Phytoestrogens

Phytoestrogens are compounds made by plants that can act in a similar way to estrogen in the body. "Phyto" just means plant.

You will meet them under different names depending on who is talking. The PMS recommendations name soya and flaxseed, the alsi in many kitchens. The NHS website names red clover. NICE NG23 uses the word isoflavones. They reach you in two ways: in ordinary food, or concentrated in capsules and powders sold as menopause remedies.

The guidelines treat the two differently, so the difference matters.

The idea behind them is simple. As estrogen falls in perimenopause, symptoms like hot flushes can follow, and a plant compound that acts a little like estrogen might soften some of that. The NHS website describes red clover in exactly those terms: plant hormones that can act in a similar way to estrogen.

What the plant compound actually does in a given woman is the part the evidence has not settled.

• As food, the Pakistan Menopause Society's healthy eating table lists soy-based foods, such as soya milk and tofu, and flaxseed alongside dal, saag, methi and chana, as part of ordinary eating rather than a treatment (Table 5). The British Menopause Society says women who already eat soya as part of their usual diet can carry on as they are.
• As supplements, the PMS recommendations ask for caution with over-the-counter supplements, because good evidence on their safety and effectiveness is limited (6.5). They say Asian ginseng has estrogen-like activity and should be avoided in women with hormone-sensitive conditions, and that sage should be used with caution after an estrogen-sensitive cancer.
• As remedies in general, NICE NG23 asks doctors to explain that the safety, quality and purity of what is in unregulated preparations may be unknown (1.4.6).

NICE NG23 gives phytoestrogens one careful sentence. Doctors should explain "that there is some evidence that isoflavones or black cohosh may relieve vasomotor symptoms associated with menopause" (1.4.7). The same recommendation goes on: many preparations are on sale, their safety is uncertain, they vary from one to the next, and interactions with other medicines have been reported.

The NHS website is cooler still. It lists red clover among the herbal remedies women take, and says such remedies may help with some symptoms but that this is not supported by scientific evidence. Even where there is some supporting evidence, it adds, the right dose and whether any benefit lasts are uncertain.

For hot flushes, NICE NG23 recommends offering HRT (1.5.1) and the PMS recommendations call it the most effective first-line medicine in women who can take it (7.1.1), and the guidelines list other non-hormonal treatments for women who cannot.

So what does that leave? Soya and flaxseed are food, and the PMS table treats them as food. Capsules and powders are supplements, and every source here asks for care with them.

Talk to a doctor or pharmacist before starting any supplement, especially if you take other medicines. The NHS website suggests exactly that, and NICE NG23 notes that interactions with other medicines have been reported.

If you have had breast cancer or another hormone-sensitive condition, take the question to your cancer team before trying a plant remedy. The PMS recommendations name hormone-sensitive conditions as a reason for caution with some of these products, and flag interactions between several supplements and tamoxifen (6.5).

If the flushes have you hunting for capsules online, that alone is reason to book an appointment about them.

Remedies travel through families. A mother's advice, a sister-in-law's capsule, a forwarded voice note from a hakeem. Most of it comes from love, and turning it down can feel like turning down the person. I want to check it with my doctor first is a way to take the advice seriously without swallowing it whole.