Romaine Lettuce

Overview

Romaine (cos) lettuce is a crisp salad leaf used as a volume base in mixed salads. It contributes vitamin K, folate, and carotenoids including beta-carotene, lutein and zeaxanthin, at very low energy density.

Within a BRAIN-aligned pattern it is a culinary-support salad vegetable rather than a distinctive neurological food. Its practical role is to carry dressings and other leaves, and to supply those fat-soluble carotenoids when eaten with dietary fat [1,2].

Food Context

Synergies

• Serve with a fat-containing dressing, avocado, or olive oil so carotenoids from the salad are absorbed more effectively [1].

Preparation

• Use raw, washed and thoroughly dried leaves so dressings coat rather than dilute.
• Do not treat romaine as interchangeable with iceberg or mixed-leaf bags; those foods differ in carotenoid and folate density.

Recipes

1 recipe containing this food

Mixed-Leaf Tahini Caesar Salad

A Caesar-style mixed-leaf salad with a tahini, anchovy, caper and Parmesan dressing, using extra virgin olive oil retained from oil-packed capers.

Nutrient Tables (per 100 g)

Core nutrients

Nutrient	Amount per 100 g	% RDA per 100 g
Energy	17 kcal	—
Protein	1.2 g	—
Total fat	0.3 g	—
Saturated fat	0 g	—
Carbohydrates	3.3 g	—
Sugars	1.2 g	—
Fibre	2.1 g	—

Key vitamins and minerals

Nutrient	Amount per 100 g	% RDA per 100 g
Folate	136 µg	34%
Vitamin A	436 µg	48.4%
Vitamin K	102.5 µg	85.4%

Bioactive compounds

Explicitly identified compounds, including individual fatty acids, with a defensible quantity or an explicit qualitative status. Asterisks (*) identify supplementary sources below. Unquantified or trace constituents are not automatically admitted to the Substances list.

Compound / class	Amount per 100 g	Notes
Beta-Carotene	5226 µg	—
Lutein + zeaxanthin	2312 µg	—

Reference intakes: US Dietary Reference Intakes for adults (19–50 years; using the higher of male/female values where they differ).

Data provenance (core / micronutrient panel): USDA FoodData Central, Lettuce, cos or romaine, raw, FDC ID 169247, SR Legacy bulk (April 2018), per 100 g edible portion, last checked 2026-09-04

Substances

Substances admitted through a supported nutrition-table row. Not every table row appears here. Cards are not BRS mappings.

5 substances in this food

Lutein

Neuroprotective carotenoid; accumulates in neural tissues and retina; supports cognitive performance

Vitamin A (Retinoids; β-Carotene precursor)

Neurodevelopment; immune regulation; antioxidant via carotenoids

Vitamin B9 (Folate; 5-MTHF)

One-carbon metabolism; methylation; homocysteine recycling

Vitamin K (Phylloquinone)

Phylloquinone (vitamin K1) from green plants; required for vitamin K–dependent carboxylation.

Zeaxanthin

Neuroprotective carotenoid; accumulates in neural tissues and retina; supports cognitive performance

References

[1] Unlu et al. (2005). Carotenoid Absorption from Salad and Salsa by Humans Is Enhanced by the Addition of Avocado or Avocado Oil. Adding avocado fruit or avocado oil to salad increased human absorption of α-carotene, β-carotene and lutein versus the same salad without added lipid.

[2] Johnson (2014). Role of lutein and zeaxanthin in visual and cognitive function throughout the lifespan. Labelled lutein/zeaxanthin context: this review is not a romaine feeding trial; romaine composition includes lutein and zeaxanthin as reported in the table.