Tomatoes are rich in moisture, vitamins and minerals, and plant nutrients. They are an excellent source of vitamins C, B6 and K, betacarotene, biotin, niacin, potassium, phosphorous, calcium, iron, zinc and selenium, as well as of many organic acids such as citric and malic acids which are responsible for the characteristic tomato flavour.
One well known benefit is its' Lycopene content. Lycopene is a vital anti-oxidant that helps in the fight against cancerous cell formation as well as other kinds of health complications and diseases.
A 4 minute video on health benefits of tomatoes ;