Can Herbal Tea Hinder Iron Absorption?

herbal tea and iron absorption
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Question: I've heard that drinking black tea may have an effect on iron absorption. Does drinking herbal tea (like chamomile, anise, and peppermint) or green tea have the same effect?

Answer: Tannins are naturally-occurring compounds found in many plants and herbs including those used to make herbal tea. Tannins have different purposes, from protecting a plant from pests to promoting its growth. They bind with iron, specifically non-heme iron from iron supplements and plant sources such as beans, peas, and nuts.

There are different types of tannins. Those found in black tea give it its dark reddish-brown color and characteristic full-bodied, astringent flavor.

Although the amount of tannins in black tea varies depending on the variety, growing condition, and processing method, black tea is considered one of the major sources of tannins in the human diet (other significant sources include red wine, oak-aged white wine, chocolate, and coffee).

Other types of tea, including green tea, white tea, and oolong tea, are also made from the same plant, known as Camellia sinensis. They generally contain different types of tannins. Factors like steeping time and the degree of fermentation affect the tannin content in tea. Fermented teas such as pu-erh and oolong tea typically contain more tannins than white tea.

Herbal teas (which are technically tisanes or infusions) can contain tannins. Although more is known about the effect of black tea on iron absorption, it's possible that herbal tea, particularly higher-tannin tea, may inhibit iron.

Herbs and spices said to contain tannins include:

  • Hibiscus
  • Chamomile
  • Cinnamon
  • Cloves
  • Guarana
  • Nettles
  • Peppermint
  • Red raspberry
  • Rose hip
  • Sage
  • Slippery elm
  • Thyme
  • Turmeric
  • Yerba mate

Rooibos and honeybush tea are sometimes said to be low in tannins, however there is little evidence that the tannin content in fermented rooibos or honeybush is less than other teas.

Should you choose a low-tannin tea?

Tannins give tea its full-bodied flavor and may have positive health effects. If sipping a cup of tea with your meals is part of your daily ritual, consider having tea in between meals instead of with meals if your primary source of iron is from plant sources. Try having it at least one hour before or two hours after meals.

If you have follow a vegetarian or vegan diet, have been told to reduce the tannins in your diet, or if you have iron-deficiency anemia, consult your healthcare provider about food and beverages that would suitable for you. 

A few other tips:

Avoid over-steeping tea. Stick to the guidelines and avoid over-steeping to reduce the amount of tannins in tea.

If you add a little milk to tea, the tannins will bind with the proteins in the milk.

Vitamin C improves the absorption of non-heme iron.

Keep in mind that too much iron in the body can cause problems. If you regularly drink tea and are concerned about whether you're absorbing the iron, talk with your healthcare provider before upping your intake of iron (particularly from supplements).

Disclaimer: The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is not meant to cover all possible precautions, drug interactions, circumstances or adverse effects. You should seek prompt medical care for any health issues and consult your doctor before using alternative medicine or making a change to your regimen.

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