What are the adverse effects of protein supplements?

From the Guidelines

Protein shakes can have potential harms, particularly if consumed excessively or by individuals with pre-existing health conditions, and should be approached with caution to minimize risks to morbidity, mortality, and quality of life. The most recent and highest quality study, 1, suggests that there is no evidence to adjust daily protein intake for health benefits, and research is inconclusive regarding the ideal amount of dietary protein. However, it recommends individualized protein intake goals based on current eating patterns.

Some potential harms of protein shakes include:

• Excessive protein intake (typically above 2g per kg of body weight daily) may strain kidney function, particularly in those with pre-existing kidney issues 1
• Commercial protein shakes may contain added sugars, artificial sweeteners, or heavy metals that could pose health risks with regular consumption
• Digestive problems like bloating, gas, and diarrhea are common side effects, especially in people with lactose intolerance consuming whey-based products
• Weight gain can occur when protein shakes add significant calories to your diet without adjusting other food intake
• Relying too heavily on protein supplements may lead to nutritional imbalances by replacing whole foods that provide essential vitamins, minerals, and fiber

To minimize these risks, it is recommended to:

• Choose high-quality protein products with minimal additives
• Stay within recommended protein intake levels (0.8-2g per kg of body weight daily depending on activity level) 1
• Use protein supplements to complement, not replace, a balanced whole-food diet
• Follow the guidelines for the general population for the recommended intakes of saturated fat, dietary cholesterol, and trans fat, and avoid trans fats 1

From the Research

Potential Harms of Protein Shakes

• Chronic high protein intake (>2 g per kg BW per day for adults) may result in digestive, renal, and vascular abnormalities and should be avoided 2
• Excessive protein intake can have adverse public health consequences 3
• Protein supplements are processed materials and often do not contain other essential nutrients required for the sustenance of a healthy lifestyle 4

Considerations for Protein Intake

• The Recommended Dietary Allowance of protein for a healthy adult with minimal physical activity is currently 0.8 g protein per kg body weight (BW) per day 2
• Dietary intake of 1.0,1.3, and 1.6 g protein per kg BW per day is recommended for individuals with minimal, moderate, and intense physical activity, respectively 2
• Higher protein intakes may help prevent age-related sarcopenia, improve satiety, and lead to greater reductions in body weight and fat mass 5

Protein Supplementation

• Protein supplementation can be beneficial for individuals who have difficulty meeting their protein requirements through regular food sources alone 6
• However, the required protein intake should be obtained from natural food sources and protein supplementation should be resorted to only if sufficient protein is not available in the normal diet 4
• There is no evidence-based link between higher protein diets and renal disease or adverse bone health 5