Ripening in the late-summer sun, filling garden baskets and salad bowls, reddening gazpacho in kitchen blenders, simmering in saucepans for spaghetti sauce, tomatoes might just be the best, maybe the only, reason for welcoming the end of summer.
And beyond the tempting taste – a blessed relief from the cardboard baseballs we get the rest of the year – tomatoes are actually good for you.
Very good, in fact, according to growing body of evidence.
Three years ago, Harvard epidemiologists and nutritionists led by Dr. Edward Giovannucci studied nearly 48,000 male health professionals and found that those who ate the most tomatoes, tomato sauce, tomato juice, and pizza (!) were 21 percent less likely to get prostate cancer than those who ate the least. In fact, the biggest tomato-eaters were 34 percent less likely to get the most virulent form of prostate cancer.
The magic ingredient is probably lycopene, a powerful antioxidant. Scientists think that antioxidants retard cancer, heart disease, and aging by combatting free radical damage to DNA and other cellular structures caused oxygen metabolism.
The Harvard team decided to study tomatoes because they knew that lycopene, a pigment known as a carotenoid that gives tomatoes their red color, winds up in high concentrations in the prostate, says Dr. Meir Stampfer, one of the authors. “Plus we knew about this intriguing Italian north-south gradient.”
That was a study showing that men in southern Italy, who eat lots of tomatoes, get less prostate cancer than men in the north, who eat fewer. Despite its size, the Harvard study doesn’t prove cause-and-effect, warns Stampfer: “People who eat tomatoes probably eat other good things.”
But other studies add to the growing view that tomatoes carry considerable health benefits.
Nearly a decade ago, a study by the Johns Hopkins School of Hygiene and Public Health found that high blood levels of lycopene were linked to lower risk of pancreatic and bladder cancer, notes Inke Paetau Robinson, a research nutritionist at the Agriculture Research Service, part of the US Department of Agriculture.
In 1991, another study found that consuming a lot of lycopene and having high blood levels of the stuff appeared to reduce the risk of precancerous lesions in the uterine cervix. Two Israeli test tube studies have also shown that lycopene slows the growth of breast and uterine cancer cells and may also help prevent tumors.
And in 1994, a large Italian study found that the risk of digestive tract cancers was reduced among men and women who ate seven servings or more of tomatoes and tomato products a week.
And it’s not just cancer risk that seems to fall with high consumption of the juicy red fruit. (Technically, tomatoes are fruits, not veggies, because they develop from flowers and have one or more seeds.)
Last year, a European study of about 1,300 men called EURAMIC, published in the American Journal of Epidemiology, studied fat samples from men who had had heart attacks and compared them with fat from men who had not. (Lycopene is stored in fat.)
The study found that men whose fat had high concentrations of lycopene had about half the risk of heart attack as those with lower levels.
Again, Stampfer, the Harvard epidemiologist and nutritionist, warns that this association doesn’t prove cause-and-effect. But it does make theoretical sense: Antioxidants in general are known to keep “bad” cholesterol (LDL) from being oxidized and thus building up as dangerous plaques on artery walls.
Although nutritionists often recommend eating fruits and vegetables raw to get the maximum health benefits, that doesn’t hold for tomatoes, notes Jennifer Nelson, director of clinical dietetics at the Mayo Clinic.
Tomato products – like pasta and barbeque sauces – that are made from cooked tomatoes actually provide more lycopene than raw tomatoes, because cooking helps free lycopene from its tight packaging with fiber, she says.
But tomato juice doesn’t raise lycopene levels much, unless it’s made from cooked tomatoes or is consumed with fat, which helps lycopene absorption.
Since the body can’t make lycopene, you have to eat it – not such tough duty since it also comes in watermelon, strawberries, and red grapefruit, though tomatoes are far and away the most abundant source.
The question is, how much lycopene do you need? Unfortunately, nobody knows, though the Harvard study found a beneficial effect with a few servings a week – and pizza counts. So does ketchup!
From a weight control point of view, tomatoes are a nearly-perfect food. A raw tomato weighing 4 1/3 ounces has only 26 calories, says Larry Lindner, executive editor of the Tufts University Health & Nutrition Letter. It also has less than half a gram of fat, one gram of protein, and six grams of carbohydrates, plus fiber and vitamins A and C.
So if your garden is churning out more tomatoes than you can handle, don’t panic. Make salads. Make gazpacho. Make pasta sauce. Give tomatoes to the less fortunate.
And if nature isn’t ripening tomatoes fast enough for your need, simply pick some and put them in brown paper bags. This traps ethylene, a natural gas that tomatoes emit as they ripen, and speeds things up.
But most important, enjoy the bounty. It’ll be gone long before you can say “Halloween.”
Sun-dried tomatoes
Just as raisins are made by drying grapes, sun-dried tomatoes are make by taking the water out of tomatoes, which concentrates the nutrients, including the calories. In fact, it takes 17 pounds of fresh tomatoes to make one pound of sun-drieds. For sun-dried tomatoes NOT packed in oil, here’s how it stacks up.
Tomatoes
Sun-dried
Fresh
Calories
258
21
Fat
3 grams
0.33 grams
Calcium
110 milligrams
5 milligrams
Folate
68 micrograms
15 micrograms
Vitamin C
39 milligrams
19 milligrams
Vitamin A
874 International Units
623 International Units
SOURCE: US Department of Agriculture and Tufts University Health & Nutrition Letter. Globe staff chart