The Best Types of Iron Supplements if Iron Upsets Your Stomach

Read more: Signs and Symptoms of Severe Iron Deficiency and Anemia

Reading the labels of iron supplements can be confusing. Iron in supplements is commonly in the form of ferrous iron, including ferrous sulfate, ferrous fumarate and ferrous gluconate. These types of iron are easy for the body to absorb, and they provide a high dose of the nutrient. However, this is the form of iron that typically causes digestive problems and is not the best iron supplement for a sensitive stomach.

Newer products and gentle iron supplements often contain a slow-release form of ferrous sulfate with mucoproteose that doesn't absorb as quickly, preventing fewer side effects. A 2013 review of studies in Current Medical Research and Opinion found a slow-release ferrous sulfate supplement to have the fewest adverse gastrointestinal effects in the 111 studies reviewed. Iron protein succinylate also had a low incidence of adverse effects.

Ferrous glycine sulfate, ferrous gluconate and ferrous sulfate without mucoproteose were shown to have more gastrointestinal side effects, and ferrous fumarate was reported most likely to cause gastrointestinal effects.

Gentle iron supplements are not without side effects, but you may find that they reduce stomach upset to a more tolerable level.

Read more: How Much Is Too Much Iron Supplement?

Although iron is best absorbed when taken on an empty stomach, taking your iron pills with a small amount of food may help prevent your upset stomach. Certain foods should not be taken at the same time as iron pills:

• Cheese
  
• Yogurt
• Milk
• Eggs
• Foods high in fiber, such as whole grains, raw vegetables and bran
  
• Tea and coffee
  

The calcium, caffeine and fiber in these foods inhibit iron absorption. Although spinach is a good source of iron and vitamin C, it contains tannic acid, which also reduces iron absorption. According to a 2017 review in Current Developments in Nutrition, spinach reduces bioavailability of iron by as much as 30 percent. You should wait at least two hours after taking your supplement before eating these foods. Instead, choose foods with vitamin C, which improves iron absorption. Some good choices include:

• Orange juice or an orange
  
• Well-cooked or canned vegetables
  
• Canned fruit
  

You can also take iron with a small piece of white bread or some refined cream of wheat cereal.

Increasing your intake of iron-rich foods may help resolve your iron deficiency sooner so you can stop taking iron pills. Eating these foods regularly can prevent iron deficiency in the future. Some of the best food sources of iron include:

• Meat
  
• Seafood
  
• Poultry
  
• Iron-fortified cereals and breads
  
• White beans
  
• Lentils
• Kidney beans
  
• Peas
  
• Nuts
  

As with supplements, you should avoid consuming dairy foods, caffeine and spinach while eating iron-rich foods. Pairing these foods with a source of vitamin C can help improve absorption.

Read more: The Best Way to Take Iron Pills