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Why You Shouldn't Eat 5 Portions
Part 4: Sugar, cancer and heart disease
Sugar and cancer
Every day we are all attacked by things that could start a cancer: particles in the air we breathe, the water we drink and the food we eat. It is estimated that at any one time we have thousands of potentially cancerous cells circulating in our bodies. But in a healthy body these are mopped up by our immune system before they can get a foothold. You will see, therefore, that just as healthy leukocytes can stop us catching a cold, they could also stop us from getting cancer.
In which case, you won't be surprised to learn that a claim that increasing sugar intakes by eating more fruit and vegetables reduces the risk of, say, breast cancer, seems to be without foundation. To test this claim, researchers at seventeen cancer research centres in the USA, Germany, Netherlands, and Sweden examined the association between breast cancer and total and specific fruit and vegetable group intakes. Their studies included 7,377 incident invasive breast cancer cases occurring among 351,825 women. They found no association for green leafy vegetables, eight botanical groups, and seventeen specific fruits and vegetables and concluded:
'These results suggest that fruit and vegetable consumption during adulthood is not significantly associated with reduced breast cancer risk.[14]
Sugar and heart disease
The popular belief that a fatty diet causes heart disease is untenable because the process that creates atherosclerotic plaques is not, as we are led to believe, fatty formations in the arteries themselves, but the intrusion of LDL particles into the walls of the arteries. Yet there is no way in which LDL can get through the lining of artery walls (endothelium) in an otherwise healthy person because the endothelium is a barrier to LDL. Let's face it; arteries wouldn't be much use if they leaked.
The only way LDL can get through the lining and into the artery wall is if that lining is damaged in some way, either by a cut or disease. This means that anything that can damage the endothelium and/or promote the formation of a clot may have a serious impact on plaque formation, growth and rupture. What is attributed merely to cholesterol is actually a combination of damage to the endothelium followed by the formation of a clot (thrombus), which contains cholesterol, over the area of damage. The endothelium then grows over the thrombus, effectively drawing it into the arterial wall (an inflammatory/healing process). This process, repeated, causes plaques to grow and eventually rupture, causing a blockage in an artery.
A cut or similar damage is unlikely in the coronary arteries: they are buried too deep in the body. But how about, say, a bacterial or viral attack which damages the endothelium? This seems more likely and it is seriously considered as a likely cause. A large number of studies have reported on associations between human coronary heart disease and certain persistent bacterial and viral infections. Particularly implicated are Chlamydia pneumoniae, a bacterium that commonly causes respiratory infections, and another ubiquitous bacterium, Helicobacter pylori.[15] Other equally ubiquitous herpesviruses and cytomegalovirus are also candidates. According to Drs K Namuzaki, Assistant Professor of paediatrics, and S Chiba, Professor and Chairman, Sapporo Medical University, Japan, 'Endothelial cells are one of the main targets of the cytomegalovirus infection.'[16]
Thus carbohydrates, particularly sugars and fruit juices, by reducing the body's ability to fight infection, may well allow this damage to occur — as well as making blood more likely to clot. These two factors could be a deadly combination.
Fruit and veg as antioxidants
Many of the conditions we experience today are caused when the fats and cholesterol in our bodies is attacked by oxygen. This is why we are told to eat fruit and veges: because they contain antioxidants. But just how useful they are in this regard was tested in 2004 by scientists at the University of Oslo, Norway.[17] The study's objective was to determine the contribution of various food groups to total antioxidant intake, and to assess just how much of the antioxidants is actually absorbed into the bloodstream from each of the various food groups. Figure 1 shows these levels. As you can clearly see, fruit and veges play very little part. Even wine, which we are also told is a great supplier of antioxidants is actually a very poor supplier. With 11.1 mmols of antioxidants out of a total of 17 mmols, coffee supplied almost twice as many usable antioxidants as all the fruit, tea, wine, vegetables and grains eaten put together.
So, should we drink lots of coffee? Well, that's probably not necessary because a review published in 2001 reported the dismal findings of several sizeable randomised trials of antioxidant vitamins, which in the main showed that not only was there no decrease in the death rates, in two studies of beta-carotene, there was a possible increased risk of heart attacks.[18] This was confirmed in a report of 2002 when the huge Heart Protection Study was forced to conclude that:
'despite assessing the combined effects of several years of substantial daily doses of different antioxidant vitamins (including 600 mg of vitamin E) in a large number of high-risk people, the Heart Protection Study has not been able to demonstrate any benefits from such supplementation.'[19]
Vitamin E Linked to Increased Risk of Heart Failure
Vitamin E has been touted for its anti-oxidant properties for years to combat the ravages of diseases such as heart disease and cancer. In 2005, came the results of a seven-year study examining the potential benefit of vitamin E in preventing cancer and cardiovascular events in older patients with vascular disease or diabetes. This not only showed no benefit from taking the supplement, it showed an increased risk of heart failure.[20]
The original HOPE (Heart Outcomes Prevention Evaluation) trial, which lasted for four-and-a-half years, had found no evidence that 400 IU per day of vitamin E affected the outcome of heart disease. Thinking that the treatment period may have been too short to show a benefit, Dr. Eva Lonn, at McMaster University in Hamilton, Ontario, and colleagues, extended the HOPE study for a further two-and-a-half years. The results now showed that, while there were no significant differences between the patients taking vitamin E and those taking a dummy pill in cancer rate, cancer deaths, major cardiovascular events — heart attack, stroke, or death from cardiovascular causes — or death from any cause, the risk of heart failure was higher in the vitamin E, as was the risk of hospitalisation for heart failure.
The HOPE Group say: 'In conjunction with its lack of efficacy, the potential for harm suggested by our findings strongly supports the view that vitamin E supplements should not be used in patients with vascular disease or diabetes mellitus.'
Last updated 7 April 2010
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