Dairy Linked To Lower Outcome Of Type 2 Diabetes

Summary
This study investigates the relationship between the level of trans-palmitoleic acid–a kind of fatty acid–and the occurrence of Type 2 diabetes. Trans-palmitoleic acid, unlike palmitoleic acid, is obtained through a diet rich in diary products and not produced by the human body. It was seen that people with higher levels of trans-palmitoleic acid had a lower incidence of insulin resistance and a healthier lipid profile. It was also associated with a lower outcome of diabetes and other related disorders.

Introduction
Fatty acids in the body can influence certain necessary physiological activities. However, the effects of most of them are yet to be established. Palmitoleic acid is one such fatty acid and research carried out in animals has shown that it could reduce resistance to insulin in the body, thereby reducing the incidence of diabetes. In earlier studies, results from human studies have been inconsistent. The authors attribute the errors to the inherent production of this fatty acid by the liver. Therefore, in this study, trans-palmitoleic acid, which is neither produced nor altered by the liver, was considered for its effects on diabetes and metabolic risk factors.

Methodology

  • The study involved 3,736 adults chosen from the Cardiovascular Health Study (CHS) in USA.
  • All the participants were evaluated for physical fitness and levels of different blood components like lipids etc. Their lifestyle, medical history and risk factors were noted.
  • They were followed up with examinations annually and were kept in contact with the researchers for the next ten years.
  • Another group of 327 healthy women was also considered and results obtained from them were used as comparative data for measuring metabolic risk factors.

Results

  • An increase in trans-palmitoleic acid level was associated with a higher high-density lipoprotein cholesterol (HDL-C) levels, lower triglycerides and lower total cholesterol/HDL-C ratio. These indicate a favorable lipid profile.
  • High levels of trans-palmitoleic acid also led to lower levels of C-Reactive Protein, a component associated with metabolic syndrome and diabetes.
  • Lower resistance to insulin was observed in people with high trans-palmitoleic acid levels.
  • High levels of trans-palmitoleic acid caused significantly lower number of new cases of diabetes.

Shortcomings/Future research
The authors suggest the occurrence of errors while obtaining results and also a biological variability in the parameters assessed. These variations could have biased the study and altered the final results. Blood glucose was not measured annually in this study; this could have altered the diabetic status of the participants. The authors recommend further experiments and clinical studies to completely assess the positive effects of trans-palmitoleic acid.

Conclusion
The positive effects of trans-palmitoleic acid, primarily obtained via dairy products, have been highlighted in this study. They have been shown to elicit a positive effect on the lipid profile as well as on a reduction in insulin resistance, thereby reducing risk of diabetes and related metabolic disorders. Since very low levels of trans-palmitoleic acid are shown to have these effects, further studies are required to assess whether it really is the active component responsible for these effects or whether it is a pointer towards a different protective factor in dairy foods. Nonetheless, with the benefits of its consumption the authors claim, “this fatty acid is a potential candidate for enrichment of dairy foods or supplementation.”

For More Information:
Trans-Palmitoleic Acid, Metabolic Risk Factors and New-Onset Diabetes in U.S. Adults
Publication Journal: Annals of Internal Medicine, December 2010
By Dariush Mozaffarian, MD; Haiming Cao, PhD; Harvard School of Public Health, Boston, Massachusetts and the Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts

*FYI Living Lab Reports Are Summaries of the Original Research.
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