Kale
Overview
Kale is a nutrient-dense leafy green providing iron, magnesium, zinc, quercetin, and carotenoids. The BRAIN diet specifically targets leafy green vegetables i.e. kale and spinach that are rich in iron, magnesium, and zinc, though this can introduce high dietary oxalate.
Within the BRAIN Diet framework, boiling kale can reduce oxalate load, improving mineral bioavailability. Kale is abundant in quercetin, a flavonoid polyphenol with antioxidant and anti-inflammatory properties [1][2].
Key Nutritional Highlights
- Reports on iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate [1]
- Reports on effect of Different Cooking Methods on Vegetable Oxalate Content [2]
- Kale is a nutrient-dense leafy green providing iron, magnesium, zinc, quercetin, and carotenoids. [1]
- The BRAIN diet specifically targets leafy green vegetables i.e. [2]
- kale and spinach that are rich in iron, magnesium, and zinc, though this can introduce high dietary oxalate.
- Boiling kale can reduce oxalate load, improving mineral bioavailability.
Food Context
Synergies
- Pair with fat (avocado, olive oil) for carotenoid absorption; co-consuming a small amount of unsaturated fat improves micelle formation and chylomicron packaging
- Pair with vitamin C sources to enhance iron absorption, with studies showing up to a fourfold increase when consumed together Hallberg et al. 1989
- Part of diverse leafy green strategy
- Practical pairings: carrots + tahini, kale + avocado, berries + yogurt/nuts
Preparation
- Boiling reduces oxalates and improves mineral bioavailability Chai and Liebman 2005
Recipes
1 recipe containing this food
Savoury Greens & Egg Breakfast Skillet
A warm savoury breakfast skillet with eggs, greens, and slow carbohydrates for steady morning energy.
Nutrient Tables (per 100 g)
Core nutrients
| Nutrient | Amount per 100 g | % RDA per 100 g |
|---|---|---|
| Energy | 35 kcal | — |
| Protein | 2.9 g | — |
| Total fat | 1.5 g | — |
| Carbohydrates | 4.4 g | — |
| Sugars | 0.8 g | — |
| Fibre | 4.1 g | — |
Key micronutrients
| Nutrient | Amount per 100 g | % RDA per 100 g |
|---|---|---|
| Iron | 1.6 mg | 8.9% |
| Zinc | 0.4 mg | 3.5% |
| Magnesium | 32.7 mg | 7.8% |
| Calcium | 254 mg | 25.4% |
| Potassium | 348 mg | 10.2% |
| Folate | 62 µg | 15.5% |
| Vitamin B6 | 0.1 mg | 8.6% |
Substances
Substances in this food: editorial (Overview / literature) plus analytical (nutrition table).
18 substances in this food
Calcium
Bone health; neurotransmission; interacts with vitamin D and K2
Copper
Cofactor in redox enzymes; dopamine β-hydroxylase; iron metabolism interplay
Iron
Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)
Lutein
Neuroprotective carotenoid; accumulates in neural tissues and retina; supports cognitive performance
Magnesium
Enzymatic cofactor (>300 reactions); neurotransmitters; mitochondria; redox balance
Manganese
Cofactor for MnSOD (SOD2); mitochondrial antioxidant defense
Phosphorus (Phosphate)
Structural phosphate in ATP, phosphocreatine, phospholipids, DNA/RNA, and signalling
Potassium
Electrolyte for nerve transmission, muscle function, and blood pressure regulation
Quercetin (and Isoquercetin)
Polyphenol; antioxidant; mitochondrial support; bioavailability improved with vitamin C
Vitamin A (Retinoids; β-Carotene precursor)
Neurodevelopment; immune regulation; antioxidant via carotenoids
Vitamin B1 (Thiamine)
Mitochondrial glucose metabolism; ATP synthesis; rapid turnover in CNS
Vitamin B2 (Riboflavin)
FMN/FAD coenzymes; redox balance; supports methylation via MTHFR
Vitamin B6 (Pyridoxine → PLP)
PLP cofactor for neurotransmitter synthesis; relies on brain PDXK activation
Vitamin B9 (Folate; 5-MTHF)
One-carbon metabolism; methylation; homocysteine recycling
Vitamin C (Ascorbate)
Antioxidant; supports iron absorption; neuronal SVCT2 transport
Vitamin K2 (MK forms)
Calcium handling; potential roles in brain health; often co-occurs with fat-soluble vitamins
Zeaxanthin
Neuroprotective carotenoid; accumulates in neural tissues and retina; supports cognitive performance
Zinc
Cofactor in neurotransmission and antioxidant enzymes; dopamine modulation
References
[1] Boiling spinach, kale, and other greens can reduce oxalate load, improving mineral bioavailability. Chai & Liebman 2005. Effect of Different Cooking Methods on Vegetable Oxalate Content
[2] Vitamin C significantly improves non-heme iron absorption by reducing ferric to ferrous iron, with studies showing up to a fourfold increase when consumed together. Hallberg & Brune 1989. Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate