Serum Albumin: Glutathione Transport & Powerful Free Radical Scavenger

I have previously discussed the essential role of albumin in human health. Serum albumin is one of the most vitally important blood proteins. Albumin is in fact the most abundant blood protein in human plasma. Epidemiological data suggests that decreased albumin values are strongly associated with an increased mortality. Albumin functions as a major transport for nutrients, electrolytes such as calcium, sodium and potassium, hormones such as T4, and vitally essential antioxidants such as glutathione. Albumin is also involved in regulating fluid balance through its modification of colloid osmotic pressure.

Additionally, albumin is produced almost entirely by the liver, and as such, diminished values of albumin are strongly suggestive of liver dysfunction, among many other issues.

Albumin & Antioxidants

Albumin is a carrier of thiol groups. Thiols are also known as “mercaptans”, meaning “capturing mercury”. The single thiol group contained in albumin constitutes 80% of the total thiol groups in blood plasma. One of the most essential thiol groups is known as Glutathione. Glutathione functions as one of the most critical free radical scavenging antioxidants in the cells. Hence, low albumin values are strongly suggestive of a decrease in thiol-rich glutathione, as well as associated with increased levels of oxidative stress and free radical toxicity.

Examples of low molecular weight antioxidants include: Vitamin C, E, Uric Acid, Alpha Lipoic Acid. Studies have demonstrated that low-molecular weight antioxidants are protective of albumin’s antioxidant carrying capacity. In these regards, supplementing with Vitamin E, C and ALA may be of great value when serum albumin values are depressed. The use of an effectively absorbed and usable form of glutathione may be further warranted under low albumin circumstances.

Albumin & Liver Function

More than 90% of the albumin in the blood is produced by the liver. Therefore low values suggest liver dysfunction. It is interesting to note that the liver’s ability to function properly is dependent upon its ability to remain protected by existing glutathione in liver cells.

Albumin synthesis is strongly influenced by dietary protein consumption. Individuals on vegetarian diets may be at an increased risk for developing albumin deficiency. Many researchers would suggest that plant protein amino acids are extremely difficult to absorb, due to the presence of cellulose in vegetable fibers. It should be pointed out that the sulfur-rich amino acids cysteine and methionine are found in very low concentrations in plant sources of protein. It is in fact these sulfur-rich amino acids which are needed to form glutathione, which is being transported by albumin.

Albumin Measurements On Blood Tests

Many functionally-oriented clincians agree that the ideal reference interval for serum albumin is approximately 4.1-5.0 g/dl, or 41-50 g/l. It is important to point out that laboratory reference ranges are statistical averages, and not ideal values. Therefore, ideal functional reference intervals should be used in preference.

Low values of albumin strongly suggest a number of scenarios related to:

• Liver dysfunction
• An increased need for thiol-rich antioxidants such as glutathione
• An increase in oxidative stress & free radical damage
• An increased need for low, molecular weight antioxidants such as Vitamins E, C, Alpha Lipoic Acid
• Dietary protein deficiency

Elevated values of albumin almost always are associated with dehydration. This is especially true if other blood proteins are elevated: hemoglobin, hematocrit, RBC, BUN, or if the serum sodium or potassium values are elevated.