Total iron-binding capacity (TIBC) is a good indicator of your body’s iron levels. Keep reading to learn more about high and low levels and what they mean for your health, as well as how to increase or decrease TIBC.

What is Total Iron-Binding Capacity (TIBC)

Total iron-binding capacity (TIBC) measures the total capacity of your blood to bind and transport iron. It is used to estimate the amount of iron stored in your body [1, 2].

TIBC is an indirect measure of transferrin, a protein that binds iron molecules and transports them in the bloodstream. Transferrin is produced in the liver and is the main iron-binding protein in the blood [3, 4].

TIBC is most often used to check for iron deficiency.

Because they measure the same thing TIBC and transferrin tests are redundant. It’s enough to measure one of them. TIBC is cheaper, but transferrin is preferable because it has well established and more accurate ranges. TIBC may, however, be a better measure in populations which have high frequencies of transferrin genetic mutations [3].

Similarly, because they both measure iron stores in the body if your ferritin levels are already available, TIBC levels are redundant and unneeded when testing for iron deficiency [5].

Some laboratories also provide UIBC or unsaturated iron binding capacity, which is the number of transferrin sites not carrying iron [6].

TIBC Normal Range

The normal range of TIBC is between 250 – 450 μg/dL (micrograms per deciliter) which corresponds to 44.8 – 80.5 μmol/L (micromoles per liter).

Low TIBC Levels

Causes of Low TIBC

1) Excess Iron Levels (Iron Overload)

The most common cause of low TIBC is excess iron in the body [7].

However, not everyone with iron overload will have low TIBC. A lot of people with iron overload will have TIBC in the normal range [8].

2) Inflammation

Transferrin is a negative acute phase protein. This means that in inflammation, as the liver increases the production of inflammation-associated proteins (e.g. CRP, ferritin) it decreases the production of transferrin. As transferrin decreases, so do iron binding capacity and therefore TIBC [9, 10].

TIBC is decreased in people who have anemia of inflammation also known as anemia of chronic disease [11, 2]. This type of anemia is caused by inflammatory cytokines and associated with underlying conditions such as infections, inflammatory disease, autoimmune disease, and cancer [12].

3) Liver Disease

The liver helps keep iron levels in balance. During liver diseases and injury, more iron is absorbed, causing TIBC to decrease [13, 14].

Also, in liver disease, the liver can’t produce transferrin effectively, which decreases total iron-binding capacity [15].

4) Kidney Disease

Low TIBC can also be caused by kidney disease accompanied by protein loss (wasting) [10, 16].

Health Effects of Low TIBC

1) Increases Heart Attack Risk

High iron levels are a risk factor for heart attack. In an observational study of over 2,000 people, low TIBC was associated with an increased risk for heart attacks. Each increase in TIBC of 1 μmol/L was associated with a 5.1% decrease in the heart attack risk [17].

2) Is Associated with Higher Cancer Risk

In a study with over 41,000 people, lower TIBC was associated with higher lung cancer risk [18].

In another study of 700+ people, lower TIBC was associated with higher risk of colon cancer [19].

3) Low TIBC is Associated with Death in Hemodialysis Patients

In a study of 807 kidney disease patients undergoing hemodialysis, patients with a TIBC under 150 ug/dL had a higher risk of death [16].

Ways to Increase TIBC

Following are ways to increase TIBC by decreasing your iron levels when they are high. Other than that, you can only correct low TIBC levels by addressing and resolving the underlying condition/disease.

1) Exercise

If your iron is high, get more exercise. Regularly exercising will help prevent your iron levels from becoming too high, as well as your TIBC from decreasing [20, 21].

2) Diet

If you have high iron levels, you should avoid foods that are high in iron, such as red meat, fish, and poultry. You should also eat foods that reduce iron absorption, including fiber, phytic acid (from whole grains), and chili [22, 23, 24, 25].

Beverages such as coffee, cocoa, green tea, and herbal teas (chamomile, lime flower, penny flower, mint, and vervain) can also reduce iron absorption [26, 27, 28, 29, 30, 31, 32].

3) Supplements

The following supplements may help reduce iron absorption in the gut:

High TIBC

Causes of High TIBC

1) Iron Deficiency

TIBC increases during iron deficiency [7].

In an observational study of 98 women, the pregnant women’s TIBC significantly increased during the third trimester of pregnancy due to iron-deficient diets [37].

Polycythemia vera is a disease in which the bone marrow makes too many red blood cells. Polycythemia vera patients may have an iron deficiency, which increases TIBC [38].

2) Oral Contraceptives

Using oral contraceptives (birth control pills) can also result in higher TIBC. In a study of 117 women, the ones who took oral contraceptives for two or more years had significantly higher TIBC levels than women who never took them [39]

Health Risks of High TIBC

High TIBC is Associated with Celiac Disease Risk

Abnormal iron levels may play a role in celiac disease development. In a study of 852 people, high TIBC levels increased the risk of developing celiac disease. For each 10 μg/dL increase in TIBC, the risk of celiac disease increased by 4.6, 3.8, and 7.9% within 1, 1 – 3, and 3 – 5 years prior to diagnosis, respectively [40].

Ways to Decrease TIBC

1) Iron-rich Diet

Eating a diet high in iron can help prevent iron deficiency. Foods that contain a lot of iron include red meat, poultry, and fish [22].

Refrain from drinks such as coffee, cocoa, green and herbal teas, as these decrease iron absorption from food [26, 27, 28, 30, 31, 32].

2) Supplements

If you have an iron deficiency, iron supplements will increase your iron levels. They are, however, associated with a lot of side effects. You also don’t want to overdo them, because iron overload increases oxidative stress in the body and has a lot of negative consequences. You may want to try and correct a mild efficiency through dietary intervention first [41, 42, 43].

Vitamin C helps increase iron absorption [44].

Irregular TIBC Levels?

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