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Why You Shouldn't Eat 5 Portions
Part 3: You can eat too much fruit and veges
Have you noticed how many cases of meningitis there seem to be, these days? I don't think I heard the word in my youth. There are also many other infectious diseases that seem to have started only in the late twentieth century: Lots of acronyms like SARS, AIDS, and MRSA; the exotically named necrotising fasciitis which has a nasty habit of eating us alive; a different flu every year; I won't go on. Even tuberculosis is returning. Why? What is happening?
Medical science has been able to prevent diphtheria and smallpox by vaccination. We reduced tuberculosis by pasteurization of milk and improved general hygiene. A clean water supply and proper sewage disposal prevented typhoid and cholera.
But, today, we in Britain and the USA are protected from these diseases because we have been artificially immunised against them and cocooned from them; not because our bodies' inherent ability to prevent infection has been strengthened. And therein lies the problem.
Animals in their natural habitat rarely get infectious diseases; neither do 'primitive' humans, despite the fact that they do not have the 'benefits' of our sterilized lifestyle. Nature ensured that we should not suffer sickness and death through infections by endowing all animals with a very effective immune system. But we in western industrialized societies seem to have lost or compromised our natural powers of protection. The evidence suggests that at least part of our loss of immunity to infectious disease lies in our incorrect diet. The good news is that we can regain our immunity quite easily.
Eat sugar, catch cold — and die?
Surely not! Colds are a fact of life — everyone gets them. They may be a nuisance but that's all, isn't it? You'd be surprised how dangerous the common cold can be. In 1954, the British Medical Journal published a paper showing that respiratory infections, particularly colds, were the most common irritating and aggravating factors in congestive heart failure.[7] In two studies of heart failure, more than half the patients had some form of respiratory infection and a direct correlation was found between the frequent occurrence of heart failure and 'even minor colds'. The common cold, it seems, can be deadly.
The role of refined carbohydrates in respiratory problems was demonstrated dramatically in a study comparing the Kikuyu and Maasai tribes.[8] The Kikuyu, living mainly on cereals, had a death rate from bronchitis and pneumonia which was ten times higher than that of the meat-eating Maasai. A similar comparison carried out at a girls' boarding-school found the same: researchers demonstrated that the incidence of colds among the girls was directly related to the amount of sugar each consumed. Their evidence showed that the girls who drank fizzy drinks and ate sweets and other refined carbohydrates suffered many more respiratory problems and colds than girls who did not. The advice given to reduce the likelihood of getting a cold was to cut out sugar and eat no bread or other products that contain either wheat or rye.
Sugars and starches lower our immunity to infectious diseases
The high level of sugar in modern diets has been of concern for many years, mainly because of its contribution to malnutrition by replacing more essential nutrients. But, while this is an important consideration, there is more to this trend.
After World War II, with the widespread use of antibiotics and vaccination, it was thought that infectious disease could be conquered. But over the last quarter of the twentieth century, we saw an increase in previously 'conquered' or rare diseases: diseases such as tuberculosis, meningitis, influenza and even the common cold, and a whole rash of new ones.
In the constant fight against disease, our bodies have a sophisticated defence mechanism — our immune system. Part of this system are cells called neutrophils, a type of leukocyte or white blood cell, which circulate in our blood streams and mop up any bacteria, viruses or other foreign bodies they come across. This process is called phagocytosis. While this process is an energy requiring mechanism that needs an adequate supply of the blood sugar, glucose, too much glucose has the effect of reducing the neutrophils' ability to ingest and kill off invading bacteria.
The measure of how many organisms one leukocyte can eat in an hour is called the 'leukocytic index' (LI). It is a simple measure: if a leukocyte eats 10 organisms in an hour, its leukocytic index is 10.
The neutrophils that we rely on to kill any invading bacteria and viruses form sixty to seventy percent of the white blood cells in our bodies. They are generally much more active than any other blood cell. It can be disastrous to our health, therefore, if their effectiveness is compromised in any way. Of all the factors in our modern world that are working against our immune defences, sugar must surely be the worst, for this is exactly what happens if we eat too much carbohydrate and too much sugar in particular.
But by 'sugar' I do not mean just the white, granulated stuff we serve from a bowl on the table; that is called sucrose; the term 'sugar' applies also to glucose, fructose (fruit sugar), maltose (grain sugar), lactose (milk sugar) and honey (a mixture of glucose, fructose, sucrose and dextrin).
Test results
Forty years ago researchers carried out a series of studies that examined how the sugar we eat weakens the ability of white blood cells to destroy bacteria. The results of the study, tabled below, showed that if a person ate no sugar for twelve hours, each white blood cell could destroy an average of fourteen bacteria. As sugar intake was increased, so the numbers of bacteria consumed was lessened, until, by the time twenty-four teaspoons of sugar were consumed (the amount in a medium piece of cheesecake or a milk shake), the white blood cells were so compromised that they could only destroy an average of one bacterium each.[9] The implications of this study should be obvious. Eat white sugar and you severely compromise your body's ability to fight infections.
| Teaspoons of sugar | Number of bacteria destroyed | This amount of sugar is found in: |
| 0 | 14.0 | – |
| 6 | 10.0 | 1 scoop of ice cream |
| 12 | 5.5 | 1 fizzy drink |
| 18 | 2.0 | Less than half a malted drink |
| 24 | 1.0 | 1 slice of sweet cheesecake |
But white granulated sugar is only one form of 'sugar' that we eat. In 1973 another study was performed to check the effects of a range of sugars on our immune system. In it, after an overnight fast and after their leukocytes had been tested for phagocytosis activity and their leukocytic index (LI) had been recorded, subjects were fed one-hundred grams of a specific carbohydrate — a sugar or starch.[10] The table below shows that all forms of carbohydrate — starch as well as sugars — reduced the white blood cells' effectiveness at destroying bacteria and other micro-organisms (the figures are averages across all subjects).
| Fasting LI | Lowest LI | Decline % | Time before returning to normal | |
| Fructose | 15.5 | 8.5 | 45.1 | more than 5 hours |
| Sucrose | 15.2 | 8.6 | 44.0 | more than 5 hours |
| Orange juice | 16.6 | 9.6 | 42.1 | more than 5 hours |
| Glucose | 16.2 | 9.6 | 40.5 | more than 5 hours |
| Honey | 15.9 | 9.7 | 39.0 | more than 5 hours |
| Starch | 15.7 | 13.6 | 13.4 | more than 5 hours |
These studies were further strengthened in 1976 in a third which tested the effect of twenty-four ounces (two cans) of sugar sweetened Cola.[11] In this test the ability of disease-fighting blood cells was halved.
Consequences
Based on these studies, any person who eats largely carbohydrate-based meals, particularly those containing sugars, and snacks with carbohydrate-based meals spread throughout the day — as the latest advice suggests we should — could lose up to half their immunity to disease for much of the waking day.
It is important to note that in the second study, the worst sugar was fructose. Fructose is the sugar found in fruit — and fruits today are generally little more than sugared water. So if you want to live a healthy life, free from infection, 'five portions of fruit' may not be such a good idea, even if vegetables are.
Diabetics
We already know that diabetes is caused by excessive intake of carbohydrates.[12] Excessive carbohydrate intake may also be why diabetics have been found to have impaired phagocytic activity when compared to normal subjects, and are thus at significantly greater risk.[13] Current dietary advice should be reviewed to ensure that diabetics are even more careful not to consume a carbohydrate and particularly a fruit based diet.
Last updated 7 April 2010
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