But are all the foods included in the Mediterranean diet equal, or are some more equal than others? And are there other foods not included in the diet that are also worth including in our dietary regimens?
As funding policies slowly start to change, researchers have been able to move from drugs research to investigations of the foods we eat. What they are beginning to discover are the so-called 'power foods'-those foods that can not only prevent disease, but can even combat them as effectively as pharmaceuticals do.
Here are some of the more recent findings, listed in the most likely way you'd consume them.
Oats. Porridge oats help to prevent arterial diseases. They combat chronic inflammation, which can lead to atherosclerosis (hardening of the arteries). Oats contain several health-giving compounds, such as avenanthramides, which have anti-inflammatory qualities, and phenolic antioxidants, which prevent blood cells from sticking to artery walls. Oats can also lower cholesterol (US Department of Agriculture (USDA)/Agricultural Research Service (ARS), 16 February 2010; www.ars.usda.gov/is/pr/2010/100216.htm).
Oats are a low GI (glycaemic index) food that take a long time to digest, so that they slowly release sugar into the bloodstream. When we eat porridge, the body produces a gut hormone, GLP-1, which makes us feel full for longer, thereby curbing cravings for snacks (Presented at the Society for Endocrinology BES meeting, 18 March 2009, Harrogate, UK).
Maple syrup. If porridge or oats are pretty much the healthiest way to start your day, it gets even better when you add maple syrup on top. The syrup contains 20 compounds that are beneficial, including phenolic antioxidants that help to fight cancer, bacterial infections and diabetes.
However, it's important to make sure that you buy pure maple syrup, and not products that have maple syrup flavouring (Presented at the Spring 2010 Meeting of the American Chemical Society, 21 March 2010, San Francisco, CA).
Grapefruit for breakfast is a healthy start to the day if you have chronic hepatitis C. The conventional treatment is a powerful drug such as pegylated interferon, but that comes with a range of side-effects such as nausea, anaemia, depression and skin rash. However, researchers in Boston have discovered that a grapefruit, or any other citrus, may work just as well. The active ingredient, naringenin, blocks a pathway in the life cycle of the hepatitis C virus (JAMA, 2008; 299: 1532).
The naringenin in grapefruit-which makes it taste bitter-may also prevent type 2 diabetes. The antioxidant helps the liver to break down fat while increasing insulin sensitivity. Researchers in Jerusalem have found that it also mimics the actions of an antidiabetes drug, but without the side-effects. Naringenin has the same positive benefits as fasting, say the researchers, which eventually causes the liver to break down fatty acids instead of carbohydrates (PLoS ONE, 2010; 5: e12399).
Yoghurt containing living 'friendly' bacteria is a probiotic that makes the gut more efficient. It also helps to ward off health problems such as diabetes and obesity. Researchers have been investigating how pro-biotics change gut microbes. In essence, says researcher Jeremy Nicolson from Imperial College London, the live bacteria commu-nicate with the gut microbes and 'remind' them how to be healthy (Mol Syst Biol, 2008; 4: 205).
Watermelon is just as effective as a statin drug for reducing blood pressure-but you would need to eat three of them a day to see any positive benefits. Watermelon is rich in the amino-acid l-citrulline, which is a better tolerated form of l-arginine, the amino acid that directly affects blood pressure. In the body, l-citrulline converts to l-arginine which, if taken directly, can cause nausea and gastrointestinal problems, especially in those who already have hypertension. In one study, nine adults with high blood pressure normalized their blood pressure after taking watermelon extract-as l-citrulline/l-arginine at 2.7 g/1.3 g daily-for six weeks (Am J Hypertens, 2010; doi: 10.1038/ajh. 2010.142).
Eggs have become bad boys in our obsession with keeping cholesterol down. But it appears that they are good for the heart after all-and reduce high blood pressure. Boiled and fried eggs produce peptides that are natural ACE inhibitors-a family of antihypertensive drugs that inhibits angiotensin-converting enzymes-with fried eggs being particularly effective for preventing cardiovascular disease, including hypertension (J Agric Food Chem, 2009; 57: 471-7).
Watercress. Add some watercress to your lunchtime salad if you have breast cancer, as it may stop the tumours from progressing. Researchers have discovered that watercress contains a compound that interferes with signals from tumour cells, and stops the body's flow of essential blood and oxygen. Starved of these essential supplies, the tumour stops growing.
So, simply eating a bowl of water-cress-around 80 g-every day is enough to switch off the cancer cells' signals, researchers at the University of Southampton have discovered. The blood tests of breast-cancer survivors confirmed that the protein that helps nourish cancer cells had been affected (University of Southampton press conference, 14 September 2010; www.soton.ac.uk/promotion/ watercress_breast_cancer_01.shtml).
Walnuts and walnut oil. If you're feeling stressed, add walnut oil-or walnuts-to your salad. Both the oil and nuts are rich in omega-3 fats, which help the body to cope with raised stress levels. These fats also lower both blood pressure and LDL, or 'bad', cholesterol levels.
When researchers at Penn State University tested the walnut diet on a group of 22 volunteers for six weeks, it was found that their resting blood pressure and responses to stressful situations improved over the study period (Penn State University press release, 4 October 2010; http:// live.psu.edu/story/48843).
Tomatoes offer a range of health benefits, and can cut your risk of cancer and heart disease. Men who regularly eat tomatoes and tomato-based products, such as tomato sauce and pizza, can cut their prostate cancer risk by 35 per cent (J Natl Cancer Inst, 1995; 87: 1767-76).
Olive oil. Dressing your salad with olive oil will help to ward off Alzheimer's disease-and may even reduce the symptoms if you already have it. The best type is extra virgin olive oil, which is especially rich in oleocanthals, a naturally occurring polyphenol that can alter the structure of the neurotoxins that contribute to the debilitating effects of Alzheimer's (Toxicol Appl Pharmacol, 2009; 240: 189-97).
Broccoli. It's the king of vegetables and it also offers a wide range of health benefits. Broccoli and other cruciferous vegetables are full of chemicals called 'sulphoraphanes', which boost the immune system. Sulphoraphane reverses the decline of cellular immune function and kick-starts dendritic cells, which will also improve immune function, say researchers from the University of California at Los Angeles (J Allergy Clin Immunol, 2008; 121; 1255-61).
Brussels sprouts. These cruciferous vegetables of the Brassica genus-like broccoli-can stop the spread of cancer. Brussels sprouts encourage the body to produce a substance called '13C' (indole-3-carbinol) that can fight cancer and block the development of cancer cells. Scientists at Ohio State University have so far tested only breast-cancer cells, but they believe it can also combat other types of cancer, such as prostate, liver and colon cancers, as well as non-Hodgkin's lymphoma.
In laboratory tests, the scientists noted that 13C destroys the molecules associated with breast cancer. The scientists have also speculated that these vegetables might also reverse some of the symptoms of Alzheimer's disease (Cancer Prev Res, 2010; 3: 818-28).
Seaweed may not be the obvious accompaniment to your evening meal, but this overlooked, mineral-rich vegetable is one of the healthiest foods you can eat. This is because it's full of fucoidan, a sulphated polysaccharide, that kills cancer/tumour cells.
Researchers at the Hashemite University in Jordan tested a seaweed extract on non-Hodgkin's lymphoma cells, and found that it suppressed lymphoma growth while leaving healthy cells intact (Presented at the Second AACR Dead Sea International Conference on Advances in Cancer Research, 7-10 March 2010, Jordan).
Brown rice. If you regularly eat white rice, just switching to brown, unprocessed rice could be all that it takes to prevent type 2 diabetes, say researchers. Making the change reduces your risk by 16 per cent, but it plummets to 36 per cent if you also change to whole grains such as whole wheat and barley (Arch Intern Med, 2010; 170: 961-9).
Shellfish are a rich source of vitamin B12, the one that is most closely associated with good mental health into old age. Those who have low stores of B12 are the most likely to suffer from brain shrinkage, which is thought to be associated with dementia and Alzheimer's disease. When researchers at the University of Oxford monitored 107 people, aged 61 to 87 years, for five years, they found that brain atrophy was six times more likely in those deficient in the vitamin. It's also reckoned that 40 per cent of the general population are deficient in the vitamin. Lead researcher David Smith said: "The rate of shrinkage of the brain as we age may be partly influenced by what we eat" (Neurology, 2008; 71: 826-32). Liver is another rich source of vitamin B12.
Fish. Eating fish a few times a week can reduce your chances of a heart attack, and the benefits are further amplified if you also supplement with omega-3 oil, say researchers from the University of Alabama. Those who eat fish once or twice a week nearly halve their chances of a heart attack that could be fatal or require hospital care, say the researchers, who followed the diets and health of 36,234 women for nine years. Those who ate three servings of fish a week were the least likely to have a heart attack, while even just one serving-especially if supplemented with omega-3 capsules-offered good protection (Eur J Clin Nutr, 2010; 64: 587-94).
In a separate study, which came to the same conclusion, researchers emphasized the importance of eating oily fish-such as salmon, sardine, trout and herring-to get the most protection for your heart. So even if you do suffer a heart attack, your chances of having a second one are reduced by 30 per cent just by eating oily fish (J Am Coll Cardiol, 2009; 54: 585-94).
Fish is also a great de-stresser. When we are stressed or depressed, we produce more proinflammatory cytokine chemicals such as inter-leukin-6. The omega-3 oils in fish are a natural anti-inflammatory, and can counteract the worst effects of stress (Perspect Psychol Sci, 2009; 4: 367-9).
o Baked rhubarb crumble. Traditional Chinese Medicine (TCM) has recognized the cancer-fighting qualities of rhubarb for thousands of years, and the West has finally come up with its own version-one that is both a treat and an anticarcinogenic: baked rhubarb crumble. Researchers at Sheffield Hallam University found that rhubarb after being baked for 20 minutes develops polyphenols, powerful anticancer chemicals that can stop cancer cells from growing and even kill them (Food Chem, 2010; 119: 758-64).
Lemonade concentrate. If you suffer from recurring kidney stones, drinking 2 L of water containing 120 mL of concentrated lemon juice every day will eventually stop stone formation. The treatment was tested in 11 patients, who reported a decrease in stone formation of 87 per cent (J Urol, 2007; 177: 1358-62).
Cranberry juice. The infection-fighting qualities of cranberry juice are well known, and scientists now believe it may also be useful against serious staphylococcal infections such as the deadly superbug MRSA (methicillin-resistant Staphyloccus aureus), prevalent particularly in hospitals and nursing homes. When women were given either cranberry juice or a placebo to drink, and had their urine mixed with strains of Escherichia coli and S. aureus that can cause a range of infections, from skin rashes to MRSA, the cranberry juice stopped both strains from growing and was especially effective against S. aureus (Presented at the 240th National Meeting of the American Chemical Society in Boston, MA, 23 August 2010).
Beetroot juice is effective for reduc-ing high blood pressure quickly. In one test, it reduced blood pressure levels in just 24 hours. Nitrate in the juice is the active ingredient, say researchers from Queen Mary University of London, and this is bio-converted to nitrite-a potent vaso-dilator-in the tissues. Just 250 mL of the juice is enough to lower blood pressure, and it's effective even in those with severe hypertension (Hyper-tension, 2010; 56: 274-81).
o Tea. Green tea is the king of the teas, providing a vast range of healthful benefits. It prevents oral cancers, even in those at high risk because of a premalignant condition. Used as an extract, it prevented high-risk people from developing the cancer; of 41 individuals tested, 58 per cent of those given the highest dose of green tea extract did not develop the cancer compared with 36 per cent in those taking the lowest dose (Cancer Prev Res [Phila], 2009; 2: 931-41).
Green tea also protects the eyes, protecting them against diseases such as glaucoma. The tea's anti-oxidants penetrate the tissues of the eye, and strengthen the lens and retina, researchers have found (J Agric Food Chem, 2010; 58: 1523-34).
Most extraordinary of all, green tea is one of the few agents that can combat a form of cancer that is believed to be incurable. It reduces lymph-node size in cases of chronic lymphocytic leukaemia (CLL). An ingredient in the tea-a polyphenol called 'EGCG' (epigallocatechin 3-gallate)-appears to be the key, say researchers after testing it in 31
CLL patients, all of whom were given EGCG extract at doses ranging from 400 mg to 2000 mg twice a day. Those given the highest dosages reported substantial reductions in lymph-node size-with no side-effects (J Clin Oncol, 2010; 28 [suppl]: 7s, abstr 6522).
However, if you want to control your diabetes, black tea is better.
On being tested against green and oolong teas, black tea proved to have the most beneficial qualities for diabetics. Black tea is richest in polysaccharides, which have glucose-inhibiting qualities. The tea was also the most effective free-radical fighter, and free radicals play a key role in the development of cancer and rheumatoid arthritis (J Food Sci, 2009; 74: C469-74).
Drinking between three and six cups of black tea every day also reduces your risk of heart disease by 45 per cent compared with drinking only one cup of tea a day. However, the benefits of tea-drinking start falling away if you drink more than six cups; in this case, the protective effect fell to just 36 per cent (Arterio-scler Thromb Vasc Biol, 2010; 30: 1665).
The polyphenols in tea also help to strengthen our bones, and you will start to see these benefits after drinking three cups a day for just a short period of time, according to researchers at the British Nutrition Foundation (Daily Telegraph, 10 June 2008; www.telegraph.co.uk/news/uknews/2104561/Drinking-tea-can-reduce-heart-attack-risk.html).
Blueberry juice. This is a powerful antidiabetic that can help in the fight against putting on weight-provided that the fruit's skin is mixed into the concoction. In this case, the drink reduces blood sugar levels in diabetics, and also protects against diabetes and obesity. It's at its most powerful after it has been 'biotransformed' (fermented) by Serratia vaccinii bacteria for three days, say researchers from the University of Montreal (Int J Obes [Lond], 2009; 33: 1166-73).
o Apple juice. Drinking just two glasses of apple juice a day can improve some of the worst effects of Alzheimer's disease.
When 21 Alzheimer's sufferers were given two 4-oz glasses of the drink every day for a month, marked improvements were seen in anxiety, agitation and delusions. Overall, the patients' caregivers believed that the drink improved both behavioural and psychotic symptoms by 27 per cent (Am J Alzheimers Dis Other Demen, 2010;
Red wine can protect against stroke and reduce your risk of cardio-vascular disease-provided that it's drunk in moderation.
The active ingredient in red wine is resveratrol, which is found in the seeds and skin of red grapes-and only red wine delivers the amount of resveratrol required to have any beneficial effect, say researchers at the Johns Hopkins University School of Medicine (Exp Neurol, 2010; doi: 10.1016/j.expneurol.2010. 03.032).
Coffee. A cup of coffee in the morning helps to reduce chronic inflammation and oxidative stress, while increasing levels of 'good' HDL cholesterol. It may also be protective against type 2 diabetes.
Coffee contains several nutrients, such as calcium, and hundreds of biologically active compounds such as polyphenols (Am J Clin Nutr, 2010; 91: 950-7).
o Pomegranate juice can slow the progress of prostate cancer, and may even work as a cancer preventative. The juice reduced levels of prostate-specific antigen (PSA) in 48 men with prostate cancer by 60 per cent. Researchers say that it could be a potent alternative treatment in cases where surgery has failed (J Urol, 2009; [suppl]: 181, 4, abstr 826).
o Dark chocolate. The flavanols in dark chocolate improve arterial health and, as a result, can "significantly" reduce high blood pressure, or hypertension, say researchers. Dark chocolate is especially effective in those who already have high blood pressure. Also, eating just a little dark chocolate every day for five years can reduce the risk of heart attack and heart disease by 20 per cent (BMC Med, 2010; 8: 39; doi: 10.1186/1741-7015-8-39).
Eating 40 g (nearly one-and-a-half ounces) of dark chocolate every day for two weeks can also improve signs of anxiety in even the most highly stressed individuals (J Proteome Res, 2009, 8: 5568-79).
Grapes. The flavonoids in grapes can dramatically reduce your risk of heart failure. Just nine servings, or handfuls, of these fruit every day can lower blood pressure and improve heart muscle function, and may even counteract the effects of a poor diet. Researchers from the University of Michigan in Ann Arbor found that grapes started to show positive effects after 18 weeks in a study of laboratory mice (J Gerontol A Biol Sci Med Sci, 2008; 63: 1034-42).
Snacking on grapes may also stop the downward spiral that often ends with type 2 diabetes and heart disease. The benefits are seen within three months, say researchers from the University of Michigan Health System, who have discovered that phytochemicals in grapes can arrest a cluster of health problems that are collectively known as 'the metabolic syndrome'. These factors include a large waist, high blood pressure, reduced glucose tolerance and raised levels of C-reactive protein, a marker of inflammation (Presented at the Experimental Biology 2010 Conference, 26 April 2010, Anaheim, CA).
Almonds have been described as the healthiest snack of them all. Eating just 73 g (3 oz) can reduce 'bad' LDL cholesterol levels by 24 per cent, lower insulin output and even help to improve gut health. Positive effects are seen after four months, say researchers. The nuts are especially effective when eaten soon after a meal (Townsend Letter, 2008; 305: 24).
o Flaxseed. Sprinkling just a few table-spoons of flaxseed on your food every day can be as effective as a drug for lowering cholesterol levels. The seeds are rich in omega-3 fats and lignans, a phytoestrogen, and were able to reduce cholesterol levels in 90 men by around 10 per cent. This is similar to the effectiveness of a statin drug, but without the risk of side-effects. The men consumed
3 tbsp/day of flaxseed for three months by sprinkling them on the food they were eating (Presented at the American Society for Nutrition Annual Meeting, 24-28 April 2010, Anaheim, CA).
Blackcurrants. These fruit reduce lung inflammation, and can improve breathing during an asthma attack. They are rich in epigallocatechin, an antioxidant, which works with the body's immune system to reduce inflammation (Mol Nutr Food Res, 2010; 54 suppl 2: S159-70).
Apples are a good source of soluble fibre, and aid the body's healing processes by transforming unhealthy cells. In general, an apple is one of the best ways to boost the immune system (Brain Behav Immun, 2010; doi: 10.1016/j.bbi.2010.01.015).
o Blueberries can offset the worst symptoms of stomach problems such as pain and bloating, and can even counteract colitis. They may even protect against developing gastro-intestinal problems in the first place. The fruit are rich in polyphenols that have both antimicrobial and anti-oxidant qualities (AlphaGalileo, 2010;www.alphagalileo.org/ViewItem.aspx?ItemID =67814&CultureCode=en).
Preparing and cooking food
The way we prepare food can be as important as the food itself. Overcook vegetables, and you lose most of their health-giving ingredients. So, here are a few cooking tips from the world of science.
Carrots. Don't chop carrots up before you cook them. Cooking them whole will retain their cancer-fighting compound falcarinol. They'll taste better, too (Newcastle University School of Agriculture, Food and Rural Development press release, 18 June 2009).
Vegetables. After cooking 20 different vegetables by six methods-boiling, microwaving, pressure-cooking, griddling, frying and baking-and measuring antioxidant levels, it was found that cauliflower lost most of its nutritional goodness after boiling and microwaving, as did peas after boiling, and zucchini (courgettes) after boiling and frying. Only green beans, beetroot and garlic kept their antioxidant levels after being subjected to most cooking methods (J Food Sci, 2009; 74: H97-103).
Vegetarian or not? Organic or not?
You are more likely to get cancer if your diet is primarily red meat, it's been found, whereas vegetarians and those who eat mainly fish are much more likely to stay cancer-free compared with meat-eaters.
Surprisingly, however, colorectal cancer is the only cancer that is more prevalent in vegetarians than in meat-eaters.
Researchers at the University of Oxford discovered the benefits of a vegetarian or fish-based diet when they profiled the health and diets of 52,700 people, grouped as meat-eaters, fish-eaters, vegetarians and vegans. Most were consuming the recommended five-a-day servings of fruit and vegetables, which are supposed to help maintain good health.
Yet, the number of cancers among vegetarians and fish-eaters was significantly lower than in meat-eaters, although the high rate of colorectal cancer among vegetarians was surprising (Am J Clin Nutr, 2009 March 18; doi: 10.3945/ajcn.2009.26736L).
Buying organic is worth the price, say researchers. Organically grown Golden Delicious apples are 15-per-cent higher in antioxidants and phytochemicals than conventionally grown varieties. The researchers, who compared organic with non-organic over a three-year period, noted that organic apples also had 10-per-cent higher concentrations of phyto-chemicals, known to have numerous health benefits, including protection against cancer and heart disease (J Agric Food Chem, 2009; 57: 4598-4605f).
As good as drugs
Although a diet of vegetables, fruits and juices is an excellent preventative, some foods can even counteract disease, and may be as powerful as drugs-but without the side-effects. Here are some foods to add to your diet if you have the following conditions.
o Alzheimer's disease: brussels sprouts, shellfish, apple juice, olive oil
o Asthma: blackcurrants
o Breast cancer: watercress, brussels sprouts, broccoli, seaweed, rhubarb
o Cancer: brussels sprouts, broccoli, seaweed, rhubarb
o Colitis: blueberries
o Dementia: brussels sprouts, broccoli, shellfish, apple juice
o Depressed immune system: broccoli, apples
o Diabetes (type 2): grapefruit, black tea, blueberry juice
Heart problems: watermelon, eggs, oily fish, beetroot juice, dark chocolate, grapes, almonds, flaxseed
o Hepatitis C: grapefruit
o High cholesterol: eggs, almonds, flaxseed
Hypertension (raised blood pressure): watermelon, beetroot juice, dark chocolate, grapes
o Kidney stones: lemonade concentrate
o Leukaemia (CLL): green tea
o Non-Hodgkin's lymphoma: seaweed
o Prostate cancer: pomegranate juice
o Staphyloccal infections: cranberry juice
o Stress: walnuts, walnut oil, oily fish
o Urinary tract infections: cranberry juice
Foods and drinks to avoid
We all know that a white-bread and processed diet lies at the root of many of the chronic diseases that are so commonly seen these days-and here's why.
Processed foods cause heart disease because they have a high glycaemic index (GI), which puts a strain on the arteries for several hours. Researchers in Israel tested processed foods on a group of healthy volunteers, who were given cornflakes, sugar, bran flakes or water-and only those who drank just the water had normal arteries afterwards. The rest suffered from poor arterial function that lasted for several hours (J Am Coll Cardiol, 2009; 53: 2283-7).
Cola drinks such as Coca-Cola and Pepsi can lead to diabetes and muscle weakness. They cause potassium blood levels to drop, which can lead to serious muscle problems. Researchers in Greece found that those who drank excessive amounts of cola could even suffer from paralysis, although victims made a full recovery once they stopped drinking it. One such victim was drinking 2-9 L/day, researchers noted, although the average consumption is less than 0.5 L/day (Int J Clin Pract, 2009; 63: 900-2).
o Red and processed meats, when eaten in large quantities, can increase your chances of cancer or even death. In a survey of 47,976 men and 23,276 women, those in the top fifth of red-meat-eaters-in other words, those who ate 62.5 g/1000 calories every day-were far more likely to die prematurely from all causes compared with those in the bottom fifth of red-meat consumption. If you can't live without meat, switch to a white meat such as chicken, say the researchers (Arch Intern Med, 2009; 169: 562-71).
WDDTY VOL. 21 ISSUE 09