Q: I've been told that adding flaxseed to my cereal every day will help prevent colon cancer. Is there any validity to this?
A: We have no clear evidence that flaxseed or any other
particular food or nutrient can prevent a disease all on its own. But
there's reason to believe that regularly eating flaxseed can potentially
help lower the risk of colon cancer—and a number of other diseases.
The seed is a highly concentrated source of cancer-fighting,
heart-healthy omega-3 fatty acids; a single tablespoon contains more
than 2 grams. But your body converts only a small amount of flaxseed's
omega-3 fats (called ALAs—they're also found in certain vegetable oils,
walnuts, and some green vegetables, like spinach and kale) into the kind
found in fish. And it's mostly the fish-based omega-3s that, in
studies, have been shown to deliver health benefits. However, recent
findings suggest that ALAs may work similarly. For example, ALAs seem to
ease inflammation in the same way that fish oils can. That's important
because chronic inflammation in organs or joints, for example, has been
linked to the development of cancer.
In addition to ALAs, flaxseed delivers a concentrated dose of fiber; a
tablespoon has nearly 3 grams. Because fiber adds indigestible bulk to
your diet, it can help you lose weight by making you feel full with
fewer calories; research also shows that fiber can lower cholesterol.
The studies on fiber's ability to ward off colon cancer are mixed, but I
find the evidence of a benefit persuasive. In countries where people
typically eat a high-fiber diet, colon cancer is much less common.
Finally, flaxseed contains generous amounts of a number of
disease-fighting nutrients: potassium, magnesium, antioxidants, and even
plant compounds that mimic estrogen and may help protect against
To get the full benefit of flaxseed, grind it just before you use it.
People typically put it on cereal, as you note, but you can also
sprinkle flaxseed on salads or bake it into bread or muffins.