effect of trans fatty acids from ruminant sources on risk factors for cardiovascular disease

Conditions: Cardiovascular Disease

Summary: the objectives of this study are to : 1) determine if vaccenic acid (trans-11-octadecenoic, a naturally occurring trans fatty acid isomer from ruminant animal products) raises ldl cholesterol in a quantitatively comparable manner as mixed trans fatty acid isomers from partially hydrogenated vegetable oils at 3% of energy intake, 2) determine if cis-9, trans-11 conjugated linoleic acid (a naturally occurring polyunsaturated fatty acid from ruminant animal products) raises ldl cholesterol compared to a control diet, and 3) demonstrate that mixed trans fatty acid isomers from partially hydrogenated vegetable oil raises ldl cholesterol compared to a low trans fatty acid diet.


Eligibility criteria:
inclusion criteria: * bmi between 20 and 38 kg/m2 * age 25 to 65 years during the intervention * fasting glucose \< 126 mg/dl * blood pressure \< 160/100 mm hg (controlled with certain medications) * total plasma cholesterol \< 280 mg/dl * fasting triglycerides \< 300 mg/dl exclusion criteria: * use of prescription or over-the-counter medications or supplements that alter lipid metabolism. * history or presence of kidney disease, liver disease, gout, certain cancers, thyroid disease, gastrointestinal, other metabolic diseases, or malabsorption syndromes. * type 2 diabetes requiring the use of oral antidiabetic agents or insulin. * history of eating disorders or other dietary patterns which are not consistent with the dietary intervention (e.g., vegetarians, very low fat diets, high protein diets). * women who have given birth during the previous 12 months, pregnant women, women who plan to become pregnant or who become pregnant during the study or lactating women. * volunteers who routinely participate in heavy exercise or volunteers who initiate an exercise program during the study. * volunteers who have lost 10% of body weight within the last 12 months or who plan to initiate a weight loss program during the next 10 months. * use of prescription or over-the-counter antiobesity medications or supplements (e.g., phenylpropanolamine, ephedrine, caffeine, during and for at least 6 months prior to the start of the study) or history of a surgical intervention for obesity. * active cardiovascular disease (such as heart attack or procedure within the past three months or participation in a cardiac rehabilitation program within last three months, stroke or history/treatment for transient ischemic attacks in the past three months, or documented history of pulmonary embolus in past six months). * smokers or other tobacco users (during the 6 months prior to the start of the study). * unable or unwilling to give informed consent or communicate with study staff. * self-report of alcohol or substance abuse within the past twelve months and/or current acute treatment or rehabilitation program for these problems (long-term participation in alcoholics anonymous is not an exclusion). * other medical, psychiatric, or behavioral factors that in the judgment of the principal investigator may interfere with study participation or the ability to follow the intervention protocol.

Keywords: trans fatty acids ruminant cardiovascular disease