When it comes to reducing your blood cholesterol with healthy eating, white meat isn't any better than red meat, according to a new study that contradicts previous medical thinking.

High levels of blood cholesterol are a leading cause of heart disease, and a condition faced by about 40 per cent of Canadian adults, according to Statistics Canada.

Diet and lifestyle changes are crucial to controlling high blood cholesterol, and some health experts said the study by doctors at the University of California, San Francisco, underscores the need for Canadians to eat less meat.

"We used to think that white meat was better than red meat for controlling blood cholesterol. What we found was there really was no difference," said Dr. Ronald Krauss, the study's senior author and a scientist at Children's Hospital Oakland Research Institute in California.

The key takeaway, Krauss said, is that consumers who want to lower their blood cholesterol should substitute plant-based proteins for both red and white meat.

"I wouldn't go overboard and say: 'You should never have red meat or you should never have white meat,'" Krauss said in an interview. "We are saying you shouldn't emphasize those proteins too heavily — keep them at a moderate level."

The study, published on June 4 in the American Journal of Clinical Nutrition, followed 113 people on six different diets prescribed by researchers to track the impact of various types of proteins on blood cholesterol levels.

Typically, research on eating habits involves questionnaires or surveys rather than determining exactly what people in the study group eat, Krauss said. This study controlled participants' diets and tested their blood cholesterol under various eating regimes determined by researchers.

The study is the largest of its kind to focus on dietary proteins, Krauss said.

It took a number of years to carry out, he said — and the results were unexpected.

Don't make big conclusions: nutritionist

Carol Dombrow, a nutrition consultant for the Heart and Stroke Foundation of Canada, said the study looks "well done" but its sample size was small.

She said it's "premature" to make any big conclusions on red versus white meat when it comes to controlling blood cholesterol.

"This is an interesting study but we need way more information to make a conclusion about it," Dombrow said in an interview. "The study does agree with pushing plant-based foods," she said, a move backed by the Heart and Stroke Foundation.

Various cuts of beef and pork are displayed for sale in the meat department at a discount market in Arlington, Va., in 2013. Red meat contains saturated fat which has been linked to blood cholesterol. However, it also contains important vitamins such as B12. (J. Scott Applewhite/The Associated Press)

Saturated and trans fats in food raise levels of low-density lipoproteins — known as LDL or "bad cholesterol" — in the bloodstream, increasing the risks of clogged arteries and heart disease, Dombrow said.

The assumption has been that red meat is higher saturated fat content than white meat, she said.

'Dangerous science'

A group representing Canadian chicken farmers lambasted the study, calling it methodologically flawed with a small sample size and confusing for average consumers.

"To me, this study cries bizarre," Gina Sunderland, a dietitian who works for Manitoba Chicken Producers, said in an interview. "People should not be restricting their intake of lean white meat protein, like chicken breasts … To make such sweeping recommendations from a small sample size … is dangerous science in my opinion."

The study isn't specific about what kind of non-meat proteins people should be eating, she said. And it didn't control for other factors like smoking, obesity or physical activity among participants that could impact blood cholesterol levels and overall health.

The focus on plant-based proteins might have been an attempt for the study's authors to publish research in line with the latest "trendy" dietary fashion, she said.

Follow the food guide

The study was financed by the U.S. National Heart, Lung and Blood Institute, and the National Institutes of Health.

However, two of the study's authors had received an unrelated grant from Dairy Management Inc., a lobby group for U.S. dairy farmers, according to the research credits.

Sunderland from Manitoba Chicken Farmers said that could spell a conflict of interest; study participants on one of the non-meat protein diets were given significant amounts of animal protein from dairy foods.

"Villainizing specific foods is not good science or public health advice for the average population," she said, arguing that people need vitamins contained in lean meats and information from the study could confuse Canadians.

Krauss and Dombrow both agreed that keeping up with shifting science can be difficult and confounding for consumers trying to stay healthy.

Following Canada's new food guide, which urges people to eat more plant-based proteins, is the best bet for a regular person scrambling to cook dinner while keeping an eye on their blood cholesterol, Dombrow said.

"Our data and other studies support increasing consumption of vegetables, fruits and unprocessed grains," Krauss said. "All of those have nutrition benefits on the risk of heart disease."