Lemon

Food · Fruit · Food, Typed Supps

A real vitamin C source — though the lemon water detox claims go well past the evidence.

Stage by stage

Intake (High acidity & vitamin C): Its citric acid and vitamin C are released immediately on contact.
Stomach (Fast-releasing vitamin C): Vitamin C and citric acid move through digestion quickly given the fruit’s acidity and water content.
Small intestine (SVCT1 transporter): Vitamin C absorbs via the same dedicated transporter as other vitamin C sources.
Immune & connective tissue (Collagen & immune support): Supports immune cell function and collagen production.

Timing

Often used as a flavor addition to water or meals rather than eaten alone.

Time to effect

Hours: Vitamin C blood levels rise within a couple of hours.

Allergens

None of the fourteen major allergens. Derived from what this food is, not from a product label.

Eating patterns

Fits: Vegan, Vegetarian, Pescatarian, Halal, Kosher, Keto, Low-FODMAP, Gluten-free.

In season

November to April in the northern hemisphere, May to October in the southern.

Satiety

The satiety index is measured on 240 kcal servings. At 29 kcal per 100 g that is 830 g of this, which is not a serving anyone eats — so the index has nothing to say about it.

Environmental footprint

0.4 kg CO2e and 83 litres of freshwater per kg, matched to "Citrus fruit" in Poore & Nemecek (2018), Science 360.

Cost band

Cheap — roughly £3 per kg, as a band midpoint rather than a price.

Key nutrients

Vitamin C
Citric acid
Fiber (with pulp)

Nutrition per 100g

Calories: 28.9
Protein: 1.5g
Carbohydrate: 0g
of which sugars: 0g
Fat: 0.3g
of which saturated: 0g
Fibre: 10.6g
Sodium: 6mg

Food vs. supplement

A whole lemon has a meaningful amount of vitamin C, but the juice of one lemon in water is a small fraction of a standard vitamin C supplement dose — the "detox" framing around lemon water isn’t a distinct measurable physiological process.

Kitchen tip

The zest carries concentrated aromatic oils and some nutrients the juice alone does not - worth using before juicing if a recipe allows.

Common myth

“Lemon water detoxes your body first thing in the morning.” In reality: It provides hydration and a small amount of vitamin C — there’s no distinct "detox" mechanism beyond your liver and kidneys’ normal, ongoing function.