A. Tianmeng (Tammy) Zhou, Dietetic Intern, Tufts Medical Center, explains: “Flaxseed has several components that are beneficial for human health. First, it contains a relatively large amount of alpha-linolenic acid, an omega-3 fatty acid, which is recognized as essential for human health. Second, flaxseed is rich in dietary fiber, both soluble and insoluble. Third, it has the highest content of lignans of all plant foods used for human consumption. (Lignans are plant chemicals that some have suggested may have anti-carcinogenic and anti-viral properties.) Flaxseed is also a good source of magnesium and several B vitamins.
“The main difference between whole and ground flax seeds is digestibility. When whole seeds are consumed, they may pass through your intestine undigested because the outer shell of a flaxseed contains insoluble fiber, which does not dissolve in water. Studies have shown that crushing and milling flaxseed make it more likely the components will be available to be absorbed. Thus, flaxseed should be cracked or ground in order to obtain its full nutritional value and health benefits. However, ground flaxseed loses its freshness more quickly than whole seeds, so it’s best to refrigerate whole flaxseeds and then crush or grind them in a coffee grinder as needed.”