Leaning towards a healthy pork diet

KM_GCClearly explaining the health benefits of lean pork consumption has been the focus of the last six years of Dr Karen Murphy’s work with colleagues at the Nutritional Physiology Research Centre, University of South Australia. A Senior Research Fellow and registered nutritionist, Karen graduated from RMIT University with a PhD in nutritional biochemistry exploring the health benefits of bioactive nutrients including lipids, fatty acids and cocoa polyphenols.

Since returning to Adelaide in 2002 to undertake a Post-Doctoral Research Fellowship and then NHMRC Industry Research Fellowship at UniSA, she has extended her research to scientifically substantiate the cardiometabolic and cognitive health benefit of foods, bioactive nutrients and dietary patterns. Some of her past research has focussed on exploring cardiovascular benefits of long chain omega-3 fatty acids, dairy foods, tea, cocoa antioxidants and lean pork.

Of particular interest to Karen was why Australian’s are low consumers of pork compared to other meats such as beef and chicken. Apart from anecdotal evidence that perhaps pork was perceived as a less healthy meat than chicken or beef, there appeared to be no good reason why this was so, given pork’s similar nutritional content to beef.

CRC research

Karen’s first Pork CRC funded research aimed to examine whether regular consumption of fresh, lean pork could improve body composition and cardiovascular risk factors in a six month parallel intervention trial.

This trial recruited 164 overweight adults who were randomly assigned to incorporate up to 1 kg pork/week by substituting for other foods or asked to maintain their regular habitual diet. The team measured plasma levels of lipids, glucose and insulin, plus such indicators of body fatness as body mass index and waist/hip circumference and blood pressure, heart rate and arterial compliance (arterial elasticity) at the beginning of the trial and then again at three and six months. A total of 144 volunteers completed and volunteers in the pork group increased their intake 10 fold by substituting pork for mainly beef and chicken. After three months, there were significant reductions in weight, BMI, waist circumference, percentage body fat, fat mass and abdominal fat in the pork group relative to controls, which persisted for six months. There was no change in lean mass, indicating that the reduction in weight was due to loss of fat mass. Lipids, glucose, insulin and blood pressure did not change.

Pork’s place

These findings were evaluated in a subsequent trial, as it was unclear whether these effects on body composition were specific to pork, or whether consumption of other high protein meat diets may have the same benefit. The team conducted another trial to compare regular consumption of pork with the two most commonly consumed meats in Australia, chicken and beef, on indices of adiposity in a nine month cross-over intervention trial. Forty nine overweight or obese adults were randomly assigned to consume up to 1 kg/week of pork, chicken or beef by incorporating it into their regular diet for three months at a time. Interestingly, the researchers found no difference in body mass index or any other marker of adiposity between consumption of pork, beef and chicken diets, indicating pork is no different to chicken or beef in terms of effects on body composition.

What’s on

This research formed the basis for the current Pork CRC funded project with Pork PhD Scholar Nerylee Watson, to evaluate the effects of a high pork protein energy restricted diet and a low pork protein energy restricted diet on weight loss, glycaemic control, cardiometabolic health and cognitive performance in men and women with type 2 diabetes. This project is currently running and is due to finish in March 2015.

Her team has recently completed a project exploring attitudes towards fresh Australian pork in 104 volunteers who had participated in one of Karen’s trials. Volunteers completed food frequency questionnaires and a written questionnaire to determine if attitudes about consumption of pork had changed before and after participating in one or both of the trials. All volunteers, including those who acted as controls in the previous trials indicated that their pork consumption had increased since participating in the trials. Most volunteers, including controls, felt the opportunity to learn more about the health benefits of pork contributed to their increase in pork consumption. In addition, those who had been required to consume pork during the intervention trials indicated that while learning more about the potential health benefits of pork had contributed to their increased consumption, so had receiving recipe books which had allowed them to prepare and consume different cuts of pork as part of tasty and enjoyable meals. Overall, pork was seen in a positive light, but more so after participation in the dietary intervention trial.

Pork poppy

Karen is a recipient of 23 research awards, including the prestigious South Australian Young Tall Poppy Award (2009). She has received close to $3 million in research funding and regularly supervisors Honours and Post-graduate students.