Luteolin, a flavone chiefly found in vegetables and fruits like carrots, cabbages, onions and broccoli, has recently captured significant attention in longevity research, making many wonder: is luteolin safe to take as a supplement?
In this comprehensive guide, we explore everything about luteolin safety, appropriate dosages and precautions. We’ll examine how much luteolin should be taken, whether luteolin supplements are safe for daily consumption and provide evidence-based insights to help make informed decisions about incorporating this promising flavonoid into longevity-focused health regimens.
What is luteolin and why is it gaining attention?
Luteolin (3′,4′,5,7-tetrahydroxyflavone) is a naturally occurring flavonoid belonging to the flavone subclass of flavonoids. This yellow crystalline compound has sparked considerable interest in recent years due to its impressive array of health benefits and therapeutic potential.
Natural sources: herbs, vegetables and fruits
Luteolin is abundantly present in over 350 plant species, often found in combination with glycosides. While widespread in many common foods, the estimated daily consumption from a typical diet is generally less than 1 mg per day, with the highest intake of flavonoids recorded in Ireland and the lowest in the Czech Republic.
Rich sources of luteolin include:
- Vegetables: celery, green peppers, carrots, artichokes, red beetroot, kohlrabi and pumpkin;
- Herbs: thyme, parsley, rosemary and oregano;
- Fruits: lemons, watermelon and kiwi;
- Oils: extra virgin olive oil.
Pharmacological properties: anti-inflammatory, antioxidant, neuroprotective
Luteolin exhibits remarkable pharmacological activities that explain the growing scientific interest in this compound:
First, it possesses potent anti-inflammatory properties by inhibiting pro-inflammatory cytokines, including IL-6, IL-1β and TNF-α. Additionally, luteolin can suppress nuclear factor-kappa B (NF-kB) signaling and reduce the expression of inducible nitric oxide synthase (iNOS).
Moreover, luteolin demonstrates impressive antioxidant capabilities, both directly through free radical scavenging and indirectly by activating the Nrf2 pathway, which increases production of antioxidant enzymes.
The neuroprotective effects of luteolin are particularly noteworthy, as it can cross the blood-brain barrier and protect against neurodegenerative conditions such as Alzheimer’s and Parkinson’s disease. Studies in mice have shown that luteolin inhibits brain microglia activity related to aging and reduces neuroinflammation, consequently improving cognitive functions.
Common uses in supplements and traditional medicine
In traditional Chinese medicine, plants rich in luteolin have long been used to treat various conditions, especially hypertension, inflammatory disorders and cancer.
Currently, luteolin is gaining popularity as a dietary supplement due to its potential health benefits. It shows promise as a natural antihistamine by inhibiting mast cell degranulation, making it potentially beneficial for allergies and asthma. Furthermore, luteolin supplements are being investigated for their potential in supporting brain health, particularly for reducing symptoms of brain fog.
Research also indicates luteolin may be valuable as an adjuvant in cancer treatment, as it has demonstrated effectiveness in preventing intestinal mucositis induced by irinotecan without affecting the anticancer efficacy.
What does the research say about luteolin’s safety?
Research on luteolin’s safety profile continues to evolve as interest in this flavonoid grows. Understanding what science tells us about its safety is essential for anyone considering luteolin supplementation as part of their longevity regimen.
Animal studies: low toxicity and high tolerance
Numerous preclinical investigations reveal that luteolin demonstrates remarkably low toxicity in animal models. In acute toxicity studies, luteolin showed no significant adverse effects even at doses substantially higher than what would typically be consumed by humans. Notably, rodent studies have established an LD50 (median lethal dose) of over 5000 mg/kg body weight, indicating excellent tolerance.
Long-term animal studies found no significant changes in blood biochemistry, hematological parameters, or organ histopathology when luteolin was administered at doses equivalent to human supplementation levels. Furthermore, genotoxicity testing has revealed no mutagenic potential in standard assays, alleviating concerns about DNA damage.
Pharmacokinetic studies indicate that luteolin has moderate bioavailability when taken orally, with peak plasma concentrations occurring approximately 1-2 hours after ingestion. The compound undergoes extensive metabolism in the liver, primarily through glucuronidation and sulfation pathways.
Human trials: limited but promising data
Although human research on luteolin specifically remains somewhat limited compared to other flavonoids, the existing data presents a reassuring picture. Clinical trials examining luteolin’s safety have primarily involved small sample sizes but consistently report minimal adverse events.
One phase I trial administered 50 mg of oral luteolin daily for 180 days with no participants experiencing significant side effects. Most impressively, all subjects completed the treatment regimen without any deficiency, suggesting excellent tolerability in humans.
Is luteolin safe to take daily?
Based on current evidence, luteolin appears generally safe for daily consumption within recommended dosage ranges, typically 50-100 mg per day for most healthy adults. Nevertheless, individual responses may vary based on genetic factors, concurrent medications and pre-existing health conditions.
For context, dietary intake of luteolin from food sources rarely exceeds 1 mg daily, making supplementation a significantly higher exposure than what’s naturally consumed. Despite this difference, no serious adverse events have been documented in studies of daily luteolin supplementation at typical doses.
Potential side effects and interactions
While luteolin demonstrates impressive potential benefits, understanding its potential adverse effects remains crucial for safe supplementation.
Mild gastrointestinal symptoms at high doses
At typical supplemental doses, luteolin is well-tolerated by most individuals. First of all, the most commonly reported side effects involve the digestive system, including mild stomach upset, nausea, bloating and general stomach discomfort. It’s worth noting that these gastrointestinal symptoms are typically uncommon and mild, often resolving by reducing the dosage. In fact, research indicates that luteolin’s toxicity appears to be dose-dependent, showing favorable biological activity at low doses while potentially affecting cell viability at extremely high concentrations.
Possible interactions with blood thinners and immunosuppressants
Luteolin may interact with certain medications, requiring careful consideration. Of particular concern are interactions with blood-thinning medications like warfarin. Accordingly, luteolin and other flavonoids can potentially bind to human serum albumin (HSA) and displace warfarin from its binding site, potentially elevating its free concentration in blood. This interaction could be clinically significant for patients with kidney or liver disease.
In addition to anticoagulants, luteolin may interact with immunosuppressive medications commonly prescribed after organ transplantation. The coadministration of tacrolimus with certain compounds may increase the incidence and severity of renal damage. Since immunosuppressants are critical for preventing organ rejection, any potential interference warrants caution.
Side effects of luteolin in sensitive individuals
Certain populations may experience unique adverse effects. Studies involving children with autism spectrum disorders reported temporarily increased irritability in approximately 50% of participants receiving luteolin treatment. Subsequently, research suggests luteolin might block progesterone effects, which could be detrimental in cases of uterine and cervical cancer.
Who should not take luteolin?
Despite luteolin’s potential health benefits, certain populations should exercise caution or avoid this flavonoid entirely based on current scientific understanding.
Pregnant or breastfeeding individuals
Pregnant women should strictly avoid luteolin supplements unless explicitly recommended and supervised by healthcare providers. Currently, there is insufficient safety data regarding luteolin use during pregnancy, making the risk-benefit profile unclear. Of particular concern, research suggests luteolin may block progesterone effects, potentially affecting hormonal balance during pregnancy.
For breastfeeding mothers, caution is equally warranted. Though studies specifically on luteolin during lactation are limited, research on similar compounds indicates that flavonoids can transfer into breast milk and may affect infant development.
People with chronic illnesses or on multiple medications
Individuals with certain health conditions or taking specific medications should be particularly cautious about luteolin supplementation:
- Those taking blood pressure medications or calcium channel blockers may experience interactions that alter medication effectiveness;
- Women with uterine or cervical cancer should avoid luteolin, as it blocks progesterone effects which could be harmful in these conditions;
- People with inflammatory bowel conditions should consult healthcare providers, as luteolin paradoxically worsened chemically-induced colitis in experimental models while helping spontaneous colitis.
Allergies to plants in the Asteraceae family
Individuals with known allergies to plants in the Asteraceae (formerly Compositae) family should avoid luteolin-rich herbs from this family. These allergic reactions can range from mild to life-threatening:
- Both immediate (type 1) and delayed (type 4) hypersensitivity reactions are possible;
- People with respiratory allergies to weed pollen may experience cross-reactivity with certain herbal medicines containing luteolin;
- Common Asteraceae plants associated with allergic reactions include chamomile, marigold and purple coneflower.
Luteolin offers promising potential benefits for longevity and overall health, particularly through its anti-inflammatory, antioxidant and neuroprotective properties. Nevertheless, approaching this flavonoid with informed caution remains essential. While research generally indicates good tolerability at recommended dosages (typically 50-100 mg daily), individual responses may vary significantly based on health status and medication regimens.
