Side effects of too much protein
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Side Effects of Excessive Protein Intake
Introduction to High Protein Diets
High-protein diets have gained popularity for their potential benefits in weight loss and muscle building. However, consuming protein above the recommended dietary allowance (RDA) of 0.8 grams per kilogram of body weight per day can lead to several adverse health effects. This article synthesizes findings from multiple studies to highlight the potential risks associated with excessive protein intake.
Bone and Calcium Homeostasis Disorders
Excessive protein consumption can disrupt bone and calcium homeostasis. High protein intake, particularly from animal sources, can lead to increased calcium excretion, which may weaken bones over time and increase the risk of osteoporosis 14. This is particularly concerning for individuals who already have compromised bone health.
Renal Function Impairment
One of the most well-documented risks of high protein intake is its impact on kidney health. Chronic high protein consumption can lead to renal dysfunction, including intraglomerular hypertension, hyperfiltration, and glomerular injury, which may progress to chronic kidney disease (CKD) 1278. This risk is exacerbated in individuals with pre-existing kidney conditions, but even healthy individuals may be at risk with long-term high protein diets.
Increased Cancer Risk
High protein intake, especially from animal sources, has been linked to an increased risk of certain cancers. Studies have shown that individuals aged 50-65 with high protein consumption have a significantly higher risk of cancer mortality. This risk is reduced when the protein is derived from plant sources 17. The mechanisms behind this increased risk may involve growth hormone receptor/IGF-1 signaling pathways, which are influenced by protein intake.
Liver Function Disorders
Excessive protein intake can also adversely affect liver function. Chronic consumption of high amounts of protein, particularly from supplements like whey protein, has been associated with liver stress and potential liver damage 12. This is particularly concerning for individuals who consume protein supplements without professional guidance.
Cardiovascular Health Risks
High protein diets have been linked to an increased risk of coronary artery disease. The consumption of large amounts of protein, especially from red and processed meats, can lead to the progression of atherosclerosis and other cardiovascular issues . This is due to the high levels of saturated fats and cholesterol often found in animal protein sources.
Other Adverse Effects
Additional adverse effects of excessive protein intake include:
- Aggression and Acne: Some studies have linked high whey protein consumption to increased aggression and acne .
- Microbiota Alteration: High protein diets can alter gut microbiota, potentially leading to digestive issues and other health problems .
- Diabetes Mortality: High protein intake has been associated with a five-fold increase in diabetes mortality across all age groups .
Conclusion
While protein is an essential nutrient for various bodily functions, excessive intake can lead to several adverse health effects, including bone and calcium homeostasis disorders, renal and liver dysfunction, increased cancer risk, and cardiovascular issues. It is crucial to balance protein intake and consider the source of protein to mitigate these risks. Further research, particularly large randomized controlled trials, is needed to fully understand the long-term effects of high protein diets on human health.
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