How much fruit and vegetables is best?
Source The Times We are all familiar with the mantra of eating “five a day”, but last week a study by the University of Oxford challenged that accepted wisdom — instead, it said, we should increase the daily intake to eight portions. Meanwhile, a new book, The Obesity Epidemic by the nutritionist Zoë Harcombe, dismissed the five-a-day “fairytale”, adding that “in terms of health and nutrition, fruit and veg have little to offer”.
“in terms of health and nutrition, fruit and veg have little to offer”
So what are we to believe? No one could ever come up with a definitive one-size-fits-all target; we are all physically different. Medical science does, however, reveal key foods that can help to prevent a host of diseases. And science tells us something else vital — how you eat them can make all the difference to the benefits they offer.
The bright-green vegetable has high levels of vitamin C, folic acid and antioxidants. These enhance our immune system and may prevent some cancers. Eating broccoli regularly helps to fend off stomach ulcers by killing the bacterial culprit, H. pylori. It also contains healthy amounts of calcium, beta-carotene, potassium, iron, fibre and protein. In addition, it helps to keep arthritis at bay by providing us with significant levels of the trace element selenium. And there’s more: broccoli contains the antioxidant sulforaphane. Tests have shown that this can protect against bowel cancer, and has anti-inflammatory properties. This has inspired American scientists to develop broccoli juice as a sunscreen that helps to stop sunburn and skin cancer.
How to eat boccoli
Raw is commonly thought healthiest, but Italian scientists have found that broccoli is more nutritious when lightly steamed. Investigators at the University of Parma say that a couple of minutes’ steaming raises the level of glucosinolates, compounds known for their cancer-fighting powers. It also takes off the bitter edge. Don’t just eat the buds: although the buds are rich in B-complex vitamins and minerals, the stem contains compounds that can protect against cancers and improve immunity. If you overcook it, don’t worry. Your stomach enzymes are good at rescuing much of the good stuff, a University of Illinois study has shown. Aim for one serving of broccoli a day.
Green tea is far richer in catechins — antioxidants that block cancer and protect arteries — than more highly processed black tea, says a report in the Journal of the American College of Surgeons. The researchers at Yale University believe this may explain why people in Asia have nearly half the rate of lung cancer and heart disease than Westerners, even though they smoke more. Catechins also protect against fatty liver disease and insulin resistance. Green tea is also a morale booster: it contains high levels of plant flavonols that promote the growth of brain cells in areas of the brain concerned with good mood and self-control, says a report in the Journal of Neuroscience. Green tea may also protect against Parkinson’s, finds a study by the Institute of Biophysics, Beijing. Antioxidant polyphenols in the tea can shield the brain’s dopamine neurons, which are lost in Parkinson’s patients.
How to drink Green Tea
Use water that’s just off the boil and leave the bag in for at least two minutes. This protects the vital ingredients. To make your drink even healthier, take it with lemon. Studies by Purdue University, Indiana, show that citrus juice protects the tea’s antioxidants from being broken down by digestive fluids in the gut.Two cups a day is best.
These little bulbs have the power to combat high blood pressure and cholesterol build-up, as well as brain tumours and other cancers. Many of the benefits come from the substance that is its main social drawback: allicin. Pharmacologists at the University of California say that allicin, a smelly element in garlic, sparks an inflammatory chain reaction that can cause pain. This may have evolved to deter animals from eating the bulbs. But allicin’s ability to inflame cells also makes our blood vessels dilate, improving blood flow and so reducing the risk of blood clots. Garlic is also linked to a reduced risk of colorectal cancer, reports the British Nutrition Foundation. This is down to the compound allyl sulphide, which prevents cancer cells from replicating. Garlic also contains three organic compounds that may protect against brain tumours, say experts at South Carolina Medical University.
How to eat garlic
Scientists at South Carolina Medical University scientists recommend that you peel garlic and let it sit for 15 minutes before cooking, so as to release the anti-cancer compounds. Meanwhile, Argentine scientists recommend that you crush the cloves, then bake them slightly before adding to food. They report in the Journal of Agricultural and Food Chemistry that this gets the most thiosulfinates out of the garlic and into your blood. These are believed to lower blood pressure and break up clotting platelets. The scientists recommend three cloves of garlic a day.
Consuming olive oil regularly appears to suppress genes that cause the inflammation behind heart disease and strokes. Researchers at Cordoba University say that the beneficial effect is down to phenol chemicals in the oil. But there is more: Gary Beauchamp, a biologist at the Monell Chemical Senses Centre, reports in the journal Nature that he found a naturally occurring chemical in fresh extra-virgin oil that works as a non-steroidal anti-inflammatory drug. He has named the compound oleocanthal. His research team calculates that a 50g daily dose of olive oil is equivalent to about 10 per cent of the ibuprofen dose recommended for adult pain relief. Beauchamp speculates that eating top-quality olive oil regularly might bring extra long-term anti-inflammatory benefits, such as reduced cancer risk.
How to eat garlic
Get the very best quality extra-virgin oil that you can. Not only does it taste marvellous, the good stuff is much higher in phenols, which reduce the activity of inflammatory genes. If you cook with it, don’t get it so hot that it smokes: its chemical make-up may be damaged. Research in the Journal of the American Medical Association in September recommends one tablespoon of olive oil a day.
Drinking moderate amounts of red wine — or eating as many unskinned grapes as you fancy — can help to protect against cancer and raise levels of good cholesterol. It can also boost your brain, says Dr Clinton Wright, Assistant Professor of Neurology at Columbia University, New York. He says that red-wine drinkers score highly in mental agility tests. Studies also show that red wine can also help insomnia: the grape skins contain melatonin, a hormone that induces sleep. And a new study has shown it can even help your weight. Researchers in Boston have found that moderate women drinkers put on less weight than those who stick to soft drinks. The findings, by Brigham and Women’s Hospital, suggest that the calories are turned into heat, not fat. Many of these benefits are attributed to resveratrol, a chemical in the skins and pips of grapes. So far, though, attempts to make a drug out of resveratrol have failed because trials have revealed serious side effects. Herbalists would argue that you need the whole grape because it contains a natural balance of elements that give an overall benefit.
How to drink red wine
Moderate drinkers tend to live longer than people who abstain completely. And choose the ruddiest, bloodiest wines that your palate can take. These will contain the highest levels of beneficial grape chemicals. To maximise the benefits without risking your health, Government Drinkaware guidelines suggest that women drink one 175ml glass of 13 per cent wine per day, men up to two glasses. Cheers!