Grant: Operating Grant

Trans fats can be formed industrially under extreme heat when making semi-solid fats. However, it is less well known that certain trans fat can also be formed naturally in ruminant animals such as cows. Vaccenic acid (VA) is the major ruminant trans fat found in foods such as dairy and beef products. While it is widely accepted that industrial trans fat increases heart disease risk, animal data from our laboratory and other scientists have shown that VA may actually lower several types of fat and cholesterol in the blood. High blood fat or cholesterol is a feature of metabolic syndrome associated with increased heart disease risk. Understanding the action of VA in humans is essential to further distinguish the effects of natural from industrial trans fat on heart disease. The objective of this study is to assess for the first time the effect of VA on blood fat, cholesterol and other heart disease risk factors in men. The proposed study will be a carefully controlled dietary intervention where the participants receive 2 weight-maintaining diets consecutively for 4 weeks each: 1) a control diet and 2) a diet rich in VA (represent 6.7% of total fat). All foods will be provided to participants to ensure adequate and equal nutrient intake and that intake of VA is maintained at targeted level throughout the study. We expect that increasing VA in the diet will significantly decrease blood fat and cholesterol levels. We also hope to assess changes in genes and pathways in important organs that control fat production (including the intestine), which will help us understand the reasons behind the proposed health effects. Collectively, these novel findings will help support the hypothesis that consumption of VA not only has different (potentially beneficial) effects in humans relative to industrial trans fat, but could be considered an effective nutritional intervention for individuals with high blood fat who are therefore at high risk for heart disease.