A typical American consumes approximately 3 or more tablespoons of vegetable oil each day. Vegetable oils, like those from soy, corn and canola, are a significant source of calories and are rich in linoleic acid (LA), which is an essential nutrient. Since the 1970s, researchers have known that LA helps reduce blood cholesterol levels, and for decades, scientists have known that consuming LA can help lower the risk of heart disease. However, some experts have been claiming recently that Americans might be getting too much of a good thing. A new study from the University of Missouri contradicts that claim.
In the study, "Effect of Dietary Linoleic Acid on Markers of Inflammation in Healthy Persons: A Systematic Review of Randomized Controlled Trials," researchers at the University of Missouri and the University of Illinois found that no link exists between vegetable oil consumption and circulating indicators of inflammation that are often associated with diseases such as heart disease, cancer, asthma and arthritis. While earlier animal studies have shown that a diet rich in LA can promote inflammation, MU animal sciences researcher Kevin Fritsche says that humans respond to LA differently.
"In the field of nutrition and health, animals aren't people," said Fritsche, an MU professor of animal science and nutrition in the Division of Animal Sciences. "We're not saying that you should just go out and consume vegetable oil freely. However, our evidence does suggest that you can achieve a heart-healthy diet by using soybean, canola, corn and sunflower oils instead of animal-based fats when cooking."
Linoleic acid is an omega-6 fatty acid that is a major component of most vegetable oils. This fatty acid is an essential nutrient and comprising 50 percent or more of most vegetable oils.
Fritsche, along with Guy Johnson, an adjunct professor of food and human nutrition at the University of Illinois, conducted one of the most thorough studies on LA questioning whether this fatty acid promotes inflammation in humans. When the evidence from numerous clinical trials was gathered and examined, Fritsche said it was clear that LA consumption did not promote inflammation in healthy people.