Last verified: today
Collard Leaf
Also known as: Collard Greens, Brassica oleracea var. viridis, Tree Cabbage, Collards
Evidence under review. — Not yet rated
Nutrient-dense leafy green with general health benefits; no clinical supplement trials available.
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What it does
Collard leaf comes from collard greens, a cruciferous vegetable in the same family as kale and broccoli. As a whole food, it is a well-known source of vitamins K, C, and A, folate, calcium, and...
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Evidence quality
Evidence base hasn't been formally rated yet. See research below.
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Clinical dose
No established dose
What the Science Says
Collard leaf comes from collard greens, a cruciferous vegetable in the same family as kale and broccoli. As a whole food, it is a well-known source of vitamins K, C, and A, folate, calcium, and fiber, along with plant compounds called glucosinolates that may support antioxidant and anti-inflammatory pathways. However, no clinical trials have been conducted on collard leaf as a supplement ingredient, so its effectiveness in capsule or extract form is unknown.
What It Doesn't Do
No clinical evidence it prevents cancer or detoxifies the body in supplement form. Not proven to lower cholesterol or blood sugar at typical supplement doses. Eating collard greens as food is not the same as taking a collard leaf extract — don't assume the same benefits transfer. No evidence it replaces a balanced diet.
Evidence-Based Benefits
Collard greens are one of the richest dietary sources of vitamin K1, important for blood clotting and bone health.
Weak EvidenceEffective at: No established dose
Contains vitamins C and A plus glucosinolates, which act as antioxidants in the body.
Weak EvidenceEffective at: No established dose
Absorption & Bioavailability
Unknown — no pharmacokinetic studies available for collard leaf supplements. As a whole food, fat-soluble nutrients like vitamin K are better absorbed with dietary fat, but this has not been studied in supplement form.
Red Flags to Watch For
- No clinical trials exist for collard leaf as a supplement ingredient — health claims are not evidence-based
- High vitamin K content may interfere with blood-thinning medications like warfarin — consult a doctor before use
- Products listing 'collard leaf' in proprietary blends may use negligible amounts with no therapeutic effect
- Over 1,000 supplement products contain this ingredient despite zero published clinical trials — a major marketing-over-science red flag
- Supplement form may not deliver the same nutritional value as eating whole collard greens
Research Sources
- General knowledge — Limited published research available
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25