The paper, published in the November edition of the Journal of the American Dietetic Association, found that the bars helped to lower levels of 'bad' LDL cholesterol in the blood due to their 1.5g plant sterol content.
Plant sterols are commonly known as a favourite ingredient among manufacturers in the functional food industry thanks to their cholesterol-lowering properties and have been used in breads, spread and chocolate.
Their inclusion in the CocoaVia products, which were launched last year through internet sales, has allowed Mars to market them as 'heart healthy' chocolate.
Researchers at the University of California-Davis tested the cholesterol of 67 men and women with elevated levels who were placed in one of two groups.
One group ate a CocoaVia snack bar twice a day and the other an equivalent placebo.
After six weeks, the group eating the Mars product had reduced their total cholesterol by 4.7 per cent and their LDL levels dropped by an average of 6 per cent.
High levels of LDL cholesterol in the blood increase the risk of cardiovascular disease (CVD) which causes almost 50 per cent of deaths in Europe, and is reported to cost the EU economy an estimated €169 billion ($202 billion) per year.
Mars research scientist Dr Catherine Kwik-Uribe said: "Heart health is a national public health priority and our study supports that offering consumers a great tasting lower calorie chocolate snack product with plant sterols, like CocoaVia bars, can be a practical and enjoyable dietary strategy."
Masterfoods US, who own the Mars brand, has conducted over 15 years of research into the benefits of cocoa flavanols and owns the patent for its Cocoapro process which extracts naturally occurring antioxidant flavanols from cocoa beans.
In June this year the US Food and Drug Administration (FDA) sent the company a warning letter expressing how worried they were about health claims attached to the CocoaVia range.
While it was not disputed that the chocolate contained a high amount of cocoa flavanols and therefore antioxidants, the FDA had a problem with the extensive 'healthy' marketing of the product it in light of the amount of saturated fat it contained.