One of the foods I get asked about the most frequently is soy. For those experiencing menopause, they want to know two things. Is soy safe to consume and can it help alleviate their menopause symptoms.
A lot of misinformation regarding soy is floating around on the internet, so it makes sense that people have questions. I’ve heard all kinds of bogus claims, like soy causes breast cancer, arthritis, and infertility. For the record, nope, no, and still no. Perhaps I’ll do a myth busting post on soy in the future addressing each one of these. For now I’m going to focus on soy and its implications for health in people experiencing menopause.
Specifically, can soy help with menopause symptoms like hot flashes and night sweats?
Let’s find out.
What are the symptoms of menopause?
The transition to menopause (also called perimenopause) comes with a long list of symptoms. Hot flashes, night sweats, joint pain, irregular periods, problems with sleep, dry skin, fatigue, trouble concentrating, migraines- just to name a few. These are the result of fluctuating hormone levels related to ovarian aging. Of course not all who go through menopause will experience all these symptoms or to the same degree of intensity. You may get lucky and only have a few mild symptoms for a couple years. If symptoms are bothersome, however, then they should be treated.
What about menopause hormone therapy?
You may have heard about menopause hormone therapy (MHT) for helping alleviate some of the symptoms that come with menopause. As with soy, there’s a lot of unnecessary controversy around MHT. This is unfortunate, because it can be the right solution for some people. MHT, like any intervention has its risks and benefits. It’s really important to understand what your individual risks are so you can make an informed choice. Ob-gyn Dr. Gunter recently discussed her experience with MHT and highlights the importance of finding a reliable source for such therapies.
For those interested in considering a food-based approach there’s a lot of research on soy to look to for potential answers.
Soy (and other foods) may mimic or block estrogen’s effects
The reason soy has been so widely studied for its impact on menopause symptoms is because it contains isoflavones. Isoflavones are a type of phytoestrogen found in many plant foods. The main isoflavones found in soy are daidzein and genistein. After eating soy, bacteria in the gut break it down to produce bioactive isoflavones which can then interact with receptors in the body that estrogen would normally interact with. This is because their chemical structure is similar to estrogen. These isoflavones may bind to some receptors and mimic estrogen’s effect, or they may bind to others, blocking estrogen’s effect. The isoflavone’s potential to mimic estrogen is the reason soy is thought to reduce hot flashes and other symptoms of menopause.
There are many foods that contain isoflavones, including soybeans, chickpeas, peanuts, pistachios, and some other nuts and fruit. Other phytoestrogen containing foods include flax seed, dried fruits like apricots, dates, and prunes, as well as sesame seeds. Soy supplements will be more concentrated, so these products have a greater effect. For this reason, people with increased risk or history of breast cancer will want to check with their health care provider before taking soy supplements. Typical amounts of soy from food sources like tofu, edamame, and soy milk are safe to consume.
hormone activity of isoflavones is based on a variety of factors
Whether or not isoflavones will be able to block or mimic the effect of estrogen depends on a few things. First, the amount of circulating estrogen, that is, the amount of estrogen your body produces normally. Note that estrogen levels fluctuate leading up to menopause, when they eventually decline. Second, the amount of isoflavones in soy containing foods, like tofu, edamame, soy milk, tempeh, miso, and natto, varies greatly. Finally, you need a healthy gut microbiota to activate the isoflavones in soy. There are a lot of variables to examine in the literature.
With so much variation on how soy can influence (or not influence) hormone activity, you might have already guessed what the research has concluded.
The research on soy for improving hot flashes is inconclusive
There is no conclusive evidence to suggest that eating soy and soy products will alleviate menopause symptoms, although it might be effective for some people. Several systematic reviews and meta-analysis in the past 10 years have looked into the effectiveness of soy on menopausal symptoms, including hot flashes.
- Franco et al. (2016) reviewed studies that focused on a variety of plant-based therapies, including soy, and their impact on menopausal symptoms. The review included 62 studies totaling over 6,500 women. The reviewers found phytoestrogen supplementation, including soy isoflavones, is associated with modest reductions in the frequency of hot flashes for some people.
- Chen et al. (2015) reviewed phytoestrogens impact on menopausal symptoms, including soy foods, and found that they appear to reduce the frequency of hot flashes without any serious side effects. The review included 15 randomized-control trials ranging from 3 months to 12 months in duration.
- Thomas et al. (2014) ‘s review included two studies on soy isoflavone preparations (6g soy germ extract and 25g soy protein in soy nuts) that found significant reductions in hot flashes, but no other symptoms. Both these studies were randomized controlled trials lasting 12 weeks, with small sample sizes (84 and 37 women).
- Lethaby et al. 2013 conducted a Cochrane Review of randomized controlled trials in perimenopausal and postmenopausal women to determine the impact of phytoestrogen containing foods on hot flashes. 13 of the included studies focused on soy and soy-derived products. Of these 13 studies, only 6 had outcomes demonstrating that soy was effective at reducing the frequency of hot flashes. Noted side effects with the soy interventions included bloating and nausea.
- Bolanos et al. (2010) reviewed 19 randomized controlled trials on soy and isoflavone concentrates (derived from soy). The reviewers found it difficult to provide conclusive results because there was a high degree of variation among the studies, in terms of type of soy intervention used and other study details. Some studies showed no benefit, and others found that there was improvement with hot flashes.
Other benefits of soy and soy products
Whether or not you decide to give soy a try for improving your hot flashes, know that there are many other health benefits soy can offer.
Soy is high in monounsaturated fats and fibre, both of which can help lower blood cholesterol and reduce your risk of cardiovascular disease. Soy is also high in calcium, magnesium, and is a high-quality source of protein – all of which are necessary for optimal bone health. Further, soy isoflavones have the potential to help reduce osteoporotic bone loss. This is especially important for those going through menopause. Both heart disease risk increases and bone loss occurs during this time. Additionally, observational studies have shown that soy is associated with reduced rates of breast and prostate cancers.
If you haven’t tried soy before, there are a lot of ways to start enjoying it regularly. If you drink smoothies, using soy milk as the liquid base is a good option. Or you could try switching to a soy milk latte. Tofu has a pretty neutral taste, so you can use it in place of poultry or meat in many different dishes. You can also marinate it and enjoy it in power bowls or as a salad topper (here’s a simple recipe for tofu cubes). Curries and stir-fry’s are good places to start for mixed dishes.
Should I try soy for my hot flashes?
If you think you are experiencing symptoms of menopause talk to your healthcare practitioner first and foremost. Symptoms like hot flashes and night sweats can have a huge impact on quality of life, so it’s worth discussing the risks and benefits of various treatment options with your health care provider. A good practitioner will be open to discussing all options with you to help you make an informed choice. Be cautious of anyone trying to sell you a whole batch of supplements, promising to cure all that ails you. Especially if they cannot properly explain the risks, benefits, and research behind them. Or if they get defensive when you question the efficacy of a suggested treatment – that’s big red flag.
For those considering a food-based approach, know that the research on soy is mixed. Since there are so many different ways to eat it (whether it be from food like tofu or soy milk, or a supplement) and the amount of isoflavones in each of these foods varies, it makes comparing studies difficult. This is generally the findings the reviews above.
All of the studies reviewed were well designed: blinded, placebo-controlled, randomized trials, and concluded there was either no benefit or some improvement with hot flashes with little to no adverse effects. Noted side-effects include gastrointestinal symptoms, like bloating and nausea. Soy is also a common allergen, so it simply might not be an option for some.
how much do i need to take?
In the most recent review, the studies showing a reduction in hot flashes with soy intake required an average 65mg of daily intake. A 3 oz. serving of tofu will provide about 20mg of isoflavones. The same sized portion of tempeh is around 30 mg of isoflavones. 1 cup of soymilk will provide 6mg. That’s quite a lot of soy over the course of the day. Of course, other foods do provide isoflavones, so you could use other foods as well. I’ve yet to look into the research on other food sources of isoflavones or combination approaches.
The 2013 Cochrane review concluded supplements containing primarily genistein (30 to 60 mg/day for 12 weeks to one year) significantly reduced hot flashes.
Isoflavones are quickly metabolized so they don’t stay inside your body long. This means you’ll have to consume them daily and consistently so. Most studies were at least 12 weeks in duration, so you may need to commit to this length of time before seeing improvements.
Bottom line
Eating soy might help reduce your hot flashes.
Aside from its potential impact on hot flashes, soy is a wonderful food to add to your eating pattern for overall health. It can improve blood cholesterol levels and help achieve optimal bone health. I eat it regularly for these reasons alone.
Before committing, ask yourself if soy is something you could eat daily. If you’re unsure, a dietitian can help you learn to add soy foods to your diet in a way that suits you. And if not? There are many other treatment options for hot flashes besides hormone replacement therapy or soy. And there are many other ways to improve heart and bone health.
Remember, no food is the be-all end-all. If you want to give it a go, great. If not, there’s something else out there that will work for you.
