CAMBRIDGE, England and BOSTON —Higher levels of biomarkers of dairy fat consumption are associated with lower risk of developing type 2 diabetes, according to new research published today in PLOS Medicine. The study in more than 60,000 adults was undertaken by an international consortium led by scientists at the Medical Research Council Epidemiology Unit, University of Cambridge, and the Friedman School of Nutrition Science and Policy at Tufts University.
International nutritional guidelines commonly recommend regular consumption of dairy products as an important source of key nutrients, and in high-income countries, low-fat dairy products are encouraged as part of overall recommendations to limit saturated fat consumption. In some research, consumption of dairy products, in particular yoghurt and cheese, has been associated with a lower incidence of type 2 diabetes. But these findings are inconsistent and the evidence remains controversial.
The FORCE Consortium was established by researchers from Europe, North America, Australia, and Asia to examine the relationships of fatty acid biomarkers with diseases. Biomarkers are tell-tale molecules in the body that can be measured accurately and consistently, and act as indicators of dietary consumption.
Concentrations in body tissue of certain types of fat—called odd-chain saturated fats (15:0, 17:0) and natural trans fat in ruminants (trans 16:1n7)—have been found to correlate with consumption of fat-rich dairy foods, both in self-reported studies and in intervention studies where participants eat a controlled diet. These biomarkers offer a complementary approach, alongside self-reporting of food consumption, to investigate associations of dairy fat consumption with type 2 diabetes in large populations.
The researchers examined specific biomarkers of dairy fat consumption from a total of 63,682 adults from 16 multi-national studies that are part of the FORCE Consortium. These participants were all free from type 2 diabetes when the first samples were taken, and 15,158 of them went on to develop type 2 diabetes over the follow-up period of up to 20 years. In each of the studies, the researchers analysed the relationships of dairy fat biomarkers with the risk of developing type 2 diabetes.
When all the results of the 16 studies were pooled the researchers found that higher concentrations of dairy-fat biomarkers were associated with lower risk of developing type 2 diabetes. This lower risk was independent of other major risk factors for type 2 diabetes including age, sex, race/ethnicity, socioeconomic status, physical activity and obesity.
For example, if people among the top fifth of the concentrations of dairy-fat markers were compared with people among the bottom fifth of the concentrations, the top-fifth people had an approximately 30 percent lower risk of type 2 diabetes.
Lead author, Dr. Fumiaki Imamura from the MRC Epidemiology Unit, University of Cambridge, said: “Our results provide the most comprehensive global evidence to date about dairy fat biomarkers and their relationship with lower risk of type 2 diabetes. We’re aware that our biomarker work has limitations and requires further research on underlying mechanisms, but at the very least, the available evidence about dairy fat does not indicate any increased risk for the development of type 2 diabetes.
“We hope that our findings and existing evidence about dairy fat will help inform future dietary recommendations for the prevention of lifestyle-related diseases.”
Senior author Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University, said: “While dairy foods are recommended as part of a healthy diet, U.S. and international guidelines generally recommend low-fat or non-fat dairy due to concerns about adverse effects of higher calories or saturated fat. Our findings, measuring biomarkers of fatty acids consumed in dairy fat, suggest a need to re-examine the potential metabolic benefits of dairy fat or foods rich in dairy fat, such as cheese.”
Despite the several advantages of evaluating fatty acid biomarkers, the researchers caution that the results cannot distinguish between different types of dairy foods (e.g., milk, cheese, yoghurt, others), which could have differential effects. While these biomarkers are known to reflect dairy fat consumption, levels of the biomarkers could also be influenced by other known or unknown factors or may not be exclusive to dairy intake. Data from non-white populations was also limited, and the authors recommend that further research should be undertaken in diverse populations where different types of dairy products may be consumed with different food preparation methods.
For copies of the paper or to speak to Dr. Imamura, please contact the MRC Press Office on 0207 395 2345 or email: [email protected]
To speak with Dr. Mozaffarian, please contact Lisa LaPoint at [email protected] or 1 617 636 3707.
For funding and conflicts of interest information, please see the study.
Imamura, F. et al. (2018) Fatty acid biomarkers of dairy fat consumption and incidence of type 2 diabetes: a pooled analysis of prospective cohort studies. PLoS Medicine. https://doi.org/10.1371/journal.pmed.1002670
About the Friedman School of Nutrition Science and Policy at Tufts University
The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school’s five divisions – which focus on questions relating to nutrition and chronic diseases, molecular nutrition, agriculture and sustainability, food security, humanitarian assistance, public health nutrition, and food policy and economics – are renowned for the application of scientific research to national and international policy.
The MRC Epidemiology Unit studies the genetic, developmental and environmental factors that cause obesity, type 2 diabetes and related metabolic disorders. The outcomes from these studies are then used to develop strategies for the prevention of these diseases in the general population. It is based at the University of Cambridge. www.mrc-epid.cam.ac.uk
The Medical Research Council is at the forefront of scientific discovery to improve human health. Founded in 1913 to tackle tuberculosis, the MRC now invests taxpayers’ money in some of the best medical research in the world across every area of health. Thirty-three MRC-funded researchers have won Nobel prizes in a wide range of disciplines, and MRC scientists have been behind such diverse discoveries as vitamins, the structure of DNA and the link between smoking and cancer, as well as achievements such as pioneering the use of randomised controlled trials, the invention of MRI scanning, and the development of a group of antibodies used in the making of some of the most successful drugs ever developed. Today, MRC-funded scientists tackle some of the greatest health problems facing humanity in the 21st century, from the rising tide of chronic diseases associated with ageing to the threats posed by rapidly mutating micro-organisms. The Medical Research Council is part of UK Research and Innovation. https://mrc.ukri.org/
About the University of Cambridge
The mission of the University of Cambridge is to contribute to society through the pursuit of education, learning and research at the highest international levels of excellence. To date, 90 affiliates of the University have won the Nobel Prize. Founded in 1209, the University comprises 31 autonomous Colleges, which admit undergraduates and provide small-group tuition, and 150 departments, faculties and institutions.
Cambridge is a global university. Its 19,000 student body includes 3,700 international students from 120 countries. Cambridge researchers collaborate with colleagues worldwide, and the University has established larger-scale partnerships in Asia, Africa and America.
The University sits at the heart of one of the world’s largest technology clusters. The ‘Cambridge Phenomenon’ has created 1,500 hi-tech companies, 14 of them valued at over US$1 billion and two at over US$10 billion. Cambridge promotes the interface between academia and business, and has a global reputation for innovation. www.cam.ac.uk