Expressed mustard oil is not currently permitted by the FDA - it’s got high levels of erucic acid, which can damage your heart. The evidence is somewhat cloudy, however, and not everyone agrees with their decision.
There are two kinds of mustard oil. The essential sort comes from ground mustard seeds suspended in liquid. The food industry uses marginal amounts to flavor pungent products like horseradish or wasabi - any more, and it can be a serious irritant.
Expressed mustard oil is squeezed out of mustard seeds in a press. It's commonly used as a cooking oil in different Asian cuisines. The FDA slapped it with an import warning within the past few years - right now, they only permit expressed oil for external use.
That's because expressed oil has unusually high levels of erucic acid. Testing by the FDA has pegged levels of the acid around 20 - 40%. Animal studies have shown that erucic acid to have serious risks; give too much to a rat, and it might develop cardiac lesions, amongst other problems. That's the main reason why expressed mustard oil is not approved for human consumption by the FDA, whereas essential mustard oil is approved for human consumption and generally regarded as safe.
This ruling by the FDA has been the subject of some controversy. Expressed mustard oil is rich in omega-3 fatty acids, which are actually good for the heart in the right ratio with their acidic cousins omega-6. The American Journal of Clinical Nutrition actually found that expressed mustard oil was good for heart health, rather than bad, in a study published back in 2004.
That study shouldn't be taken as gospel - the FDA is in the business of weighing available evidence rather than conclusively proving whether or not different foods are "good" or "bad." Still, there's a vocal contingent of mustard oil stans in the United States who buy up bottles marked for external use and employ them to cook Thai food instead.
The New York Times did a fairly balanced write-up of expressed mustard oil in 2011; they quoted a handful of nutritionists and scientists who determined that a dash of the expressed stuff likely won't kill you. If you have a history of heart problems, however, you may want to steer clear.
Possible short-term side effects
- allergic reaction
Possible long-term side effects
- bodily inflammation
- cardiac lesions
- increased lung cancer risk
Ingredients to be aware of
- erucic acid
- rich in omega-3 fatty acids
- promotes hair health
- promotes skin health
- may help treat gum disease
- may promote heart health