Iron in Your Diet: Not Enough or Too Much?

Iron is an essential nutrient in everyone’s diet, and it’s the most common mineral deficiency, especially in women and children. 

You need to consume enough iron for proper growth and development and create red blood cells, which carry oxygen throughout the body. Not enough iron can make you weak with anemia. Too much iron can overload the blood and cause iron poisoning.

Eating a well-balanced diet doesn’t mean you get enough iron.

Just because a steak-and-eggs breakfast, for example, is a good source of heme iron (iron from animal sources) doesn’t mean that your body will absorb all of it.

“Despite adequate iron intake from foods, iron deficiency can still occur,” says Nicole Wilkerson, MMN, RD, LD, a clinical dietitian with the University of Miami Health System. “The foods and beverages we eat and drink can either aid or impair the body’s absorption of iron. Tannins inhibit iron absorption. These compounds are found in coffee, tea, wine, barley, and unripe fruits, such as green bananas.”

In contrast, Vitamin C enhances the absorption of non-heme iron (from plant sources). “It’s important to eat Vitamin C in combination with iron-rich food sources,” Wilkerson says. “For example, when eating a kale salad, absorption of the iron from the kale is more likely with the addition of bell peppers, citrus, or tomatoes.”

How can you tell if you’re getting enough iron?

The following symptoms can be signs of iron deficiency or anemia, which must be confirmed with a blood test.

• Extreme fatigue and weakness
• Pale skin
• Chest pain
• Rapid heartbeat
• Shortness of breath
• Headache, dizziness, or lightheadedness
• Cold hands and feet
• Inflammation or soreness of your tongue
• Brittle nails
• Poor appetite or unusual cravings for non-food items

If left untreated, anemia can get worse and lead to an enlarged heart or heart failure, delayed growth and development in infants and children, increased risk of infections, and premature birth/low birth weight for pregnant women.

Women who menstruate are more likely to become iron deficient or anemic than those who don’t regularly get their period or are in menopause.

Wilkerson says, “If you are experiencing any common signs of iron deficiency or anemia, talk to your primary care physician who can order a blood test. If bloodwork shows deficient levels of iron, it’s important to include rich sources of iron in your diet, as nutrients are best absorbed when consumed via food sources.”

Should you take an iron supplement?

Sometimes changing your diet alone will not raise iron levels to a normal level. Discuss with your doctor if taking a supplement is a good option for you.

When taking an iron supplement, you may experience stomach discomfort, nausea, and/or constipation. “To avoid adverse side effects, start with a lower iron dose and alternate by taking it every other day,” Wilkerson says. “Although iron is best absorbed on an empty stomach, you can prevent nausea by pairing it with a small amount of food that contains Vitamin C. Avoid taking iron for at least two hours before or after consuming calcium-rich foods, such as dairy. If you get severe stomach discomfort, nausea, or constipation, consult with your primary care physician to assess if another form of iron might ease these side effects.”

How much is too much iron?

If you’re consuming too much iron (typically, this happens when taking high-dose iron supplements for long periods), you may experience certain warning signs. 

• stomach pain
• nausea
• chronic fatigue
• cirrhosis of the liver or liver cancer
• diabetes
• irregular heart rhythms
• skin color changes (bronze, gray, green)

Just like iron deficiency, iron poisoning or overload can be diagnosed only with a blood test.

Excess iron accumulates in internal organs, like the liver, heart, and pancreas. This can lead to liver disease, heart problems, or diabetes. You most likely don’t have iron overload if you menstruate monthly or donate blood regularly.

What are good sources of iron?

Sources of heme iron (iron from animal sources):

• eggs
• red meat
• pork
• poultry
• fish
• seafood/shellfish

“If you are vegetarian or vegan, it is imperative that you consume plenty of non-heme iron,” Wilkerson says. “You can get this type of iron from fortified grains, legumes, nuts, seeds, darky leafy greens, broccoli, brussels sprouts, potatoes, and dried fruits.”

Sources of non-heme iron (plant sources of iron):

• beans
• blackberries, raspberries
• bran flakes cereal
• broccoli
• brown rice
• Brussel sprouts
• bulgur
• cantaloupe
• carissa
• corn
• couscous
• dark leafy greens
• dried fruit
• hummus 
• iron-fortified cereals, bread, oatmeal, and pasta
• jackfruit
• lentils
• lima beans
• nuts
• oat bran 
• orange
• papaya
• passion fruit
• pearled barley 
• peas
• plantains
• potato and sweet potato with skin
• quinoa
• sapodilla
• seaweed
• seeds (pumpkin, sesame, hemp, flax)
• soursop
• soybeans
• spirulina
• tamarind
• tofu and tempeh
• tomato paste and sauce
• watermelon
• wild and white long-grain rice (enriched)

Dana Kantrowitz is a contributing writer for UMiami Health News. Reviewed by Nicole Wilkerson, MMN, RD, LD, clinical dietitian with UHealth in June 2026. 

Originally published on: August 27, 2021

Tags: heme vs non-heme iron, iron, Iron deficiency anemia, Nicole Wilkerson, Nutrition