’s plant sciences department and from Plant Gene Resources of Canada, the Saskatoon-based national germplasm bank. Most of the samples were oat breeding lines and cultivars from Aaron Beattie, an oat breeder at the university and long-term partner in oat research with Qiu, but they also tested some wild Avena species to get a general idea of the range in avenanthramide levels.

Analyzing samples for avenanthramides is fairly complex. Qiu explains that oats contain up to 20 different types of avenanthramides, although normally there are only three major ones, which are known as avenanthramide-A, avenanthramide-B and avenanthramide-C. So his lab tested about 30 different germplasm samples for those three avenanthramides. The tests showed quite a wide range in avenanthramide levels.

His lab is now working on the second of the project’s two objectives: to find out how avenanthramides are made in the oat plant. “To improve this trait in oat varieties, you have to know the biosynthetic pathway – how avenanthramides are synthesized biochemically in the plant, what genes control the synthesis, what kinds of enzymes are involved, and all these kind of things,” Qiu says.

He adds, “If we know the genes involved, then oat breeders can design a molecular marker for the trait.” A molecular marker is a short sequence of DNA associated with a specific trait. Breeders use these types of markers to quickly screen germplasm for the desired traits in the lab, making their breeding efforts more efficient and effective.

Qiu notes, “I’ve talked to oat breeders here, and they haven’t made avenanthramides a priority trait in their breeding programs. Right now, they are focusing on things like disease resistance and yield. But you never know how things might go in the future.”

From superfood to super-duper food?
Down the road, if breeders are able to develop oat varieties with higher amounts of avenanthramides, then there could potentially be benefits along the oat value chain. “With an increased amount of avenanthramides, companies could use more oats in products like lotions and creams where they want anti-itching and anti-inflammatory properties,” says Shawna Mathieson, POGA’s executive director.

“And people would have even more reasons to eat this ‘superfood.’ Oats are already recommended by many doctors because the fibre in oats helps to reduce cholesterol. Some studies have shown that individuals with high cholesterol who consume just three grams of soluble fibre every day, or about the amount in a bowl of oatmeal, can lower their cholesterol. Avenanthramides have also been linked to prevention of cardiovascular disease and to protection against colon cancer and skin irritation. So higher avenanthramide levels would make oats even better for consumers.”

As research information about the health benefits of eating avenanthramides increases and as consumers become aware of these benefits, then higher levels of avenanthramides in oats could help to increase oat consumption by health-conscious consumers. She says, “That would mean higher sales and hopefully higher profitability not only for oat producers but also for those down the oat value chain.”

Qiu thinks avenanthramides could play a valuable part in further improving the reputation of oats as a functional food. “Although oats already have a healthy image, people are only paying attention to the beta-glucan content. But oats are not just about beta-glucan; they also have avenanthramides. Right now avenanthramides are used for cosmetics, but consuming avenanthramides is also good for you. Adding avenanthramides to the good image of oats would create more demand,” he says.

“For instance, people drink red wine because of the polyphenolics, but oats have a unique group of polyphenolics with stronger antioxidant activity than wine polyphenolics. People drink tea partially because of the tannins and other polyphenolics, but oats have avenanthramides with a better activity. So why not eat more oats?”

February 18, 2016  By Carolyn King