How Do Chronic Diseases Affect Nutrition?

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Eating good foods is sound advice, but this changes under certain chronic disease conditions. There may be special considerations regarding dietary needs when there is a chronic condition. So how can these conditions affect nutrition? It varies according to each disease. Examining special disease conditions and the organs they affect will provide some information about the foods to eat and why this is important.

Kidney Disease

The nutritional components of foods have elements that an impaired body may not be able to deal with. For example, the kidneys filter the blood of the body. The kidney’s function is to retain what is usable for the body and to excrete what is not. This includes water and electrolyte balance, as well as other minerals and vitamins. When the kidneys are damaged they cannot filter the blood as well, so a reduction of salts (electrolytes) and other minerals such as phosphorous is necessary. Blood phosphorous increases in kidney disease and with it a corresponding decrease in calcium levels. This can result in fragile bones that break easily, so increasing calcium by taking supplements may be needed.

Decreasing the amount of water drunk throughout the day is important as well since the impaired kidney function may inhibit the formation of urine. If the body cannot rid itself of water, then water buildup in the body can be harmful to the kidneys as well as other organs like the heart. In addition a decrease in the amount of protein in the diet may be recommended by a physician. Protein metabolism by-products include urea which must be excreted by the kidneys. If the kidneys are not capable of excreting urea, there is a buildup in the bloodstream. There may be corresponding fatigue and loss of appetite.

Heart Disease

The heart is a muscle that pumps blood throughout the system. Chronic conditions effecting the heart’s ability to circulate blood throughout the circulatory system often result from deposits of cholesterol in the blood vessels which narrows the vessel and require an increase in pressure to move the blood.

Dietary changes for someone who has experienced heart disease include decreasing the amount of salt in the diet and decreasing foods containing fats, particularly trans fats that tend to increase LDL cholesterol levels. Fruits, vegetables and whole grains are recommended as part of the diet for people who have heart disease.


Phenylketonuria results from an inability to metabolize phenylalanine, an amino acid found in high concentrations in proteins. Phenylketonuria is a test performed on every newborn to determine is there is an inability to breakdown phenylalanine. The buildup of phenylketonuria results in mental retardation.

Dietary choices for someone with phenylketonuria should include lots of fruits and vegetables while avoiding high protein foods like nuts, chicken, beef, beans and eggs.


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