Fight Cancer With Antioxidant-Rich Foods

Fight Cancer With Tomatoes

Prevent Cancer With Lycopene
Credit: Renee Silverman's Photostream

Prevent Cancer With Fried Tomatoes

Fight Cancer With Lycopene


Raw fruits  and vegetables are usually seen as better promoters of good health compared to cooked ones.  Therefore, it sounds unusual that cooked tomatoes  have higher potentials for fighting cancer than fresh ones. This unusual characteristic of tomatoes is due to the effect of heat on lycopene, an important cancer-fighting carotenoid antioxidant in the tomatoes. Heat (thermal energy) changes the configuration of lycopene to a form (isomer) that has a higher bioavailability.  Compared to raw tomatoes, cooked tomatoes and tomato products have higher bioavailability values for lycopene, a value that  determines their potential for fighting cancer.

  How Does Heat Effect Lycopene?

 Heating enhances the anti-cancer potential of tomatoes by producing a small but a significant change, in the molecular configuration of lycopene.   The uncooked tomato has a lycopene structure  in the trans configuration.  This  trans form is the natural form of the lycopene molecule and it is  a form that is poorly absorbed in the small intestine.  Cooking tomatoes changes this trans configuration of lycopene to the cis form, an isomer of lycopene  that  is more easily absorbed.

  Cooking tomatoes raises the bioavailability of lycopene in the tomatoes.  In turn, this change raises the cancer-fighting  potential of tomatoes. It should be noted that this change in the isomer of lycopene does not change lycopene to a different compound. It only changes it to a form that is readily absorbed and utilized by the body.

  What  Is Bioavailability? 

 Bioavailability of a nutrient is a measure of the extent to which an ingested  nutrient is absorbed from the intestine.  Alternatively, bioavailability of a nutrient is reflected by the fraction of the consumed nutrient that gets into the  blood stream.  Some factors that effect nutrient bioavailability include  factors that hinder or enhance its release from the food metrix.  In the case of tomato, thermal energy helps to release lycopene by breaking the elements that bind it to the  tissues of the tomato fruit. The  primary effect of heat in changing lycopene to the cis isomer and  the secondary effect of liberating it from the food metrix  combine to increase the bioavailability of this antioxidant phytonutrient.

   Lycopene, a Fat-Soluble Nutrient

 Lycopene is a fat-soluble nutrient.  Fat soluble nutrients are soluble in fats and oils, and they show little or no solubility in water.  Fat-soluble nutrients are more readily absorbed by the body when they are cooked in oil or consumed with oil. When tomato is fried in oil, the effects of oil and heat combine to raise the bioavailability of lycopene . 

 More lycopene bioavalability is also seen in tomato products, such as catchup, tomato paste and tomato sauce compared to raw tomatoes. This increased availability of lycopene in tomato products reflects the treatment to which tomato was subjected during processing and packaging.

 Importance of  Nutrient Bioavailability

 Bioavailability of nutrients is an important variable to consider when you are eating to maintain good  health.  The digestive environment ( eg., stomach acidity)and the interactions between some ingested nutrients can effect the bioavailability of some nutrients.   For example a decrease in fat content of the digested food can lower the bioavailability of vitamins A and E; whereas, a decrease in stomach acid can impair the absorption ofvitamin B12.  Another important example is the relationship between vitamin C and the availability of iron, a key player in the supply of oxygen and energy to the body. A decrease in vitamin C content lowers theabsorption of iron.  

 Knowing  about these conditions and interactions is helpful for getting the most benefits from important nutrients  in your foods such as iron and vitamin B12. Iron and vitamin B12 are two nutrients that can boost your  energy level and  support mental alertness.  Bioavailability matters, because eating proper nutrients in adequate amounts is not always sufficient to assure good health.

Prevent Cancer With Lycopene-Rich Foods

Prevent Cancer With Tomatoes

Increase the Bioavailability of Lycopene by Heating
Credit: Renee Silverman's Photostream