Evaluation of Health Benefits of Conjugated Linoleic Acid (CLA)-Enriched Dairy and Beef Foods

Evaluation of Health Benefits of Conjugated Linoleic Acid (CLA)-Enriched Dairy and Beef Foods

Summary

NE Iowa RC&D, Inc., Iowa State University, Coolee Region Organic Producers, and local producers joined to carry out a second project that will be a human feeding study using CLA enriched food items verses non-CLA items. The purpose of this research will be to verify the health benefits of this acid in humans, to quantify how much CLA needs to be ingested to have an effect on health, as well as creating new practices for farmers to enhance the diets of their livestock to obtain an increased level of CLA in the final product.

Objectives/Performance Targets

This project will conduct an experiment that evaluates CLA-enriched dairy and beef foods from farmers on contract with CROPP. The farmers will use grazing systems to raise livestock and produce dairy products with high CLA content for the experiment. The milk and beef they produce will be processed and then prepared to create several different foods that will be incorporated into typical U.S. diets for a human feeding study. The study then will examine the health benefits of humans consuming CLA-enriched dairy and beef foods by evaluating the effect of feeding diets containing these CLA-enriched foods on concentration of cholesterol, individual lipoproteins, glucose, glucagon, and insulin in blood plasma, bone density, body weight and composition, and glucose tolerance. Results will be widely distributed through publication, field days and presentations. Several positive project outcomes are expected.

Short-term outcomes of the project will enhance the quality of life for participants and encourage sustainable agricultural systems. Specific short-term outcomes include:
Improved human health, quantified through the direct effects of CLA-enriched foods on measures of human health.

Because pasture feeding is the management system found to produce CLA-enriched foods, (outcome of our current SARE-funded project), intermediate outcomes of this research will improve the profitability for farmers that utilize sustainable management systems including:
Greater economic viability for dairy and beef producers that use sustainable high CLA pasture systems. Once the benefit to humans is demonstrated, high CLA content meat and dairy products are expected to increase in market value. Therefore, producers using the sustainable, high CLA pasture system, will be able to obtain a premium price in new and emerging markets and increase the market share for high CLA content pasture-fed animals.

The long-term outcomes of this project will enhance the quality of life for farmers and ranchers, rural communities, and society as a whole by providing a better understanding of CLA as an indicator that links healthy lands and healthy animals to healthy humans. Long-term benefits will include:
Improved health of the land and of human communities. This will be accomplished through a demonstration of the economic, environmental, and health justifications of management systems that result in greater utilization of pasture-based feeding systems for production of animal-derived foods on marginal land.

Accomplishments/Milestones

This project officially began in spring of 2005 because of the lateness in receiving the signed contract back from SARE. A news release was done and sent out about the new project in June of 2005 and a PowerPoint presentation was developed by a summer intern at NE Iowa RC&D to be used for future presentations on the project.

Food production:
During the summer months of 2005, the CLA products for the study were developed. Milk was obtained from Dan Baker to be processed into cheddar cheese, mozzarella cheese, ice cream, and butter. However, only a soft cheddar cheese was successfully produced out of the milk that was collected because of errors in the confirmation of an appropriate production facility for the batch sizes that we needed. This error was brought to our attention only a couple of weeks prior to the start of the study. Ice cream and butter were therefore obtained from pasture fed operations that have commercially available products. The ice cream was purchased from Picket Fence Creamery near Woodward, Iowa, and the butter was obtained from PastureLand in southeastern Minnesota.

The summer months also were spent finding pasture-fed beef and feedlot beef. The pasture-fed beef we acquired from Thousand Hills Cattle, and the feedlot beef we acquired through the ISU Meat Labs. Both were ground to 80% lean, and stored in the ISU Meat Lab storage freezers.

Feeding Trial:
After screening potential subjects on campus, 12 were selected to participate on the basis of plasma total cholesterol and low-density lipoproteins. One subject was unable to continue participation after the first week, and one had to stop after the fourth week. This left ten subjects to complete the study: four on the CLA treatment and six on the control. Blood was taken every two weeks. We have some data from the study, but we do not want to comment on them until we determine with greater certainty the macronutrient content, the lipid profile, and the cholesterol content of the diets that were fed to the subjects. These data should be available by March, 2006.

The next feeding trial:
These preliminary data allowed us to reevaluate some of the procedures and criteria for the upcoming block of subjects. The upcoming block will take place in June, July, and the beginning of August in the summer of 2006. This block will aim to have 24 subjects for eight weeks. The differing aspects include an improved glucose tolerance test, more in-depth lipid analysis, and confirmation of the composition of the diets prior to feeding the subjects from the values we obtain from the first block. Assuming a successful feeding trial, these data will be available by December of 2006.

Impacts and Contributions/Outcomes

This project will contribute to all of NCR-SARE’s broad-based outcomes and impact sustainable agriculture in the North Central Region. The NCR SARE’s program benefits the environment by supporting research that provides information to promote sustainable grazing systems that result in soil conservation, improved water quality, and healthier landscapes. The project will add value to milk and beef products raised through pasture-based system and increase market share to increase farmer/rancher profitability.

This project strengthens rural communities by providing options for small to medium dairy and livestock production systems to stay in business by increasing profitability. Each 400-cow dairy operation in northeast Iowa is estimated by Iowa State University to bring in over 16 jobs and nearly $600,000 to local communities each year. The sustainability of these dairies, as well as cattle operations, is dependent on the value of the product they produce. This potential increased value makes this project important to the viability of the rural communities by sustaining the small and medium production systems that provide substantial cash flow.

This project also will impact sustainable agriculture in the North Central Region by providing documentation and education that will increase the demand for CLA-enriched food products that are derived from pasture management systems.

Collaborators: