Albumin
Composed By Muhammad Aqeel Khan
Date 10/8/2025
Introduction
About 50–60% of all blood proteins are albumin, the most prevalent plasma protein in the human body. It plays a critical role in maintaining fluid balance, transporting essential substances, and serving as a key indicator of overall health. Produced by the liver, albumin is not just a biochemical marker in blood tests—it’s a vital player in physiological processes, and abnormalities in its levels can indicate serious underlying conditions.
This article explores albumin’s structure, synthesis, functions, normal ranges, the clinical significance of abnormal levels, diagnostic methods, treatment options, and diet tips for supporting healthy albumin production—backed by scientific evidence and references.
Structure of Albumin
Albumin is a globular protein that dissolves in water and has a molecular weight of about 66.5 kDa. A single polypeptide chain comprising 585 amino acids is folded into three homologous domains (I, II, and III), each of which has two subdomains (A and B). Because of the hydrophobic pockets created by this special structure, albumin may bind and move a variety of substances.
Isoelectric point: ~4.7 (slightly acidic protein)
Half-life in plasma: ~20 days
Primary location: Circulates in plasma but also found in interstitial fluids.
Synthesis of Albumin
Hepatocytes(Wikipedia), or liver cells, are the only cells that can produce albumin using a multi-step process:
Transcription of the albumin gene in the nucleus.
Translation on ribosomes attached to the rough endoplasmic reticulum.
Post-translational modifications and folding with the help of chaperone proteins.
Secretion into the bloodstream via the Golgi apparatus.
The rate of albumin synthesis is influenced by nutritional status, hormonal signals (e.g., insulin, cortisol), and liver function. In healthy adults, the liver produces about 10–15 grams of albumin per day.
Functions of Albumin in the Human Body
Albumin is a multi-functional protein, and its roles include:
1. Maintaining Oncotic Pressure
One of albumin’s primary functions is to maintain colloid osmotic (oncotic) pressure, which keeps fluid from leaking out of blood vessels into surrounding tissues. A fall in albumin levels leads to edema (swelling) due to fluid accumulation.
2. Transport of Substances
Albumin serves as a carrier protein for:
Hormones (e.g., thyroxine, cortisol)
Fatty acids
Bilirubin (preventing its toxicity)
Drugs (warfarin, antibiotics, aspirin)
3. Buffering Capacity
In plasma, albumin serves as a pH buffer, preserving the acid-base equilibrium.
4. Antioxidant Role
By binding reactive oxygen species and free radicals, albumin lessens oxidative stress.
5. Nutrient Reservoir
In extreme starvation, albumin can be broken down to supply amino acids for essential functions.
Normal Albumin Levels
Normal serum albumin levels in adults:
3.5 – 5.0 g/dL (35 – 50 g/L)
Levels may vary slightly depending on the laboratory and population studied.
Clinical Significance
Because albumin reflects both liver function and nutritional status, it is a key biomarker in diagnosing and monitoring diseases.
Low Albumin (Hypoalbuminemia): Indicates liver disease, kidney disease (nephrotic syndrome), malnutrition, inflammation, or protein loss via the gut.
High Albumin (Hyperalbuminemia): Less common; usually due to dehydration or excessive protein intake.
Albumin levels are also used in:
Prognostic scoring systems such as Child–Pugh score for liver cirrhosis.
Critical care monitoring, where low levels are linked to poor outcomes.
Causes of Abnormal Albumin Levels
Low Albumin (Hypoalbuminemia)
Liver diseases: Cirrhosis, hepatitis, liver failure.
Kidney diseases: Nephrotic syndrome, chronic kidney disease.
Protein-losing enteropathy: Intestinal conditions causing protein loss.
Severe malnutrition: Kwashiorkor, anorexia nervosa.
Chronic inflammation/infection: Sepsis, autoimmune diseases.
Burns or trauma: Due to protein loss from damaged skin or tissue.
High Albumin (Hyperalbuminemia)
Dehydration: Concentrates albumin in blood.
High-protein diet: Rare cause.
Certain medications: Corticosteroids, insulin.
Effects of Abnormal Albumin Levels
Low albumin leads to:
Peripheral edema (swelling in legs, ankles)
Ascites (fluid in abdomen)
Poor wound healing
Increased drug toxicity (less protein binding)
Fatigue and weakness
High albumin generally causes no direct symptoms but indicates underlying dehydration or metabolic imbalance.
Diagnostic Methods
Albumin levels are measured in:
One component of a metabolic panel is the serum albumin test.
Urine albumin test – detects kidney damage (microalbuminuria).
Serum protein electrophoresis – evaluates different protein fractions.
Liver function tests – albumin is considered alongside bilirubin, ALT, AST.
Treatment Options
Treatment focuses on the underlying cause:
Liver disease: Antiviral therapy, lifestyle changes, liver transplant in severe cases.
Kidney disease: Blood pressure control, dietary protein management.
Malnutrition: Adequate protein and calorie intake, sometimes supplementation.
Inflammation/infection: Treating the cause normalizes albumin.
In critical care, intravenous albumin infusion may be used for severe hypoalbuminemia, burns, or shock—but it’s not a long-term solution.
Foods to Support Healthy Albumin Levels
Albumin is made from amino acids, so adequate dietary protein is essential. The following foods are excellent sources:
High-Quality Animal Protein
Eggs (especially egg whites)
Lean meats (chicken, turkey, beef)
Plant-Based Protein
Legumes (lentils, chickpeas, kidney beans)
Nuts and seeds (almonds, pumpkin seeds, chia seeds)
Whole grains (quinoa, brown rice, oats)
Other Supportive Foods
Leafy greens (spinach, kale) – for vitamins and minerals aiding protein metabolism.
Olive oil and avocado are examples of healthy fats that promote liver health in general.
Nutritional Tip:
Importance in Overall Health
Albumin’s roles in fluid balance, nutrient transport, drug binding, and antioxidant defense make it a cornerstone of human physiology. Persistently low levels are associated with increased morbidity and mortality in hospitalized patients, highlighting its importance as both a functional protein and a diagnostic marker.
Conclusion
Albumin is much more than just a line on a lab report—it’s a lifeline protein that reflects your nutritional status, liver and kidney health, and overall resilience. Keeping albumin within its normal range requires a combination of balanced nutrition, liver and kidney health maintenance, and prompt treatment of underlying conditions.
References
Peters T Jr. All About Albumin: Biochemistry, Genetics, and Medical Applications. Academic Press; 1995.
Soeters PB, Wolfe RR, Shenkin A. Hypoalbuminemia: Pathogenesis and Clinical Significance. J Parenter Enteral Nutr. 2019;43(2):181–193. doi:10.1002/jpen.1451.
Vincent JL, Dubois MJ, Navickis RJ, Wilkes MM. Hypoalbuminemia in acute illness: Is there a rationale for intervention? Ann Surg. 2003;237(3):319–334.
National Institutes of Health (NIH). Dietary Protein and Health. 2021.
Levitt DG, Levitt MD. Human serum albumin homeostasis: a new look at the roles of synthesis, catabolism, renal and gastrointestinal excretion, and the clinical value of serum albumin measurements. Int J Gen Med. 2016;9:229–255.