Why Dietitians Advise Against Drinking Tea with These Iron-Rich Foods

Tea is beloved for its delicious taste, hydrating qualities, and easy accessibility. It’s also loaded with antioxidants, which help combat oxidative stress and protect your cells from harmful molecules. But have you heard that pairing tea with certain foods might hinder iron absorption? Curious about the science behind it? We reached out to registered dietitians for their expert opinions on this issue.

The Connection Between Tea and Iron Absorption

Tannins, a type of polyphenol or antioxidant found naturally in plant foods, are abundant in black tea, followed by green tea. These compounds are partly responsible for the many health benefits associated with tea. However, there's a catch—it's widely believed that tannins hinder the absorption of iron, a crucial mineral for maintaining healthy blood.

Tannins can indeed bind to iron, making it more challenging for the body to absorb, explains Johanna Salazar, M.S., RDN. But as with many nutritional aspects, there are exceptions. For one, most research conducted so far has focused on iron absorption in animals rather than humans. This is important because animal studies do not always replicate the effects seen in humans, says registered dietitian Maddie Pasquariello, MS, RDN. Additionally, some studies have only examined short-term impacts, like iron absorption after a single meal, or used tannin doses far higher than what a person would typically consume.

Moreover, few extensive studies have shown that consuming a moderate amount of tea, such as one to three cups daily, significantly harms iron levels, notes Pasquariello. So, if you're generally healthy and enjoy your daily cup or two of tea, it's unlikely that the habit will lead to iron deficiency.

The situation changes if you already suffer from iron deficiency, a condition affecting almost one-third of U.S. adults. In such cases, excessive tea consumption—drinking several liters per day—may pose risks to iron levels, according to Pasquariello. If you're concerned about your iron intake or have an existing deficiency, it may be wise to limit tea consumption. Alternatively, you could switch from black tea, which is particularly high in tannins, to green or white tea.

Non-Heme vs. Heme Iron

When considering iron absorption, it's important to note that the type of iron matters. Heme iron, which comes from animal-based foods like meat, poultry, and fish, is more readily absorbed by the body. Non-heme iron, on the other hand, is found in plant-based sources such as dark leafy greens, legumes, dried fruits, and iron-fortified grains, explains Pasquariello. While heme iron is easily absorbed, non-heme iron isn't as efficiently processed, according to Salazar.

Tannins primarily impact the absorption of non-heme iron. This means they are less of a concern when it comes to heme iron, or iron sourced from animals.

Foods to Avoid Eating with Tea

Leafy Green Vegetables

Leafy green vegetables like spinach, kale, and Swiss chard are excellent sources of non-heme iron. Since non-heme iron is not as easily absorbed by the body, it's worth being mindful of your tea intake if you're concerned about iron absorption or if you don't consume meat, poultry, or fish. For example, you could opt to drink tea separately from your meals or switch to green tea instead of black tea, suggests Pasquariello.

Beans

Beans, being a source of non-heme iron, are another food you might want to consume apart from tea. However, there's an interesting twist: beans, like tea, also contain tannins. Instead of worrying too much about how these tannins might affect your iron absorption, consider pairing beans with a source of vitamin C, which can enhance the absorption of non-heme iron. Good options include bell peppers, tomatoes, and a splash of lemon juice.

Tofu

When it comes to iron, tofu is an excellent plant-based option. Just half a cup of tofu provides around 36% of your daily recommended iron intake, while the same portion of steak only offers about 16%, according to Pasquariello. However, since the iron in tofu is non-heme, it is not absorbed as efficiently as the heme iron found in steak. If you have low iron levels and are a regular tea drinker, it might be a good idea to skip the tea when eating tofu.

Nuts

Nuts are another great source of non-heme iron. Cashews, in particular, are rich in this mineral, providing around 19% of the recommended daily intake for women, according to Pasquariello. While it's true that nuts, like tea, naturally contain tannins, combining the two foods won't necessarily have a negative impact on your long-term health. If you're looking to improve iron absorption from nuts, try pairing them with vitamin C-rich foods such as strawberries or oranges for a flavorful snack.