First you will need to determine what type of body you are, you can google and determine this. Most women (70%) will be yin, but there are also two types of yin and two types of yang.
My reading says that if you are Yin these are foods and supplements that can help reduce hot flashes:
Vitamin E - supplement with lowest recommended dosage, foods: wheat germ oil, canola oil, sunflower oil - nourishes yin and anchors yang heat
Flaxseed - supplement with lowest recommended dosage, original form - nourishes and supports the function of the liver, lungs, and large intestines
Soybeans - not compatible
Magnesium - tolerable in food but not recommended as a supplement, eat dark leafty greens, pumpkin seeds, cashews, almonds, seafood, beans, whole greens, avocados, yogurt, bananas - promotes the downward flow of energy, roots the mind and spirit
Sage - very compatible, original form or as a supplement - promotes harmonious flow of yang heat throughout the body
Wild (Chinese) Yam - very compatible, original form (can be found in Asian food markets or as a supplement) - supports and nurtures yang energy, and to a lesser degree yin energy
If you are Yang body type:
Vitamin E - very compatible (see above)
Flaxseed - supplement with the lowest recommended dosage (see above)
Soybeans - very compatible, original form or in tofu, tempeh, soy-based yogurt - nourishes yin and has cooling energy
Magnesium - supplement with the lowest recommended dosage (see above)
Sage - not compatible
Wild (Chinese) Yam - tolerable but not recommended (see above)