Too much protein can be dangerous: Hidden health risks you should know

In recent years, high-protein diets have become a popular trend among fitness enthusiasts, athletes, and bodybuilders aiming to build muscle or lose fat quickly. However, a comprehensive review published in the ISRN Nutrition journal warns that consuming protein beyond the recommended dietary allowance (RDA) of 0.8 grams per kilogram of body weight per day may pose serious health risks . After analyzing 32 human studies, researchers found that excessive protein intake, especially from red meat and supplements, can negatively affect bone density, kidney and liver function, and even increase the risk of certain cancers and heart disease. These findings underscore the importance of moderation and medical guidance in protein consumption.


Excessive protein and bone health risks
The study found that consuming excessive amounts of protein can lead to hypercalciuria, a condition characterised by the excretion of excessive calcium through urine. This imbalance depletes calcium reserves from bones, weakening skeletal strength and increasing the risk of osteoporosis and fractures. Women with high animal protein intake showed higher rates of bone loss and forearm fractures. The researchers also noted that calcium supplements were not enough to counter the negative calcium balance caused by excessive protein consumption.


Strain on kidney function
Excessive dietary protein places an additional acid load on the kidneys, elevating the glomerular filtration rate and leading to increased excretion of calcium and sodium. This raises the likelihood of developing kidney stones, particularly uric acid and calcium oxalate stones. Over time, such strain can accelerate kidney function decline, especially in people with pre-existing renal issues.


Increased cancer risk
The review linked high meat and protein intake to a higher risk of several cancers, including colon, stomach, pancreatic, and breast cancers. Cooking meat at high temperatures produces heterocyclic amines, compounds known to be carcinogenic. Saturated fats found in red and processed meats further compound this risk. The findings suggest that moderating red meat consumption and opting for plant-based or lean protein sources could significantly reduce cancer risk.


Impact on liver function
High-protein diets, particularly those relying on supplements, can overburden the liver. The study observed elevated liver enzyme levels (transaminases) and signs of hyperalbuminemia, indicators of liver stress. Though reversible after discontinuing excessive intake, long-term protein overconsumption may harm liver health and metabolism.


Link to coronary artery disease
Participants consuming high-protein diets demonstrated worsened coronary artery disease outcomes, with higher levels of lipid buildup and inflammation in blood vessels. Diets rich in protein and saturated fats were found to exacerbate cardiovascular strain, potentially leading to atherosclerosis and related heart conditions.

Protein is vital for muscle growth, tissue repair, and overall health, but balance is essential. The ISRN Nutrition review urges adults to stay within the safe limit of 0.8 grams per kilogram of body weight per day, unless medically advised otherwise.

Excessive protein, especially from meat-heavy or supplement-based diets, may do more harm than good. Experts recommend diversifying protein sources, such as including legumes, tofu, fish, and nuts, and consulting healthcare professionals before adopting high-protein regimens for long-term wellness.