Can Drinking Tea Reduce Iron Absorption From Food?

Herbal tea

Verywell / Anastasia Tretiak

Some studies have suggested that drinking coffee, tea, and other caffeinated beverages inhibits iron absorption, but can herbal teas, such as chamomile, peppermint, or ginger tea, also reduce iron absorption?

This article looks at how tea affects iron absorption, what the research shows, as well as which teas are best and when to drink them.

How Tea Decreases Iron Absorption

Two naturally-occurring compounds in tea that are said to inhibit iron absorption include tannins and oxalates. These bind with iron, specifically non-heme iron found in plant foods such as beans, peas, leafy green vegetables, and nuts. (The other type of iron, heme iron, is found in animal foods such as meat, chicken, and fish.)

Tannins are chemicals found in different plant-based foods like nuts, tea, vegetables, and fruits. They're a type of polyphenol that has antioxidant and anti-inflammatory properties.

Tannins may hinder your body's ability to absorb iron from foods. However, they also have antioxidant properties, which may help prevent heart disease, cancer, and other conditions.

Tannins in Black Tea

Tannins found in black tea give it its dark reddish-brown color and characteristic full-bodied, astringent flavor. Tannins have different purposes in nature, from protecting a plant from pests to promoting the growth of the plant.

Although the amount of tannins in black tea varies depending on the variety, growing conditions, 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 made from the same plant as black tea, 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.

Tannins in Herbal Teas

Herbal teas (which are technically tisanes or infusions) can contain tannins. Although more is known about the effect of black tea on iron absorption, some claim 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
  • Rosehip
  • Sage
  • Slippery elm
  • Thyme
  • Turmeric
  • Yerba mate

Rooibos and honeybush teas 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.

Types of Foods That Affect Iron Absorption

Certain types of foods can enhance iron absorption, while others inhibit it.

Plant foods with non-heme iron: Only 1% to 10% of the iron in foods from beans, peas, leafy green vegetables, and nuts gets absorbed by the body.

Foods with heme iron: The iron in foods like meat, poultry, and seafood is not affected by other dietary factors so it is absorbed at a much higher rate. Studies have shown 25% to 30% of heme iron gets absorbed by the body.

Foods containing vitamin C: This vitamin can enhance the absorption of non-heme iron, so including foods containing vitamin C in your meal may increase how much iron you absorb from that meal. Vitamin C-rich foods include citrus fruits, red peppers, kiwifruit, broccoli, strawberries, brussels sprouts, potatoes, and tomatoes.

Your food choices and the composition of a meal can make a difference in iron absorption. Including animal protein and foods with vitamin C may enhance iron absorption and reduce the negative effects of tea drinks on iron absorption.

What Research Says About Tea and Iron

The research on the effects of herbal tea on non-heme iron absorption is limited.

Studies from several decades ago showed the consumption of black tea and coffee inhibits iron absorption from prescribed meals, with coffee having about half the inhibitory effect of tea. One cup of tea decreased iron absorption by 49% and two cups of tea decreased absorption by 66% in healthy subjects.

A 2017 review found that although certain tannins may inhibit iron absorption during one meal, there is little research demonstrating tannins' effect on iron absorption over the long term. More studies are needed to determine these effects.

Another study published in 2017 found tea consumed with a meal decreased non-heme iron absorption, but tea consumption one hour after a meal didn't decrease iron absorption to the same extent.

There is very little conclusive research to say how tannins in herbal teas affect iron absorption.

Should You Drink Tea With Your Meal?

If you have followed 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 be suitable for you.

Avoid over-steeping tea to reduce the number of tannins and oxalates in tea. Choose vitamin C-rich foods to improve 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 iron, talk with your healthcare provider before increasing your intake of iron (particularly from supplements).

Drinking tea in between meals (rather than with a meal) may be another way to prevent tannins and oxalates from reducing iron absorption. Waiting one hour after a meal to drink tea may prevent a decrease in iron absorption.

Summary

Tannins and oxalates in tea may inhibit iron absorption, especially non-heme iron found in plant-based foods. Certain foods, such as animal protein and vitamin C-rich foods improve iron absorption and are less likely to be affected by tea consumption.

People who follow a vegan or vegetarian diet or have iron-deficiency anemia may want to talk with a healthcare provider about whether they should modify their intake of beverages like tea and coffee.

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
Cathy Wong

By Cathy Wong
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.