What is lycopene?

Lycopene: A Red-Orange Carotenoid Antioxidant

Lycopene is a red-orange carotenoid pigment and potent antioxidant found primarily in tomatoes and tomato-based foods, and to a lesser extent in pink grapefruit and watermelon. 1

Chemical Properties and Sources

Lycopene belongs to the carotenoid family but, unlike beta-carotene, has no provitamin A activity in humans. Its key characteristics include:

• A natural red pigment responsible for the deep-red color of ripe tomatoes
• Found predominantly in:
  • Tomatoes and tomato products (highest concentration)
  • Pink grapefruit
  • Watermelon
  • Pink guava
  • Papaya 2

Lycopene exists primarily in the all-trans configuration in fresh tomatoes, but food processing can cause isomerization to cis-isomers. Interestingly, processing tomatoes (cooking, making into sauce) can actually increase lycopene bioavailability by:

• Breaking down cell walls
• Weakening bonds between lycopene and the plant matrix
• Enhancing cis-isomerization, which improves absorption 3

Health Effects and Biological Activity

Antioxidant Properties

Lycopene is considered the most powerful antioxidant among carotenoids, with a physical quenching rate constant with singlet oxygen almost twice as high as beta-carotene 4, 3. It directly interacts with reactive oxygen species (ROS) to combat oxidative stress.

Potential Health Benefits

Several studies have reported associations between tomato products consumption and reduced risk of certain cancers, though the evidence remains uncertain whether lycopene itself is responsible for these effects:

1. Cancer Risk Reduction:

   • Several studies suggest consumption of tomato products may reduce risk of some cancers
   • However, it remains uncertain whether lycopene is the specific micronutrient responsible 1
   • May have potential protective effects against prostate cancer 1

2. Cardiovascular Health:

   • May help reduce risk of cardiovascular diseases
   • Helps lower LDL (low-density lipoproteins) and improve HDL (high-density lipoproteins) levels
   • May reduce blood pressure via inhibiting angiotensin-converting enzyme 2

3. Other Potential Benefits (less established):

   • Possible protective effects against osteoporosis
   • Potential benefits for neurodegenerative diseases
   • May help with hypertension management 4

Important Considerations for Consumption

Food vs. Supplements

The American Cancer Society guidelines emphasize several important points about lycopene consumption:

• Food sources are preferred: Even if lycopene in foods is associated with lower cancer risk, high doses taken as supplements may not be more effective or safe 1
• Absorption factors: Lycopene absorption is enhanced when:
  • Consumed with small amounts of fat
  • Consumed in cooked or processed tomato products rather than raw tomatoes 1
  • The cis-isomers (formed during cooking) have higher bioavailability than all-trans isomers 3

Safety Profile

No adverse effects or toxicity have been reported with natural lycopene consumption from food sources 4. However, caution is warranted with high-dose supplements as their safety and efficacy profile differs from food sources.

Clinical Implications

The evidence suggests that while tomato products may have health benefits, isolated lycopene supplements may not provide the same advantages:

• Studies comparing lycopene supplements to whole tomatoes found that tomato consumption may be preferable to pure lycopene 1
• The benefits of eating whole vegetables and fruits likely exceed the effects of any individual constituent due to synergistic effects 1

Healthcare providers should recommend patients obtain lycopene through regular consumption of tomato products and other lycopene-rich foods rather than through supplements, as part of an overall healthy diet rich in vegetables and fruits.