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Broccoli has long been recognised as a superfood. I remember learning about its immense nutritional value, early on in my nutrition training. And almost twenty years on (yikes!) there’s still no disputing the fact that broccoli is a powerhouse of goodness and a tremendous health asset.

So what’s so great about broccoli? In this article we take a closer look at one phytochemical in particular that you’ll find in broccoli; the mind-blowing ways it can impact your health and how you can best harness these powerful effects.

The cruciferous family
Broccoli belongs to the cruciferous family of vegetables. Also included in this group are broccoli sprouts, cauliflower, rocket, cabbage, chard, bok choi, Brussels sprouts, collard and mustard greens, horseradish, kohlrabi, radish, daikon radish, kale, turnip, wasabi, Swiss chard and watercress.

Digging a bit deeper into the cruciferous family
In order to understand the health benefits of consuming cruciferous vegetables such as broccoli, it’s important to dig a bit deeper into the specific plant compounds they contain and the way they are metabolised in the body.

Cruciferous vegetables contain sulphur-containing compounds called glucosinolates. One particularly noteworthy glucosinolate compound is called glucoraphanin and this is found in particularly high levels in broccoli sprouts and sprouts.

When the broccoli plant is injured, an enzyme called myrosinase catalyses the conversion of glucoraphanin into an isothiocyanate metabolite called sulphoraphane. This conversion is initiated by the plant as a protective mechanism in response to injury and it seems that we can benefit from sulphoraphane’s protective qualities too. Research into the physiological activities of sulphoraphane has accelerated since its discovery in the early 1990s by Paul Talalay & Yuesheng Zhang, and it is now highly regarded as being incredibly beneficial for health. In fact, it is likely that sulphoraphane is one of the primary reasons why broccoli is associated with so many beneficial health effects.

“The conversion of glucoraphanin to sulphoraphane is initiated by the plant as a protective mechanism in response to injury & it seems we can benefit from sulphoraphane’s protective qualities too.”

So what does sulphoraphane do?
Discovered only relatively recently, in the 1990s, there is much we likely still don’t know about sulphoraphane’s actions. One thing we do know however is that it has an important role to play in Nrf2 (Nuclear factor erythroid 2-related factor 2) activation. In fact, sulphoraphane may well be the most potent natural activator of Nrf2 that we know of currently.

“Sulphoraphane has an important role to play in Nrf2 activation.”

What’s so significant about Nrf2 activation?
The Nrf2 pathway is extremely important for regulating our protective cellular enzymes and proteins, including many with antioxidant and detoxification functions. In simple terms, the Nrf2 pathway enables cells to protect themselves against various stressors and insults. It has been estimated that the Nrf2 pathway controls between 3-5% of cellular proteins. These include many involved in phase II detoxification, glutathione (the master antioxidant) synthesis and quinone reductase enzymes which reduce potentially damaging quinones to hydroquinones. These important cellular mechanisms are an integral part of protection against a wide variety of chronic diseases and ageing. In fact, ageing is associated with a progressive reduction in Nrf2 activity and a gradual increase in brain oxidative stress, and long-lived animal species are known to have higher Nrf2 signalling levels.

Nrf2 supports every aspect of health, not just female hormonal health
Broccoli has long been associated with supporting female hormonal health, and it is undoubtedly a great food for this. You can hopefully see now though, that there are valid reasons for encouraging everyone to include it in their diets. Increasing sulphoraphane intake to support the Nrf2 pathway is all about supporting the very foundations of health, right at the level of cellular protection. When cells are able to protect themselves against potentially harmful factors such as oxidative stress, and when detoxification processes are working optimally; just about every aspect of health stands to benefit as a result; from mitochondrial function, inflammation balance and exercise performance to hormone balance, brain function, reduced chronic disease risk, healthy ageing and so much more.

"The Nrf2 pathway ensures cells are able to protect themselves against various stressors and insults.”

So, sulphoraphane supports Nrf2 activation, but how can you increase your intake?
• It’s important to remember that sulphoraphane is not what’s present in the intact plant. It’s only when a plant is  injured that the myrosinase enzyme is released to convert glucoraphanin into sulforaphane.

• The first step is to include in your diet, cruciferous vegetables which contain high levels of glucoraphanin. Broccoli seeds contain the highest levels of glucoraphanin, followed by broccoli sprouts and then the mature broccoli plant. Since broccoli seeds are not typically part of our diets; broccoli sprouts and broccoli are the preferred food sources.

• The next step then is to consider how to optimise the conversion of glucoraphanin to sulphoraphane. When preparing broccoli, it is useful to wash, chop and leave for a short while before eating or heating. ‘Chopping’ is akin to ‘injury’ for the plant and it is at this point that the myrosinase enzyme will be released and start converting glucoraphanin to sulphoraphane. Another good reason to chew thoroughly, as chewing has a similar effect on this conversion.

• Another important consideration is how you cook your broccoli. Heating denatures the myrosinase enzyme, so raw or lightly steamed are best. Broccoli sprouts are not only high in glucoraphanin but they are also typically eaten raw in a salad. Go a step further and throw a handful of broccoli sprouts in with your smoothie ingredients – giving you added benefits of more sulphoraphane conversion when you ‘chop’ the raw broccoli sprouts in this way.

What you choose to cook your broccoli with can also impact how much sulphoraphane is formed. Mustard seeds contain the myrosinase enzyme so broccoli teamed with mustard seeds or mustard seed powder are a synergistic culinary match.

• It will likely come as no surprise that the gut microbiota has a part to play here too. Some of our commensal gut bacteria can produce the myrosinase enzyme; so if glucoraphanin reaches your intestine; your gut bacteria can enable its conversion to sulphoraphane at this point. Another very strong argument for maintaining a healthy diversity of commensal gut bacteria.

• And finally, what about supplements? Sulphoraphane is not very stable and is highly reactive, whereas its precursor glucoraphanin is very stable. You can therefore take glucoraphanin derived from broccoli seeds in supplement form and this is best supplied with a source of myrosinase such as mustard seed powder to support its conversion to sulphoraphane.

Broccoli benefits & beyond
From glucoraphanin to sulphoraphane to Nrf2 activation, the potential widespread benefits of including broccoli or broccoli sprouts in the diet are loud and clear; the only thing you need to decide then is how you are going to do that. I find it mind blowing that our health can benefit from these incredible molecules that plants produce to protect themselves. Another little wonder of our world.

For further reading on the subject take a look at some of our female health resources:
Functional Medicine Guide to Oestrogen Balance
Diindolylmethane (DIM), Indole-3-carbinol (I3C), Sulforaphane and Calcium-d-glucarate - What Are The Different Benefits?
Female Health Clinical Guide

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Nutri Advanced has a thorough research process and for any references included, each source is scrutinised beforehand. We aim to use the highest value source where possible, referencing peer-reviewed journals and official guidelines in the first instance before alternatives. You can learn more about how we ensure our content is accurate at time of publication on our editorial policy.