Protein and Life Expectancy

Protein and Life Expectancy

In this article, we will talk about strategies to live longer and how to improve our human biology. Above all, we will discuss how protein is connected to life expectancy.

Everyone knows the modus operandi of Medicine: finding the problem, fixing it and helping the individual to go back to its basal situation. This is how Medicine works in general.

We owe many things to this “Medicine”, which can heal cancer or bone fractures. But there is another type of Medicine, one that is meant to improve our health without us being necessarily sick.

Researchers such as Valter Longo (1) and his team are treading new paths. In fact, they are trying to find out what strategies encourage the longevity in human beings.

Obviously, modern Medicine indirectly assesses the risk factors. That is why doctors waste a lot of time every day trying to convince their patients to stop drinking alcohol, smoking or sedentarism.

But, what can we do to prolong said life expectancy and, even more importantly, our “health expectancy”, that is, living longer and healthier?

Let’s see what we can do

The Role of Protein in Longevity

One of the first things that called my attention was the issue about the protein recommendations

Lately, the tendency shows that we are more permissive and generous when it comes to taking protein. We live in a sarcopenic and obese society. But a big part of the population is starting to change their eating habits. In fact, they are increasing the protein intake while reducing the carbohydrates or fat, which helps to improve the cardiovascular and metabolic risk factors in the short and long term.

The problem comes when we analyze the diets of populations with many centenarians.

Every single one of them, with few exceptions, relate a high protein supply with less survival, more mortality and less longevity

But stay calm. Let me explain, then, those studies that replace carbohydrates with protein are wrong?

First of all, we need to clarify a couple of things:

Low protein intake with age

After reaching a certain age, a low protein intake clearly increases the mortality and fragility (2), specially in those subjects older than 65 years.

In fact, those individuals who follow a low protein diet after this age do not only have a higher risk of total mortality. Moreover, they also have a higher risk of mortality related to cancer when compared to those who follow a normal or hyperprotein diet.

This is understandable because the elderly have a higher anabolic resistance, chewing problems, hyporexia and different habits.

Role of the IGF-1 Hormone

The most popular hypothesis that justifies the protein-survival relation is an anabolic environment led by the IGF-1 hormone. If it remains high for many years, it can stimulate the cell growth (onset of cancer) and lower our survival.

Surprisingly, one of the main positive changes of intermittent fasting or fasting mimicking diets is reducing said IGF-1.

Apart from the IGF-1, the essential amino acid methionine has been put into question. In fact, an excessive intake could explain the deleterious effects of taking too much animal protein (3).

Actually, rats with a low methionine diet live longer, are more resistant to stress (Paracetamol toxic infusion and hepatic damage), lower IGF-1, glucose and insulin (3)

Centenarian populations

Yeah, studying centenarian populations is really cool. But we need to ask ourselves a fundamental questions: can we compare them to us, that is, to a western lifestyle?.

These are a few statements that I believe can answer the question:

  • Few athletes among centenarians: Although they have a very high physical activity. If we put fitness trackers on them, they would easily walk more than 20000 steps every day. We know that physical exercise and muscle damage involve higher protein requirements.
But is it necessary to take the same amount of protein in those who do not associate said muscle damage with physical exercise? Is the protein turnover the same?
  • Much lower inflammation levels among centenarians: which involves a lower protein catabolism and lower anabolic resistance.
Without any doubt, they will use the protein better than us.
  • Healthier digestive system: one of the aspects that we tend to overlook is our digestive system and its ability to absorb macronutrients. Do you believe that 1.8 grams of protein per kg of body weight are always 1.8 grams of protein?
Once again they will use the protein more effectively, even if the net amount is lower.
  • No Obesity or Overweight: One of the reason why we have increase the protein intake is to lose body fat, which helps to deal with obesity and overweight.

Old man doing exercise

Centenarian populations simply do not need more protein/em>

Then, if I follow a high protein diet, will I die soon? The answer begins by answering the following question: are you taking more or less protein that what you should?

Replacing saturated fatty acids for unsaturated ones

The big epidemiological studies state that replacing saturated fatty acids for poly and monounsaturated ones (MUFA and PUFAs) is beneficial for the cardiovascular system.

However, there is still uncertainty when it comes to claiming that fatty acids are harmful for our health.

Rather, it seems to be an additional benefit of MUFAs and PUFAs for cardiovascular health: probably fluidizing membranes, improving the intracellular behavior and reducing the inflammatory processes.

Moreover, by reducing the saturated fatty acid intake we tend to eat less animal protein. Consequently, this also contributes to the previous point.

Do not blame a macronutrient

Blaming a specific macronutrient or sub-macronutrient, such as saturated fatty acids, does not make much sense.

Instead, we should gather a series of findings:

  • Pre-clinical findings (animals)
  • Epidemiological findings (populations)
  • Clinical findings (patients)
  • Centenarian populations (who have achieved it)

Now we can draw more or less interesting conclusions about what factors affect our life expectancy.


Protein can improve your quality of life, although an excess is related to a shorter life expectancy

Vegetable or low protein diets are related to a longer life expectancy.

The challenge seems to be how much protein is too much. In fact, each person has a different situation in this regard. Therefore, the macronutrient percentage is relative and it seems not be determinant.

For instance, even though plant-based and high carb diets tend to be the best for survival, a epidemiological study proved the opposite. The “Health Professionals Follow-up Study” (4) followed 44548 men for 20 years and concluded that low carb and vegetable diets had a lower total and cardiovascular mortality.

Then, is the food quality a key factor? Is it the same to follow a hyperprotein diet with processed and red meat and one based on sardines, wild salmon and legumes?

Obviously, the answer is no.


  1. Brandhorst S, Longo VD. Dietary Restrictions and Nutrition in the Prevention and Treatment of Cardiovascular Disease. Circ Res. 2019;
  2. Levine ME, Suarez JA, Brandhorst S, Balasubramanian P, Cheng CW, Madia F, et al. Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metab. 2014;
  3. Miller RA, Buehner G, Chang Y, Harper JM, Sigler R, Smith-Wheelock M. Methionine-deficient diet extends mouse lifespan, slows immune and lens aging, alters glucose, T4, IGF-I and insulin levels, and increases hepatocyte MIF levels and stress resistance. Aging Cell. 2005;
  4. Fung TT, van Dam RM, Hankinson SE, Stampfer M, Willett WC, Hu FB. Low-carbohydrate diets and all-cause and cause-specific mortality: two cohort studies. Ann Intern Med. 2010;

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About Borja Bandera
Borja Bandera
Borja Bandera, a young doctor dedicated to the areas of nutrition, exercise and metabolism, combines his clinical activity with his vocation for dissemination.
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