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Importance of Iron in Our Body

Kitchen man woman Iron is very important in maintaining many body functions, including production of haemoglobin which carries oxygen in our blood.

Iron is essential in transporting oxygen through blood. Strenuous exercise increases the amount of oxygen the body requires and places an increased burden on the body’s iron stores. Being iron deficient can impact the ability to meet the additional demands placed on the body during physical exercise and as a result, there is a negative impact on performance.

Iron plays an important role in a number of other cellular processes such as the production of myoglobin in muscle. Like hemoglobin, myoglobin carries oxygen specifically within the muscles. Low myoglobin count weakens aerobic function and physical performance. There are clinical studies and supporting data suggesting that iron replacement can improve fatigue scores and physical performance.1 Iron replacement can come in the form of dietary intake and iron supplementation.

Making dietary changes is an important step in providing iron that the body needs. One of the best ways is to improve one’s dietary intake by consuming food that help increase iron intake (called “iron enhancers”) and by avoiding food that impair iron absorption (also known as “iron inhibitors”).2

Iron enhancers include ascorbic acid or vitamin C that occurs naturally in vegetables and fruits. Ascorbic acid enhances the absorption of various nutrients including iron. Food that are rich in beta-carotene also help as iron enhancers. Beta-carotene is present in fruits and vegetables such as carrots, corn, red grapes, oranges, peaches, prunes, red peppers, spinach, sweet potatoes, tomatoes and yellow squash. Heme iron, more readily absorbed by the body, comes from good and readily available sources such as red meat (including liver), poultry meat, fish and oysters. Surprisingly, moderate alcohol consumption (two drinks a day for males; one drink a day for females) also enhances the absorption of iron.3

On the other hand, it is also important to note “iron inhibitors” which are found in iron binding phenolic compounds (tannins); including tea, coffee, and most red wines. Phytates present in cereal bran, bread made from high-extraction flour, breakfast cereals, oats, rice, pasta products, cocoa, nuts and seeds. Calcium such as milk, cheese, soy proteins also affects the absorption of iron in the body.3

Aside from consuming food that’s rich in iron and avoiding those that hinder iron absorption, another way to rebuild iron stores in the body is by taking iron supplements.

Iron is best absorbed on an empty stomach but to minimize the side effects of taking iron supplements like stomach cramps, nausea or diarrhea, it can also be taken with a small amount of food. Iron supplements should not be taken at the same time with milk, calcium, antacids, caffeine and food that are rich in high fiber.

The information contained in this article is not intended or designed to diagnose, prevent, treat or provide a cure for any condition or disease, to ascertain the state of your health or be substituted for medical care. Merck encourages you to seek the advice of your doctor or healthcare professional if you have any questions or concerns arising from the information in this article.


  1. Low et al. Cochrane library of systematic reviews. 2017
  2. FAO. Human vitamin and mineral requirement. FAO Corporate Document Repository. Accessed 9 April 2015.
  3. Iron Disorders Institute. Achieving Iron Balance with Diet. Accessed 25 April 2017.