Brassica: A Comprehensive Reference on the Genus, Its Bioactive Constituents, and Dietary Supplement Uses
1. Identity: Botanical Classification, Species, and Natural Sources
Brassica is a genus of flowering plants belonging to the family Brassicaceae (also known historically as Cruciferae, the "mustard family"), within the order Brassicales. The Brassicaceae, commonly known as the mustard family, is the largest family within the Brassicales plant order, consisting of more than 4,600 known species and 340 genera. The family stands out as one of the most frequently cultivated and consumed plant groups in the world, with around 338 genera and more than 3,700 species.
Among all the Brassicaceae family genera, the Brassica genus is the most known and economically important, including important vegetables, oilseed crops, and forage species; key species include Brassica nigra L., Brassica oleracea L., and Brassica rapa L. Additional important species include B. carinata and B. juncea. The genus encompasses an extraordinary diversity of edible crops that differ dramatically in morphology yet share a common genomic heritage.
The most commercially and nutritionally significant species in the supplement context is Brassica oleracea L., which has diversified into numerous botanical varieties through centuries of cultivation. This morphologically diverse species includes several common vegetables, notably cabbage, kale, broccoli, and cauliflower. Formally recognized varieties within the NCBI taxonomy include:
- Brassica oleracea var. capitata — cabbage
- Brassica oleracea var. gemmifera — Brussels sprouts
- Brassica oleracea var. italica — broccoli
- Brassica oleracea var. alboglabra — Chinese kale
- Brassica oleracea var. acephala — kale
- Brassica oleracea var. botrytis — cauliflower
Species from this family are regarded as one of the richest sources of health-promoting phytochemicals, such as minerals, trace elements, polyphenols, vitamins, and isothiocyanates; many species, such as Brassica oleracea, Brassica napus, and Brassica juncea, are of great economic importance.
1.1 Common Forms and Preparations as a Dietary Supplement
Brassica-derived dietary supplements are available in multiple forms. Dietary supplements may be found in many forms such as tablets, capsules, softgels, gelcaps, liquids, or powders. Specifically for Brassica products:
- Dried whole vegetable powder: Brassica and/or kale can be in dehydrated, powdered form; the Brassica ingredient may include any material derived from plants in the Brassicaceae family, for example, broccoli.
- Broccoli sprout powder and extracts: Glucoraphanin is commercially available as a supplement. Broccoli sprouts are a leading natural reservoir of glucoraphanin, which acts as a precursor to sulforaphane (SFN).
- Standardized glucoraphanin extracts (e.g., TrueBroc®): One producer extracts glucoraphanin from broccoli seeds, where it is more concentrated than in the sprout or adult broccoli, using a natural hot water process, and markets the resulting branded glucoraphanin for use in dietary supplements, foods, and beverages.
- Vegetable concentrates with active myrosinase: An improved dietary supplement form is a stable, gently blanched and dehydrated brassica vegetable powder containing glucosinolates and endogenous myrosinase enzyme that has not been inactivated.
- Indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM) isolates: Cruciferae family vegetables are remarkably high in phytochemicals such as Indole-3-carbinol (I3C) and Diindolylmethane (DIM), which are widely known as nutritional supplements.
- Microgreens and broccoli sprout homogenates have also been used in research settings as fresh, food-based supplement sources.
Typically, cruciferous vegetables are not consumed immediately after harvesting; therefore, the storage and processing of such vegetables have a significant impact on glucosinolate content and the health benefit of consumption. Freezing has been shown to result in higher retention of glucosinolates compared to refrigeration; storage of broccoli at 6°C for 35 days resulted in a sulforaphane loss of 29%, compared to losses of approximately 13% after freezing at −18°C for 60 days.
2. Traditional and Historical Use
2.1 Ancient Mediterranean Civilizations
The documented history of Brassica as a food and medicine reaches back thousands of years. Brassica oleracea was cultivated from ancient times and used as both food and herbal medicine; from the time of ancient cultures including Greeks, Romans, and Egyptians, it was well known that cabbage juice could reduce constipation and was also used as a laxative, as an antidote to mushroom poisoning, or a treatment for hangovers and headaches. Cabbage was also historically used to stop sunstroke or relieve fevers, and its leaves were used to soothe swollen feet and to treat childhood croup.
Literary evidence confirms the depth of Roman engagement with Brassica. The presence of brassica can be found in the earliest works of Latin comedies (Plautus) as well as in the most ancient Latin prose (Cato); repeated references to coles, not only in the technical texts of scientific writers, but also in their frequent use in comedies, satires, and epigrams of the first century CE, indicate that the use and properties of coles were so deep-rooted in Roman tradition that they were able to immediately pass understandable allegories, proverbs, and metaphors to the reader. Cato, drawing from ancient Greek texts, considered the cole a vegetable superior to any other — a panacea for all types of diseases; the medical text of Aulus Celsus describes brassica among the most nutritious vegetables, although also listed among the indigestible.
Romans committed particular attention to the Brassica genus and other Brassicaceae species, with the main recorded use being medicinal (83.3%); other plants of the family were used for food (40.0%), magical, and ornamental purposes.
2.2 Asian Traditions
An ancient Chinese treatise on agriculture from around 3,000 years ago mentions Brassica rapa var. chinensis (bok choy) only briefly, but proves that it was cultivated at the time. In traditional Chinese medicine, cabbage is used to treat liver and gallbladder disorders due to its high levels of vitamins A and C, as well as fiber; the leaves are also used to relieve sore throats and coughs.
In the Indian subcontinent, the closely related species Brassica juncea (Indian mustard) has a rich and well-documented history. In ancient India, references to mustard seed preparations appear in texts dated around the 1st century CE; the Charaka Samhita, one of the classical Ayurvedic treatises, mentions mustard seeds under medicinal spices used for digestive complaints. Subsequent medieval compendia such as the Sushruta Samhita and the Ashtanga Hridayam expand on mustard oil's applications in fomentation therapies (upanaha) to relieve joint and muscle stiffness. In Ayurvedic medicine, mustard greens are used to treat respiratory problems such as bronchitis and asthma.
B. carinata has traditional medicinal value and is well known for its therapeutic potential in addressing wounds and alleviating gastrointestinal disturbances. Brassica nigra (black mustard) was used as a spice in Turkey, a medicinal plant in Ethiopia, and a vegetable crop in the Aegean islands.
2.3 Mustard Seeds as a Global Condiment and Medicine
Due to their high concentration of glucosinolates, Brassica seeds have been traditionally used as a spicy food condiment (e.g., Dijon mustard in France). The pungency of these preparations, now understood to arise from isothiocyanates generated enzymatically from glucosinolates, was therefore historically linked to therapeutic applications: seeds are cold-pressed to extract mustard oil rich in sinigrin — a glucosinolate — and when ground or chewed, this compound interacts with the enzyme myrosinase to yield allyl isothiocyanate, responsible for the characteristic pungency.
Brassica vegetables have also exhibited anti-inflammatory activity that has been known for a long time and have been used for different irritations of the human body. Current perception of the medicinal value of Brassica does not diverge too much from the ancient tradition.
3. Key Constituents and Active Compounds
3.1 Glucosinolates: The Signature Compound Class
Brassica species are well known for their abundant accumulation of essential nutrients and bioactive phytochemicals, encompassing a diverse array of vitamins, minerals, and compounds such as indole phytoalexins, phenolic acids, and glucosinolates. The glucosinolates are the most pharmacologically studied class exclusive to the Brassicaceae family.
All glucosinolates are composed of a basic structure consisting of a β-D-thioglucose group, a sulfonated oxime group, and an amino acid-derived side chain. Glucosinolates are activated by enzyme-dependent hydrolysis to their respective isothiocyanates. Glucosinolates present in Brassica plants can be categorized into two groups: aliphatic, including well-known examples such as sinigrin, glucoiberin, glucoraphanin, gluconapin, and progoitrin; and indole, represented by glucobrassicin.
These compounds are products of the hydrolysis of glucosinolates, secondary metabolites of plants from the Brassicaceae family, which are considered to have no biological activity on their own, while hydrolysis is catalyzed by the endogenous enzyme myrosinase (β-thioglucosidase) or human gastrointestinal microbiota.
3.2 Sulforaphane (SFN)
Sulforaphane [SFN: 1-isothiocyanato-4-(methylsulfinyl)butane] belongs to the isothiocyanate class of phytochemicals; glucoraphanin, a glucosinolate precursor of SFN, is found in cruciferous vegetables such as broccoli, cabbage, cauliflower, and kale. SFN (molecular formula C₆H₁₁NOS₂) is the biologically active isothiocyanate produced by the metabolism of glucoraphanin by the enzyme myrosinase.
Glucoraphanin (4-methylsulfinylbutyl glucosinolate) is a major glucosinolate component of broccoli; young broccoli sprouts have been found to contain significantly higher levels of glucoraphanin, with concentrations 20–50 times higher than those found in mature broccoli.
SFN is a dietary isothiocyanate derived from glucosinolates present in several cruciferous vegetables belonging to the Brassica genus, including cauliflower, broccoli, kale, cole crops, cabbage, collards, and Brussels sprouts, as well as other genera such as radish, mustard, and cress.
SFN is produced by the action of the enzyme β-thioglucoside glucohydrolase (myrosinase) on glucosinolates; however, this enzyme is physically separated from the substrate, so the plant must first undergo cell disruption (through chewing, cutting, or milling) to generate the enzymatic hydrolysis and production of SFN.
SFN has been reported to exhibit a wide range of biological effects including antioxidant, antimicrobial, anticancer, and anti-inflammatory activities.
3.3 Indole-3-Carbinol (I3C) and 3,3′-Diindolylmethane (DIM)
Indole-3-carbinol (I3C) belongs to the class of compounds called indole glucosinolates, obtained from cruciferous vegetables, and is well known for its anticancer properties. Hydrolysis of glucobrassicin by plant or bacterial myrosinase produces multiple indoles, predominantly indole-3-carbinol (I3C); I3C and its major in vivo product, 3,3′-diindolylmethane (DIM), are effective cancer chemopreventive agents in preclinical models and show promise in clinical trials.
Indole-3-carbinol and its metabolite 3,3′-diindolylmethane (DIM) target multiple aspects of cancer cell cycle regulation and survival, including Akt-NF-κB signaling, caspase activation, cyclin-dependent kinase activities, estrogen metabolism, estrogen receptor signaling, endoplasmic reticulum stress, and BRCA gene expression.
3.4 Other Bioactive Compounds
Beyond glucosinolate-derived compounds, Brassica species provide a broad range of additional bioactive nutrients. Isothiocyanates (ITCs) are the most characteristic compounds, considered responsible for the pungent taste of these vegetables; besides ITCs, Brassicaceae vegetables are also rich in carotenoids, phenolics, minerals, and vitamins.
Brassicaceous vegetables contain vitamins C, E, and K, as well as folate, minerals, and dietary fiber; Brassica generally contains high amounts of vitamin C and can provide up to 50% of the daily recommended dietary intake of this vitamin. Kale (a variety of Brassica oleracea) is particularly rich in vitamins (A, C, K), minerals (Ca, Fe, K), dietary fiber, glucosinolates, polyphenols, carotenoids, flavonoids, and chlorophylls. Additionally, Brassica leaves contain chlorophyll, fiber, and secondary metabolites like kaempferol and quercetin glycosides.
Both glucosinolates and isothiocyanates are involved in the perception of the distinctive aroma and taste of Brassicaceae species; the former are mainly responsible for their bitterness, while the latter are responsible for their pungency.
4. Mechanisms of Action
4.1 The Keap1–Nrf2 Pathway
The best-characterized molecular mechanism of Brassica bioactives centers on the transcription factor nuclear factor erythroid-2-related factor 2 (Nrf2). The KEAP1-NRF2 system is a key molecular target for chemopreventive agents such as sulforaphane; NRF2 is a master regulator of the expression of a subset of genes that produce proteins responsible for the detoxification of electrophiles and reactive oxygen species, as well as the removal or repair of some of their damage products.
Enhanced transcription of Nrf2 target genes provokes a strong cytoprotective response that enhances resistance to carcinogenesis and other diseases mediated by exposures to electrophiles and oxidants. It is believed that chemopreventive enzyme inducers affect the interaction between KEAP1 and NRF2 through either mediating conformational changes of the KEAP1 protein or activating phosphorylation cascades targeting the KEAP1-NRF2 complex.
Activation of the Nrf2-ARE pathway subsequently leads to the upregulation of key downstream elements such as NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, and glutathione peroxidase 1, playing a pivotal role in countering oxidative stress.
4.2 Phase I and Phase II Enzyme Modulation
In cancer treatment contexts, SFN has demonstrated the ability to selectively induce cell death in cancer cells, inhibit histone deacetylase, and sensitize cancer cells to chemotherapy; SFN also shows chemoprotective properties through inhibiting phase I metabolizing enzymes, modulating phase II xenobiotic-metabolizing enzymes, and targeting cancer stem cells.
4.3 Epigenetic Mechanisms
SFN upregulates a series of cytoprotective genes by activating Nrf2; accumulating evidence supports that epigenetic modification is an important factor in carcinogenesis, and studies have shown that SFN can reverse epigenetic alterations in cancers by targeting DNA methyltransferases (DNMTs), histone deacetylases (HDACs), and noncoding RNAs.
Sulforaphane has been demonstrated to inhibit or retard tumor incidence and progression in models of breast, colon, stomach, and lung cancer; the molecular mechanism involves multiple pathways, including the inhibition of inflammatory cytokine production and downregulation of NF-κB activity.
4.4 Anti-Inflammatory and Neuroprotective Actions
SFN has been shown to exert neuroprotective effects through the activation of the Nrf2 pathway, the modulation of neuroinflammation, and epigenetic mechanisms. Another prominent feature of NRF2 activation with high relevance to chemoprotection is inhibition of inflammation.
4.5 Mechanism of Indole Compounds
I3C and its metabolite DIM induce overlapping and unique responses in multiple cancer cell lines and tumors, including growth inhibition, apoptosis, and antiangiogenic activities; the mechanisms are complex and dependent on cell context, with I3C and/or DIM activating or inactivating multiple nuclear receptors, inducing endoplasmic reticulum stress, decreasing mitochondrial membrane potential, and modulating multiple signaling pathways including kinases.
5. Scientific Evidence by Area of Use
5.1 Cancer Chemoprevention
This is the most extensively studied health application of Brassica bioactives. Brassica vegetables and their components, the glucosinolates, have been suggested as good candidates as dietary coadjutants to improve health in non-communicable diseases (NCDs), including cancer.
Epidemiological evidence: Many epidemiological studies point out that Brassica vegetables protect humans against cancer, since they are rich sources of glucosinolates in addition to possessing a high content of flavonoids, vitamins, and mineral nutrients.
Clinical and translational evidence (Qidong, China trials): These mechanistic studies supported the development and conduct of a series of clinical trials in Qidong, China for the optimization of dose and formulation regimens seeking to reduce body burdens of environmental carcinogens; in Qidong, exposures to food-borne and air-borne toxins and carcinogens are considerable, and hepatocellular carcinoma can account for up to 10% of adult deaths in some rural townships, with chronic infection with hepatitis B virus coupled with aflatoxin exposure likely contributing to high liver cancer risk.
I3C and DIM have been studied extensively in different types of cancers, including breast, prostate, endometrial, colorectal, gallbladder, hepatic, and cervical, as well as cancers in other tissues.
Limitations: Different preclinical and clinical studies have been performed in the last decade; however, concerns have been posed regarding the lack of established and standardized protocols. The different concentrations of bioactive compounds used, time of intervention, sample size, and the lack of blinding are factors that may influence the studies' outcomes. Over the last decade, clinical trials demonstrating SFN's chemoprotective effects have predominantly utilized broccoli sprouts as a dietary source.
5.2 Type 2 Diabetes and Cardiometabolic Health
In a 4-week parallel, randomized, double-blind placebo-controlled study including 81 human participants with type 2 diabetes, 10 g/day broccoli sprout powder (providing 225 μmol sulforaphane daily) decreased fasting serum insulin and insulin resistance by 18.2% and 14.2%, respectively.
Positive results were also seen in a randomized double-blind placebo-controlled study including 97 Scandinavian patients with type 2 diabetes; patients consumed broccoli sprout extract providing 150 μmol sulforaphane per day, or a placebo, over a 12-week period.
A systematic review stated that supplementation with broccoli sprouts containing high levels of SFN increased plasma total antioxidant capacity and decreased the oxidative stress index, lipid peroxidation, serum triglycerides, oxLDL/LDL-cholesterol ratio, serum insulin, insulin resistance, and serum high-sensitive C-reactive protein.
The findings of a Phase 1 clinical trial demonstrated that 100 grams of fresh broccoli sprouts over a 7-day period provided cardiovascular benefits, which included favorable changes in blood lipids.
Limitations and meta-analysis findings: The studies in which SFN has been utilized as the intervention material are few, are of short duration, and include small numbers of participants. Few human trials have focused primarily on cardiometabolic outcomes; due to the lack of adequate data, as well as high levels of heterogeneity between studies in terms of intervention duration, dosage, and health status of participants, one meta-analysis was unable to detect any significant effects on glycemic, oxidative, and inflammation-related biomarkers. Meanwhile, existing literature suggests that adherence to a broccoli sprout-containing diet positively attenuates glycemic profiles and diabetic status.
5.3 Neurological and Psychiatric Conditions
Preclinical evidence suggests that glucosinolates and their metabolites, particularly sulforaphane, exhibit several biological properties that may be relevant to neurological and psychiatric conditions. In addition to its potential as a therapeutic agent for neurological disorders and cancer treatment, SFN has shown promise as a potential treatment for cerebral ischemic injury and intracranial hemorrhage.
Cognitive function is reported to be improved by the simultaneous intervention of sulforaphane intake and brain training in human studies. Clinical conditions investigated with broccoli sprout preparations include autism spectrum disorder (ASD), schizophrenia, bacterial and viral infections, prostate, lung, breast, skin, and head and neck cancers, osteoarthritis, type 2 diabetes, sickle cell disease, fatty liver, and asthma.
Limitations: The neurological evidence base remains predominantly preclinical. Sulforaphane is protective in models of diabetes, neurodegenerative disease, and other inflammatory processes, likely reflecting additional actions of Nrf2 and interactions with other signaling pathways; translating this efficacy into the design and implementation of clinical chemoprevention trials faces numerous challenges, including the selection of the source, placebo, and dose, as well as standardization of the formulation of the intervention material.
5.4 Antimicrobial Activity: Helicobacter pylori
Studies show that a diet rich in sulforaphane can fight against Helicobacter pylori, the pathogen causing stomach ulcers. This has been examined in both animal models and some human pilot studies, though large-scale RCT evidence in humans remains limited.
5.5 Detoxification and Environmental Carcinogen Elimination
The health benefits of sulforaphane have been widely studied in humans; sulforaphane intake reduces the level of urinary 8-hydroxyguanosine, an oxidative stress marker, and it decreases gamma-glutamyl transpeptidase and alanine transaminase levels, which are indicators of liver dysfunction. In addition, sulforaphane intake mediates the excretion of mycotoxins and air pollutants and improves mild asthma symptoms.
5.6 Liver Health
I3C and DIM have summarized protective effects against cardiovascular, neurological, reproductive, metabolic, bone, respiratory, liver, and immune diseases, infections, and drug- and radiation-induced toxicities. Liver-specific evidence includes the Qidong clinical program targeting aflatoxin-related hepatocellular carcinoma risk.
Overall evidence assessment across all areas: Most of the reports about I3C and DIM protective effects against various diseases are only from preclinical studies; this emphasizes the dire need for large-scale clinical trials on these phytochemicals against human diseases. A large and growing body of laboratory and preclinical data exists, along with a burgeoning body of clinical evidence addressing the potential of sulforaphane not only in the prevention of environmental carcinogenesis, but in the prevention or amelioration of a very large, diverse, and seemingly unrelated series of conditions. For most indications beyond cardiometabolic biomarkers, evidence is preliminary or limited to small-scale human trials.
6. Body Systems and Health Areas
Based on the published scientific literature, Brassica bioactives have been investigated across the following body systems:
- Oncology / Cancer prevention: These constituents confer a multitude of biological benefits to Brassica plants, particularly in safeguarding cardiovascular health and mitigating cancer risk. Breast, colon, prostate, cervical, stomach, lung, and skin cancers have all been studied.
- Endocrine / Metabolic system: Glycemic regulation, insulin resistance, and type 2 diabetes management.
- Cardiovascular system: Lipid profiles, oxidative stress markers, and vascular function.
- Nervous system: Neuroprotection, neurodegenerative disease, autism spectrum disorder, schizophrenia.
- Gastrointestinal / Hepatic: Liver enzyme normalization, H. pylori suppression, colon cancer prevention.
- Respiratory system: Sulforaphane has been reported to protect against cystic fibrosis, rhinitis, arthritis, asthma, and other lung disorders.
- Immune system: I3C and DIM offer protection due to their antioxidant, anti-inflammatory, antiapoptotic, immunomodulatory, and xenobiotic properties.
- Thyroid: Both potentially protective (anti-thyroid cancer) and potentially goitrogenic effects have been investigated (see Safety section).
7. Dosage Forms and Dosages Reported in Studies
The following dosages are reported only as stated in cited peer-reviewed sources and should not be interpreted as recommended doses:
- Broccoli sprout powder — Type 2 Diabetes (4-week RCT, n=81): 10 g/day providing 225 μmol sulforaphane daily; a 5 g/day arm providing 112.5 μmol SFN was also tested.
- Broccoli sprout extract — Type 2 Diabetes (12-week RCT, n=97): 150 μmol sulforaphane per day.
- Fresh broccoli sprouts — Cardiovascular (Phase 1 trial, 7 days): 100 grams of fresh broccoli sprouts daily.
- Sulforaphane-rich powder in capsules (pharmacokinetic study, n=20): 200 μmol sulforaphane, producing a Cmax of 0.7 ± 0.2 µM at 3 hours, with a half-life of 1.9 ± 0.4 hours.
- DIM supplementation (clinical studies in humans with existing disease): Supplementation with DIM at 200–400 mg/day is reported not likely to represent a risk, with the caveat that co-administration of some drugs could cause an adverse effect.
- Forms used in cardiometabolic trials: Broccoli sprouts were given as powder, capsules, and fresh or dried vegetables; the sulforaphane yield of sprouts ranged between 225 μmol per 10 g to 112 μmol per 5 g.
Trial durations have varied between one and 12 weeks in cardiometabolic intervention studies. SFN bioavailability from dietary sources is a critical determinant of its efficacy in humans.
8. Safety Considerations and Known Interactions
8.1 Goitrogenic Effects and Thyroid Function
Brassica vegetables are a rich source of sulfur compounds, such as glucosinolates and isothiocyanates, which provide health benefits but are also suspected of having a goitrogenic effect. Progoitrin and indolylic glucosinolates degrade to goitrin and thiocyanate, respectively, and may decrease thyroid hormone production.
However, the clinical picture is nuanced. Radioiodine uptake to the thyroid is inhibited by 194 μmol of goitrin, but not by 77 μmol; collards, Brussels sprouts, and some Russian kale (Brassica napus) contain sufficient goitrin to potentially decrease iodine uptake by the thyroid, but turnip tops, commercial broccoli, broccoli rabe, and kale belonging to Brassica oleracea contain less than 10 μmol of goitrin per 100-g serving and can be considered of minimal risk.
There is little reliable evidence that the consumption of normal dietary levels of cruciferous vegetables affects thyroid function. The consumption of 150 g of cooked Brussels sprouts per day for four weeks did not show any negative effect on thyroid parameters; the only studies with negative outcomes were a case report where 1–1.5 kg of raw bok choy was consumed daily over several months, and observational studies from the 1970s where children consumed large amounts of milk from cows fed high glucosinolate-containing food crops.
The vast majority of results from a systematic review of 123 articles cast doubt on previous assumptions claiming that brassica plants have antithyroid effects in humans. Historically, brassica vegetables have been suspected of negatively impacting thyroid gland function, particularly evident in livestock consuming raw or silage brassica plants; this negative effect was most pronounced in regions with concurrent iodine deficiency in water and soil.
8.2 Interaction with Vitamin K-Dependent Anticoagulants (Warfarin)
Brassica species, including Brassica oleracea var. acephala (collard), var. capitata (cabbage), var. gemmifera (Brussels sprouts), and var. italica (broccoli), contain relatively high levels of Vitamin K and are capable of potential warfarin antagonism. Since warfarin acts by inhibiting the generation of vitamin K-dependent coagulation factors, consistent changes in Brassica intake can alter anticoagulant stability in patients on this drug.
8.3 Nitrile Formation as a Processing Consideration
Under specific reaction conditions such as pH, temperature, and presence of iron, reaction products different from isothiocyanates, such as thiocyanates and nitriles, can also be generated from glucosinolates. Glucosinolates can also be converted by myrosinase enzymes into nitriles such as sulforaphane-nitrile, non-nutrients that are considered contraindicated for health. This is an important consideration in supplement processing and formulation.
8.4 Trimethylaminuria (Fish Odor Syndrome) and FMO3 Interaction
Trimethylaminuria patients could see worsening symptoms if ingesting significant amounts of Brussels sprouts or taking I3C or DIM supplements, because glucosinolate hydrolysis products can interact with the flavin-containing monooxygenase 3 (FMO3) enzyme system involved in trimethylamine metabolism.
8.5 Bioavailability Variability and Study Design Limitations
Different preclinical and clinical studies have been performed, but concerns have been posed regarding the lack of established and standardized protocols; the different concentrations of bioactive compounds used, time of intervention, sample size, and the lack of blinding are factors that may influence studies' outcomes. In-depth research is required to improve the bioavailability of I3C and DIM to achieve desirable protective effects.
8.6 Safety of DIM Supplementation
The pharmacokinetics and pharmacodynamics of DIM have been studied in both rodents and humans; urinary DIM is a proposed biomarker of dietary intake of cruciferous vegetables; and one important clinical finding is that supplementation with DIM at 200–400 mg/day is not likely to represent a risk, with the caveat that co-administration of some drugs could cause an adverse effect.
References
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