The Roles of Sugar & Insulin In The Risk of Cancer Development and Growth
Elevated blood glucose levels have also been associated with increased risks of the following cancers:
- pancreas, liver, colon and endometrium.
High insulin levels are associated with increased risks of the following cancers:
- colon, endometrial, breast and pancreatic
Elevated blood levels of IGF-I (insulin-like growth factor-1), a protein associated with the release of insulin, have been associated with increased risks of the following cancers:
- prostate, breast and colorectum.
What is IGF-1 (Insulin-Like Growth Factor-1) and what is its' role in cancer?
- IGF-1 is a very important protein (hormone) that stimulates cells to grow and is involved in multiple aspects of metabolism (protein, fat and carbohydrate).
- Read more about IGF-1 here.
- Read about IGF-1's role in cancer development and growth here.
What is insulin resistance?
What causes insulin resistance?
Learn more about insulin resistance from Dr Oz.
- It is a state in which your cells are not responding to insulin appropriately, so the sugar in your blood cannot get into your cells.
- To compensate, your pancreas pumps out more insulin to try to get the sugar out of your blood and into your cells.
- The hyperinsulinimia (high blood insulin) that results is able to maintain normal blood sugar levels and delay the onset of diabetes.
What causes insulin resistance?
- It is estimated that 1 in 4 people (without diabetes) has a genetic predisposition for insulin resistance.
- Whether or not the insulin resistance develops depends (in large part) on your eating and exercise habits.
- Not being physically active is a huge reason why insulin resistance develops.
- In addition, gaining weight/body fat (especially around the middle) is a common trigger. And once you have insulin resistance, it’s more difficult to lose weight. So, obesity and insulin resistance is really a viscous cycle--obesity contributes to insulin resistance, and insulin resistance contributes to weight gain!
- People who maintain a healthy weight and enjoy regular physical activity rarely develop insulin resistance, even if they have an underlying genetic predisposition.
Learn more about insulin resistance from Dr Oz.
Carbohydrates are the main source of glucose (sugar) in your diet.
(Carbohydrates get converted into glucose during digestion)
Cancer cells require sugar to grow.
- Keeping blood glucose down to a low or normal range seems to be important.
Insulin is produced whenever there is sugar in the blood.
- Individuals with high insulin levels (and an associated protein, "IGF-1") appear to have an increased risk of cancer progression and recurrence.
Some carbohydrates raise blood glucose and insulin higher than others.
- It is important to understand their distinction.
Stay away from refined ("bad") carbohdrates as much as possible, as these rapidly raise blood sugar and insulin (high glycemic index). These include:
Complex carbohydrates include:
- white sugar
- honey
- high-fructose corn syrup
- evaporated cane juice
- flour-based products (cookies, cakes, white bread, crackers, french fries, candy, pastries, etc.)
Complex carbohydrates include:
- Whole grains (brown rice, buckwheat, wild rice, quinoa, barley, whole-wheat pasta, whole-grain bread, etc.)
- Vegetables
- Legumes (beans, chickpeas, lentils, whole and split dried peas, etc.)
- Fruit (particularly the non-tropical fruits: apples, pears, oranges, grapefruits, peaches, plums, apricots, berries, etc.)
Does the sugar in fruit feed cancer? (by david servan-schreiber, md, phd)
A reader asked me the following question, and I wanted to share my response with you, since many of you may be wondering about this.
- "QUESTION: “We’re told that cancer feeds on sugar. And there’s a lot of sugar in fruit. Should we avoid eating fruit? Or eat only acid fruits? If there’s sugar in fruit, how come we can eat them even when we have cancer? I hope you can answer, even though this is just a small question, because there are lots of fruit in the summer and I don’t know what to tell my Dad, who has prostate cancer.”
- ANSWER: The level of glucose in the blood is increased when fruit is eaten, but much less than in the case of refined sugars or white flour. This is partly because fruit contains fiber and many other components along with fructose (which is the form of sugar contained in fruit and in honey), and these additional components modulate the effect of the fructose.
- So, for example, although fructose can “make you fat”, it doesn’t increase the level of insulin in the blood, or the level of IGF, the growth hormone that accompanies insulin.
- There’s even a pilot study that suggests that men suffering from prostate cancer (non-metastasized, in the case of this study), and who drink half a pint of pomegranate juice (which contains fructose) every morning, manage to slow considerably the progression of their tumor. Another study observed a similar effect in mice grafted with prostate cancer, whose diet contained an equivalent quantity of pomegranate juice. I’m attaching the references of these studies.
2009 confirmation : Don't give sugar to breast cancer (by david servan-schreiber, md, phd)
"A large Swedish study has once again shown a link between the quantity of food consumed with a high glycemic index and the risk of developing breast cancer.
- Researchers at the Karolinska Institute (which gives out the Nobel prize for Medicine every year) followed 61,000 women for 17 years. Using detailed nutritional questionnaires, they were able to measure each woman's "glycemic load" (the quantity of food consumed that had a high glycemic index) at the beginning of the study. [1] According to their results, the risk of developing an estrogen-positive and progesterone-negative breast cancer increased in an almost linear fashion with the glycemic load. In other words, the higher the glycemic load, the higher the risk.
- As I explained in Anticancer, food with a high glycemic index (white sugar, white flour and bread, pastries, white rice, sweet drinks, desserts etc) lead to the release of hormones such as insulin and IGF growth factor. In turn, these hormones stimulate factors for inflammation and the growth of cancerous cells. In 2002, researchers from the University of Toronto reported on women in remission for breast cancer who had been followed for a number of years. Those with the highest levels of insulin at the beginning of the study were twice as likely to suffer a relapse and three times more likely to develop metastases than women whose diet contained less sugars and who thus had lower levels of insulin. [2]
- It's not just breast cancer. Colon cancer is also sensitive to the effect of sugars in the diet. It's very likely that other cancers are too, although the association has not been systematically studied in most of them.
- Reminders
- To avoid increasing the levels of glucose and insulin in your blood, eat mostly whole grain cereals in combination:
- Multi-grain bread (containing at least four different wholegrain flours if possible); wholegrain pasta (or, if you eat pasta made from refined flour, cooked al dente; brown rice (or, if you must absolutely eat refined rice, basmati or Thai varieties); wholegrain couscous; quinoa (the cereal of the Incas, which delivers more protein than rice and can agreably replace it); buckwheat; rye; oats, linseed flour.
- The presence of more fiber in food contributes to eliminating toxins and carcinogens that penetrate the body by nutritional or other means. In addition fibers also contribute to reducing spikes in blood-sugar levels, and thus insulin and IGF.
- In addition:
- Combine your meals with garlic, onions, and shallots, which decrease the glycemic index of the food that is eaten.
- Absolutely avoid sweet drinks and prefer green tea, or water flavored with a little lemon, mint, orange or tangerine peel (organic!).
- Avoid sweet desserts and prefer desserts based on fruit, perhaps together with a little melted or grated dark chocolate (more than 70% cocoa content), or with ginger; you can add some agave syrup or acacia honey if you really find it difficult to do without the sweet taste of sugar.
BIBLIOGRAPHY
1. Larsson, S.C. et. al., Glycemic load, glycemic index and breast cancer risk in a prospective cohort of Swedish women. Int J Cancer, 2009. 125: p. 153-157.
2. Goodwin, P.J., et al., Fasting Insulin and Outcome in Early-Stage Breast Cancer: Results of a Prospective Cohort Study. Journal of Clinical Oncology, 2002. 20: p. 42-51."
- Avoid sweet desserts and prefer desserts based on fruit, perhaps together with a little melted or grated dark chocolate (more than 70% cocoa content), or with ginger; you can add some agave syrup or acacia honey if you really find it difficult to do without the sweet taste of sugar.
Be wary of sugar (by david servan-schreiber, md, phd)
"A new study confirms how important it is to limit the dietary intake of sugar so as not to stimulate cancer
- I’m scheduled to give a talk tonight at the Mount Sinai Hospital in New York, but I’m writing this to alert you to a new report by another New York hospital, the Department of Epidemiology of Albert Einstein College of Medicine, working as part of the Women's Health Initiative Observational Study of 93,676 women. The report confirms the link between a high level of insulin – which indicates the level of sugar in the blood, and the risk of breast cancer.
- In this massive study, the risk of breast cancer in menopausal women who were not undergoing hormonal treatment (which is now contra-indicated in the United States and Europe, except in cases of specific menopausal symptoms that are difficult to manage in other ways) was 2.4 (140 percent increase in risk), while the risk associated with hormonal treatment was lower, at about 2.0 (100 percent increase in risk). The authors conclude that the link between obesity and breast cancer in menopausal women is probably entirely due to higher levels of insulin and estrogen hormones in women who are significantly overweight (Body Mass Index > 30).
- This confirms one of the main conclusions featured in my book Anticancer: A New Way of Life, the important role of a diet excessively rich in sugar (“high glycemic index”) in the appearance of certain cancers. It once again underscores how important it is to communicate to patients who have already developed cancer that it is vital that they adopt a low glycemic-index diet, in order to reduce their levels of blood-sugar (“glycemia”), and thus diminish the secretion of insulin and its malignant influence on the growth of cancer cells.
- Low-glycemic-index diets – like the Mediterranean diet, which many of us have found so easy to adopt – have already demonstrated their favorable effects on every other parameter of health: cardiovascular disease, dementia, and inflammatory diseases. So let’s get cooking!
