Iron Content In Oatmeal

Introduction

The normal requirement of iron 

Approximate daily dietary iron estimates for 18 mg/day. This figure varies depending on the age and gender of an individual, for instance, while adult men (above 18 years old) require about 8.7mg per day, it's almost double that for adult females (19 to 50 years old). 

Premenopausal women are at a higher risk of developing iron deficiency anemia, thus they must consume more iron from their diet to compensate for losses. Interestingly, since iron is precious for multiple physiological functions, our body has evolved to spend iron very cautiously and recycle waste products for iron re absorption. Around 90% of our required daily iron is recycled back from the breakdown of red blood cells, and erythrocytes. Erythrocytes contain iron-bound heme porphyrin groups which allow them to carry oxygen throughout the body. Net daily loss of iron is around 1 mg/day, which should be replenished with iron from consumed foods. Vitamin C further enhances iron absorption, while calcium inhibits iron uptake, thus food combination can also be important for the maintenance of healthy iron intake.

Functions of iron

Iron is a mineral which is essential for the normal functioning of many proteins, thus involved in numerous vital processes occurring in the body. Its physiological role is centered around (but not reduced to) its importance for normal hemoglobin structure. Hemoglobin is a protein in red blood cells, erythrocytes, that allows our red blood cells to bind and carry oxygen molecules throughout the body and oxygenate our tissues. Iron is bound to haem, which is a porphyrin molecule bound to various proteins with diverse functions. Apart from oxygen-carrying function, iron-containing haem-proteins carry out different functions, such as activation of molecular oxygen and electron transport. To summate, iron is needed for maintenance and appropriate regulation of oxygen transport, cellular respiration, energy generation, mitochondrial electron transport, building and synthesis of nucleic acids (DNA,RNA), as well as balanced work and proliferation of cells of the immune system and their protection from free radical attacks. Nearly every individual cell and cellular organism depend on sufficient iron to survive.

Iron deficiency disease

Consequences of inadequate iron intake include serious health complications, such as iron-deficiency anemia. This condition is caused by insufficient amounts and increased loss of red blood cells and associated oxygen-carrying function, which occurs as a result of long-term downfall in iron levels. The onset of iron deficiency anemia is gradual, as iron levels fall critically low and associated consequences become apparent. For instance, on average it takes around 8 years for a person to become anemic due to iron deficiency. Health complications include severely disrupted physical performance, and impaired tissue oxygenation (due to a fall in maximal oxygen-carrying capacity and oxygen consumption of the muscles). Inadequate oxygen delivery to the muscles causes an inability to perform numerous biochemical processes within the tissues, which in turn results in physical, cognitive and mental impairment.

Is oatmeal a good source of iron?

What are oats and oatmeal?

(A brief note about the types of oats)

It has been well-established that the consumption of plant-based diets can have a positive effect on human health and prevent the onset of numerous diseases. In particular, whole grain cereals have been associated with balanced healthy eating, since those are naturally low in unsaturated fat, and rich in fiber, antioxidants, important minerals, and vitamins. 

According to US FDA, whole grains are defined as “the intact, ground, cracked, flaked or otherwise processed kernel after the removal of inedible parts such as the hull and husk”. (drewnowski)

Oats (family of Poaceae or Gramineae; genus Avena) are further classified into 27 known subspecies. Most commonly consumed species are Avena sativa, or cultivated oats.

There are 8 main forms of oats:

Newly harvested raw oats, are oats before kernels are separated from inedible parts, hulls and husks. Those can be seen where oats are harvested, in the fields.

Whole oat groats (cleaned), grain kernels that are cleaned from inedible parts, take the longest to cook and are considered to be the healthiest and are digested the longest (with the lowest glycemic index).

Steel Cut Oats (also called Irish oats),  those grains are cut into several pieces with a steel-metal blade. This type cooks quicker than whole oat groats since the pieces are smaller and water can penetrate those more easily.

Scottish Oats, in Scotland oats are stone-ground, resulting in smaller bits of grain. These cook faster into creamier porridge (as compared to mentioned oat types).

Rolled / Old-Fashioned Oats are made by steaming and rolling oats into flakes. These oats have stable healthy oils, which help them to stay fresh for longer.

Quick/Instant Rolled Oats are made by steaming the grains and rolling them into extra-thin flakes. This allows them to cook within a couple of minutes, and while their nutritional value remains the same, these are processed faster in our gut and causes an increase in the glycemic index 

Oat Bran is the outer shell of the oat groat, those are low in saturated fat, thus much lower in calories, and packed with higher amounts of protein and dietary fiber.

Oat Flour is a whole grain flour made by blending the entire oat kernel into fine flour, it  can be used in baking, or as a thickener.

Oatmeal is a porridge made from various types of oats (not oat bran or oat flour) from de-husked, steamed, and flattened, or coarse, milled, steel-cut oat grains. 

Nutritional facts of oats

Iron content in oats

Oats are highly nutritious whole grain, it is rich in numerous minerals and micronutrients, such as group of vitamins B, folate, Mn (Manganese), Mg (Magnesium), Se (Selenium), Zn (Zinc), Cu (Copper) and Fe (Iron).

The nutrient contents of oats are influenced by external factors, including cultivation, harvesting, post-harvesting conditions.

According to the USDA Food Data Central database 100 g of raw oat cereal contains anywhere between 3-4,5 mg of dietary iron.

Health benefits of oats

Oats contain various nutrients and bioactive compounds that have beneficial health effects. For instance, they are known to have a 

Oats are a great source of dietary fibers which are non-digestible polysaccharides that are known to have anti-inflammatory effects, boost the natural immune system and promote healthy microbiota. 

How to add oats into the diet?

Oats can be easily integrated into a balanced diet by introducing oatmeal porridge for breakfast a couple of times per week, adding oat bran into the smoothies and other cereals, cooking and baking with oatmeal flour, or even by making your own home-made granola or oat-containing bars for a quick snack. Oats are a highly energetic meal and are great for maintaining high energy levels and normalizing blood sugar levels.

Do oats inhibit iron absorption?

Numerous studies have been reporting low iron bio availability from the oat cereal,  which potentially can be explained by sufficient levels of calcium present in the oats ( which is known to restrict iron absorption). Additionally, physic acid is known to reduce iron bio availability by 8 times. Naturally, some oats will have lower levels of physic acid due to post-harvesting processing of the grains, in particular removal of the hull. One way of preventing negative effects associated with phytic acid is soaking oats in the boiling water overnight. 

Other iron-rich foods

Dietary iron can be found in two forms: heme iron, which comes from animal hemoglobin and myoglobin, and nonheme iron, which is found in both animal and plant sources. Uptake of heme iron occurs much easier (15-35%), compared to that of non-heme iron (>10%).³ This is because in its independent form, iron reacts with other substances in the digestive tract, and its absorption is fully determined by balance between iron uptake enhancers and inhibitors.⁵ Plant-based diets usually contain high amounts of iron-binding acids (phytate), phenolic compounds, and calcium, which suppress iron absorption of iron in animals. Accompanying iron-rich foods with absorption enhancers, such as ascorbic acid (vitamin C), meats, seafood and poultry will help to enhance iron bioavailability (how well iron can be obtained from food).⁶

According to the US Department of Agriculture (USDA), rich sources of iron include:

• Fortified breakfast cereals (1 serving containing 18 mg of iron ( 100% of the recommended intake) )
• Seafood ( 85 grams containing 8 mg of iron (44 % of the recommended intake))
• Canned white beans (1 cup containing 8 mg of iron (44 % of the recommended intake))
• Liver (3 ounces containing 5 mg of iron (28 % of the recommended intake))
• Spinach (  ½ cup containing 3 mg of iron (17% of the recommended intake))
• Tofu (  ½ cup containing 3 mg of iron (17% of the recommended intake))
• Red kidney beans, edamame beans and chickpeas  ( ½ cup containing 2 mg of iron (11% of the recommended intake))
• Green peas ( ½ cup containing 1 mg of iron (6% of the recommended intake))
• Bread (  1 slice containing 1 mg of iron (6% of the recommended intake))
• Mixed nuts ( ¼ cup  containing 1 mg of iron (6% of the recommended intake))

Summary

Whole grains, including oats, are crucial for maintaining a healthy balanced diet. Besides being a great source of energy, oatmeal is rich in important nutrients and protein. Although its a naturally potent source of iron, its iron bio availability can be hindered by other minerals and chemicals contained in the grain. Thus, choosing and adapting processing and cooking methods can help to enhance iron absorption from oats and maximize their health benefits.