Why tomatoes are such a wonder food, and ways to get best out of them
The tomato helps prevent cancer and strokes, and build muscle. Learn which ones to buy for sauces and salads and how best to prepare them
Tomayto, tomahto: however you choose to pronounce it, there is no denying that tomatoes are one of the best foods to add to your plate.
Eating more of them has been shown to boost health and decrease the risk of certain cancers (prostate, ovarian, gastric, pancreatic), osteoporosis, UV light-induced skin damage, cognitive dysfunction and cardiovascular disease. Tomatoes also contain other protective mechanisms, such as antithrombotic and anti-inflammatory properties.
The source of the tomato's health-boosting prowess is thought to be lycopene, a powerful antioxidant responsible for the fruit's deep red colour and which fights off toxins that can cause DNA and cell damage. Tomatoes are the biggest source of dietary lycopene and, unlike most fresh fruits and vegetables, the compound has even greater bioavailability after cooking and processing.
Many scientific studies have demonstrated the tomato's benefits. One of the more recent studies, published last year in the medical journal Cancer Epidemiology, Biomarkers and Prevention, suggests that men who eat more than 10 portions of tomatoes a week have an 18 per cent lower risk of developing prostate cancer.
Researchers at the universities of Bristol, Cambridge and Oxford arrived at this finding after examining the diets and lifestyle of 1,800 men aged from 50 to 69 with prostate cancer compared with 12,000 cancer-free men.
For post-menopausal women at risk of breast cancer, a tomato-rich diet may help protect against the disease by aiding a healthy body weight. Such a diet had a positive effect on adiponectin, a hormone involved in regulating blood sugar and fat levels, according to a 2013 study in the Journal of Clinical Endocrinology & Metabolism.
Another study, which appeared in 2012 in Neurology, found that eating tomatoes and tomato-based foods is associated with a lower risk of stroke. Among more than 1,000 men in Finland aged between 46 and 65, those with the highest levels of lycopene in their blood were 55 per cent less likely to have a stroke than those with the lowest amounts of lycopene, the study found.
Summer is tomato season, so now is the best time to savour its goodness. There are hundreds of varieties of tomatoes, differing in appearance, texture, juiciness and flavour.
"All tomatoes in general are healthy, but people have different perceptions about which is best," says Peter Find, executive chef at The Ritz-Carlton Hong Kong, which has just begun offering a special spread of tomatoes as part of its organic salad bar.
Among the rainbow of varieties on offer - all from a certified organic farm in Jiangxi province - are brown, green, yellow, orange, red, striped, ribbed and cherry tomatoes.
Colour isn't just about aesthetics: research shows different hues have different nutrient profiles, too. Ohio State University researchers, for example, developed orange tomatoes for a 2007 study and found they contained a different form of lycopene. This new type, although at lower levels, was much more readily absorbed into the body than lycopene from red tomatoes.
Green tomatoes, on the other hand, may help build bigger, stronger muscles and protect against muscle atrophy caused by ageing and a variety of conditions such as cancer, heart failure and orthopaedic injuries.
In a study published last year in the Journal of Biological Chemistry, University of Iowa scientists discovered that tomatidine, a compound from green tomatoes, generates changes in gene expression that are essentially opposite to the changes that occur in muscle cells when people are affected by muscle atrophy.
Tomatidine is produced when alpha-tomatine, which is found in tomato plants and, in particular, in green tomatoes, is digested in the gut. Healthy mice supplemented with tomatidine grew bigger muscles, became stronger and could exercise longer. However, further research is needed to find out the safety and efficacy of the compound in humans.
If you plan on eating tomatoes raw, such as in salads, Find recommends buying organic tomatoes, which tend to be sweeter and have higher concentrations of sugars, vitamin C and lycopene compared with conventional tomatoes.
If you're making pasta sauce, just get local deep red tomatoes from your neighbourhood wet market. "After cooking, you cannot taste the difference anyway," says Find.
Raw tomatoes are best enjoyed with some light seasoning. About 15 minutes before serving them, Find recommends sprinkling on a little salt (to draw the water out), coarse black pepper (for a "kick") and sugar (to balance out the acidity). Just before eating, dress lightly with lemon juice and some extra virgin olive oil.
Top Hong Kong chef Peter Find on how to make the most of tomatoes
Different varieties of tomatoes and how best to enjoy them, according to chef Peter Find.
Black krim (brown): tangy, rich, sweet, soft and juicy. Best paired with rocket salad, as the sweetness offsets the bitterness of the greens. Also good with burrata, mozzarella, goat cheese or Greek yogurt.
Tigerella (green): very sour and crunchy, it is best diced or cubed for a refreshing salad. Its low water content makes it good for frying: just coat in cornmeal or oats and pan fry.
Sun gold (orange and yellow): it's more settled in flavour and not as sweet as its red counterpart, but it does tend to absorb a lot of flavour very well.
Ox heart (red): it doesn't have a very intense flavour but is very meaty, so can take on a lot of flavour from spices and herbs. It's very juicy and good for making tomato or pasta sauce.
Roma (red): sweet and juicy, it's good for slicing. Enjoy with mozzarella. Also good for pasta sauce.