Sugar, Fruit and Cancer

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This is an annoying video, but the central section, the actual interview with Dr Clement, contains some very good points which I think summarise sugar and its link to cancer.

We are made of billions of cells; elsewhere I have heard this likened to our bodies being big hairy bags of chemical reactions.  All our cells need energy to run on, and that energy is glucose, oxygen and essential fatty acids.  Oxygen is easy – breathe in and you get some.  Essential fatty acids are omega 3 oils principally found in oily fish and gamma linolenic acid, best found in borage seeds but better known as evening primrose oil.  Glucose is the body’s sugar and whatever we eat we convert to glucose, even if we go hard core and live on steak for a fortnight.  However, to supply sufficient glucose to run the huge army of cells that is us, we only need eat lettuce. When we eat more sugar than this, this is overload.

Dr Clement makes the excellent point that over the years we have bred fruits to be sweeter and sweeter -in other words, to contain more and more sugar.  He says that the average fruit is now 30 times sweeter than the original fruit.  He also points out that processed sugars were hardly ever eaten en masse until the late twentieth century – nobody except the aristocracy could afford them.  However, over the past 100 years, processed sugars (sucrose, fructose, most honeys, agave syrup and so on) have become cheaper and cheaper and so now the most sugar is eaten by the poorest.  What is absolutely certain is that we all eat too much sugar and that includes fruit.  It is gaining acceptance that white sugar is bad for you, but not so many realise the huge dangers that lie in our over sweet fruit and excessive fruit consumption – never mind drinking fruit juice.

Dr Clement goes on to point out that all this sugar weakens our pancreas, which constantly has to produce insulin to fight the tide of sugar flowing in, so even small amounts of sugar stress it and all this leads to sugar floating about the blood stream, as mentioned in the previous sugar blog.  As I said, sugar is sticky and in the blood it attracts microbes (bacteria and viruses) and mutagens (cancer and fibrocystic problems etc) since these things live on sugar.

Again, as touched on in the previous blog, all our cells have a natural life span and, put rather simplistically, a cancer cell is a cell that should have died, but it hasn’t.  It is very much alive and multiplying.  It has been clearly understood for decades that cancer cells feed on sugar – as Dr Clement points out, even conservative science acknowledges this. 1 Since  multiplying needs a great deal of energy, cancer cells are sugar hungry.  Eat a biscuit and it is feast time. Same goes for a banana or a sweet drink.

A common method of monitoring cancer growth is a PET scan; the patient is injected with a type of glucose, then put in the scanner.  The cancer cells light up and so the rate of growth can  be monitored.  At Stanford University, a researcher extracted fructose from apple juice, injected that into some cancer patients undergoing a PET scan and got the same result as if he had used glucose.

There was a study published in 1985 which showed the results of a 10 year study done in Korea on a million and a quarter men and women, aged 30 – 95.  This clearly showed that those with the highest fasting serum glucose were most at risk for developing not only cancer, but dying prematurely from all causes of death.2  The association of high fasting blood sugar was strongest for pancreatic cancer in both men and women.  For the men, their cancer risk was particularly great for the oesophagus, colon/rectum and liver; for the women, the cancers were the liver and the cervix.  However, if we look at the paper, it can be seen that the cancer incidence rises for each cancer along with the rise in blood sugar.

Finally, the study cited in footnote 1 is about cancer metabolism and was published in Jan 2012.  From the section on Diet and Cancer the authors say,

Epidemiological studies have highlighted that the populations having low sugar, low fat culinary traditions present lower incidence of cancer.  Furthermore, studies in mice have showed that feeding the animals a low carbohydrate, high protein diet, not only decreased cancer development but also slowed tumour growth.

So it seems a wise precaution to restrict sugar intake.

  1. Muñoz-Pinedo C, El Mjiyad N, Ricci J E.  Cancer metabolism: current perspectives and future directions.  Cell death and disease (2012)3, e248 pub on line 12 Jan 2012 []
  2. Jee SH, Ohrr H etc.  Fasting serum glucose level and cancer risk in Korean men and women.  JAMA 2005;293(2):194-202 []

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