How important is the lysine content in proteins?

If you have ever dealt with different dietary options, you have certainly encountered some basic requirements for the protein content of your diet. The recommended daily intake is usually given as 1 g / kg body weight or 0.8 g / kg Lean Body Mass. It may be minimal rather than the recommended protein intake, as not all amino acids are useful to the body. From my point of view, I want to show you the most interesting moments from the lecture of Dr. Peter Ballerstedt, who spoke at the Low Carb San Diego 2021 conference. It is interesting that some things that are very clear to animal breeders and used for their optimal nutrition are unknown or not used in human nutrition. And lately, the situation has worsened due to the ideology of climate change or animal welfare.

The main topic is the usability of the proteins we eat. You may know that proteins are made up of amino acids. Amino acids are like the dices of the LEGO building block kit from which all life on Earth is built. You probably have no idea how perfect this kit is. Unlike a children's kit, it contains only 21 components. Really! Only twenty-one dice. From this you can build all living organisms, all enzymes, nanomachines of our factories (cells), automatic machines, production lines, contro! machines, sensors and motors. We basically have two categories of these components, essential, we don't make them ourselves and we have to get them in our food, there are nine of them, and non-essential ones, our body can make them ourselves, there are twelve of them.

There is a different representation of individual amino acids in different foods. If an amino acid is missing to assemble the desired protein, the protein cannot be assembled and excess amino acids are excreted.. Animal keepers have to deal with this, because these nitrogen-containing feces are harmful to the environment. We can demonstrate this in this example.

Lysine deficiency reduces the utilization of other proteins (Unbalanced barrel) and the effect of its supplementation (Barrel with added lysine)

The most deficient amino acid is lysine. Lacking lysine is a major problem in protein intake. The body uses only as much protein as its lysine content allows. Thus, lysine supplementation can achieve higher protein utilization. Conversely, with a lysine-poor diet, it is easy for your protein intake to be deficient, even if weight of it seems to be fine. Tables from many countries around the world indicate that protein intake is insufficient in many countries. This is manifested by typical signs of malnutrition. But what is surprising if we adjust protein intake according to digestability and lysine content, even in the US, about 40% of people, especially women, are malnourished. They just don't have all the amino acids.

And what would you say that enough protein affects the fat content in the body. For example, the fat content of pork can be reduced by adding lysine to the feed. This will significantly increase the usability of proteins, especially from plant sources. You can see the difference in the following picture of the meat marbling scale, marked by arrows.

The whole thing is related to the effort to protect the environment as much as possible. You need to get rid of ideology and really start using the available data. Otherwise, the human effort to improve things will result in senseless measures that will only make the situation worse, both in terms of a healthy diet and in terms of environmental impact. If we correct the ecological load according to the usability of lysine, we get these interesting graphs. Make your own opinion.

Greenhouse gas (GHG) production per tonne of protein for various products, right after correction for absorbable lysine content (from left wheat, rice, maize, eggs, pork, milk)

Water consumption per tonne of protein for different products, right after correction according to the content of absorbable lysine (from left wheat, rice, corn, eggs, pork, milk)

Even more telling is the carbon footprint graph, which takes into account other critically missing nutrients.

But that is not all. The protein content can be very easily degraded by further processing. And again, the amino acid lysine plays a key role in this. It degrades easily, combines with simple sugars and is then poorly absorbed (so-called glycation). In this study, they tested three specially prepared milk powders. Lysine was glycated by heat treatment at 50 ° C (55 and 504 hours) and deteriorated from the original 3% to 20% and 50%, respectively. Lysine absorption, as measured by blood lysine content, was reduced by up to 92%.

Area under the curve (AUC) indicating glycine absorption at 3%, 20% and 50% glycation (GLYC)

Cereals are the world's largest source of protein in the table. Many countries do not have enough quality protein for their people, so cereals could be considered a relatively good source. However, the content of absorbable lysine is only about 50%, in addition, we modernize the content of valuable lysine even more by modern processing, the worst example is extruded chips (1% of usable lysine). Baking is also one of the worst ways of processing grain (20% usable lysine). Cooking will probably be more gentle, but any heat treatment of proteins in the presence of carbohydrates (sugars) will reduce the content of absorbable lysine even more. It's like throwing protein in the trash. So isn't it easier and more environmentally friendly to eat animal protein?

Ruminants can use lysine-poor plant foods and elevate content of lysine. Things that seem clear and unambiguous at first glance turn out to be more complex and often quite the opposite. Engagement for certain ideologies is not a good precondition for an objective assessment of the benefits and risks of directives and recommendations. In particular, the responsible institutions should honestly and objectively evaluate the benefits and problems they cause.