We recently received this question from a patient regarding concerns about flaxseed safety and side effects.
Like many other foods, flax contains very small amounts of cyanide compounds, especially when consumed raw. Heat, especially on dry flax seeds, breaks these compounds down. However, our bodies neutralize a certain amount of these compounds, and the U.S. government agencies say that 2 tablespoons of flaxseed (about 3 tablespoons of flax meal) is safe and probably an “effective dose” for health purposes.
In 1978 the FDA indicated concern about the cyanide in flaxseed. However, this concern was abandoned in 1982 when flaxseed was permitted in bread in levels of 10-12 percent. The FDA stated that there was no concern that there would be “…any more exposure to hydrogen cyanide than from other foods such as lima beans, fava beans, chickpeas, cassava, yams, cashews or almonds.”
A lot of research about flax show little or no problems from eating it — and actually has shown many benefits, including being a good source of omega-3 fatty acids, fiber, and antioxidants. Therefore, flaxseed/flaxseed oil is on the Block Center’s list of recommended fats, though, like all sources of healthier fats, we suggest it be used in limited quantities.