Proteins are the building blocks of life and every living cell uses them for both structural and functional purposes. They are long chains of amino acids linked together like beads on a string, then folded into complex shapes. There are 9 essential amino acids that you must get through your diet, and 12 that are non-essential, which your body can produce from other organic molecules. The quality of a protein source depends on its amino acid profile. The best dietary sources of protein contain all essential amino acids in ratios appropriate for humans. In this regard, animal proteins are better than plant proteins. Given that the muscle tissues of animals are very similar to those of humans, this makes perfect sense.
The basic recommendations for protein intake are 0.36 grams of protein per pound of body weight (0.8 grams per kg) daily. This translates to 56 grams of protein for a 154-pound (70-kg) individual. This meager intake may be enough to prevent downright protein deficiency. Yet, many scientists believe it’s not sufficient to optimize health and body composition.
People who are physically active or lift weights need a lot more than that. Evidence also shows that older individuals may benefit from a higher protein intake.
Protein is an essential macronutrient. Although the recommended daily intake may be enough to prevent deficiency, some scientists believe it’s insufficient to optimize health and body composition.
Protein Does Not Cause Osteoporosis
Some people believe that a high protein intake can contribute to osteoporosis. The theory is that protein increases the acid load of your body, which then causes the body to take calcium out of the bones to neutralize the acid.
Even though there are some studies showing increased short-term calcium excretion, this effect does not persist over the long term. In fact, longer-term studies do not support this idea. In one 9-week study, replacing carbohydrates with meat did not affect calcium excretion and improved some hormones known to promote bone health, like IGF-1.
A review published in 2017 concluded that increased protein intake does not harm the bones. If anything, the evidence pointed to a higher protein intake improving bone health. Multiple other studies show that a higher protein intake is a good thing when it comes to your bone health. For example, it may improve your bone density and lower the risk of fractures. It also increases IGF-1 and lean mass, both known to promote bone health.
Long-term studies show that a high protein intake may improve your bone health. It does not cause osteoporosis.
Protein Intake and Kidney Damage
The kidneys are remarkable organs that filter waste compounds, excess nutrients and liquids out of the bloodstream, producing urine. Some say that your kidneys need to work hard to clear the metabolites of protein from your body, leading to increased strain on the kidneys. Adding some more protein to your diet may increase their workload a little, but this increase is quite insignificant compared to the immense amount of work your kidneys already do. About 20% of the blood your heart pumps through your body goes to the kidneys. In an adult, the kidneys may filter around 48 gallons (180 liters) of blood every single day. High protein intake may cause harm in people with diagnosed kidney disease, but the same doesn’t apply to people with healthy kidneys.
The two main risk factors for kidney failure are high blood pressure (hypertension) and diabetes. A higher protein intake benefits both. In conclusion, there is no evidence that a high protein intake harms kidney function in people who don’t have kidney disease. On the contrary, it has plenty of health benefits and may even help you lose weight.
A high protein intake has been shown to accelerate kidney damage in people who have kidney disease. However, higher protein diets don’t adversely affect kidney function in healthy people.