A ban on trans fats in restaurants in New York state has been linked to hundreds of fewer heart attacks and strokes, a new study finds.

And as both the U.S. and Canada move to crackdown on the artery-cloggers, the findings have the potential to save millions of lives over the coming decades.

Artificial trans fats, also known as partially hydrogenated oils, are often used by food manufacturers in baked goods, yeast breads, fried foods, chips, crackers and margarine to enhance shelf life, flavour and texture.

Eating industrial trans fatty acids raises levels of low-density lipoprotein (LDL), or "bad" cholesterol, while also lowering levels of high-density lipoprotein (HDL), or "good" cholesterol.

Higher consumption of trans fats is also associated with greater risk of stroke, coronary heart disease and sudden cardiac death.

To explore the public health benefits of a trans fat ban, U.S. researchers took advantage of a natural experiment that unfolded in New York state.

New York City was the first major urban area in the U.S. to introduce a trans fat ban at restaurants, bakeries, caterers, cafeterias, soup kitchens and street booths, starting in July 2007. A number of state counties also followed suit.

In a study published Wednesday in JAMA Cardiology, Dr. Eric Brandt and his team compared hospitalizations for heart attack or stroke in 11 New York counties that adopted bans, and 25 counties that did not, between 2002 and 2013.

"When we looked at what happened [three years] after bans were implemented, there was a 6.2 per cent decline in heart attacks and strokes," said Brandt, with Yale University's School of Medicine.

That translates to 43 fewer heart attacks and strokes per 100,000 people.

U.S., Canada take action

Trans fats have long been tied to the risk of heart disease. In 1993, an expert panel convened by the World Health Organization recommended people reducing their intake of trans fats.

And starting next year, American food manufacturers will have to ask the U.S. Food and Drug Administration for permission to use trans fats in their products.

Health Canada, meanwhile, proposed a prohibition on industrially produced partially hydrogenated oils just last week, which would virtually eliminate it from foods. The federal agency says the ban would take effect one year after the final regulatory decision is reached.

Trans fats from partially hydrogenated oils are still found in some pre-made baked goods. ( Joe Raedle/Getty)

There is no recognized safe amount of dietary trans fats, Brant said, as even small amounts can be harmful. A large order of fries, for example, can contain 3.5 grams of trans fat.

Brandt said when he talks to heart patients, quitting smoking and trans fat top his advice list.

Cardiologists and dietitians often advise consumers to avoid trans fats by checking labels on packaged foods to see if partially hydrogenated oil is in the ingredient list.

"We are what we eat," said Dr. Beth Abramson, a Toronto-based cardiologist and spokesperson for Heart & Stroke. "Pick up a label, read it, and make a healthy choice."

Heart & Stroke estimates as many as 30,000 cardiac deaths per decade could be prevented in Canada if people replaced trans fats with healthier oils, such as olive and canola oils.

"Preventing one heart attack and stroke is a meaningful difference when we're talking about patients," Abramson said. "But preventing thousands of heart attacks and strokes, it's almost overwhelming."

The organization also cautions that lowering or eliminating trans fat in packaged food won't necessarily make foods more nutritious, as overall calories, salt and sugar content, and saturated and unsaturated fat content also make a difference.