Lycopene is a type of carotenoid antioxidant and is what gives tomatoes their red colour. Several epidemiological studies have found that high blood levels of lycopene are associated with a number of health benefits, including a reduced risk of heart disease, diabetes and even certain cancers.
As one of the most potent antioxidants, dietary intake of lycopene enhances the skin’s natural sun protection factor (Stahl and Sies 2012), helping to protect the skin against sun damage (kind of like a mild sunscreen). Lycopene also strengthens the skin by inhibiting the activity of collagenases (Rizwan et al 2011) (enzymes that break down collagen which plays an important role in maintaining the elasticity of the skin).
Cardiovascular system benefits
It is also this antioxidant activity that is thought to contribute to lycopene’s ability to protect against cardiovascular disease by slowing the process of atherosclerosis (hardening of the arteries) which occurs over time as cholesterol molecules become oxidised (Hadley et al 2003). Tomatoes are also an excellent source of potassium, a nutrient known to help lower blood pressure (Willcox et al 2003).
There is also emerging evidence that other mechanisms, apart from tomato’s antioxidant action, are involved in its ability to reduce the risk of certain cancers. Lycopene has been shown to interfere with growth factors that stimulate cancer cell growth (Sharoni et al 2012 & Yang et al 2011), as well as enhance the body’s immune defence system against cancer cells (Preet et al 2013).
Although there is currently no official recommended intake of lycopene, it would be fair to suggest the consistent inclusion of 1-2 servings of tomato or tomato-based products would confer health benefits, with one such study finding that those who consumed 10 or more servings on average of tomato products each week had almost a 35% reduction in the risk of developing prostate cancer (Giovannucci et al 1995).
Whilst many nutritionists advocate the consumption of fresh produce, in the case of tomatoes, tinned or tomato paste from a jar may actually be better as lycopene becomes more bioavailable (more easily absorbed by the body) when cooked (Gartner et al 1997). The cooking process breaks down the cell walls and fibre of raw tomato to free the lycopene. Cooking also lowers the vitamin C content to a certain extent, but the increase in lycopene bioavailablility well and truly makes up for the loss.
Food sources of lycopene:
2 tablespoons (35g) tomato paste (12mg lycopene)
½ cup (100g) canned tomato puree (15mg lycopene)
½ cup (125ml) tomato juice (12.5mg lycopene)
1 medium (150g) fresh tomato (3.8mg lycopene)
Opting for tomato-based pasta dishes, including tomato paste in homemade sauces and salad dressings and adding sundried tomato to salads/sandwiches/wraps, tomato paste to casseroles and tinned tomatoes to curries are some easy ways to increase your consumption of tomato and lycopene.
Furthermore, as lycopene is a fat-soluble nutrient it is important to consume tomato-based products with a source of fat to aid absorption. This would be as simple as some avocado or a drizzle of olive oil over a salad containing fresh tomatoes or the use of a couple of teaspoons of oil in the cooking process of a meal containing tomato paste or tinned tomato.
One final note; although tomato sauce (ketchup) is technically a tomato-based product, be careful as the majority of commercial tomato sauces on the market are around 25% sugar, with several popular brands containing 35-40% sugar (the majority of which is added, not what is naturally occurring in tomato). To put things in perspective, the average chocolate sauce contains 40-50% sugar.
Stay tuned for a tasty recipe featuring tomatoes I’ll be sharing soon.
Gartner et al (1997), ‘Lycopene is more bioavailable from tomato paste than from fresh tomatoes’, American Journal of Clinical Nutrition, 66(1): 116-122.
Giovannucci et al (1995), ‘Intake of carotenoids and retinol in relation to risk of prostate cancer’, J Natl Cancer Inst, 87(1): 1767-1776.
Hadley et al (2003), ‘The consumption of processed tomato products enhances plasma lycopene concentrations in association with a reduced lipoprotein sensitivity to oxidative damage’, The Journal of Nutrition, 133(2): 727-732.
Preet et al (2013), ‘Lycopene synergistically enhances quinacrine action to inhibit Wnt-TCF signalling in breast cancer cells through APC, Carcinogensis 34(2): 277-286.
Rizwan et al (2011), ‘Tomato paste rich in lycopene protects against cutaneous photodamage in humans in vivo: a randomized controlled trial’, The British Journal of Dermatology, 164(1): 154-162.
Sharoni et al (2012), ‘The role of lycopene and its derivatives in the regulation of transcription systems: implications for cancer prevention’, The American Journal of Clinical Nutrition, 96(5): 1173S-1178S.
Stahl and Sies (2012), ‘B-Carotene and other carotenoids in protection from sunlight’, American Journal of Clinical Nutrition, 96(5): 1179S-1184S.
Willcox et al (2003), ‘Tomatoes and cardiovascular health’, Critical Reviews in Food Science and Nutrition, 43(1): 1-18.
Yang et al (2011), ‘Growth inhibitory efficacy of lycopene and B-carotene against androgen-independent prostate tumor cells xenografted in nude mice’, Molecular Nutrition and Food Research, 55(4): 606-612.