Next to water, tea is the most popular beverage in the world, which is generally a good thing: Besides being tasty and soothing-or energizing, depending on what you’re going for-a seemingly endless body of research has linked it with a huge number of mental and physical health benefits. Most recently, for example, studies have shown that tea is associated with a lower risk of depression, ovarian cancer, Parkinson’s disease anddementia.

Given its array of perks, it would seem that the more tea you drink, the better, but new research sheds light on serious risks that may come with sipping certain varieties. Tea can contain or absorb various toxic compounds, depending on lots of things–including its soil, environment, and harvesting, storage and brewing methods. A number of studies have found excessive levels of toxic elements in many different types. Check out the potential dangers below, and learn how to minimize or avoid them–and still have your cup of tea!

Know the Potential Risks

Heavy Metals: In a 2013 study from the Journal of Toxicology, researchers tested 30 teas and found that all had high amounts of lead-which can cause heart, kidney and reproductive problems. Around 73% of teas brewed for three minutes, and 83% percent of those brewed for 15 minutes, had potentially unsafe amounts, and 20 percent of teas brewed for 15 minutes contained unsafe aluminum levels. A 2015 study discovered that teas with added citric acid had elevated aluminum, cadmium and lead, and lemon tea bags produced levels 10 to 70 times higher.

Fluoride: According to research published in 2013, fluoride levels in economy teas exceeded daily recommended levels and had three times the amount of more expensive varieties. “The higher priced teas were observed to have lower fluoride concentrations,” says study co-author Laura Chan, PhD, a professor at the University of Derby in the UK, probably due to differences in the parts of the plant that are harvested and the techniques used to do so. Consuming too much fluoride can damage teeth, bones and joints, and we absorb even more of it when fasting.

Pyrrolizidine Alkaloids: A November 2015 study from the journal Food Chemistry analyzed 44 samples of herbal teas intended for babies and pregnant and breastfeeding women. They found that 38 of them–86 percent!–tested positive for pyrrolizidine alkaloids, toxins produced by some flowering plants that can cause liver damage. This finding has particular importance for pregnant and lactating women because they can pass the compounds along to the fetus or baby, who is more vulnerable to the toxic effects of pyrrolizidine alkaloids because of their low body weights.

How to Stay Safe and Keep Sipping

1. Keep brew time under three minutes, and “avoid tea from regions that are more contaminated,” like China, India and Sri Lanka, says Gerry Schwarfenberg, MD, of the University of Alberta, Edmonton in Canada, one of the researchers in the 2013 heavy metals study. “Tea from China has high levels of lead and aluminum, likely from contaminated soil due to coal fired power plants.” Consider opting for white tea–its “leaves are young and have less time to absorb heavy metals,” and serve in glass instead of china, which could have lead in the glaze. You can minimize the effect of heavy metals through adequate intake of essential minerals and vitamin D.

2. Go for tea leaves over bag tea or lemons teas. Powder-based “lemon tea in bags is usually of worse quality than tea leaves” and has “higher amounts of noxious metal than tea infusions made from whole leaves,” says Magdalena Jeszka-Skowron, PhD, of the Poznan University of Technology in Poland, who is one of the authors of the lemon tea study. Brew bag tea for less time than leaves to get less noxious metals, and hold off on adding lemon to your tea until it’s done brewing and you’ve removed the leaves or bag. Otherwise, “when you add lemon to the tea, its pH becomes lower and more noxious metals are extracted to the tea.”

3. To reduce fluoride exposure, again–limit brewing time, and stick to the pricier blends if you drink more than four cups of tea daily. “If anyone wishes to reduce their fluoride intake, consuming pure blends such as Assam, Ceylon, Oolong or Darjeeling would be a way to achieve this,” says Chan. And to minimize the amount you absorb, don’t drink on an empty stomach.

4. Mix it up–don’t stick to one brand or product. “Instead, mix different suppliers and products,” says Till Beuerle, PhD, of the Braunschweig University of Technology, an author of the study on pyrrolizidine alkaloids. For instance, don’t drink just one peppermint tea from a single brand, but different types of tea from different companies. As for teas with elevated levels of the plant-based toxin, the “biggest problems for the moment are rooibos, and to a lesser extend peppermint, chamomile and other herbal teas like fennel and mixtures thereof, but black teas have also been found positive, while almost no positive samples occurred so far in pure fruit teas.”