Phytochemical against Cancer: Tomatoes - A Misunderstood Fruit

As this blog looks at the effects of nutrition on gene expression, I have been taught the effects of phytochemicals, which come from plants that we consume. A plant-based diet is important for maintaining health (Heber 165). Substances in fruits and vegetables alone and in combination with one another, have been shown to have specific anticancer effects. In these posts, I will be looking at specific phytochemicals, incorporating them into my diet and lifestyle.

Lycopene from Tomatoes and Tomato Products (Heber 168-169)

Lycopene in tomatoes has been found to inhibit proliferation of serval types of cancer cells, including those of breast, lung, and endometrium (i.e. lining of the uterus - womb). Tomato products, including ketchup, tomato juice, and pizza sauce, are the richest sources of lycopene in the American diet, accounting for more than 3/4 of the total lycopene intake of Americans. Several studies have linked the consumption of tomatoes and tomato products with a decreased risk of cancer and cardiovascular disease. 

Ripe tomatoes off the vine!

The health benefits of lycopene have been attributed to its antioxidant properties, although other mechanisms of lycopene action are possible, including the modulation of intercellular communication, hormonal and system changes, and alterations of metabolic pathways. In breast cancer cells, lycopene can interfere with insulin-like growth factor 1-stimulated tumor cell proliferation.

The relationship between lycopene intake and prostate cancer risk has been reported by studies linking low plasma levels of lycopene with increased risk. Lycopene administration may reduce proliferation and increase apoptosis in human prostate tissue where lycopene is the predominant carotenoid. 

The antiproliferative properties may extend to other types of cancer, including that of breast, lung, and endometrium, and lycopene may inhibit cholesterol synthesis and enhance LDL degradation (low-density lipoproteins; aka bad cholesterol because when in excess, it can collect on the walls of blood vessels - this can cause blockage and eventually lead to heart disease). Several studies have established that the processing of tomato products into sauces, soups, and juices increase bioavailability. 

In a recent review of functional properties of food research from Dr. Heber's laboratories, it demonstrates that it is relatively simple to influence circulating levels of lycopene with administration of only 177 mL (6 fluid ounces) of mixed vegetables juice daily.

Cooked vs. Raw Tomatoes:

So, why is it better to cook your tomatoes rather than eat them raw? Well, it all comes down to lycopene, which is trapped inside the tomato plant cell by the cell walls. In order to get access to the lycopene, it is necessary to break down the cell walls to have the lycopene readily available for consumption. Chopping and heating does the job.

Lycopene is more available from cooked tomato products and juices than from whole tomatoes, and these products are the the primary sources of lycopene in our diet (Heber 194). So, we would get lycopene from tomato-based pasta sauce (ex/ marinara), tomato soup, tomato juice, and ketchup; over 80% of the lycopene in the American diet comes from these tomato products (Heber 194).

However, please keep in mind that ketchup and tomato sauces are packed with relative high amounts of sugar. It can definitely add up if not careful, so be sure to read the food label for content and quality. Moderation is key.

My Personal Experience with the Infamous Fruit and How I Cooked with Tomatoes:

Tomatoes were paired up with chopped kale for the main dish.

So, a confession: as a little kid, I have always had a dislike toward tomatoes when eating it in its raw form. It was something about the texture and taste of tomatoes that made me spit it out if I was fed it. I could not stand tomatoes in its raw form. I would have a frown on my face when I see it on my plate; either I would push it to the side or give the slice of tomato to my cousin (my brother doesn't like them either, so this dislike toward tomatoes may run in the family). I liked ketchup sauce but despised the fruit when eating them whole or sliced up. My childhood consisted of avoiding this fruit at all cost.

Now that I have grown to an adult, I have come in terms with this red fruit. I have began to eat them slowly but surely. After learning about this fruit and its benefits, I knew that I had to incorporate it into my diet. So, I decided to incorporate into my meal by sautéing into my dish. First, I sliced and diced them into small pieces. My dislike toward them still lingered, so I wanted to make sure that they were small enough that I could cook them without spitting it out.

Tomatoes and green peppers sliced and diced.

So, with the diced tomatoes, I cooked in grounded turkey, kale, green peppers, corn, broccoli, green beans, green peas, and spinach - seasoned with salt and tumeric for taste. This was my first time really cooking with tomatoes, so I didn't know what to expect. Instead, to my surprise, the tomato pieces reduced to a sauce. I was able to not really taste it. There were pieces here and there, but I still ate the whole meal.

My finished product. The tomatoes were reduced to a sauce, but pieces still lingered (as seen if you look close enough).

Overall, tomatoes and I are now friends. With all of the benefits that tomatoes offer, it was only about time that I grew up from my childhood dislike for this fruit. However, there are still some conditions with this friendship. I still can't eat tomatoes raw unless they are in an In-n-out burger or the taste/texture is hidden by something else in the meal. Food preferences depend on the individual, but the tomato is still a fruit that offers a variety of health benefits.

Information about tomatoes was taken from Dr. Heber's course reader, Winter 2014 (pages have been cited). All photos were taken by me.