Conjugated linoleic acid (CLA) is found in dairy products, particularly cheese. One study has suggested that CLA may protect against breast cancer in postmenopausal women, but this has not been proven. ref

Flax seed contains both lignans and alpha linoleic acid
which block the effect of estrogen. Breast cancer rates
are lowest in parts of the world where flax seed intake
is high. ref

Soybeans are high in phytoestrogens. Plants contain phytoestrogens, which have a molecular shape similar to the human hormone estrogen. Although breast cancer rates are lowest in parts of the world where soy intake is high, there is conflicting research—soy may increase breast
cancer risk in some women. ref

Food for Thought cont'd

While there is strong evidence that a low-fat diet, rich in fruits and vegetables can reduce breast cancer risk, attempts to pinpoint the exact foods or food components responsible have been inconclusive. Studies of soy, flax seed, fish oils (omega-3 fatty acids) and the anti-oxidants (vitamins C,E,A and selenium) have shown that these substances act dramatically on the body’s internal hormonal and chemical environment. ref Since breast cancer has a strong hormonal component, it seems possible that these foods might have a role in cancer prevention. Unfortunately, research to date is inconclusive. ref

Without evidence that any one “super-food” can protect against breast disease, the wisest food choices remain those recommended under the "healthy diet" section of this site.