We all know that we need to “eat our vegetables” to stay healthy. Leafy greens, beets, carrots, peppers, onions, and garlic all have health benefits, but there is one vegetable that rises above all the rest regarding its health-promoting properties: Broccoli sprouts! Read on to learn about the numerous health benefits of broccoli sprouts and how to grow your own organic broccoli sprouts at home.
What are broccoli sprouts?
Broccoli sprouts are young (typically three-to-four-day old) broccoli plants that look like alfalfa sprouts but have the sharp taste of radishes. They are a rich source of glucoraphanin, a precursor to the powerful phytochemical sulforaphane. While glucoraphanin is found to a degree in all cruciferous vegetables, it is most abundant in broccoli sprouts. In fact, three-day-old broccoli sprouts contain 10-100 times more glucoraphanin than full-grown broccoli! (1, 2) Glucoraphanin is converted into sulforaphane by the enzyme myrosinase, which is released when broccoli sprouts are “injured,” usually by chopping, blending, or chewing. Broccoli sprout supplements containing glucoraphanin typically contain myrosinase as well to ensure that the ingested glucoraphanin is converted into sulforaphane.
While broccoli sprouts contain many other beneficial compounds besides sulforaphane, my focus in this blog series will be on sulforaphane because it has been intensely studied and offers numerous health benefits.
The health benefits of broccoli sprouts and sulforaphane
Reduces autism symptoms
Sulforaphane readily crosses the blood-brain barrier, the semipermeable border that separates circulating blood from the brain and accumulates in the central nervous system. Once in the brain, sulforaphane induces the activity of enzymes that have neuroprotective effects. (3) In fact, several studies indicate that it improves symptoms of autism, an increasingly prevalent neurodevelopmental disorder.
A small clinical trial found that supplementation with sulforaphane-rich broccoli sprout extract improved social interaction, abnormal behavior, and verbal communication in young men with moderate- to severe autism. (4) Broccoli sprout extract improves these characteristics of autism because it reverses biochemical abnormalities that underlie the disease process, including oxidative stress, decreased antioxidant levels, depressed glutathione synthesis, reduced mitochondrial function, increased lipid peroxidation, and neuroinflammation. A similar study found that broccoli seed extract significantly improved social responsiveness in autistic children and improved urinary metabolites associated with the autism disease process. (5) Together, these findings suggest that broccoli sprouts may be a useful natural treatment for individuals on the autism spectrum.
Promotes the healing of TBI
Traumatic brain injury (TBI) is a form of brain dysfunction caused by an outside force such as a violent blow to the head. The damage causes oxidative stress, depletion of antioxidants, and brain inflammation. Sulforaphane, with its ability to cross the blood-brain barrier, promotes healing of TBI by upregulating antioxidant pathways and preventing neurotoxicity. (6, 7, 8)
Should kids and athletes involved in contact sports eat broccoli sprouts prophylactically? Based on this research, probably!
Inhibits neurodegenerative disease
The prevalence of Alzheimer’s disease and Parkinson’s disease is rapidly rising in the U.S. Unfortunately, conventional treatment options for these diseases do little to address the underlying causes and often have serious adverse effects. Fortunately, studies suggest that sulforaphane may be a useful intervention for these neurodegenerative diseases because it corrects underlying aspects of the diseases process, rather than merely alleviating symptoms. In an animal model of Parkinson’s disease, sulforaphane has been found to inhibit the loss of dopaminergic neurons; dopaminergic neuron death is a crucial feature of Parkinson's disease that promotes devastating motor and non-motor symptoms. Sulforaphane also protects against amyloid-beta-induced neuronal death in Alzheimer’s disease, thus helping to preserve brain function. (9, 10)
Alleviates depression and anxiety
The beneficial effects of sulforaphane on the brain are not limited to autism, TBI, and neurodegenerative diseases; sulforaphane also improves depression and anxiety! Sulforaphane exerts antidepressant effects by inducing the anti-inflammatory Nrf2 pathway, by inhibiting the body’s stress response, and by reducing stress-provoked inflammation. (11, 12)
The plethora of environmental toxins to which we are exposed daily means we could all use some extra assistance with detoxification! Fortunately, broccoli sprouts and sulforaphane can help. Sulforaphane induces phase 2 liver detoxification, the stage of liver detox that converts toxic metabolites into less-toxic compounds, which are then excreted by the body. (13) It dramatically increases glutathione, the body’s master antioxidant and detoxifier, and promotes the rapid and sustained detoxification of environmental pollutants, such as benzene and acrolein. (14) Finally, sulforaphane also decreases the liver enzymes ALT, ALP, and gamma-GTP, indicating that it reduces stress on the liver and restores healthy liver function. (15)
Sulforaphane has antimicrobial effects against a wide range of human pathogens. It inhibits the growth of both normal and antibiotic-resistant strains of Helicobacter pylori, a bacterium that infects the stomach and contributes to the development of peptic ulcers. (16, 17) Sulforaphane also eradicates E. coli, another gastrointestinal pathogen; Pseudomonas aeruginosa, a nosocomial pathogen found in hospitals; and Staphylococcus aureus, a bacterium implicated in a vast range of illnesses such as skin infections, pneumonia, and toxic shock syndrome. (18) The antimicrobial effects of sulforaphane appear to be related to its inhibitory effects on bacterial signaling, referred to as “quorum sensing;” essentially, it prevents bacteria from communicating with each other and altering their gene expression so that they can no longer evade the host immune system.
Currently, 50 million Americans suffer from an autoimmune disease. Unfortunately, the conventional treatments for autoimmune (AI) diseases are primarily palliative and limited to drugs and surgery. There is a pressing need for novel treatments that correct the underlying causes of AI disease. Excitingly, sulforaphane has demonstrated promising effects in the alleviation of autoimmunity! It suppresses pro-inflammatory cytokines and autoreactive immune cells that precipitate autoimmune attacks. (19, 20) While clinical trials in humans are lacking, this research suggests that sulforaphane beneficially alters the autoimmune disease process, making broccoli sprouts one food I would recommend to just about anyone with an autoimmune disease!
Boosts the immune system
Sulforaphane doesn't just alleviate autoimmunity; it also strengthens the immune system, when necessary. Research indicates that sulforaphane stimulates the activity of natural killer cells to clear the body of the influenza virus. (21) It also boosts T helper 1 (Th1) immunity and reverses the decrease in immunity that occurs with aging. (22)
Alleviates asthma and lung inflammation
Sulforaphane may be a useful preventive agent and treatment modality for respiratory diseases. It relieves bronchoconstriction in asthma by upregulating Nrf2, a molecule that regulates the body's production of antioxidants and protects against oxidative stress and inflammation, two factors that contribute to the pathogenesis of asthma. Sulforaphane also protects alveolar epithelial cells, the cells that compose our lungs, from cigarette smoke and air pollution-induced injury. (23, 24, 25)
Protects skin from UV damage
Fascinating research indicates that sulforaphane acts like an internal “sunscreen!” It protects skin from UVA radiation, a type of radiation that extends deep into the dermis of the skin and can lead to premature skin aging, wrinkling, and suppression of the immune system. (26) Sulforaphane induces these skin-protective effects by upregulating Nrf2, which as I previously mentioned, is a potent regulator of antioxidant pathways in the body.
Perhaps one of the most exciting applications of broccoli sprouts and sulforaphane is in the prevention and treatment of cancer. Sulforaphane modulates biochemical signaling pathways that induce apoptosis (programmed death) of cancer cells and inhibits metastasis and angiogenesis, the spread of cancer cells and the development of new blood vessels for facilitating cancer growth, respectively. (27) It has anti-cancer activities against cervical, breast, bladder, renal cell carcinoma, lung, colon, and prostate cancer. Sulforaphane also potentiates the effects of the chemotherapy agents cisplatin and doxorubicin while simultaneously reducing their toxicity. This means sulforaphane may be used in conjunction with conventional cancer treatments. (28)
Improves heart health
Sulforaphane promotes a healthy heart and circulatory system! It reduces blood pressure, inhibits platelet aggregation in blood vessels, improves endothelial function, and protects against atherosclerosis. (29, 30, 31) It also lowers low-density lipoprotein (LDL) cholesterol, the form of cholesterol that is associated with an increased risk of cardiovascular disease when elevated. (32)
Chronic inflammation is an underlying cause of obesity; conversely, correcting inflammation can facilitate weight loss and normalize the metabolic disturbances associated with obesity, including insulin resistance and non-alcoholic fatty liver disease. A recent study found that glucoraphanin, the precursor to sulforaphane, mitigates obesity through several mechanisms: It increases mitochondrial biogenesis in fat tissue, thereby increasing metabolic function; improves glucose tolerance and insulin sensitivity; and decreases levels of a pro-inflammatory bacterium (Desulfovibrionaceae) associated with metabolic dysfunction. (33)
Promotes bone health
Osteoporosis is increasingly being recognized as an inflammatory disease influenced by epigenetic factors such as diet and lifestyle choices. Research indicates that sulforaphane epigenetically modifies bone homeostasis and may thus be a useful intervention for preventing and treating osteoporosis. In animal studies, sulforaphane stimulates the activity of osteoblasts, the bone-building cells of the body, and decreases the activity of osteoclasts, the bone-degrading cells in our bodies, by activating the Nrf2 anti-inflammatory pathway. (34) These changes result in higher bone volume, a feature inversely associated with osteoporosis.
How to grow your own broccoli sprouts
The health benefits of broccoli sprouts appear to hinge on the regular consumption of them; in other words, broccoli sprouts are not a "quick fix” treatment but rather something you should incorporate into your daily life. While there are several broccoli sprout/sulforaphane supplements on the market, growing your own broccoli sprouts at home is far more economical and can also be quite fun! There are just a few supplies you’ll need to get started growing your own sprouts:
Ball glass jars (quart size)
Sprouting lids (these jar lids have a mesh top, rather than solid metal, that allows the sprouts to breathe)
Sprouting stands (these will enable you to invert the jars as the sprouts are growing so water can drain out)
Add two tablespoons of broccoli seeds, such as Food to Live Organic Broccoli Seeds, to a wide-mouthed glass quart jar. Cover with a few inches of filtered water and cap with the sprouting lid. Store in a warm, dark place overnight.
8 hours later, drain off the water and rinse with fresh water. Drain the fresh water.
Place the sprouting jar upside down at a 45-degree angle on a sprouting jar stand. Place in sunlight.
Rinse and drain the sprouts every 8 hours for approximately 5 days, or until the leaves are dark green.
Once the sprouts are dark green, they are ready to eat! I recommend tossing them into salads and wraps. You can store the sprouts in a mason jar with a standard lid in the fridge.
The exact dosage of broccoli sprouts needed to obtain health benefits is not definitive. However, I decided to a do my own math to calculate the potential therapeutic dosage of broccoli sprouts based on some of the studies I outlined above.
Calculating glucoraphanin and broccoli sprout dosages
To determine the dosage range of glucoraphanin/sulforaphane used in the clinical trials I’ve mentioned here, let’s do a little math:
In the clinical trials, the dosage of broccoli sprout extract is standardized for glucoraphanin, the precursor to sulforaphane. Assuming (optimistically) that all the glucoraphanin will be converted to sulforaphane in the body by myrosinase, let’s use the glucoraphanin measurements that were provided.
In several of the studies, the low end of the dosage range for broccoli sprout extract was approximately 222 micromol of glucoraphanin (GR) per day. To find out how many mg of glucoraphanin that is, we need to use the following equation:
moles of x = grams of x/ molar mass of x
The molar mass of glucoraphanin is 437.493 g/mol
Taking the low end of the dosage range, 222 micromol GR per day, we get this equation:
0.000222 mol GR = x grams of GR/ 437.493 g per mol
When we work through this equation, we arrive at a dosage of 97.1 mg of glucoraphanin per day. This amount of GR is found in approximately 100 g of broccoli sprouts. This suggests that consuming 100 g of broccoli sprouts per day may be a good place to start.
You may need a small food scale to weigh your broccoli sprouts so you can get as close to the 100 grams of broccoli sprouts/day dose as possible.
Eating broccoli sprouts is a safe, effective, nontoxic, low-cost way to boost your health and reduce your risk of many health conditions. I hope this article has convinced you to give broccoli sprouts a try! If you have ever tried broccoli sprouts before or are considering trying them, let me know in the comments below. I’d love to hear your thoughts!
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