Threonine Restriction Promotes Health in Mice
Calorie restriction, eating up to 40% fewer calories while maintaining optimal micronutrient intake, improves health and reliably extends life in most species. In humans it produces robust improvements in health, but we experience a much lesser degree of life extension than short-lived species such as mice. Calorie restriction research has given rise to a number of lines of work in which specific dietary components (such as individual essential amino acids) are restricted, to try to identify which of these components are responsible for the benefits. A sizable fraction of the calorie restriction response is thought to be triggered by low dietary intake of the essential amino acid methionine, for example. In contrast to that body of work, researchers here restrict threonine, another essential amino acid, in laboratory mice, and observe an interesting set of benefits.
The current classification of essential amino acids (EAA) is based on the nutritional requirements for growth and vitality under nil dietary supply of an amino acid. However, humans rarely face dramatic protein/amino acid insufficiency, and for the first time in human history, nutritional excesses mean the amount of overweight people outnumber the amount of underweight people on a global scale. This calls for a reconsideration of amino acid functions in nutrition, now based upon health-related criteria.
One approach is dietary protein dilution (DPD), where protein is reduced and replaced by other nutrient sources, and is distinct from caloric restriction. Unlike severe protein/amino acid restriction, which is not compatible with vitality, moderate DPD promotes longevity in multiple species including flies, rodents, and perhaps humans. Furthermore, DPD also affects health-span and preclinical studies have demonstrated that DPD can retard age-related diseases such as cancer, type 2 diabetes, and dyslipidemia/fatty liver disease. Notably, dietary protein intake rates are positively related to type 2 diabetes risk as well as all-cause mortality in humans.
Here, by mimicking amino acid supply from a casein-based diet, we demonstrate that restriction of dietary EAA, but not non-EAA, drives the systemic metabolic response to total amino acid deprivation; independent from dietary carbohydrate supply. Furthermore, systemic deprivation of threonine and tryptophan, independent of total amino acid supply, are both adequate and necessary to confer the systemic metabolic response to amino acid restriction.
Dietary threonine restriction (DTR) retards the development of obesity-associated metabolic dysfunction. Liver-derived fibroblast growth factor 21 is required for the metabolic remodelling with DTR. Strikingly, hepatocyte-selective establishment of threonine biosynthetic capacity reverses the systemic metabolic response to DTR. Taken together, our studies of mice demonstrate that the restriction of EAA are sufficient and necessary to confer the systemic metabolic effects of DPD.
It's known that L-Arginine increase lifespan in humans. Maybe its possible to make in vitro meat with less of the amino acids that are unhealthy and still have the same taste.
How much more are we gonna keep beating that dead horse of the failed mouse model?
"Dietary threonine restriction (DTR) retards the development of obesity-associated metabolic dysfunction"
Japan is full of unhealthy obese people eating Natto/Edamame beans, fish/shellfish, lamb, beef, eggs, chicken, pork, and seaweed. you know, all these low threonine foods.
I would be really surprised if it turned out that limiting one single group of nutritions,b except probably sugars and fats. In fact, we already have examples of what happens during malnutrition. There results are rarely beneficial.
The only scenario I could think of an aging body cannot correctly process an execs of something and we need to reduce it to go back to the preferred balance or some disease where the adsorption is not working. In this scenario the balance would be huge individual and varying over time
Fwiw, Collagen is significantly lower in Threonine as a percentage of amino acids than muscle meat.
The idea that restriction of specific nutrients can extend life or even healthspan is still far from certain in humans. So many confounding factors such as total caloric intake, individual genetic or epigenetic differences affecting metabolic pathways, activity levels etc all participate. Just think about how different diets/macronutrient compositions work so well for some people and are intolerable/detrimental to others.
But for the sake of argument, lets just assume that eating more complete protein (all ecenciall amino acids) daily was going to take a few years of your lifespan or more realistically, your healthspan. Lets even suppose you might develop cancer or diabetes 5 years earlier than others reaching your old age. Sounds quite bad doesn't it?
However, when you consider the important rolls of protein in maintaining vitality and strength throughout ones life, particularly from childhood to late adulthood, some potential unconfirmed and weakly supported risks really shouldn't take centre stage.
If we must cut out nutrients to extend our healthspan, a good place to start would be refined sugars/carbs, trans fats, oxidised seed oils and heavy metal contamination. I say this despite being a huge fan of carbs personally, I just think it's important to be honest.
Lastly, I personally find complete animal proteins much more filling and far less enjoyable to consume than plant proteins or refined carbs. But the benefits I've experienced from massively increasing animal protein intake include; increased cognition, mood lift and complete reversal of anhedonia, more stable energy, better skin health and decreased compulsive binging on refined/processed high sugar foods. This is despite me actually often having stronger cravings for such foods whilst on a high protein diet. The key to my success I suspect is the extra self-control imparted by ecencial amino acids replenishing important neurotransmitters in the brain.
PS, just a quick additional point that I think is really important. If there turns out to be a strong performance-longevity trade off, especially if that performance includes good mental health, then I'll always choose performance over longevity. What's the point in living longer or healthier, if you must sacrifice the quality of your life?