What is lycopene? What is lycopene found in?

Lycopene is a type of organic pigment called a carotenoid, which can be converted to vitamin A in the body. It is derived from tomatoes and other red fruits and vegetables, such as red carrots, watermelons, grapefruits, and papayas [i]. It is said to be particularly rich in cooked tomato paste [ii].

The potential for higher absorption of lycopene through food is also greatly affected by dietary composition. As it is a lipid-soluble compound, consuming lycopene with fat increases its rate of absorption (bioavailability) [iii].

What enhances or reduces absorption of lycopene?

The processing of tomatoes by heating converts the all-trans lycopene to various cis isomers. Cis isomers are thought to be better absorbed and utilised by the human body [iv].

Antioxidants are compounds that can help prevent cell damage caused by unstable molecules called free radicals. Such damage can lead to DNA damage causing chronic disease and conditions. Lycopene has the greatest antioxidant potential among carotenoids. Benefits of lycopene have been seen in cases of infertility, metabolic syndrome and liver damage [v]. Lycopene is also known to benefit high blood pressure, high cholesterol, and many other conditions.

What are the benefits of lycopene?

Prostate support

Both benign prostatic hyperplasia (BPH) and prostate cancer are conditions of the prostate gland. The prostate gland sits directly below the bladder in men. Its purpose is to create the fluid part of semen.

In both benign prostatic hyperplasia (BPH) and prostate cancer the prostate is enlarged due to growth in the tissue. However in benign prostatic hyperplasia, this growth in tissue is benign, meaning it is not spreading to other parts of the body, as prostate cancer can.

It is said there is a potential inhibitory effect of lycopene on prostate cancer. There are various molecular pathways activated by lycopene that could ultimately suppress cancer growth. Lycopene has been found in studies to effectively suppress the progression and proliferation of cancer growth by inducing cancer cell death. This has been explored in both humans and test tube studies [vi].

Cognitive function

Decreases in cognitive function can be related to increases in oxidative stress and chronic inflammation, which occur with ageing. A systematic literature review found one review reported significant associations between lower lycopene intake and higher rates of Alzheimer's disease mortality. On this basis, further investigation was warranted by the writers of the review [vii]. The study population which included 6968 individuals over the age of 50 years was assessed at two different points in time. Carotenoids in the blood were assessed, including lycopene, were measured at the start of the study and again in the year 2000. Data regarding Alzheimer's related death, showed participants who has died due to Alzheimer’s had significantly lower serum levels of lycopene compared with those who had not died due to Alzheimer’s. These results suggest a potential association between decreases in serum lycopene and death attributable to Alzheimer’s [viii].

Another study found that low carotenoid levels could play a role in cognitive impairment in general. Participants included 589 community-dwelling men and women aged 68–79 years. The study used tests such as the Mini-Mental State Examination, on participants and assessed different types of carotenoids in the blood. The correlation between low lycopene intake and higher rates of low cognitive function was made [ix].

Metabolic function: Obesity and diabetes

A review of over 200 articles revealed the actions lycopene exhibits as an anti-obesity and anti-diabetic agent in different organs and tissues, including fat tissue, liver, kidney, pancreas, brain, ovaries, intestine, and eyes [x].

Oxidative stress has been implicated in the onset of insulin resistance, in the formation of diabetic conditions. This is due to the increased concentrations of reactive oxygen species which activate inflammation in the body, attenuating the insulin response and subsequent glucose uptake by cells. Meaning the body is less capable of using glucose as energy fuel in our cells [xi]. Furthermore, pancreatic β-cells, which produce the hormone insulin, may be particularly susceptible to free radicals consequently impairing insulin production in the pancreas [xii].

Lycopene in its natural form in food could enhance these protective properties, more so than isolated lycopene extracts alone. In a randomised controlled trial, lycopene was seen to reduce inflammation and improve cholesterol readings via an improved level of high density lipoprotein (HDL). This type of cholesterol is known as good cholesterol because this molecule carries cholesterol back to the liver. These results were seen in moderately overweight middle-aged individuals after a 12-week intervention with a lycopene-rich diet. Overall the findings show the heart-protective properties of increased lycopene intake in the diet [xiii].

Metabolic syndrome is defined by a group of abnormalities associated with the development of cardiovascular disease and type 2 diabetes mellitus. Another observational study evaluated food consumption and activity levels in relation to the development of metabolic syndrome. The results showed that higher concentrations of lycopene in the blood are significantly associated with increased number of steps and a lower risk of developing metabolic syndrome [xiv].

Antioxidant protection

In addition to providing some protection against cancer [xv], lycopene can also offer protection against substances which can damage our cells including pesticides and herbicides in food [xvi]. Examples include protection against the liver damage induced by DDVP [xvii]. The same antioxidant protection has shown to be effective against MSG (Monosodium Glutamate). A study was conducted in rats whereby it was shown lycopene protects brain tissue by inhibiting cell death signalling induced by MSG via the action of inhibiting lipid peroxidation [xviii]. It has also been shown to induce death of candida fungi, which may be useful in cases of candida overgrowth [xix].

Sunburn

Lycopene is said to provide some protection against harmful UV rays, which cause sunburn. A study was completed whereby participants were exposed to UV rays before and after consuming either 16 mg of lycopene from tomato paste or a placebo. Over the 12-week study, participants in the group given the tomato paste contains lycopene had less severe skin reactions in response to the UV exposure [xx].

Research also shows that a combination of carotenoids including lycopene, rather than just lycopene independently, have a greater benefit in terms of skin protection against UV rays [xxi] .