Does eating soy help with hot flashes? As with all research the evidence is mixed. Some studies say “yes” and some say “no.” But MOST of the studies show that soy DOES help. In fact, replacing animal protein with soy protein is just plain better for you. But remember there is no one magic food that will cure your hot flashes. Soy foods need to be used in partnership with an overall healthy diet. Not in addition to your McDonalds hamburger, French fries and coke.
So let’s jump right in. Here’s what I wanted to know and I bet you do too —how much is enough? What about using soy isoflavone supplements? Is it ok to eat soy if I have a family history of breast cancer? Can soy interfere with thyroid function? If you have any other questions, just leave me a comment at the end of my post.
How much soy do I need to eat to make a difference?
The phytonutrient in soy thought to be responsible for “cooling you off” is called isoflavones or more specifically, genistein.¹ ² Studies show we need about 25- 50 mg per day. If your hot flashes are really bothersome, I’d probably shoot for the 50 mg per day. Isoflavones are found in small amounts in a number of legumes, grains, and vegetables, but soybeans and fermented soybean products are by far the most concentrated source of isoflavones we can eat. And fermented soy has an extra bonus, in that it is brimming with good-for-your-belly probiotics too, which help keep the gut bacteria healthy.
Yes, you can buy isoflavone powdered supplements but more on that in minute.
Here is a chart of soy foods and the relative genistein content. I didn’t add the meatless products like soy hotdogs and soy cheese because content in minimal, like 1- 5 mg.
| Foods | Genistein (mg) |
| Miso, ½ cup | 24 mg |
| Soy beans (edamame), ½ cup | 24 mg |
| Tempeh, 3 ounces | 21 |
| Soybeans, dry roasted, 1 ounce | 19 |
| Soy Milk, 1 cup | 17 |
| Soy Yogurt, | 12 |
| Tofu, 3 ounces | 12 |
What about using soy supplements or soy protein powder?
Oh, I love soymilk in a smoothie, but as you can see, one cup only contains ~ 17 mg. So I have thought about using soy protein powder. But you need to be careful about what you buy. Soy protein isolate powder prepared by an ethanol wash process generally lose most of their associated isoflavones, while those prepared by aqueous wash processes tend to retain them. You need to read the label. I also know of soy powder called Soy Revival. It was invented by an MD for his mother and you can order it online. I am not endorsing it, but only giving you the information to check it out.
But I’ve heard Soy might be bad for my thyroid?
The research suggests that soy may not affect thyroid function if you have a normal thyroid. You may have heard that soy has so-called “goitrogenic” compounds (as do broccoli-family vegetables and flax seeds), which can interfere with thyroid function in people that do not eat enough iodine. If you are like me and use Kosher salt, then this could be the case. But the answer is still not to avoid these super healthy foods but to just make sure you get enough iodine. Read here for more about iodine.
However, soy may be dangerous if you already have an existing thyroid problem and take medication for it. This is because soy products may interfere with how the body absorbs the medication making it less effective. A general tip if you take thyroid medication would be to wait a few hours between taking your thyroid medication and consuming any soy products. And talk to your physician about soy and any thyroid medications you may be taking.
What about Soy and Breast Cancer?
The phytoestrogens in soy protect against cancer³ even for women with active estrogen receptor positive breast cancer. Here’s why, the phytoestrogens, in soy protect the breast tissue from the more powerful ovarian estrogens. And consuming soy products actually reduce the risk of breast cancer even for breast cancer survivors. Not only does soy prevent breast cancer, but women with breast cancer eating soy live longer. Check out this video by Dr. Michael Greger, M.D. on nutritionfacts.org. But of course, this is topic you should discuss you’re your doctor.
I think that about covers it. Any other questions? Ask away! But also know that soy isn’t the only answer for hot flashes. I’ll be discussing other lifestyle changes you can make to help too like stress management and exercise. Stay tuned!
¹http://www.ncbi.nlm.nih.gov/pubmed/15243277
²http://www.ncbi.nlm.nih.gov/pubmed/21163595
³http://www.ncbi.nlm.nih.gov/pubmed/11694655
Soy foods chart: http://lpi.oregonstate.edu/infocenter/phytochemicals/soyiso/index.html#menopause
[…] Rich and creamy, I know this Triple Berry Tofu Smoothie will hit your sweet spot. The 4 ounces (1/2cup) of tofu provides 9 grams protein and over 15 mg of isoflavones. If you are a hot flash sufferer and wondering about the soy debate be sure to read my post on soy here. […]