We live in an era when a large proportion of people in the world are overfed but undernourished. A big part of the problem lies with the over-reliance on ultra-processed foods. However, there is also a lot of confusion about what constitutes a ‘healthy, balanced diet’ and the best way to feed ourselves for optimum health.
In today’s nutrition landscape, meat remains one of the most controversial yet nutrient-dense foods available. Over the coming months, we are going to dive into a range of different topics related to the nutritional value of meat, but for now, let’s start with the basics.
Protein
Meat is probably best known as a great source of high-quality protein. But what is it about the protein in meat that makes it nutritionally important?
Protein is one of three primary macronutrients that provide energy to the human body, along with fats and carbohydrates. However, the importance of protein to our health and well-being goes well beyond energy. Protein plays a foundational role in how our body functions, heals and stays in balance. Every single cell in our body contains and uses protein.
Different proteins are responsible for a large portion of the work that is done in cells; they are necessary for the proper structure and function of tissues and organs. Without sufficient protein, our bodies cannot operate optimally. However, not all sources of protein are equal in their ability to provide what we need.
Protein is made up of different amino acids, which are the building blocks our body uses to grow, repair and maintain tissues. There are 20 different amino acids in total, and the sequence of amino acids determines a protein’s structure and function.
While some amino acids can be synthesised in the body, there are 9 amino acids that humans can only obtain from dietary sources, which are termed essential amino acids. Foods that provide all the essential amino acids are called complete protein sources and include all animal sources of protein (meat, dairy, eggs, fish).
Meat is a particularly good way to get all the essential amino acids in the right proportions, as its amino acid profile is almost identical to that of our own muscles. This is particularly important for efficient protein synthesis in the body.
If we have all the essential amino acids in the right proportions simultaneously, then our bodies can build whatever proteins they require.
It’s a bit like having all the right LEGO blocks available for the model you want to create when you need to build it!
Protein from animal sources is also a highly digestible source of protein, meaning that the body can efficiently absorb and utilise the protein it contains. This makes meat a particularly efficient way of delivering the protein we need for a given weight of food or number of calories.
Whilst the exact proportions and numbers will depend on the type of meat, one serving (85g) of cooked red meat can provide 50% of the average person’s daily protein requirement for approximately 8% of their total calorie intake. That’s one reason that including high-quality sources of protein is important as part of weight management or loss.
The other way that high-quality protein can support our ability to manage our weight is its impact on satiety – feeling full after a meal. Protein is relatively hard for the body to digest; consequently, it stays in the stomach and small intestine longer, leading to a sustained feeling of fullness.
The energy we derive from protein is also gradually released into our bloodstream. In combination, this means that protein in the diet is an important strategy in managing our hunger levels and our overall energy intake.
Nutritional density
In addition to being an excellent source of complete, highly digestible protein, meat is also extremely nutrient-dense. It contains a wide range of the different vitamins and minerals we need for optimum health in their most bioavailable forms. Bioavailability refers to the body’s ability to digest, absorb and convert the nutrients in food to the forms of those nutrients required for functionality in the body. Whilst a food can contain a high amount of a certain nutrient, that does not mean that our bodies have full access to that nutrient.
A good example to illustrate this is Vitamin A. Our bodies require vitamin A in the form of retinol, otherwise known as pre-formed Vitamin A.
The best sources are generally animal foods, whilst plant foods like carrots contain the precursor to Vitamin A, beta-carotene, which needs to be converted.
Generally, conversion is relatively poor, and significantly larger amounts of the precursor are required compared to the pre-formed version.
This situation is exacerbated in individuals with a genetic variation that reduces their ability to convert beta-carotene to retinol.
Iron is another key nutrient that is found in different forms in different foods. The two types of iron in food are haem and non-haem iron. Haem iron found in meat is much easier for the body to absorb and use than non-haem iron found in plant foods such as spinach.
Additionally, meat improves the uptake of non-haem iron, so a combination of meat with plant-based sources improves the body’s ability to absorb this critical mineral.
Below is a rundown of some of the key vitamins and minerals provided by meat and why we need them.
Over the coming months, we will be providing some more in-depth insight into some of these key nutrients, their role in our health and why animal products are a key way to ensure we are getting enough in our diets.
- Vitamin A is essential to the normal structure and function of the skin and mucous membranes, such as in the eyes, lungs and digestive system. It is particularly important in relation to growth, maintaining healthy vision, the immune system and red blood cell formation.
- Vitamin B12 is an essential nutrient that is important for red blood cell production, nerve and brain health, and DNA synthesis. Animal-derived foods, such as meat, are the only good dietary sources of vitamin B12. Meat also supplies several other B vitamins, including B3 and B6, important for energy metabolism and a range of other functions in the body.
- Vitamin D is important for bone formation, immune health, in particular, reduced levels of inflammation, muscle tone and function, and the metabolism of minerals, including calcium.
- Selenium is a powerful antioxidant that helps protect cells from damage caused by free radicals and serves a variety of functions in the body, including the production of thyroid hormones.
- Zinc is involved in numerous enzymatic reactions in the body, including immune function, wound healing, brain development and functioning, and DNA repair.
- Iron is important for oxygen transport, energy metabolism, and immune function. Meat is one of the best sources of haem iron, which is the form easiest for the body to absorb.
As well as providing an impressive array of vitamins and minerals, meat also provides a range of different antioxidants which help to prevent damage to cells and reduce inflammation. A key one of these is glutathione, with higher amounts in grass-fed beef than in grain-fed.
In fact, typically compared to grain-fed beef, grass-fed beef has a higher overall antioxidant content. This is because the nutritional value of meat depends on the feed of the animal. This also applies when we look at the fatty acid profile of meat.
Fat
As with all real foods that contain fat, meat contains a range of different types of fat, known as fatty acids. Whilst some people avoid meat over concerns about its saturated fat content, about 50% of the fatty acids in beef are monounsaturated or polyunsaturated. In fact, the main fatty acid in beef is oleic acid, the main monounsaturated fat found in olive oil.
Meat is also a valuable source of long-chain omega-3 polyunsaturated fats (EPA and DHA), considered essential fatty acids for health, as we are very poor at converting short-chain fatty acids into these versions. Fats such as omega-3 and oleic acid are essential for heart health, brain function, and reducing inflammation in the body.
Grass-fed beef usually contains less total fat than grain-fed beef, and the composition of fatty acids is also different. Grass-fed beef contains similar amounts of omega-6 polyunsaturated fatty acids to grain-fed beef. However, it contains up to five times as much of the long-chain omega-3 polyunsaturated fats, providing a more favourable omega 6:3 ratio.
Additionally, beef and lamb contain another beneficial fatty acid called conjugated linoleic acid (CLA), with grass-fed beef having about twice as much as grain-fed.
Over the coming months, we will be exploring some key misconceptions about eating meat, including issues concerned with saturated fat and the link to heart disease, and the different reasons you might think eating meat is bad for your health.
Spoiler alert – a lot of what you may think you know about meat is not based on modern, robust scientific evidence, and in combination with other whole foods, meat can form the basis of a healthy, balanced diet that supports our overall physical and mental health.
