Is Too Much Protein Bad for You?
The health community was up in arms recently over a March 2014 study by the University of Southern California that equated eating too much protein to cigarette smoking. After tracking 6,318 adults over two decades, the researchers claimed that consuming a high animal-protein diet during middle age doubles the risk of mortality and the chance of developing cancer by four times. For the study, a high-protein diet qualified as getting at least 20 percent of daily calories from protein.
The possible reason behind the perceived risk is that protein regulates the hormone IGF-I, which helps the body grow, but is linked to cancer vulnerability. The study also confirmed that eating more protein after age 65 aided in disease prevention and protection.
The National Health Service in the UK, however, pointed out several flaws in this research. For example, it did not take physical activity into consideration, the participants’ diets were monitored only over an initial 24-hour period, and it was based on data not specifically collected for this study.
The recommended dietary allowance (RDA) of daily protein varies by gender, age, and body size. In general, the approximate RDA is 46g for adult women and 56g for adult men. However, a standard clinical recommendation is 0.8g of protein for every kilogram (2.2 pounds) of body weight, according to registered dietician Carmen Roberts. She also notes that extreme athletes or people in times of growth need to consume a higher amount of protein than the average person. This includes children, pregnant women, and body builders. You also need more protein when you’re older than 65. This is because we lose lean body mass as we age.
So, can too much protein be harmful for your health? Here’s the real story behind some of the common claims.
The claim: It can damage your kidneys
One of the major concerns with high-protein intake is how it affects the kidneys. A 2003 study found that for people with kidney problems, a low-protein diet helps slow renal kidney failure. However, it also noted that the impact of a high-protein diet on healthy individuals with no kidney problems is unknown. The New York Times has cited several studies finding that high-protein diets do not harm kidneys of healthy adults. But it does increase the decline of kidney function in people with kidney insufficiency or disease.
People with kidney disease need to carefully monitor their protein intake because damaged kidneys can’t filter properly. Too much protein can strain the kidneys, making it harder to eliminate waste products. So patients with kidney disease are advised to follow a low-protein diet.
Also, excessively high-protein diets could put an extra load on the kidneys if followed for a very long period of time, says Roberts. This wear and tear on the kidneys can cause renal deficiency because the kidneys can only filter so much. When your body digests and breaks down protein, one of the byproducts is nitrogen. “Putting excessive nitrogen load on your kidneys can lead to kidney problems over a long period of time,” explains Roberts.
The bottom line: No need to worry too much. Unless you’re gulping down protein shakes every hour and eating a rotisserie chicken for each meal, chances are you’re not consuming enough protein to damage your kidneys.
The claim: It’s bad for your liver
Severely damaged livers can’t process proteins correctly, resulting in toxic waste buildup that can negatively impact the brain. Another toxic by-product of protein is ammonia. The liver breaks down ammonia before it is filtered out through the kidneys. According to the National Liver Foundation of India, too much protein can hurt people with liver disease because it increases the amount of ammonia in the blood.
The bottom line: Still, unless you have severe liver disease and/or damage, high amounts of protein won’t hurt your liver.
The claim: It’ll hurt your heart
This belief may center more on quality rather than quantity of protein. Red meat is often tied to heart disease risk, but this theory is shot down by other studies suggesting there’s not sufficient evidence linking the two. One thing that is certain is that red meat contains a lot of saturated fat, which is directly tied to heart disease. Roberts suggests people look for higher quality, heart-healthy protein sources to include in their diet instead of only red meat. The Harvard School of Public Health has said that replacing red meat with healthier protein options, such as fish, can reduce cardiovascular risk.
The bottom line: Mix up your diet. Swap out the steak and burgers a few times a week for fish, chicken and beans. Your heart (and your waistline) will thank you.
The claim: It will lead to osteoporosis
Protein comprises about 50 percent of human bone volume and one-third of bone mass. Some researchers believe a high-protein diet leads to increased acidity in the blood due to high sulfur amino acid content. To protect itself from these high ph levels, the body compensates by pulling calcium from the bones to act as a buffer. Excess protein byproducts can also bind to circulating calcium in your blood, explains Roberts, so your body gets rids of it through urine instead of storing the extra calcium in your bones where it should be. So over a long period, high-protein diets can lead to weaker bones and osteoporosis. Some experts now say that maintaining an adequate level of calcium is key to keeping high-protein levels beneficial instead of dangerous.
The bottom line: Consume a proper amount of calcium along with your protein, especially if you have a family history of osteoporosis.
The claim: It causes intestinal problems
Your gastrointestinal tract is a delicate system. Throwing too much of one thing into it can upset the balance. Some people have more sensitive GI tracts than others. Roberts says diarrhea can be a complication of high-fat protein foods. Conversely, people following a very high-protein diet have reported constipation if they’re limiting their fresh fruit and vegetable intake. Fresh produce is an important fiber source that helps move waste throughout the system.
The bottom line: Eat a good amount of fruits and vegetables—and avoid fatty foods if you have GI troubles.
Your protein intake
People often think they’re not getting a proper amount of protein, says Roberts, when in reality most Americans eat more than enough protein. The 46g RDA may sound like a lot, but it adds up quickly. The most important thing is the quality of your protein sources and receiving an adequate amount.
Also, you don’t have to load up on protein after every workout. “Carbohydrates are a better fuel after a workout than just pure protein itself,” advises Roberts. Carbohydrates help replenish the energy in your muscles. It’s best to eat a little protein with carbs after a high-intensity workout, such as peanut butter and banana. But most Americans eat enough protein throughout the day and don’t exert themselves enough to require eating after a workout.
If you’re still concerned about your protein consumption, talk to your doctor. Each person’s needs are unique and some medical conditions may require more or less protein than the average person needs.