What is Sulforaphane?
Sulforaphane is a sulphur-rich compound derived from the naturally occurring chemical group glucosinolates, which are found in cruciferous vegetables.
In the body, glucosinolates are broken down into several different compounds including indoles, nitriles, thiocyanates and isothiocyanates. While interesting research on various health-promoting effects has been found on each sub-group, isothiocyanates have received a particularly large amount of attention. Of all the isothiocyanates, sulforaphane has been extremely well researched, with a wealth of studies reporting sulforaphane exhibits a wide range of beneficial biological effects including antioxidant, anticancer, neuroprotective and detoxifying activities.
In this blog, we will cover the benefits of sulforaphane for females with oestrogen dominance, as well as letting you know which foods you can find sulforaphane in, how to maximise sulforaphane levels in foods and who might need to be avoid sulforaphane-containing vegetables.
Oestrogen Dominance and PMS
Oestrogen Dominance is a hormonal imbalance in women that occurs where there is either higher than normal levels of oestrogen or an imbalanced ratio of oestrogen and progesterone. An imbalance of oestrogen in the body can result in symptoms associated with PMS such as bloating, irritability, cramping, heavy bleeding, clotting, headaches, cravings and weight gain. Long term, oestrogen dominance has also been associated with oestrogen-related diseases such as polycystic ovarian syndrome, fibroids, endometriosis, hormone-dependent cancers, inflammatory disorders and autoimmune disorders.
To rebalance oestrogen in the body, excess oestrogen must be metabolised and excreted out of the body. For this process to happen, our bodies detoxification systems need to be working effectively. While detoxification is a complex and multi-system process, two key aspects need to be in order for hormone rebalancing to occur, which are liver detoxification (phase 1 and 2) and our digestive system.
Hormones are converted and metabolised into different forms by the liver, but it can get a bit confusing as hormones exist in the body in many different forms. For example, oestrogen’s exist in the body in the three primary forms (E1, E2 and E3). It is the role of the liver to convert the different forms of oestrogen into secondary compounds which can then be removed from the body via the digestive system.
From a dietary perspective, cruciferous vegetables have been shown to have a powerful effect on hormones as they contain various compounds, one being sulforaphane, which has been shown to support the two stages of liver detoxification, which is a critical step of rebalancing excess oestrogen levels in the body.
However, it is important to know that while sulforaphane can support the process of liver detox, that isn’t the job done and dusted. For estrogen cleared to be cleared you still need to have optimal digestive function to carry the oestrogen metabolites out of your body. Sulforaphane is just one supportive part of the puzzle.
Where Can You Find Sulforaphane?
The cruciferous vegetables that are rich in sulforaphane include bok choy, broccoli, brussels sprouts, cabbage, cauliflower, Chinese cabbage, choy sum, collard greens, horseradish, kale, kohlrabi, mustard greens, radishes, sweet potato and turnips.
To get plenty of sulforaphane in your diet, you just need to eat more green veg. As you can see from the list of vegetables above, sulforaphane is present in lots of vegetables, which means you can get a good dose through your diet as long as your eating plenty of vegetables.
For a high amount of food-based sulforaphane, you can also look out for broccoli sprouts at your local market or supermarket. Broccoli sprouts have the highest amount of sulforaphane (20 to 50 times greater than mature broccoli) and can be easily incorporated into meals in salads, or as a garnish for your meals.
The correct selection and preparation of cruciferous vegetables are crucial to maximising the best possible nutrient value, as preparation methods affect the quality and quantity of glucosinolates, sulforaphane, polyphenols and the antioxidant action. Steaming, blanching and stir-frying at temperatures lower than 100°C provides the greatest conservation of glucosinolates and sulforaphane. Cruciferous vegetables should be stored in a cool, dark refrigerator to retain the colour of the plants and the firmness of the stalks. Signs of softness, wilting or yellowing all indicate the loss of nutrients.
Is There Anyone Who Shouldn’t Be Consuming Sulforaphane-Rich Foods?
In addition to sulforaphane, cruciferous vegetables also contain goitrogens. Goitrogens are naturally occurring organic substances that can inhibit the absorption of iodine by the thyroid gland. By inhibiting the uptake of iodine, goitrogens can interfere with normal thyroid hormone production which can result in thyroid abnormalities. Because of this, many patients with hypothyroidism have been advised to completely remove goitrogenic vegetables from their diets which means missing out on the hormone balancing effects of sulforaphane. However, this is not necessarily applicable to everyone with hypothyroidism. Having a moderate amount of goitrogenic vegetables is not going have a significant effect on the thyroid unless the person is iodine deficient (which you can be tested for with your GP) and/or is only consuming goitrogenic vegetables (without any other vegetables).
It is however important to note that consuming goitrogenic vegetables raw does result in a higher amount of goitrogens, so people with hypothyroidism should avoid juices, smoothies and large portions of raw salads containing these vegetables.
For example, kale in a breakfast smoothie, a brussels sprouts salad for lunch and a large side of broccolini and cauliflower with dinner would be excessive for someone with hypothyroidism, but a couple of serves of cooked cruciferous vegetables (alongside plenty of vegetables from non-goitrogenic vegetables) per day should be well tolerated.
So in summary, for those with hypothyroidism, no raw goitrogenic vegetables and be sure you are having plenty of other vegetables alongside the goitrogenic ones.
Most of the cruciferous vegetables contain significantly large amounts of vitamin K, which aids in the formation of blood clots. Therefore, any patients that have been prescribed blood-thinning medication such as warfarin should be cautious of consuming excessive amounts of cruciferous vegetables due to the high of vitamin K content and potential for blood clotting.
Alternative Medicine Review. (2010, September). Sulforaphane Glucosinolate Monograph. Retrieved October 2, 2019, from http://altmedrev.com/archive/publications/15/4/352.pdf
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Su, X., Jiang, X., Meng, L., Dong, X., Shen, Y., & Xin, Y. (2018). Anticancer Activity of Sulforaphane: The Epigenetic Mechanisms and the Nrf2 Signaling Pathway. Oxidative Medicine and Cellular Longevity, 2018, 1-10. doi:10.1155/2018/5438179