It’s easy to fall down a number of rabbit holes when it comes to nutrition for hormonal health. One such nutritional claim is that cruciferous vegetables play an important role in ‘balancing hormones’. Let’s take a look at whether there’s any evidence to back this up.

What are cruciferous vegetables?

These are vegetables of the Brassicaceae family of plants, hence why we also call these ‘brassicas’ in the UK and Ireland.

This classification includes a wide range of vegetables such as:

• Broccoli

• Cauliflower

• Brussels sprouts

• Kale

• Cabbage

• Turnip

• Rocket

• Radish

• Bok choy

• Watercress

Cruciferous vegetables all have individual nutritional profiles, but they tend to be a good source of polyphenols, fibre, folate, and vitamins C, E, and K. They also contain substances called glucosinolates, which are chemicals that contain sulphur and cause the bitter taste and strong smell of brassicas.

Research has found that consuming these vegetables is associated with a number of health benefits, including a possible lower risk of certain types of cancer as well as reduced all-cause mortality (1).

Cruciferous vegetables & oestrogen

The main claim related to cruciferous vegetables and hormone levels is that these help to ‘balance’ or even ‘cleanse’ oestrogen levels.

Oestrogen is not only important for female health and reproduction, this hormone plays an important role in a variety of body systems. This is why having oestrogen levels that are too high or too low is linked with a higher risk of a number of diseases (2). For example, the Western diet and lifestyle is linked with high oestrogen, which in turn can increase the risk of breast cancer (3, 4).

These claims are related to a type of phytochemical found in cruciferous vegetables called indole-3-carbinol (I3C) which is produced when the glucosinolates in the vegetables are broken down. In turn, I3C produces a compound called 3,3-Diindolylmethane (DIM) when digested (5). These compounds may reduce oestrogen levels by blocking oestrogen receptors (6).

Consuming cruciferous vegetables has been linked with reductions in certain types of cancer, including breast cancer (7). But this evidence is mixed and there are a number of ways that cruciferous vegetables can reduce cancer risk beyond possible interactions with oestrogen, such as reducing inflammation and protecting DNA from damage (7).

There are also claims that this group of vegetables helps the liver to ‘detoxify’ or ‘metabolise excess oestrogen’. Phytonutrients in cruciferous vegetables have been shown to support liver health and function, including detoxification processes (8). But there are mixed findings related to this, as not all cruciferous vegetables have the same effect and unusually large amounts may be needed to make a significant impact.

Taking a step back to see the wider picture, a good intake of fruit and vegetables in general is also associated with a reduced risk of breast cancer (9). Similarly, a varied and balanced Mediterranean-style diet is linked with balanced oestrogen levels, improved fertility and overall better health (10, 11, 12).

Summary

There is evidence that these vegetables may play a role in reducing cancer risk, which may be related to reducing or keeping oestrogen within a healthy range.

But more studies are needed to investigate this, and there are many other reasons why cruciferous vegetables may be linked with a lower risk of certain cancers.

Hormones and cancer risk are both complex and impacted by many different factors, many of which are beyond our control. So it’s definitely a stretch to suggest that cruciferous vegetables alone will ‘balance’ your hormone or oestrogen levels or directly impact cancer risk.

Of course including cruciferous vegetables in your diet is good for overall health. But there’s no need to limit your vegetable intake to just this group as we get other benefits from different fruit and vegetables. To cover all your bases aim to consume a variety of vegetables, and plants in general in your diet.

If you are struggling with a hormonal-related issue please seek individual advice from qualified health professionals.