Iron Sources and Functions
All of the nutrient minerals work together to keep you healthy and feeling good. Here is a summary of the role of iron, a trace mineral, in your good health.
|What it does||A component of oxygen-carrying hemoglobin; necessary for muscle contraction and energy metabolism; part of DNA synthesis|
|Daily needs||[Infants: 0.27-11mg][Children: 7-15mg] [Men: 8 mg] [Women: 8-18mg] [Pregnancy: 27 mg][Lactation: 9-10 mg]|
|Not enough||Anemia characterized by weakness, paleness, fatigue, poor immunity, palpitations|
|Too Much||Constipation, other digestive disturbance SEVERE: Joint pain, damage to organs, skin discoloration|
|Foods||Red meats, eggs, legumes, dried fruits, molasses, shellfish, cashews|
*The lower value is for infants up to 6 mos., higher value is for infants up to a year old.
† The first value is for children 1-3 with the amount increasing until age 18.
Higher amounts of iron needed during women’s reproductive years
The daily iron recommendation for women is given in a range from 8-18 mg per day. The higher amount is for women in their reproductive years. The daily recommendation for women drops to the lower value after menopause.
The globin brothers, hemo- and myo-
The iron in your body is found mainly in two proteins—hemoglobin and myoglobin. Both of these proteins have an iron component that helps to transport and release oxygen. It is for this reason that you need iron to feel well. Hemoglobin transports oxygen from the lungs to all parts of your body, while myoglobin is the oxygen-containing protein in your muscles.
A lesser-known function of iron is its role as part of an enzyme necessary for DNA synthesis. This means that iron is necessary for reproduction, growth, and healthy immune function.
A balancing act
Your body has a complex system for absorbing, storing and excreting iron that helps to keep the balance of iron at its proper level. Just in case you need it, your body stores extra iron reserves in your spleen, bone marrow and liver.
Where’s the beef?
Red meat is the most obvious food source of iron. However, other meats, such as liver and shellfish are also significant sources, as are fish and poultry. Egg yolks are also a great source of iron.
Vegetarian sources of iron include the following:
Soy... Dried fruits... Legumes... Nuts and seeds... Potatoes... Peas... Tomato juice... Broccoli... Mushrooms... Cereals and Blackstrap molasses...
A number of foods such as breads and cereals are often fortified with iron. Check the labels of the foods you buy to discover their iron content.
Two types of iron
There are two types of iron that you can get from your diet. One is “heme” iron that only comes from animal flesh foods. The other type of iron is called “non-heme” iron and is found in both animal and plant foods. It appears that the heme iron that you eat is actually more readily absorbed into your system. In addition to the more easily absorbed heme iron, animal flesh foods also contain a peptide that helps in the absorption of the non-heme form of iron.
--Caveat about Iron Sources and Functions: Those on a strict vegetarian diet are only getting the non-heme form of iron. In addition, they are not getting the peptide that helps your body to absorb it. Consequently, they may become iron deficient, since it is estimated that only about 10% of the iron from a vegetarian diet is absorbed by the body. By eating Vitamin C foods with meals, you can increase the absorption of non-heme iron.
What you eat can affect iron absorption
There are some dietary factors that help iron absorption, such as the presence of the peptide in animal flesh foods and the presence of Vitamin C.
Conversely, other factors can inhibit iron absorption, such as certain vegetable proteins and the presence of substances found in beans and grains, as well as the tannic acid found in teas and coffee. Heme iron seems to be less affected by these dietary factors than the non-heme form.
Most common deficiency
Health experts generally agree that worldwide, iron is the nutrient that is most likely to be deficient. This applies to both developed countries and underdeveloped countries, particularly in vulnerable parts of the population, such as children and pregnant women.
In developed countries where food is plentiful, iron deficiency may stem from poor food choices, restricted diets, or, in some cases, poor absorption due to digestive tract disease. In underdeveloped countries, iron deficiency is more likely caused by an absence of iron-rich foods or enough food of any kind. Excessive bleeding and heavy sweating from intense physical exertion can also cause iron deficiency.
Iron can be toxic
As a rule, healthy individuals do not need to worry about iron toxicity. Your body has an amazing ability to balance the amount of iron in your system. However, those with a genetic disorder called “hemochromatosis,” may develop iron toxicity, due to their inability to stop the absorption of excess iron. There are also certain population groups, such as black South Africans, who are subject to iron toxicity due to a high intake as well as a genetic pre-disposition.
Although you should be able to obtain enough iron from your healthy diet, you may choose to take an iron supplement, particularly if you are in one of the high-risk groups for iron deficiency—pregnant and pre-menopausal women, children and vegetarians. Some health experts believe that iron chelates or iron in the form of ferrous sulfate is better absorbed than other forms of iron. If you choose to supplement with iron, be sure to eat plenty of fiber and drink a lot of water to avoid constipation, a possible side effect of taking iron supplements.
Iron supplementation can affect the efficacy of certain medications, and certain medications can have an effect on iron absorption. As always, if you are on medication, consult with your doctor and pharmacist regarding drug interactions with supplements.
--Caveat for Iron Sources and Functions: Children are at risk from iron-containing supplements, and not just from ingesting the whole bottle. Even a few iron pills taken by a child can have devastating results. This is one of the most common causes of accidental poisoning of children.
The upper intake level for adults for iron that has been established is 45 mg per day.