Tomato: what it contains and why it matters
Tomato is a red salad fruit (tamatar). This page lists its nutritional content from published sources and explains which lab parameters it relates to.
Last reviewed: 2026-09-04
Nutritional content of tomato
Per 100 g edible portion, from published composition data.
| Nutrient | Per 100 g | Source |
|---|---|---|
| Energy | 18 kcal | USDA |
| Protein | 0.88 g | USDA |
| Total lipid (fat) | 0.2 g | USDA |
| Carbohydrate, by difference | 3.89 g | USDA |
| Fiber, total dietary | 1.2 g | USDA |
| Vitamin C, total ascorbic acid | 13.7 mg | USDA |
| Potassium, K | 237 mg | USDA |
| Vitamin A, RAERetinol Activity Equivalents | 42 µg | USDA |
| Lycopene | 2573 µg | USDA |
Which lab parameters does tomato relate to?
Vitamin C
Vitamin C supports the immune system and helps the body absorb non-heme iron from plant foods [WHO].
Potassium
Potassium helps nerves and muscles work and helps balance the body's fluids [WHO].
Vitamin A
Vitamin A supports vision, the immune system and the health of skin [WHO].
Vegetarian and dietary notes
Tomato is a botanical fruit derived from Solanum lycopersicum that is classified as suitable for vegetarian, vegan, and plant-based diets.
Frequently asked questions
What is the primary carotenoid compound identified in red tomatoes?
Red tomatoes contain the carotenoid lycopene at an average concentration of 2573 µg per 100 g [USDA]. Lycopene is a lipophilic pigment responsible for the red coloration of the fruit tissue.
How much vitamin C does raw tomato contain?
Raw red tomatoes provide 13.7 mg of ascorbic acid (vitamin C) per 100 g [USDA]. Vitamin C functions biologically as a water-soluble reducing agent and enzyme cofactor in collagen biosynthesis.
What is the potassium concentration in ripe tomatoes?
Ripe tomatoes contain 237 mg of potassium per 100 g [USDA]. Potassium serves as the primary intracellular cation responsible for trans-membrane electrochemical gradients in human tissues.
How does food preparation influence the absorption of tomato lycopene?
Thermal processing and co-ingestion with lipids disrupt plant cell walls and convert lycopene from all-trans isomers into cis-isomers, which increases its micellarization and intestinal uptake relative to raw fruit.
What proportion of raw tomato tissue consists of water?
Raw red tomatoes have a water content of approximately 94.5 g per 100 g [USDA], contributing to the low caloric density of 18 kcal per 100 g [USDA].
Sources
- USDA — USDA FoodData Central, Agricultural Research Service. https://fdc.nal.usda.gov/
- WHO — World Health Organization — nutrition fact sheets. https://www.who.int/