SULFORAPHANE: BENEFITS,SIDE EFFECTS, AND FOOD SOURCES
Sulforaphane is a natural plant compound found in many cruciferous vegetables like broccoli, cabbage, cauliflower, and kale.
It has been linked to health benefits, such as improved heart health and digestion.
This article reviews sulforaphane, including its benefits, possible side effects, and food sources.
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What Is Sulforaphane?
Sulforaphane is a sulfur-rich compound found in cruciferous vegetables like broccoli, bok choy, and cabbage. It has been shown to provide powerful health benefits.
In these foods, it’s in the inactive form glucoraphanin that belongs to the glucosinolate family of plant compounds.
Sulforaphane is activated when glucoraphanin comes into contact with myrosinase, a family of enzymes that play a role in the defense response of plants.
Myrosinase enzymes are only released and activated when a plant is damaged. Therefore, cruciferous vegetables must be cut, chopped, or chewed to release myrosinase and activate sulforaphane (1Trusted Source).
Raw vegetables have the highest levels of sulforaphane. One study found that raw broccoli had ten times more sulforaphane than cooked broccoli (2Trusted Source).
Steaming vegetables for one to three minutes may be the best way to optimize sulforaphane levels when cooking (3Trusted Source).
It’s best to cook the vegetables below 284˚F (140˚C), as exceeding this temperature results in a loss of glucosinolates like glucoraphanin (4Trusted Source).
For this reason, it’s best to avoid boiling or microwaving cruciferous vegetables. Instead, eat them raw or lightly steamed to maximize their sulforaphane content.
Sulforaphane is a naturally occurring compound in cruciferous vegetables like broccoli, cabbage, and kale. It’s activated only when vegetables are chopped or chewed. The highest levels of sulforaphane are found in raw vegetables.
Animal, test-tube, and human studies have indicated that sulforaphane may offer a number of health benefits.
May Have Anticancer Effects
Cancer is a potentially fatal disease characterized by the uncontrolled growth of cells.
Sulforaphane has been shown to have anticancer properties in a number of test-tube and animal studies, reducing both the size and number of various types of cancer cells (5Trusted Source, 6Trusted Source, 7Trusted Source).
Sulforaphane may also prevent cancer cell growth by releasing antioxidant and detoxification enzymes that protect against carcinogens — substances that cause cancer (8Trusted Source, 9Trusted Source, 10Trusted Source).
Keep in mind that these studies use a concentrated form of sulforaphane, so it’s unclear whether the amounts found in fresh foods have the same effect.
What’s more, it’s still unclear whether sulforaphane could be used in a clinical setting to lower cancer risk and reduce cancer growth in humans (10Trusted Source).
That said, population studies have linked a higher dietary intake of cruciferous vegetables like broccoli with a significantly reduced risk of cancer (11Trusted Source).
Researchers believe that compounds in these vegetables — including sulforaphane — are responsible for the potential anticancer properties (12Trusted Source).
May Support Heart Health
Both test-tube and animal studies show that sulforaphane may boost heart health in a number of ways (13Trusted Source).
For instance, sulforaphane may benefit heart health by reducing inflammation. Inflammation may lead to narrowing of your arteries — a major cause of heart disease (14Trusted Source, 15Trusted Source).
Research in rats also indicates that sulforaphane may reduce high blood pressure, which may prevent heart disease (16Trusted Source).
Despite these promising findings, more research is needed to determine whether sulforaphane could improve heart health in humans.
May Have Antidiabetic Effects
Type 2 diabetes is a chronic disease affecting millions of people worldwide.
Those with type 2 diabetes can’t effectively transport sugar from their blood to their cells, making it difficult to maintain healthy blood sugar levels.
A 12-week study in 97 people with type 2 diabetes examined how consuming broccoli sprout extract — equivalent to 150 µmol of sulforaphane — daily affected blood sugar levels (17Trusted Source).
The study found that sulforaphane effectively reduced fasting blood sugar levels by 6.5% and improved hemoglobin A1c, a marker of long-term blood sugar control. These effects were particularly strong in participants who were obese with poor diabetes control (17Trusted Source).
Sulforaphane’s beneficial effect on blood sugar levels are supported by animal studies as well (18Trusted Source, 19Trusted Source).
Other Health Benefits
Studies show that sulforaphane may have other health benefits as well:
May treat certain symptoms of autism. A study in 29 young men with autism found that daily doses of 50–150 µmol of sulforaphane for 18 weeks improved symptoms of autism like social interaction and verbal communication (20Trusted Source).
May protect against sun damage. Studies suggest that sulforaphane may protect against ultraviolet (UV) skin damage caused by the sun (21Trusted Source, 22Trusted Source, 23Trusted Source).
May protect against brain damage. According to animal studies, sulforaphane may have the potential to improve recovery and reduce mental decline after a brain injury (24Trusted Source, 25Trusted Source, 26Trusted Source).
May improve constipation. In a 4-week study in 48 adults, eating 20 grams of sulforaphane-rich broccoli sprouts improved symptoms of constipation. No effect was found for alfalfa sprouts, which are sulforaphane-free (27Trusted Source).
It’s important to note that most of these studies were performed on isolated human cells or animals.
Thus, further research is needed to confirm whether sulforaphane would have the same effects in humans (28Trusted Source).
Sulforaphane has been associated with various health benefits and may beneficially affect cancer, heart disease, diabetes, and digestion. More high-quality research is needed to understand the extent of these effects in humans.
Side Effects and Safety Concerns
Consuming sulforaphane in amounts found in cruciferous vegetables is considered safe with few — if any — side effects (8Trusted Source).
Additionally, sulforaphane supplements are available for purchase at health food stores and online retailers.
These supplements are typically made from broccoli or broccoli sprout extract and generally concentrated, containing more sulforaphane than what’s naturally found in food.
Glucoraphanin — the precursor to sulforaphane — supplements are also available combined with myrosinase for activation. These are marketed as a way of increasing sulforaphane production in your body.
While there are no daily intake recommendations for sulforaphane, most available supplement brands suggest taking around 400 mcg per day — typically equalling 1–2 capsules.
Mild side effects have been associated with sulforaphane supplements, such as an increase in gas, constipation, and diarrhea (17Trusted Source, 29).
Despite their growing popularity, more research is needed to determine the ideal dose, safety, and effectiveness of sulforaphane supplements in humans (14Trusted Source).
Sulforaphane appears to be safe with few to no side effects. Sulforaphane supplements are available on the market as well. Their safety and effectiveness in humans are still unknown.
Sulforaphane can be obtained naturally from a range of cruciferous vegetables. These vegetables not only provide sulforaphane but also many other important vitamins, minerals, and antioxidants.
To increase your intake of sulforaphane, include more of the following vegetables in your diet:
cabbage, both red and white varieties
arugula, also known as rocket
It’s important to cut the vegetables before you eat them and chew them well to activate sulforaphane from its inactive form, glucoraphanin.
To optimize your intake of sulforaphane, eat vegetables raw or cooked at temperatures below 284˚F (140˚C) (4Trusted Source).
To further boost your intake, add mustard seeds or mustard powder to your meals. These ingredients are rich in dietary myrosinase, which can help increase the availability of sulforaphane, particularly in cooked vegetables (30Trusted Source, 31Trusted Source).
Sulforaphane can be found in cruciferous vegetables like broccoli, kale, cabbage, and watercress. To maximize your sulforaphane intake, eat vegetables raw or cooked at low temperatures with a sprinkle of mustard seeds or mustard powder.
The Bottom Line
Sulforaphane is found in cruciferous vegetables like broccoli, cauliflower, and kale. It may offer anticancer, antidiabetes, and other benefits.
Still, most research has been done in animals and isolated cells. Thus, more high-quality human studies are needed to better understand sulforaphane’s possible health benefits.
Adding more sulforaphane to your diet by incorporating more cruciferous vegetables into your meals is a nutritious and tasty way to boost your health.
Written by Daisy Coyle, APD
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