With the likes of pomegranates, blue-berries and goji berries getting most of the press attention these days, the humble apple is often overlooked. But the latest evidence shows that apples have numerous health-boosting benefits to rival even the most super of superfruits.
Crunch against cancer
Eating lots of fruit and veg is known to slash your risk of cancer, but apples might be especially useful.
According to an Italian study involving just over 7600 participants, eating one or more apples every day was associated with a reduced cancer risk compared with eating less than one apple a day. The biggest reductions were seen in cancers of the mouth and throat, larynx, colon/rectum and oesophagus (Ann Oncol, 2005; 16: 1841-4).
Other research shows that apples might be able to protect against lung cancer. In one Hawaiian study, there was a 40 to 50-per-cent lower lung-cancer risk in participants with the highest intakes of apples, onions and white grapefruit compared with those who consumed the lowest amounts of these foods. The decreased risk in lung cancer was seen in both men and women and in almost all ethnic groups (J Natl Cancer Inst, 2000; 92: 154-60).
If you prefer your apples peeled, however, you might be missing out on the anti-cancer benefits. Tests at the University of Wisconsin revealed that apple peel can slow the growth of prostate and breast cancer cells-probably because of the "exceptionally high" levels of antioxidants it contains, which are known to have anticancer effects.
The research team 'treated' human prostate, breast and other cancer cells with an extract of apple peel from organic Gala apples. They found that both types of cells grew more slowly and survived for less time after coming into contact with the apple-peel extract. The scientists also reported a rise in levels of maspin, a protein that helps to suppress tumour growth (Nutr Cancer, 2010; 62: 517-24).
Help your heart
Apples may also play a role in keeping our hearts healthy. In a recent trial by researchers at Florida State University, 160 postmenopausal women were randomly assigned to one of two groups: one ate 75 g of dried apple per day (equivalent to two medium-sized apples); the other ate the same amount of dried plums (prunes).
After six months, total cholesterol levels were significantly lower in the dried-apple group compared with the prune group. What's more, the driedapple group had a 24-per-cent reduction in LDL, or 'bad', cholesterol levels compared with levels when they started the trial (J Acad Nutr Diet, 2012; 112: 1158-68).
Other research suggests that eating apples might be a way to prevent stroke. A decade-long study carried out in The Netherlands discovered that eating white fruits and vegetables, such as apples, pears and cauliflower, slashed the risk of stroke by about 50 per cent. On the other hand, green, orange/yellow and red/purple fruits and vegetables were not linked to stroke incidence, the researchers found (Stroke, 2011; 42: 3190-5).
Quercetin, a potent antioxidant present in apples, may be partly responsible for the fruit's heart-healthy effects. Research has shown that as quercetin intake increases, the risk of heart disease decreases (Adv Nutr, 2012; 3: 39-46). Quercetin is also found in onions, berries, red wine, and other foods and drinks, but apples are one of the top sources.
Keep hunger at bay
Eating an apple before a meal could help you lose weight, according to some evidence. Researchers at Pennsylvania State University discovered that people who ate an apple 15 minutes before having lunch consumed 15-per-cent fewer calories than those who ate nothing beforehand. They also ate less than those who had apple juice or apple sauce before the meal, and reported feeling fuller.
Interestingly, adding fibre to apple juice did not enhance its appetite-suppressing action, suggesting that it's something about the whole solid fruit-not just the fibre-that is important for the satiating effect (Appetite, 2009; 52: 416-22).
In another study, 411 over-weight women with high cholesterol were instructed to eat either an apple, pear or oat cookie three times a day for 12 weeks. The results showed that the participants who ate either apples or pears had significant weight loss (1.22 kg, or 2.7 lb) after 12 weeks, whereas those eating the oat cookies saw no significant weight loss. The fruit eaters also had significantly lower blood glucose levels compared with the cookie eaters (Nutrition, 2003; 19: 253-6).
Defend against diabetes
In a study assessing flavonoid intakes (the beneficial plant pigments found in foods like apples, onions and citrus fruit, as well as in drinks like tea and red wine) in more than 38,000 women, apples were the only flavonoid-rich food associated with a reduced risk of type 2 diabetes. Women eating one or more apples a day had a 28-per-cent lower risk of having type 2 diabetes compared with those who ate no apples. Antioxidant compounds in the fruit such as catechins (also found in green tea), beta-carotene and vitamin C could be responsible for the results, the researchers said (J Am Coll Nutr, 2005; 24: 376-84).
A more recent study, involving more than 200,000 men and women, came to much the same conclusion although, in this case, it was blueberries and pears as well as apples that had similar protective effects (Am J Clin Nutr, 2012; 95: 925-33).
Protect against asthma
An intriguing study by Utrecht University researchers in The Netherlands suggests that women who eat apples during pregnancy might be able to protect their children against developing asthma.
More than 1200 children and their mothers completed the study, which assessed the consumption of fruit, vegetables, fruit juice, wholegrain products, fish, dairy products and fat spreads during pregnancy.
The researchers found that apples were the only food that was beneficially associated with asthma. The mums who ate the most apples during pregnancy were significantly less likely to have a child with asthma or wheeze than those who ate the least apples (Thorax, 2007; 62: 773-9).
Another study, involving 1601 young adults in Australia, reported that apple and pear intakes were associated with a decreased risk of asthma and a reduction in hypersensitivity of the lungs ('bronchial hyperreactivity'). Total fruit and vegetable intake was not associated with asthma risk or severity (Am J Clin Nutr, 2003; 78: 414-21).
Again, it's thought that the high levels of antioxidants in these fruits were largely responsible for the anti-asthma effect.
An apple a day . . .
According to a comprehensive review of all the relevant studies so far, the humble apple may even help to guard against developing Alzheimer's disease, osteoporosis and gastro-intestinal problems (Adv Nutr, 2011; 2: 408-20).
So, forget those exotic 'superfruits' and stick with your teacher's favourite to fill you up and help fend off disease.
Factfile: Which apple's best?
Some apples might do a better job of keeping the doctor away than others, according to some research. Two important compounds in apples that appear to be important for health are flavonoids and phenolics-and different varieties of apples vary greatly in how much of these they contain.
According to tests carried out by researchers at Cornell University in Ithaca, NY, of 10 most commonly consumed varieties in the US, Fuji apples had the highest total phenolic and flavonoid compounds, followed closely by Red Delicious, Northern Spy and Gala, whereas Cortland and Empire apples were among the varieties with the lowest amounts of phenolics and flavonoids.
The researchers also discovered that the antioxidant activity of apples differed from one variety to another and was positively associated with the level of phenolics-in other words, the apple varieties with the higher levels of phenolics tended to have greater antioxidant activity (Nutr J, 2004; 3: 5).
WDDTY vol 23 no.6