Albumin is a protein made in the liver that has many functions in the body. In the book "Krause's Food and Nutrition Therapy," author Mary D. Litchford reports that albumin accounts for around 60 percent of protein found in blood plasma, or the liquid part of blood. Unless you are in the medical profession, you may have never heard of albumin, thus being told by your physician that the cause of your swelling is due to low serum albumin may be confusing.
Functions of Albumin
In addition to being the major transport vessel for various hormones, enzymes, minerals, fatty acids and other metabolites, the main function of albumin is to maintain something known as oncotic pressure. Basically, this means that albumin is highly responsible for keeping water inside of blood vessels. Though not an exact comparison, think of the way gelatin is able to hold water in the formation of jello. When serum albumin levels decrease, the water in the plasma seeps into the empty space surrounding the cells where water doesn't usually collect, leading to swelling.
Causes of Low Albumin
Albumin typically decreases during illness, particularly illnesses that have an inflammatory component. When the body is under inflammatory stress, the liver focuses on producing inflammatory proteins, like cytokines, rather than albumin. In addition to decreased production by the liver, albumin that has already been produced and entered the bloodstream may be broken down for use in making proteins that will help fight the illness. As the illness resolves, albumin levels will begin to return to normal. In a few cases, severe protein-energy malnutrition may lead to decreased serum albumin levels.
Can Nutrition Increase Albumin Levels?
Historically, albumin has been used as a marker of nutritional status, so often nutritional supplements would be prescribed to help increase albumin levels. More recently, science shows that low albumin is highly related to the disease state rather than nutritional status, so the effectiveness of eating a high-protein diet or drinking nutritional supplements is questionable. There are forms of malnutrition, such as kwashiorkor, defined as chronic negligible protein calorie intake, where restoring adequate protein and calorie intake is important in improving albumin levels. Aside from such cases, however, as long as you consume a balanced diet that includes adequate protein -- 0.8 g per kilogram per day for the average individual without illness -- the food you eat will likely not have an effect on your albumin level.
If you have swelling and your physician has identified the cause to be low albumin levels, listen to his advice. If the cause is due to illness, he will likely encourage you to continue eating a balanced diet with adequate protein while your illness resolves. He may recommend protein intake levels slightly higher than the average requirement, which is normal in many illnesses. If he finds that you have low albumin due to malnutrition, adequate nutrition will be integral in getting your body back to health.