While you may have been told to eat your broccoli and cauliflower when you were a kid, I don’t think anyone actually anticipated the amazing effects that these cruciferous vegetables are capable of having on health. 

From anti-inflammatory & antioxidant properties to their ability to support conditions that include cancer, diabetes, heart conditions, ageing, depression, behavioural conditions (ADHD & autism) and neurodegenerative conditions (eg. Alzhiemer disease). We now have the science to back up what mum said in the kitchen all those years ago! (1) 

What are cruciferous vegetables?

Cruciferous vegetables are part of the Brassica genus of plants. They include the following vegetables, among others: arugula, bok choy, broccoli, broccoli sprouts, brussels sprouts, cabbage, cauliflower, collard greens, horseradish, kale, radishes, rutabaga, turnips, watercress and even wasabi!

What’s so good about cruciferous vegetables?

Cruciferous vegetables are a good source of vitamins A, C, E, K, B vitamins, iron, potassium, calcium, selenium, magnesium and fibre.

However, cruciferous vegetables contain another extremely important group of nutrients known as glucosinolates or isothiocyanates in their active form. In this article we are focusing on one particular type of isothiocyanates called sulforaphane. 

What is sulforaphane?

Sulforaphane is a type of isothiocyanate that is activated through an enzyme called myrosinase when cruciferous vegetables are either crushed, chopped or chewed, however is inactivated from sustained cooking or high temperatures. The highest levels of sulforaphane are found in raw vegetables (2).  

Sulforaphane’s health benefits are believed to be through both anti-inflammatory and antioxidant properties. Sulforaphane is the most potent naturally occurring inducer of what’s called the ‘NRF2 pathway’ that controls hundreds of genes by acting on antioxidants in the body. 

NRF2 pathway can also help to improve liver detoxification by deactivation phase 1 enzymes and activating phase 2 detox enzymes that are important for removing inflammatory chemicals from the body (3).

Sulforaphane and cancer

Sulforaphane may help to reduce the risk of cancers and to help to kill cancer cells through liver detoxification, supporting antioxidant and anti-inflammatory pathways, and preventing DNA damage (a common cause for cancer).

One study found that that eating 5 servings or more of cruciferous vegetables a week may help to reduce bladder cancer risk (4). Increased Cruciferous vegetable may also help to reduce breast cancer risk, that may be explained by the detoxifying actions of sulforaphane in shifting oestrogen metabolism (breakdown) in the body (5)(6).

One study found a 55% reduction in lung cancer risk in smokers by eating 4.5 servings of cruciferous vegetables a month (7), while another study found a 57% reduction in bladder cancer and 43% overall mortality in bladder cancer through the intake of at least of serving of raw broccoli per month (average intake 3.9 servings/month) (8). 

While more research is still needed on sulforaphanes effects on cancer, these are pretty incredible results!

 

Sulforaphane and diabetes

A 12-week study in 97 with type 2 diabetes found that broccoli sprout extract (rich in sulforaphane) helped to improve blood sugar control perhaps through activating the NRF2 pathway (9). To support this claim further, these anti-diabetic effects of sulforophane were also found in animal studies as well (10,11).

Sulforaphane and Heart health 

Consumption of cruciferous vegetable may also help to lower heart disease risk. Inflammation plays a large role in heart conditions. Sulforaphane found in cruciferous vegetables can activate many antioxidants in the body through the NRF2 pathway that can help to reduce inflammation. 

Through these inflammatory effects sulforaphane may protect heart health by reducing high blood pressure, atherosclerosis (clogged arteries), and ischaemia (reduced blood supply)(12,13, 14, 15, 16)

Sulforaphane inflammation and ageing 

Inflammation and DNA damage are believed to be involved in the ageing process. Keeping inflammation low seems to be a major factor in living to be a centenarian. Lower inflammation is also associated with prolonged physical functionality and cognitive abilities (17).

Cruciferous vegetables have been found to reduce inflammatory chemicals (tumor necrosis factor-α (TNF-α), interlukin-1β (IL-1β), IL-6, CRP) and reduce DNA damage that play a role in inflammation and therefor may slowdown the ageing process! (18, 19,20)

Sulforaphane and brain health

Depression is considered to be an inflammatory disease and affects approximately 350 million individuals worldwide with approximately 10% of US adults using anti-depressing medications. This highlights the need for alternative approaches to reduce depression. Numerous studies have suggested the potential role for sulforaphane in the treatment and management for depression due to its potent anti-inflammatory effects (21, 22, 23, 24, 25).

Other studies have also highlighted sulforaphanes beneficial anti-inflammatory effects in autism (26),schizophrenia (27), Alzheimers disease (28) and Parkinson’s disease(29).

How to get the most sulforaphane in your diet

It’s important to cut the vegetables before you eat them and chew them well to activate the myrosinase enzyme to activate sulforaphane from its inactive form, glucoraphanin. Heating can reduce the myrosinase enzyme, so it’s best to eat your cruciferous vegetables raw or cooked at temperatures below 140˚C (30).

You can also boost your sulforaphane intake by adding mustard seeds or mustard powder to your meals. Both mustard seeds or mustard powder are rich in dietary myrosinase that can help to increase the availability of sulforaphane in cooked vegetables (31,32). 

Warnings/contraindications

There has been some concern for isothiocyanates on in those with thyroid conditions.  Isothiocyanates may disrupt thyroid hormone function and potentially act as a goitrogen by competing with iodine uptake. Long-term studies in iodine-deficient or hypothyroid animals showed no ill effects with high dose sulforaphane supplementation, however. While iodine deficiency is rare, a person considering sulforaphane supplementation should consult their physician to have their thyroid hormone levels monitored (33, 34).

So, what's the bottom line?

Sulforaphane is potent antioxidant and anti-inflammatory compound found in cruciferous vegetables like broccoli, cauliflower, and kale. It may be beneficial in supporting conditions that include cancer, diabetes, heart conditions, ageing, depression, behavioural conditions (ADHD & autism) and neurodegenerative conditions (eg. Alzhiemer disease).

While most studies have been done in animal and cell studies, the human studies that have been done so far have demonstrated sulforaphane as an awesome nutrient in improving health!

 

If you have any questions or need further support with your health, feel free to email our head nutritionist Ben at ben@13seeds.com.au

Disclaimer:

This article does not constitute medical advice and does not take into consideration your personal circumstances. Please see your medical professional before implementing the above.

References: 

1. https://pubmed.ncbi.nlm.nih.gov/21593509/
2. https://pubmed.ncbi.nlm.nih.gov/18458837/
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4680839/
4. https://pubmed.ncbi.nlm.nih.gov/10203279/
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4358431/
6. https://pubmed.ncbi.nlm.nih.gov/11410091/
7. https://pubmed.ncbi.nlm.nih.gov/20423504/
8. https://pubmed.ncbi.nlm.nih.gov/20551305/
9. https://pubmed.ncbi.nlm.nih.gov/28615356/
10. https://www.ncbi.nlm.nih.gov/pubmed/30091431
11. https://pubmed.ncbi.nlm.nih.gov/26165427/
12. https://pubmed.ncbi.nlm.nih.gov/26583056/
13. https://pubmed.ncbi.nlm.nih.gov/22325157/
14. https://pubmed.ncbi.nlm.nih.gov/15630296/
15. https://pubmed.ncbi.nlm.nih.gov/25238321/
16. https://pubmed.ncbi.nlm.nih.gov/19729611/
17. https://www.researchgate.net/publication/282500653_Inflammation_But_Not_Telomere_Length_Predicts_Successful_Ageing_at_Extreme_Old_Age_A_Longitudinal_Study_of_Semi-supercentenarians
18. https://pubmed.ncbi.nlm.nih.gov/25165394/
19. https://pubmed.ncbi.nlm.nih.gov/24630682/
20. https://pubmed.ncbi.nlm.nih.gov/26133502/  
21. https://pubmed.ncbi.nlm.nih.gov/26711676/
22. https://pubmed.ncbi.nlm.nih.gov/21037214/
23. https://pubmed.ncbi.nlm.nih.gov/9367546/
24. https://pubmed.ncbi.nlm.nih.gov/23623252/
25. https://pubmed.ncbi.nlm.nih.gov/26721468/
26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7527484/
27. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4423155/
28. https://pubmed.ncbi.nlm.nih.gov/23253046/
29. https://pubmed.ncbi.nlm.nih.gov/23518299/
30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2722699/
31. https://www.ncbi.nlm.nih.gov/pubmed/29806738
32. https://www.ncbi.nlm.nih.gov/pubmed/23411305
33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6422739/
34. https://pubmed.ncbi.nlm.nih.gov/16965241/