Health problems due to low and high-protein diets

 Health Concerns Related to Protein Intake

Many people living in developing countries suffer from malnutrition and disease because dietary protein supplies are limited. In contrast, the residents of developed countries tend to eat more protein than they need and may boost their intake even higher by consuming protein or amino acid supplements. Getting sufficient amounts of protein is required for good health, but getting too little or too much can have serious health problems.

Protein-Energy Metabolism (PEM):

Protein deficiency rarely develops as an isolated condition. It most often occurs in combination with a deficiency of energy and results in a condition known as protein-energy malnutrition (PEM), or protein-calorie malnutrition (PCM). In many developing areas of the world where diets are often low in protein and energy. PEM is a very serious public health concern. Although PEM can affect people of all ages, its most devastating consequences are seen in children. Without adequate protein and energy, children fail to grow normally, and many develop diarrhea, infections, and diseases and die early in life. Of the 55,000 people who die of hunger each day, nearly two-thirds are children.

PEM usually occurs as either marasmus or kwashiorkor. These conditions differ in the severity of the overall energy and protein deficit and the related clinical characteristics.

Marasmus: 

Marasmus is the result of chronic PEM. It is caused by diets containing minimal amounts of energy, protein, and other nutrients. The word marasmus means "to waste away". Over time, the severe lack of energy and protein results in a "skin and bones" appearance, with little or no subcutaneous fat.

 Marasmus usually develops in infants who either are not breastfed or have stopped breastfeeding in the early months. Often, the weaning formula used is incorrectly prepared because of unsafe water and because the parents cannot afford sufficient infant formula for the child's needs. The latter problem may lead the parents to dilute the formula to provide more feedings, not realizing that this deprives the infant of essential calories, protein, and other nutrients. 

An infant with marasmus requires large amount of energy and protein to restore growth, development, and overall health. Unless the child receives adequate nutrition, full recovery from the disease may never occur. Most brain growth occurs between conception and the child's first birthday. If the diet does not support brain growth during the first months of  life, the brain may not fully develop, resulting in poor cognitive and intellectual growth. It results from a severe deficit of energy and protein, which causes extreme loss of fat stores, growth impairment, muscle mass, and body weight.

Kwashiorkor: 

 Kwashiorkor is a word from Ghana that means "the disease that the first child gets when the new child comes. From birth, an infant in developing areas of the world is usually breastfeed. Often by the time the child is 12 to 18 months old, the mother is pregnant or has already given birth again. The mother's diet is usually so marginal that she cannot produce sufficient milk to continue breastfeeding the older child. This child's diet then abruptly changes from nutritious human milk to starchy roots and gruels. These foods have low protein densities compared with their energy content. Additionally, the foods are usually high in plant fibers and bulk, making it difficult for the child to consume enough to meet energy needs and nearly impossible to  meet protein needs. Many children in these areas also have infectious and parasites that elevate protein and energy needs and often precipitate the development of kwashiorkor.

The presence of edema in a child who still has some subcutaneous fat is the hallmark of kwashiorkor. Other major symptoms of kwashiorkor are apathy, diarrhea, listlessness, failure to grow and gain weight, infections, and withdrawal from the environment. These symptoms also complicate other diseases that may be present. For example, measles, a disease that normally makes a healthy child ill for only a week or so, can become severely debilitating and even fatal in a child with kwashiorkor.

 Many symptoms of kwashiorkor can be explained on our knowledge of proteins. Proteins play important roles in fluid balance, growth, immune function, and the transport of other nutrients. Thus, protein deficiency can severely compromise these functions.

The condition occurring primarily in young children who have an existing disease and consume a marginal amount of energy and severely insufficient protein. It results in edema, poor growth, weakness, mild to moderate weight loss, and an increased susceptibility to further infections and diseases.

High-Protein Diets:

Diets containing an excessive amount of protein do not provide additional health benefits. Instead, high protein intakes may increase health and disease risks. One area of concern is the effect of excess protein on kidneys. Recall that the kidneys are responsible for excreting excess nitrogen as urea. Thus, high-protein diets may overburden the kidneys' capacity to excrete nitrogen wastes. Additionally, because water is needed to dilute and excrete urea, inadequate fluid intake can increase the risk of dehydration as the kidneys use body water to dispose of the urea. These concerns are greatest for people who already have impaired kidney function. A lower protein diet with adequate fluid intake is recommended for these individuals to help preserve kidney health.

When excess protein is primarily from a  high intake of animal proteins, the overall diet is likely to be low in plant-based foods and consequently low in fiber, some vitamins (vitamin C and E and folate), minerals (magnesium and potassium), and beneficial phytochemicals. Animal proteins are often rich in saturated fat and cholesterol and may be cured to create hot dogs, ham, salami, and luncheon meats. As a result, these diets can increase the risk of cardiovascular disease and cancer. Although very high intakes of meat, particularly processed meat, are associated with increased risk of cardiovascular disease, a more modest intake of meat consumed as part of a varied diet containing healthy amounts of unsaturated fatty acids appears to have little effect on heart disease.

High protein diets also may increase urinary calcium loss and eventually lead to a loss of bone mass and an increased risk of osteoporosis. These findings are somewhat controversial, however, and are less of a concern for individuals with adequate calcium intakes.

Other concerns, particularly with athletes, are the health risks associated with excess protein and amino acid supplementation. Our bodies are designed to obtain amino acids from dietary sources of whole proteins. This assures a supply of amino acids in proportions needed for body functions and prevents amino acid toxicity, especially for methionine, cysteine, and histidine __ the most toxic amino acids. When individual amino acid supplements are taken, chemically similar amino acids cam compete for absorption, resulting in amino acid imbalances and toxicity risk.