You Say Tomato, I Say Lycopene
A particular carotenoid called lycopene is what gives tomatoes their red colour, and while some lycopene is found in other red coloured foods (e.g. pink grapefruit, watermelon), it is tomatoes which contain the highest amount.
Lycopene studies have proven it to provide a variety of health benefits, including lowering cholesterol, reducing blood pressure, and helping to prevent some cancers (especially breast, gastric, lung, and prostate).
Given the association of high lycopene intake (through consuming tomato products) with reduced cancers, and as the death rate due to liver cancer has increased in North America, some scientists decided to see “whether dietary tomato consumption can inhibit high-fat diet (HFD)–promoted hepatocellular carcinoma (HCC) development.”
In this experiment, mice were “initiated with a hepatic carcinogen (diethylnitrosamine) at 2 weeks of age. At 6 weeks of age, the mice were randomly assigned to a HFD (60% of energy as fat) with or without tomato powder (TP) feeding for 24 weeks”.
The outcome of this study demonstrated that dietary tomato intake prevented high fat diet-induced inflammation, and high fat diet-promoted liver cancer development. In fact, the results showed that those mice receiving tomato in their diet had a significant reduction in liver cancer development: 67% reduction in incidence of cancer; 83% reduction in the number of tumours; and 95% reduction in tumour volume.
Interestingly, much of the benefits of tomato consumption was as a result of “increased gut microbial richness and diversity. Tomato powder feeding increased the richness and diversity of gut microbiome and improved some beneficial bacteria, which in turn helps regulate hepatic inflammation, hepatic lipid metabolism, and hepatic circadian clock by gut–liver interaction.” (Study)
Other Benefits of Lycopene
A high intake of lycopene is associated with a decreased risk of chronic lung lesions, and aids in the prevention of COPD (a type of obstructive lung disease) induced by smoking, as well as reducing incidence of lung cancers. (Source)
I found this lung study on a COVID-19 database since “having COPD (including emphysema and chronic bronchitis) is known to increase your risk of severe illness from COVID-19.” (Source)
One study is titled: “Lycopene improves sperm quality: A promising nutrient for the treatment of male infertility.” (Source) And, another states that, “human trials have reported improvement in sperm parameters and pregnancy rates with supplementation of 4-8 mg of lycopene daily for 3-12 months”. (Study)
As one of the most potent antioxidants in the vegetable kingdom, “lycopene has been found to be efficient in ameliorating cancer insurgences, diabetes mellitus, cardiac complications, oxidative stress-mediated malfunctions, inflammatory events, skin and bone diseases, hepatic, neural and reproductive disorders.”
When rats were fed a diet high in saturated fats, which has been linked to the development of cognitive impairment, lycopene “significantly attenuated learning and memory impairments and prevented the reduction in dendritic spine density. Thus, this study indicated that lycopene helps to protect HFD induced cognitive dysfunction.” (Source)
When we add this cognition study to the opening study (on a high fat diet and liver cancer), the one thing we can clearly take away from this material is that if you have a high fat diet, you should be consuming a good amount of tomatoes. But be sure you have those tomato products with that dietary fat.
Tomatoes Need Fat
As this study showed, “after ingestion of the salads with fat-free salad dressing, the appearance of alpha-carotene, beta-carotene, and lycopene in chylomicrons was negligible. Essentially no absorption of carotenoids was observed when salads with fat-free salad dressing were consumed. A substantially greater absorption of carotenoids was observed when salads were consumed with full-fat than with reduced-fat salad dressing.” (Study)
Thus, as has been well established, tomato sauce made with a quality fat, such as olive oil, will provide far more lycopene than tomato foods consumed without fat in the meal. As pointed out above, a fat-based salad dressing will help absorb lycopene from tomatoes in a salad, but when the tomatoes are rendered into fat, as with sauces, the lycopene bioavailability soars.
Scientists have also found that the best way to absorb lycopene is to eat tomatoes which are cooked or processed (such as tomato juice). Cooking and processing breaks down the plant’s cell walls, making lycopene more bioavailable.
Blood Type and Tomatoes
Those familiar with my writings know that I am a believer in the Blood Type Diet, therefore I must point out that certain blood types are best to avoid tomatoes, especially if they have arthritis, or other inflammatory conditions. Tomatoes are to be avoided by blood types A, B, and AB. However, that does leave type O blood, which is the most common blood type (38%).
Can’t escape your need for tomatoes, but cursed with the wrong blood type? There is a solution, though it appears fairly time consuming.
This website shows you how to eliminate most of the lectins from tomatoes, and the process looks like this:
Wash the tomatoes before cooking.
Boil the tomatoes at high temperature for at least 10 minutes.
Cool the tomatoes in icy water.
Peel off the tomato skin.
To make removing the skin easier, cut over the skin before boiling.
Scoop out the seeds, which will remove the last possible chance of lectin residue.
Leave the Meat Out of Your Sauce
Researchers at Ohio State University found that the absorption of lycopene from food is counteracted by the presence of iron in the meal. In their study they gave subjects a tomato shake, with some participants also receiving an iron supplement.
Results indicated a dramatic reduction in blood levels of lycopene in those who had the iron supplement along with their tasty tomato shake.
Since tomato sauce is often consumed in dishes such as spaghetti and meatballs, and meat is high in iron, they advise that those who are consuming tomato sauce for the health benefits of lycopene, should limit the use of other ingredients that are too high in iron.
Now, while these scientists mention that legumes and spinach are high in iron, and perhaps should be avoided in this case, I would suggest that plant-derived iron is far different than that found in supplements or meat. Therefore, I would not be concerned about using iron-containing plant foods in tomato-based meals.
They also suggest that conventional bread and pasta may be of concern, since those made with white wheat flour are usually fortified with iron. Here I would agree with them, as the iron found added to white flour is the same as that used in iron supplements (which they used in their experiment). (Source)
Finally, as always, for greatest health benefit I must recommend that one make every effort to choose organically grown tomatoes, and tomato products. To wit: “Organic tomatoes were richer in lycopene (+20%), vitamin C (+30%), total phenolics (+24%) and flavonoids (+21%) and had higher (+6%) in vitro antioxidant activity.” (Source)