Heart disease is a leading cause of death in Ireland with approximately 10,000 people dying from it each year, according to the Irish Heart Foundation.
Raised cholesterol levels are among the key contributory factor to heart disease and this has led to extensive research into low cholesterol foods as well as cholesterol lowering food ingredients, such as plant stanol esters.
The prospect of dramatically more effective cholesterol lowering food ingredients has now been opened up thanks to research being carried out at Teagasc’s Moorepark dairy research centre.
This research is looking into the potential beneficial properties of a bacterium known as Lactobacillus mucosae DPC6426 in this regard.
This is not widely used in food production at present but is approved for that purpose as Teagasc Moorepark principal research officer Dr Catherine Stanton explains.
“It is a food grade strain of bacteria but it is used in food production very often. Our research into it began back in 2006 when we were given funding by the Department of Agriculture to conduct a research project into food ingredients which would be good for cholesterol and heart health.”
The research started out by looking at a proven cholesterol lowering substance and then searching for a bacterium which would produce something with a similar effect. In this instance the substance was the oat beta-glucan polysaccharide found in porridge which has been approved by the US FDA as a cholesterol lowering food.
Bacteria cultures
The search began in Teagasc's own extensive collection of bacteria cultures. "We have a very big collection of cultures," says Stanton. "We have about 6,000 of our own and we isolated other new ones from mammalian sources as well. We found some that produced beta-glucan type molecules and we narrowed them down to Lactobacillus mucosae. The polysaccharide it produces is not exactly beta-glucan but it is a very similar soluble fibre."
Because the fibre isn’t precisely the same, Stanton and her team couldn’t be sure it would work as a cholesterol lowering agent. This led to a study where it was fed to mice which had been bred to be prone to artherosclerosis and fed on a high cholesterol high fat diet. When the Lactobacillus mucosae was fed as a supplement there was a 50 per cent reduction in the cholesterol levels compared to those mice which were not given it. The animals fed on the Lactobacillus mucosae supplemented diet also exhibited other health gains.
“This was a very positive result,” Stanton points out. “Other cholesterol lowering supplements, such as plant stanol esters which inhibit cholesterol absorption, only reduce it by between 10 per cent and 15 per cent.”
Having established its health giving properties the team then had to find out if it would work in foods. After all, not all food ingredients that are good for us are necessarily tasty or appetising to look at. In this case the results have been very promising.
“It worked as a fermenter of yogurt but we didn’t use it on its own for that,” Stanton explains. “You can also add it in as an adjunct to the main culture in the process. We found that not only did it make very good yogurt but it actually improved low fat yogurts. When you leave low fat yogurt in the fridge for a while it separates out in a process known as wheying off and this leaves a clear watery liquid on top of the yogurt.
“The Lactobacillus mucosae helps bind it together and stops this from happening. It also gives it smoother and better mouth-feel. Low fat products tend to suffer in comparison to their full fat alternatives because the fat is a key component of the taste and it will be interesting to see if the addition of Lactobacillus mucosae might help in that regard.”
With the health benefits established and its use in the manufacturing process having been tested and proven, the next stage is commercialisation and the project has received funding from the Enterprise Ireland Commercialisation Fund to help bring the new product to market.
“Further studies are required before it is ready for commercial use,” Stanton notes.
"Firstly, we have to compare it to other competitor products to see how it performs in terms of lowering cholesterol. It will have to be superior to the other products if it is to be used by food companies. After that we have to get European Food Safety Authority (EFSA) approval for it as a product which is safe to use. For example, we have to study its antibiotic resistance profile to ensure that it doesn't cause people to become resistant to clinically used antibiotics."
Human study
The final phase is the human study. "This will involve healthy people with elevated cholesterol but who aren't on any medication for it. We will test the product on them to support the data we already have from the animal trial and we hope to gain enough evidence to get EFSA approval for its health giving properties."
Stanton points out that the project has been very much a collaborative effort. "We couldn't have done this on our own," she says. "We have worked in very close collaboration with Prof Noel Caplice and Prof Fergus Shanahan of UCC on it. The contribution of UCC has been critically important. The results so far are very promising and we hope by the end of the project in 2016 to have a product which is very attractive for use by Irish food companies and which will help improve people's heart health."
