Remember soy? It used to be everyone’s favorite vegan dairy alternative until research in the 90s and early 2000s started rolling out about the potential negative health effects of soy, and it quickly became a dietary enemy. The food remains controversial today, because despite some of the dangers of soy, it can also be healthy. Here’s how soy stacks up.

The Truth About Soy

Soy is a plant that can be a great source of protein, especially for vegans. It also contains tons of vitamins and minerals and has been shown to benefit cardiovascular health, help with weight loss, and may even reduce risk of death in women with breast cancer.

However, there are also some dangers of soy to be aware of. Soy contains certain phytochemicals, which are plant-based, natural chemicals, that mimic estrogen, called isoflavones. Some research has found that these could promote the growth of breast cancer cells, impact fertility, and impair thyroid function. But natural, non-GMO sources of soy actually have other phytochemicals that balance out some of these estrogen-like compounds.

How to safely consume soy

If you want to healthily eat soy, the most important thing to keep in mind is where it’s coming from. The majority of the soy available in the U.S. is adulterated in some way. It’s been heavily processed and has added preservatives, dyes, and sugars, losing much of it’s nutritional benefits along the way.

But organic, non-GMO soy in its purest, least processed form can be a healthy part of your diet in moderation, around 3-5 times a week. Look for sources of soy like edamame, miso, and tofu and avoid heavily processed soy, such as bars and powders.

Talk to your doctor if you’re planning to consume soy, especially if you have a thyroid condition or history of cancer.

Robin Berzin, MD is the founder and CEO of Parsley Health. This post originally appeared on Parsley Health.