Heart-smart diets receive berry good news

“The take-home message for the consumer would be, eat your fruits and vegetables.”

– WILHELMINA KALT, AAFC

If the latest cholesterol-lowering medication turns out to be blueberries, you can thank a pig.

Feeding blueberries to pigs can lower their cholesterol levels by up to 15 per cent, Agriculture and Agri-Food Canada scientists have found.

And if it works for pigs, it’ll probably work for people.

Our porcine friends are a good model for human health research. Like us, they are omnivores with similar metabolic systems. They have similar blood pressure and heart rates and are also susceptible to what scientists call diet-induced vascular disease.

That means AAFC’s blueberry study could have implications for human health, according to lead researcher Wilhelmina Kalt.

Feeding trials

AAFC recently conducted two feeding trials with pigs to determine the effects of blueberry supplements in the diet on blood plasma lipid levels.

The first trial involved supplementation at dietary rates of one, two per cent and four per cent in a ration consisting of soy, oats and barley. The results were, shall we say, berry interesting.

All rates produced lower cholesterol levels. The greatest reduction occurred with the two per cent supplement, which saw total HDL and LDL cholesterol levels lowered by 11.7, 15.1 and 8.3 per cent respectively.

A two per cent supplement is roughly equal to two cups of blueberries daily in a human diet.

The second trial involved feeding pigs a diet of 1.5 per cent blueberries in a 20 per cent soy, oats and barley ration. Total cholesterol reductions were eight per cent but only in animals given additional cholesterol, salt and fructose supplements.

The results were published recently in the British Journal of Nutrition.

Rich

The reason blueberries appear to lower cholesterol is that they are rich in phytochemicals (plant-derived chemical compounds with potentially health-promoting properties). Most fruits and vegetables contain phytochemicals but blueberries are especially high on the list.

The bottom line is what our mothers always said.

“The take-home message for the consumer would be, eat your fruits and vegetables and get a nice diversity of phytochemicals in the diet. Typically, more colour equals more phytochemicals,” Kalt said in an interview from the AAFC research station at Kentville, Nova Scotia.

Exactly why blueberries appear to have cholesterol-lowering properties is unclear. Kalt said it could be because they contain flavenoids – chemicals which scientists believe may prevent the oxidation of LDL (the “bad”) cholesterol, thus protecting cells from free radical damage.

Another reason could be that the soy, oats and barley in the pigs’ diet may have worked “synergistically” to affect plasma lipids, she said.

The health benefits of blueberries have been touted for some time. Research into the effects of blueberries on vision goes back 50 years. More recent work has focused on their antioxidant properties. But this is the first time a study has suggested a direct link between blueberries and cholesterol levels, Kalt said.

(A word of explanation: the reason Kalt and her colleagues used pigs is that they had to kill and dissect the animals to test for results. This made for a singular lack of human volunteers.)

Human health

Admittedly, there’s not much in this for hog producers. The study deals with the potential impacts of nutraceuticals and functional foods on human health, using the pig as a model. Pigs don’t live long enough to develop cholesterol problems causing heart disease.

Even if they did, a blueberry diet for commercial swine is a non-starter. The Canadian Food Inspection Agency does not list blueberries as a registered livestock feed. Technically, this means meat from blueberry-fed pigs cannot be marketed.

But there may be other benefits. William Caine, an AAFC scientist at Lacombe, Alberta, plans to study blueberries’ therapeutic benefits as an antiinflammatory on older sows with joint problems. Caine hopes to begin work next year. [email protected]

About the author

Comments

explore

Stories from our other publications