Beef Nutrition Study
A study comparing pasture-raised beef with grain-finished beef and with plant protein.
Not all protein foods are equally nutritious, as a study comparing pasture-raised beef with grain-finished beef and with plant protein, has revealed. Scientists at the Riddet Institute and Massey University conducted the research as part of, The Role of Red Meat in Healthy and Sustainable New Zealand Diets, a programme funded by the Meat Industry Association of New Zealand, Beef + Lamb New Zealand, the High-Value Nutrition National Science Challenge and the Ministry of Business, Innovation and Employment.
Most New Zealanders know a healthy diet calls for a balance of fruit, vegetables, grains, milk and milk products and protein foods – along with treats, of course (think hot chocolate on a winter’s evening.) When considering the protein part of a meal, though, scientists at the Riddet Institute, and others, say what is often missing from conversation is an understanding that not all protein foods are equal. Protein derived from an animal source (a juicy barbecued steak, for example) is 100 percent available to the human digestive system. Meat lover or not, also on most people’s plates is protein derived from plants (such as beans and lentils) which have a different nutrition profile and bioavailability, ranging from 40 percent to 80 percent.
New research by scientists, led by Drs Lovedeep Kaur and Mike Boland, has compared pasture-raised beef (the predominant beef system across New Zealand) with grain-finished beef, and a plant-based alternative. Their work forms part of the larger research programme, The Role of Meat in Healthy and Sustainable New Zealand Diets.1
The research team examined how the human digestive system responds to differing food compositions and how the component proteins and lipids (fats and oils) within those foods are released for our bodies to use. To understand this, they employed laboratory-based ‘in vitro’ digestion simulators, imitating how a human digests food in the stomach, and beyond.
The scientists confirmed that while an animal’s protein composition is largely determined by its genetics, the composition of fat in an animal is largely affected by what it has been eating.
They found protein from both the pasture-raised and grain-finished beef was digested by the human body in a similar way - but there were significant differences in the way lipids were digested with meat from pasture-raised animals. Meat digested from the pasture-raised New Zealand beef showed higher total amounts of free long-chain omega-3 polyunsaturated fatty acids (PUFAs) and lower amounts of free, long chain saturated fatty acids (SFAs), than meat from grain-finished cattle. The role of long chain SFAs in increasing the risk of cardiovascular disease and, conversely, that of omega-3 PUFAs in providing health benefits is well established in food science research2.
As these fatty acids are reported to promote lowering of total cholesterol and fats in the bloodstream of people with high blood cholesterol, dietary intake of long-chain omega-3 PUFAs is recommended in guidelines worldwide (the United Nation’s Food & Agriculture Organization, United States Department of Health, as well as dietary guidelines here in New Zealand from the Ministry of Health, Health Navigator and the Nutrition Foundation).
This finding makes for potential health benefits of consuming pasture-raised beef, say Drs Kaur and Boland. They found that the plant-based alternative tested in this study had no long chain omega-3 PUFAs, as well as showing much lower protein digestibility. Dr Kaur says the research also highlights that meat protein is generally highly digestible, and meat with higher digestibility is better for the human body.
“Scientists generally agree that higher rates of release of amino acids – protein building blocks – during the digestion of meat leads to beneficial effects in muscle in the human body, such as maintenance or gain in muscle mass. This is particularly important for the elderly in managing sarcopenia – the muscle wasting that occurs as we age – and for athletes who want to increase muscle mass, for example.”
Adequate protein intake varies depending on gender and age – teenage boys and pregnant and breast-feeding women also need more – as its main role in the human body is to generate growth and repair. It helps in the formation of muscles, hair, nails, skin and organs, such as the heart, kidneys and liver.
Drs Kaur and Boland are part of the Riddet Institute’s Sustainable Nutrition Initiative, which aims to create a better understanding of the food system and opportunities for improvement in order to sustainably feed the global population with the nutrients required by the human body. The meat research programme they led focussed on not only analysing and improving the nutritional value of foods, including meat and plant-based foods, but also improving the quality of meat and meat products, particularly low-value meat cuts or improving tenderness of muscle cuts, says Dr Kaur.
“Some of the innovative technologies we are continuing to develop include how to more rapidly achieve the optimum texture that is usually the result of a longer cooking time. This research will help to position our primary sector to earn more from what are currently lower value cuts.”
A further note on the research methods of the study, supplied by Riddet Institute:
The standard Riddet static in vitro digestion model was used (based on Minekus et al., 2014) to study protein and fat digestion of samples of beef meat from grain and grass-fed animals (n=5). The digestion model simulates oral, gastric and small-intestinal digestion. A non-meat food was chosen a control to compare with the meat samples. Both meat and non-meat samples was processed using common processing techniques before testing for digestibility.
1 The research undertaken by the Riddet Institute is the second part of The Role of Red Meat in Healthy and Sustainable New Zealand Diets study. Part one, undertaken by AgResearch, analysed the overall nutritional profiles of beef, both pasture-raised and grain-finished. University of Auckland researchers are now overseeing the final two stages – clinical studies investigating both the short-term and long-term wellbeing and health effects of red meat consumption. The research programme is funded by the Meat Industry Association of New Zealand, Beef + Lamb New Zealand, the High-Value Nutrition National Science Challenge and the Ministry of Business, Innovation and Employment.