The Side Effects of Protein Drinks on the Kidneys
Drinking too much protein drinks can be bad for your kidneys. Image Credit: nevodka/iStock/GettyImages
Americans spend billions of dollars on supplements each year in an attempt to improve their health; however, some experts think that high-protein drinks and kidneys aren't a good combination. There's some evidence that consuming too much protein can increase your risk of developing kidney stones.
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However, for most healthy people, the risk is low. On the other hand, if you have kidney disease, you need to monitor your protein intake. It may be best to avoid protein drinks altogether. Always follow the advice of your doctor or a qualified nutritionist who's familiar with your medical history.
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How Your Kidneys Work
To grasp why protein would have an effect on your kidneys, it's helpful to understand how your kidneys actually work. Your kidneys, which are located just below your rib cage on each side of your spine, are one of your body's major filtration organs. Their main job is to filter wastes and any extra fluid out of your blood and then out of your body, through your urine. Your kidneys also filter metabolic byproducts, like acid, to maintain the proper balance of water, salt and electrolytes.
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All of your blood passes through tiny filtration vessels called nephrons, which filter your blood, removing the waste products and returning any necessary nutrients to it. When your kidneys are healthy, they remove waste and extra fluid out of the blood, but allow protein to stay. On the other hand, if your kidneys aren't working properly, some of the protein in your blood can make its way into the nephrons and, eventually, into your urine.
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High-Protein Drinks and Kidneys
Because the kidneys filter everything that comes into your body and your blood, some experts have speculated that consuming too much protein can put excess strain on the kidneys that increases your risk of developing kidney disease.
The theory is that when you eat too much protein or drink too many high-protein drinks, it increases the amount of urea (a waste product that's leftover over after the protein is broken down) in your blood. As a result, the kidneys have to work harder and, eventually, this increased workload can damage the filtration system of the kidneys, leading to decreased kidney function.
But the science doesn't support the theory. Researchers reviewed more than 2,000 studies on protein and kidney function and published their findings in a report in the Journal of Nutrition in November 2018. After looking over previous evidence, they concluded that consuming a high-protein diet (which they defined as 1.2 to 2.4 grams of protein per kilogram of body weight), had a small effect on the filtration rate of the kidneys, but that effect was trivial in people with healthy kidneys.
Researchers went on to say that this small increase in kidney filtration is a normal adaptive response to eating more protein and that it doesn't increase the risk of developing chronic kidney disease. However, it's important to note that this applies only to those with healthy kidneys. If you already have existing kidney disease and you drink too many protein drinks or consume too much protein powder, side effects are more likely.
Protein and Kidney Disease
If you have chronic kidney disease, kidney function is already decreased. Because of this, you have to be extra careful with how much work you make your kidneys do. Healthy kidneys can handle the extra load of excess protein, but damaged kidneys can't. According to the National Institute of Diabetes and Digestive and Kidney Diseases, eating more protein than you need makes your kidneys work harder, and this can speed up the progression of kidney disease.
On the other hand, a March 2018 report in Chronic Diseases and Translational Medicine notes that a low-protein diet may slow the progression of kidney damage in those with moderate to advanced kidney disease or failure. Another report published in PLOS One in November 2018 had the same findings. Researchers also concluded that eating less protein can help improve heart health in those with chronic kidney disease.
A Word About Kidney Stones
Although the research shows that using high-protein drinks doesn't have a significant, long-term effect on healthy kidneys, a July 2013 report in ISRN Nutrition explains that too much protein may increase your risk of developing kidney stones. When you eat a lot of protein or consume too many high-protein drinks, it increases the amount of acid in your blood. In an attempt to buffer this extra acid, your body pulls calcium out of your bones.
All of this extra acid and calcium passes through your kidneys and increases your risk of developing two different types of kidney stones: calcium kidney stones and uric acid kidney stones. The report notes that, if you have a history of kidney stones, your risk may be even higher.
Kidney stones are uncomfortable, and even quite painful, but for the most part, they resolve on their own without any type of invasive treatment. If you drink protein drinks, you can decrease your risk of developing kidney stones by drinking a lot of water. This reduces the concentration of acid and calcium in your urine and increases your urinary output, which can help prevent the formation of stones.
Other Protein Powder Side Effects
Kidney issues may not be a huge concern with protein drinks, but if you overdo it on the protein supplements or whey protein, side effects that have nothing to do with your kidneys are possible. According to Harvard Health Publishing, eating too much protein may set you up for:
High cholesterol
Increased risk of heart disease
Weight gain
Constipation and/or diarrhea
However, Harvard Health also notes that these effects may not be caused by the protein directly, but may be connected to eating the wrong types of protein, like a lot of processed meats, that are also higher in unhealthy fats and artificial ingredients.
Read more: 5 Sketchy Things to Avoid in Your Protein Powder
General Protein Recommendations
There's no definitive answer to how much protein you should eat, since needs may vary based on your age, sex and activity level, but the general recommendation is to stay around 0.8 grams per kilogram of body weight. That means if you weigh 150 pounds, you'd need about 55 grams of protein per day.
Harvard Health Publishing notes that, while your needs may be differ from this general recommendation, it's a good idea not to exceed 2.0 grams per kilogram of body weight, no matter who you are. For a 150-pound person, this would mean staying under 136 grams of protein daily.
However, if you have kidney disease, your goal numbers probably look a little different. Of course, you always want to follow your doctor's recommendations, but the March 2018 report in Chronic Diseases and Translational Medicine notes that a typical low-protein diet for kidney disease provides around 0.6 to 0.7 grams of protein per kilogram of body weight, while a very low-protein diet clocks in at 0.3 to 0.4 grams per kilogram.
Are High Protein Diets Safe For People With Kidney Problems?
People with kidney problems must monitor quality and quantity of proteins in their diet
Highlights Excess load of proteins on kidneys can cause worsen renal condition
Protein intake has to monitored according to renal parameters
Protein is an important nutrient for the body
Diets high in protein are usually recommended for people who are trying to lose weight. A high protein diet refers to a meal plan where protein contributes to around 50-55% or more of the calories. Typically, for all healthy individuals with no medical condition, a high protein diet is pretty safe to follow. But, if you are a kidney patient, you might be required to be a little careful with your protein intake. This is because the kidney function is compromised to eliminate all the waste products of protein metabolism, says nutritionist Neha Dhulla.
High protein diet for kidney patients: important things to know
Excess load of proteins on kidneys can cause damage and worsen the renal condition. Guidance from a nephrologist and a qualified nutritionist is of prime importance.
Intake of protein in kidney patients is typically decided by the doctor based on the severity of the disease, renal parameters, nutrition status and the patient's weight. Because protein cannot be completely eliminated from the diet, it is very important to carefully plan the diet in compliance with the patient.
Also read: No, A High-Protein Diet Is Not Affecting Your Kidney
Ask her if protein-rich foods are harmful for kidney patients and she says that the quality and quantity of proteins - and not protein-rich foods per se - needs monitoring for kidney patients. "Proteins are one of the most essential nutrients that the body requires for growth and maintenance. Thus, it cannot be generalised that proteins are harmful for kidney patients. The source of protein and the quantity of proteins, depending on the patient's severity of kidney damage, has to be taken into consideration. Accordingly, the diet for kidney patients has to be planned," says Neha.
Planning a diet for kidney patients varies at different stages of kidney disease, hence there is no single diet that can be used for all. Every patient is different and hence - the diets have to be customised. "Along with the protein intake, one also has to keep in mind the potassium, phosphorus and the sodium levels of the patient. Also, fluid intake has to be regulated in cases where there is a fluid restriction. This is calculated based on the patient's urine output and dialysis settings," she explains.
People with kidney problems should be careful with their protein intake
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A person with chronic kidney disease who is not on dialysis will have to restrict the intake of proteins depending on the renal parameters, however, a patient who is on dialysis will have some allowance in protein intake. "High-quality proteins like lean cuts of meat, eggs, soy proteins, nut proteins, beans etc are recommended to include in a renal diet. Dairy proteins are usually high in potassium and phosphorus - hence their intake has to be regulated accordingly. Renal protein supplements are also a good option to incorporate high-quality proteins that are low in sodium, potassium and phosphorus," she adds.
Also read: 6 Kidney-Friendly Foods You Must Include In Your Diet
She gives the following tips to improve kidney health
1. Keep yourself well hydrated (Except for end-stage kidney disease where there is fluid restriction)
2. Consume a balanced diet: A balanced diet is the key to keep all the diseases at bay. Ensuring that your diet contributes to all vitamins and mineral requirement is important to stay fit. Restrict your intake of fried, processed and unhealthy foods to a minimum.
3. Keep a check on your weight: Staying in the optimal weight range reduces the risk of developing most of the metabolic diseases. Diabetes, in the long run, is known to affect kidneys adversely. High blood pressure directly affects the kidneys.
4. Routine check-ups should be done at regular intervals.
Also read: Heal Your Kidneys Naturally With These Simple Remedies
Protein-rich foods for weight loss
If you are on a weight loss diet, make sure you choose healthy protein sources. Beans, nuts, lean protein, low-fat dairy products, egg whites, pulses are all included in the list of healthy protein sources. Deep fried and processed meats should be avoided for weight loss. Also, the quality of carbohydrates in a high protein diet plays a very important role. Complex carbohydrates and fibre rich foods have to be included. "However, any high protein diet should always be followed under the strict guidance of a qualified nutritionist," concludes Neha.
(NehaDhulla, Manager - Clinical Practices and Nutrition at Digestive Health Institute by Dr. Muffi)
Disclaimer: This content including advice provides generic information only. It is in no way a substitute for qualified medical opinion. Always consult a specialist or your own doctor for more information. NDTV does not claim responsibility for this information.
7 Effects of Protein Intake on Renal Function and on the Development of Renal Disease
55 to 88 years (Figure 7-6). In both groups, there was a similar pronounced dependence of clearance on protein intake; in the older subjects, a lower intercept was seen, reflecting the effect of age on GFR. If protein intake is not controlled, the apparent decline in GFR with age will be exaggerated, because older subjects consume less protein than younger subjects (Kerr et al., 1982).
Third, Tobin and Spector (1986) measured creatinine clearance in 198 normal men on two occasions, 10 to 18 years apart, and correlated the decline in clearance during this interval with protein intake: no relationship was detected. They found no evidence that a high intake of protein caused a progressive reduction in renal function.
Fourth, high-protein feeding (60%) for 2 years in rats had no effect on the percentage of sclerotic glomeruli (Collins et al., 1990).
Fifth, the progressive decline in renal function seen in rats after partial nephrectomy (Brenner et al., 1982) may be unique to this species. In dogs with 75 percent nephrectomy, GFR does not decline progressively with time for the ensuing 4 years, whether protein intake is high or low (Bovée, 1991). In baboons followed for 5 years after subtotal nephrectomy and on either 8 percent protein or 25 percent protein diets, renal failure did not occur; GFR, measured as inulin clearance, increased sharply in baboons fed 25 percent protein, and this difference tended to disappear with time (curiously, creatinine clearances did not decrease with time in either group). Even in baboons fed 8 percent protein, a slow decline in GFR with time was seen (5% per year). Proteinuria did not differ between the two groups and did not progress (Bourgoignie et al., 1994). In human kidney donors, mild proteinuria (but not albuminuria) is often seen, and the incidence of hypertension may be increased, but progressive renal failure rarely if ever occurs, and there is no correlation between protein intake and proteinuria (Anderson et al., 1985; Hakim et al., 1984). Such individuals are not generally advised to restrict their protein intake (Rocher and Swartz, 1987), although some clinicians have recommended that these individuals do so until the question is settled (Bay and Hebert, 1987). Likewise, protein restriction is not advised for persons with a solitary normal kidney (Mitch, 1989).
From these observations, it is clear that protein restriction does not prevent the decline in renal function with age and, in fact, is the major cause of that decline. A better way to prevent the decline would be to increase protein intake. Indeed, protein malnutrition in the elderly is a far more prevalent problem (Morgan et al., 1956; Rudman et al., 1989) than is nitrogen retention as a consequence of an age-related decline in renal function.
AUTHOR'S CONCLUSIONS AND RECOMMENDATIONS
Concerns about an adverse effect of high protein intake on renal function, and in particular on its decline with age, appear to be ill advised. Putting aside the potential adverse effects of protein intake on nephrolithiasis or on morbidity
