Deficiencies and Excesses of Protein
Although protein deficiencies are prevalent in certain populations around the world, they’re not very common in the United States where many of us consume a lot ore protein than typically recommended. However, some of the following people might be at risk for not getting enough protein to meet their needs:
• Those who don’t consume enough total calories, either because of poverty or an eating disorder such as anorexia
• Older Americans who might consume fewer total calories and/or have trouble chewing meats and other tough protein-rich foods
• Those who follow vegetarian or began diets and don’t get enough high-quality protein
• Those who have a disease or chronic illness that makes it difficult for them to consume adequate amounts of nutrient-rich foods
If you don’t consume enough protein-rich foods each day, you won’t get enough of the essential amino acids you need to make body proteins that support the growth and maintenance of body tissues among other functions. Even if you do consume enough total protein, unless you’re consuming adequate amounts of foods that are rich in high-quality protein (including animal-derived foods and soy foods), your diet might fall short on essential amino acids.
Getting inadequate amounts of protein can be especially damaging to older people. As we age, our body composition shifts; we lose muscle mass and accumulate more body fat. Too little dietary protein can degrade body protein even more, which means the body is less able to heal wounds and fractures and fight infections. Muscles might also feel weaker, which can make it more difficult to move and increase the risk of falling. Some experts believe the recommended dietary allowance (RDA) for protein for older people should be raised by 25 percent to 1.0 gram per kilogram of body weight.
Another consequence of inadequate protein intake (when overall calorie intake is also insufficient to meet daily needs) is that the body compensates by breaking down its own body proteins to create energy in the form of glucose – the main fuel source for the brain, lungs, and entire nervous system. This prevents body proteins from doing the important jobs they’re meant to do.
Over time, too little protein and/or too few calories can cause protein-energy malnutrition (PEM). Two severe types of PEM include:
• Kwashiorkor – Kwashiorkor is malnutrition caused by inadequate consumption of dietary protein, often in impoverished countries. Symptoms include poor growth, weakens, apathy, edema, and increased risk for infection.
• Marasmus – Marasmus is malnutrition caused by consuming too little protein and too few calories. Muscle, fat, and other body tissues break down to create energy for the body. Other symptoms include weight loss and impaired immune function. Marasmus can occur in people who have malabsorption or kidney problems.
Too much dietary protein can strain the kidneys, whole job is to remove wastes from the blood, among other important functions. Excess protein can also cause bones to excrete calcium, which can increase the risk of bone loss and osteoporosis.
Consuming more dietary protein than you need – especially from high-calorie sources – can lead to excess total calorie intake. The body will take that extra protein, break it down, and store it as body fat.
Too many protein-rich animal foods, including fatty meats and whole milk dairy products, can contribute too much total fat, saturated fat, and cholesterol to the diet. This can increase the risk for developing cardiovascular disease, high blood cholesterol, hypertension, and other conditions.
Too many protein-rich foods might also leave less room in the diet for nutrient-dense food choices such as fruits, vegetables, and whole grains. If you have too many high-protein foods at the expense of these, you might consume less total fiber and lower amounts of the vitamins, minerals, and other beneficial substances these plant foods provide.
Recommended Dietary Allowances for Protein
More specific daily protein recommendations are provided by the RDAs. These were created to help most people meet their individual needs. The RDA for protein assumes that the dietary pattern provides enough calories and key nutrients to prevent proteins from being used to create energy and instead allow them to be used to perform their many functions.
Protein-energy malnutrition (PEM) is a condition that results from inadequate intake of dietary protein and energy (measured as calories) over a long period of time. It can lead to the breakdown of body tissues (including muscle tissue) and increase the risk of infection.
Ideal body weight is a desirable and healthful weight range based on height.