Protein and Kidney Damage: What Should You Know?

Despite the myths, a high protein diet is safe and doesn't cause kidney or liver damage.

Written and verified by the nutritionist Saúl Sánchez Arias.

Last update: 21 June, 2022

For many years, there was speculation that a high protein intake could cause kidney damage and other health problems. For this reason, a moderate intake of this nutrient, which is essential for our overall health, was discouraged. Then sarcopenia appeared on the scene and has become an increasingly common problem. Keep reading as we take a look at the facts on protein and kidney damage.

Proteins are fundamental structural and homeostatic elements, and are involved in many different processes in the body.

It’s beneficial to ensure a high intake, as we’ll describe below. The first thing to be clear about is that those of animal origin are of higher quality than those of vegetable origin.

Protein and kidney damage: is there a link?

Although it’s true that in people with renal or hepatic pathologies an excessive intake of proteins (and other nutrients) could be inadvisable, in healthy people there’s no reason to pay attention to this recommendation. Quite the contrary.

Current dietary guidelines recommend a daily intake of at least 0.8 grams of protein per kilogram of body weight in sedentary people. In athletes these requirements are easily doubled.

And the most recent research has failed to link protein intake with kidney or liver damage over the years. Quite the contrary. A deficit of these nutrients could affect the tissues, initiating a situation of catabolism.

It’s considered more harmful to propose a diet with little protein than to initiate a type of diet with a high protein content. It’s also recommended to combine the regular intake of proteins of high biological value with the regular practice of physical exercise. This will help you to get the most out of these nutrients. Muscle will remain active and in constant adaptation, avoiding catabolism.

Do proteins affect bone health?

There has also been speculation that proteins could have a negative effect on bone tissue. This isn’t true either.

While a high protein diet may stimulate renal excretion of calcium, this effect hasn’t been linked to osteoporosis. There are even trials, such as one published in the Journal of Frailty, Sarcopenia and Falls, that associate a high-protein diet with a lower risk of fracture.

Current evidence seems to indicate that the key to bone health lies in strength exercise, exposure to sunlight and adequate calcium intake. Consuming enough protein will also make a difference, as it keeps the muscle in a functional state, allowing it to cushion the impacts on the bone.

How much protein to eat?

Regarding the optimal daily dose of protein, there is some controversy.

It seems clear that athletes should prioritize the intake of these nutrients to achieve tissue recovery after exercise. For those who are sedentary, it’s possible that they should also give greater importance to protein, in order to ensure that the muscle remains strong.

However, it’s important to point out that at least half of the proteins in the diet must be of high biological value. We’re talking here about those of animal origin.

They have all the essential amino acids inside and a good digestibility score. As we increase the protein intake, the quality of the protein matters less. But if we’re in the lower ranges of intake, this factor is decisive.

It can even be a good alternative to include supplements in the diet to help meet the requirements. In this case, whey isolates should be the preferred choice, since their concentration is higher. In addition, they don’t contain lactose, a sugar that can cause digestive problems to some people.

Proteins don’t cause kidney damage in the medium term

Proteins don’t cause kidney or liver damage over time, even in high doses. Only in people with some kind of previous pathology would it be necessary to monitor the intake of these nutrients to avoid overloading the organs.

However, we’re talking about very specific situations which aren’t so frequent. It doesn’t apply to the general population.

Finally, it’s important to emphasize that, in addition to meeting protein requirements, it’s essential to achieve a high rate of physical activity. Above all, it’s necessary to prioritize strength work. In this way, inflammation can be controlled and the tissue is always kept functional.