If you have dietary restrictions, there’s a good chance you’ve eaten a soy product.

Vegetarian? Have a tofu burger! Lactose intolerant? Try soymilk! Trying to cut fat? Soy ice cream, soy custards, and even soy puddings abound!

The last decade has seen a huge surge in the popularity of soy. Between 2000-2007 alone, the US market saw the introduction of 2,700 new soy-based products, and increasingly soy is finding its way into many of our processed foods in the form of soybean oil, soy lecithin, or soy protein.

This versatile ingredient has become the poster food for healthy living, but not everyone is on board. Researchers like Dr. Joseph Mercola and the Weston A. Price Foundation argue that only fermented soy foods are beneficial, and that the compounds in unfermented soy do more harm than good. So what’s the deal? Is soy a go-to or a no-go? We’ve looked into the science and broken it down for you.

Heart Health ~ Mildly Beneficial

We already mentioned the boom in soy products since the year 2000, which was due in part to the FDA’s 1999 approval of the claim that the consumption of soy proteins could help prevent coronary artery disease (something any soy-based product could now claim in their marketing). The FDA based their approval on research that showed that consumption of soy protein, as compared with other (usually meat-based) proteins, helped lower levels of LDL or “bad” cholesterol.

However, according to a study by the American Heart Association in 2006, “earlier research indicating that soy protein has clinically important favorable effects as compared with other proteins has not been confirmed.” A separate 2006 review showed that claims that soy could assist in cancer prevention and treatment were much less significant than previously thought. While soy may be marginally beneficial to your heart health, there are many poorly understood risks to your other systems that may outweigh that benefit.

Digestive Health ~ Risky

There are many aspects of soy that may compromise a well functioning digestive system. One of soy’s isoflavones (genistein) is also known to be a goitrogen, meaning a chemical that may contribute to the formation of goiters or to the malfunction of the thyroid. While short-term studies have shown that soy is unlikely to cause thyroid problems unless the consumer is iodine deficient, more studies are needed to understand long lasting effects, especially with regards to thyroid function in women and children.

Soy also contains a relatively large amount of trypsin inhibitors. Trypsin is a chemical produced in the pancreas that helps break down proteins during digestion. The trypsin inhibitors found in soy form a chemical bond with the trypsin, which prevents the chemical from doing its job. High levels of heat during soy processing can help neutralize these inhibitors, but it can also destroy the nutritional content of the soy.

It is also worth nothing that most of the soy grown in the US is genetically modified. There are currently no studies on the long term effects of genetically modified foods on human health, but they may be linked to a slew of health problems ranging from food sensitivities and allergic reactions to contribution to chronic illnesses like ADHD, depression, and autism.

Reproductive Health ~ Potentially Dangerous

Soy products contain compounds known as isoflavones (sometimes called phytoestrogens). These compounds can act like estrogen when consumed because they are able to bond with the estrogen receptors throughout our body. Phytoestrogens are less potent than natural estrogen, so a diet high in isoflavones may block out natural hormones and have a masculinizing effect in women, while still having a feminizing effect in men.

Because so many of the body’s systems are regulated by hormones there’s concern that eating a lot of soy-based products could interfere with these systems.