Tomatoes are not only one of our favorite foods, but they're also one of the most important, from a nutrition standpoint. As you'll see in the chart, tomatoes are a reliable source of vitamins and minerals--they are especially notable for being high in vitamin C and a good source of vitamin A. Nutrients in a Ripe Red Tomato:
- Serving Size -- 5.5 ounces (148 grams)
- Calories -- 35
- Protein --1 gram
- Carbohydrates -- 6 grams
- Fat -- 1 gram
- Sodium -- 10 milligrams
- Potassium -- 360 milligrams
- Dietary Fiber -- 1 gram
% of Daily Values
- Vitamin A -- 20%
- Vitamin Cup-- 40%
- Potassium -- 10%
- Iron -- 2%
Exhaustive Survey Links Tomato Intake to Reduced Risk of CancerA thorough review of scientific literature strengthens the evidence that eating tomatoes and tomato-based products can provide powerful protection against many kinds of cancer. Dr. Edward Giovannucci, a leading cancer researcher at Harvard Medical School, reached this conclusion after analyzing the results of 72 studies on the health effects of tomatoes.
"The antioxidant properties of lycopene, a carotenoid found primarily in tomatoes, have raised interest in the tomato as a food with potential anticancer properties," says Dr. Giovannucci, whose research review appeared in the February 17, 1999, issue of the Journal of the National Cancer Institute. Some studies examined dietary differences between cancer patients and people free of the disease, while others measured lycopene levels in blood plasma. A total of 57 studies present convincing evidence of a relationship between tomato consumption or blood lycopene level and the risk of cancer.
The data are strongest for cancers of the prostate gland, lung and stomach, but also extend to several other kinds, including breast, pancreatic, colorectal, esophageal, oral and cervical cancers. According to Dr. Giovannucci, these benefits were observed whether the diets contained fresh or processed tomatoes.
Researchers believe that lycopene neutralizes harmful free radicals that can damage cells and trigger cancer. But researchers believe that cancer protection most likely comes from a complex interaction between lycopene and other phytochemicals and nutrients present in tomatoes.
The author advises that current recommendations should emphasize the health benefits of diets rich in a variety of fruits and vegetables, including tomatoes and tomato-based products. Though there is strong evidence connecting lycopene and cancer protection, researchers are not in agreement about how this occurs.
Tomato Nutritional Glossary
The healthy good looks of a fresh, red ripe tomato are not just skin deep. Tomatoes are packed with health-promoting vitamins and disease-fighting phytochemicals: in particular, the antioxidant lycopene. The remarkable tomato nutrition story is full of technical terms. The following is a glossary of terms related to this important diet-disease link.
ANTIOXIDANTS Substances that have the ability to inactivate harmful FREE RADICALS. There is growing scientific evidence that a diet high in antioxidants may protect against certain chronic diseases such as cancer, coronary heart disease, and cataracts. Substances in food that are not vitamins or minerals and demonstrate antioxidant activity are sometimes referred to as PHYTOCHEMICALS. LYCOPENE is an example of a phytochemical with potent antioxidant activity that is present in tomatoes.
BETA-CAROTENE The carotenoid in tomatoes with the most vitamin A activity. It also has ANTIOXIDANT activity. It was once thought to be a major player in cancer prevention, but recent scientific studies show less encouraging results, possibly because beta-carotene was studied alone rather than in association with other vitamins and antioxidants.
CAROTENOIDS The source of vitamin A activity in tomatoes. Carotenoids are plant pigments, responsible for the bright rosy color of tomatoes. Carotenoids are fat-soluble, which means they are better absorbed in the presence of oil or fat. They are converted into Vitamin A retinoids essential for normal vision, growth, reproduction and a healthy immune system. There are a number of different carotenoids in tomatoes, including BETA-CAROTENE and LYCOPENE. A medium tomato supplies 20% of our daily value for vitamin A. PHYTOCHEMICALS Hundreds of substances produced naturally by plants to protect themselves from disease. Their exact roles in promoting human health are still under investigation, but many show antioxidant activity. Lycopene is a phytochemical.
FREE RADICALS Highly reactive oxidation byproducts created by normal cell metabolism and environmental factors such as pollution. Free radicals lack electrons and try to steal them from other molecules, setting up a chain reaction that causes cellular damage. This damage is thought to be a fundamental cause of many degenerative diseases and the aging process. If free radicals attack the molecules involved in normal cellular reproduction, cells may become cancerous. Free radicals can damage the molecules responsible for moving cholesterol through the bloodstream, resulting in a build- up of plaque in arteries. Researchers believe that lycopenes help reduce free radicals.
LYCOPENE The predominant carotenoid in tomatoes, lycopene does not convert to vitamin A, but may have enormous significance in disease prevention due to its potent activity. Lycopene is the most abundant carotenoid in human blood and tissues. Tomatoes are the primary source of lycopenes in our diet.
VITAMIN C Also referred to as ascorbic acid, vitamin cup plays a vital role in combating infection, keeping gums healthy and healing wounds. Vitamin cup is also involved in bone health and in regulating blood pressure. One medium tomato meets 40% of our daily need for vitamin C. This vitamin also functions as an ANTIOXIDANT and may have an additional role in prevention of chronic diseases, such as cancer and heart disease.