Effect of Trans Fatty Acids From Ruminant Sources on Risk Factors for Cardiovascular Disease

Effect of Trans Fatty Acids From Ruminant Sources on Risk Factors for Cardiovascular Disease

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.

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.