Local study targets blood pressure impacts of beta-glucan fibre
There’s a lot of buzz around fibre — and for good reason. While all fibres are types of carbohydrates, there are several varieties. One example is beta-glucans — a soluble fibre that has been linked to gut, heart and immune health.
To learn more about the health benefits of beta-glucan, researchers at the University of Manitoba and Agriculture and Agri-Food Canada (AAFC) are conducting a nutritional study looking at how and if eating beta-glucan derived from oats affects blood pressure.
Fibre is a super-nutrient. It slows the absorption of glucose — which evens out our blood-sugar levels — and lowers cholesterol and inflammation. A fibre-rich diet is associated with better gastrointestinal health and a reduced risk of heart attacks, strokes, high cholesterol, obesity and Type 2 diabetes
“The goal of this project is to find out whether beta-glucan from oats has any effect on managing a healthy blood pressure,” says Dr. Sijo Joseph (Thandapilly), a research scientist with AAFC and co-investigator of the study.
Beta-glucan is found in oats, brown rice, barley, baker’s yeast and medicinal mushrooms such as maitake and shiitake. Beta-glucan acts as a soluble fibre prebiotic (which is like food for your probiotics) in your gastrointestinal tract, helping your gut’s probiotics – also known as beneficial bacteria —function optimally. Probiotics are live active cultures (usually in the form of bacteria and yeast) that help keep your gut healthy. The main job of probiotics is to maintain a healthy balance in your body. Think of it as keeping your body in neutral. They help food digest, produce vitamins and fight off “bad” bacteria that are associated with disease.
“(Beta-glucan) is a very important molecule,” Joseph says. “Our ancestors had higher levels of fibre in their diet but because of our refined and processed foods, we are getting very little. Oats and barley are some of the ways we can enrich fibre in our diet.”
For years, beta-glucan has been used in alternative medicine for everything from cold and flu prevention to fibromyalgia. More recently, it has been studied extensively for its beneficial effects on heart and gut health, as well as been shown to boost immunity and stabilize blood sugar levels. Studies have even found beta-glucan intake can lower total and LDL cholesterol. LDL (low-density lipoprotein) cholesterol is often called the “bad” cholesterol because it collects in the walls of your blood vessels, raising your risk for heart disease and stroke.
But research is minimal for beta-glucan intake and blood pressure. That’s where this pilot study comes into play.
“Beta-glucan in both barley and oats already has Health Canada health claims that it can lower blood cholesterol — but there is nothing on blood pressure. Since we have similar studies on cholesterol and glycemic response, we believe it could work,” says Joseph. “Previously, we did a study in hypertension in rats and we found a very high potential for beta-glucan in lowering blood pressure. So, we wanted to test that in humans.”
Joseph says the goal of their nutritional study is to reach four grams of beta-glucan per day. To do this, the research team, including Dr. Thomas Netticadan, Dr. Lovemore Malunga and Dr. Nancy Ames, came up with a specific meal formulation in the form of a breakfast cookie that will contain a certain amount of carbohydrates, protein and fat to be nutritionally adequate. Two types of breakfast cookies will be developed — one with beta-glucan and one without.
For the study, the research team will be sending packages of the breakfast cookies to subjects who will then measure their blood pressure using ambulatory monitors (portable blood pressure recording devices.)
The study is unique in that it’s been designed to be zero contact — both the cookies and ambulatory monitors will be delivered to participants’ homes and all follow-up will be conducted via secure virtual chat or online.
“My colleague, Dr. Rebecca Mollard, and I wondered how we could do these trials and minimize (COVID-19) risk,” says Dylan MacKay, principal study investigator and assistant professor in food and human nutritional sciences and internal medicine at the University of Manitoba.
MacKay says they have a system where the consent process is now done online.
“Participants will have the ability to discuss (the study) with us over a secure online connection,” he says. “Our visits are virtual but we’re not removing that opportunity for people to ask questions and get an understanding of what they’re agreeing to.”
The study will consist of two four-week periods: one treatment period (cookies containing beta-glucan) and one control period (cookies containing no beta-glucan) with a four week period in between where no cookies are given. The total trial time from start to finish will be around three months.
During the treatment period, participants will eat two breakfast cookies made from oats containing a total of four grams per day of beta-glucan (each cookie contains two grams) whereas the control period will provide breakfast cookies made primarily from wheat with no beta-glucan. The study will be located at the Chronic Disease Innovation Centre in Seven Oaks General Hospital in Winnipeg.
“Each cookie intervention period is four weeks — so they get cookies for a total of eight weeks, and in the middle of those four-week trials, they have a four-week washout period where there’s no intervention,” says MacKay. “We don’t know which cookie they’ll get so we can look at the results of one cookie versus the other. We’re piloting to see if there’s a difference based on blood pressure.”
Participants will be asked to wear an ambulatory blood pressure monitor for 24 hours per day for three consecutive days at the beginning and end of each treatment period — these monitors automatically measure blood pressure every 15 to 30 minutes during the day and 30 to 60 minutes in the evening.
“The gold standard in measuring blood pressure in trials now is ambulatory blood pressure measuring devices,” says MacKay. “What (these monitors do) is overcome the idea of ‘white coat syndrome’ where if you’re afraid of having your blood pressure measured, your blood pressure typically goes up. Some people get elevated blood pressure just by going to the doctor.”
The team will be dropping off digital scales to people’s homes so they can report body weight and participants will be asked to fill out a dietary recall, which is an online questionnaire that captures information about foods they’ve eaten.
“We’re not controlling (what people eat) outside of giving them breakfast cookies, so we want them to continue with their normal diet,” MacKay says. “The idea being that people are creatures of habit, for the most part. We’re hoping that the only difference that we’re going to see in blood pressure is likely due to the beta-glucan.”
High systolic blood pressure (SBP) and/or high diastolic blood pressure (DBP) can cause damage to blood vessels and result in cardiovascular disease or even a heart attack or stroke, which are among the leading causes of hospitalization and death in Canada, according to Statistics Canada.
“Blood pressure is a silent killer. With diabetes, you get thirsty and tired. For cholesterol, you get fatigue. Our goal is to come up with a dietary approach to managing blood pressure,” Joseph says. “(With beta-glucan) you get health benefits and can reduce the health care burden. If you can reduce risk factors, that means fewer people with cardiovascular problems — it all helps the public health system.”
Results from the 2016-19 Canadian Health Measures Survey (CHMS) indicate that among Canadian adults aged 20 to 79, 23 per cent reported they had been diagnosed with hypertension by a health-care professional, were taking anti-hypertensive medication or had high measured blood pressure equivalent to stage 2 hypertension.
Results of the nutritional study will be shared at national and international scientific conferences. Joseph notes that more robust studies may be needed along with a larger population to help fulfil the health claims.
The study will take place in 2022 and the research team is looking to recruit approximately 24 participants between the ages of 40 and 75 with higher than normal blood pressure and currently not taking any blood pressure management medications. If you’re interested in participating in this nutritional study, email [email protected].
Published in the Winnipeg Free Press