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Long-Term Benefits of Linoleic Acid In Type 2 Diabetes

High linoleic acid level could reduce type 2 risk by 43 percent, new study found.

Polyunsaturated fatty acids such as omega-3 and omega-6 fatty acids are beneficial for improving lipid profiles in healthy individuals and among patients with type 2 diabetes.

Supplementation with omega-3 fatty acids lowers triglycerides and VLDL cholesterol, but they might also increase LDL cholesterol. Latest evidences suggest omega-3 fatty acids are not related to mortality, hypertension, cardiovascular disease as well as the risk of microvascular complications in patients with type 2 diabetes. Meanwhile, the metabolic effects of omega-6 fatty acids remain largely unknown and there is little available evidence regarding their potential role in the prevention of type 2 diabetes. A pooled analysis of international studies was assessed to find the associations of linoleic acid and arachidonic acid biomarkers with incident type 2 diabetes.

Researchers analyzed data from 20 prospective cohort studies from ten countries, including Iceland, Netherlands, United States, Taiwan, United Kingdom, Germany, Finland, Australia, Sweden, and France. All included study participants were between 49-76 years old with a body mass index of 23.3–28.4 kg/m2 and had data for linoleic acid and arachidonic acid biomarkers at baseline. Any participants with type 2 diabetes at baseline were excluded from the study. Researchers defined incident type 2 diabetes as having one or more of the following criteria: a fasting glucose concentration ≥ 126 mg/dL (7 mmol/L), a glucose concentration ≥ 200 mg/dL (11.1 mmol/L) as measured by a 2-h post-oral glucose tolerance test, new use of insulin or oral hypoglycemic medication, fasting or non-fasting HbA1c concentrations ≥ 6.5%, or by self-reported physician diagnosis in some cohort.

During a follow-up period of 366,073 person-years, 4,347 cases of incident type 2 diabetes were documented. Data from the study show that biomarker levels of linoleic acid were inversely associated with incidence of type 2 diabetes, with a lower risk in continuous analyses per interquartile range (p<0.0001) and in categorical analysis (p<0.0001). The magnitude of the association was significant, with high linoleic acid levels associated with a 43% lower relative risk of type 2 diabetes despite the difference in age, body mass index, sex, race, omega-3 levels, aspirin use, or polymorphism in the fatty acid desaturase (FADS) gene. “The people involved in the study were generally healthy and were not given specific guidance on what to eat. Yet those who had the highest levels of blood omega-6 markers had a much lower chance of developing type 2 diabetes. This is striking evidence!” says Dariush Mozaffarian, senior author of the Friedman School of Nutrition Science and Policy at Tufts University in Middlesex County, MA.

Researchers also reported there was no significant association between levels of arachidonic acid and incidence of type 2 diabetes (p=0.38). Together with previous findings, researchers suggest that high levels of dietary omega-6 fatty acids are not harmful and they actually can lower the risk of type 2 diabetes. “Some scientists have theorized that omega-6 is harmful to health. But based on this large global study, we have demonstrated little evidence for harms, and indeed found that the major omega-6 fat is linked to lower risk of type 2 diabetes,” researchers say.

Multiple races and ethnicities were included in the study, but most participants have European descent causing a low statistical power with respect to differences in other ethnic groups. In addition, there was fewer available data on adipose tissue, which reduced power and precision to assess its relevance for type 2 diabetes. Researchers also noted many of the studies included in this analysis were observational; therefore, they are unable to prove cause and effect between higher linoleic acid levels and reduced risk of type 2 diabetes. Despite these limitations, the findings are relevant and researchers believe that linoleic acid has long-term benefits for the prevention of type 2 diabetes and arachidonic acid is not harmful.

Practice Pearls:

  • Omega-6 polyunsaturated fatty acids (PUFAs), particularly linoleic acid, have long-term benefits for the prevention of type 2 diabetes.
  • Levels of linoleic acid were inversely associated with incident type 2 diabetes, whereas levels of arachidonic were not associated with type 2 diabetes.
  • Omega-6 fatty acids are not harmful and they can lower the risk of T2DM by 43 percent.

References:

Jason W, Matti M, Fumiaki I, Nathan T, Andres K, Janette G, Xia Z, Wei-Sin Y. Omega-6 fatty acid biomarkers and incident type 2 diabetes: pooled analysis of individual-level data for 39 740 adults from 20 prospective cohort studies. The Lancet Diabetes & Endocrinology. 2017 Oct 11.

 

Kay Lynn Tran, Doctor of Pharmacy Candidate: Class of 2018; LECOM College of Pharmacy