Does Sugar Feed Cancer?

Written by Jacki Glew, MS, RD, LDN - Clinical Nutrition Manager for the Block Center for Integrative Cancer Treatment

Does sugar feed cancer?  Well, yes and no.  Um, OK – yes.

All cells use sugar – aka glucose – for their primary fuel source, so sugar does indeed feed all cells.  But if you’ve ever had a PET scan, you know that before you get your scan, you get to drink a lovely shake of radioactive glucose or get an injection of a similar concoction.  Cancer cells are very greedy; they like to gobble up glucose much more quickly than non-cancerous cells, which is why the cancer cells light up on the screen during your scan.

All carbohydrate-containing foods contain sugar to some degree.  So this means even healthy foods like whole grains, beans, fruits, and even vegetables contain some sugar.  The glycemic index basically tells you how fast a particular food will raise your blood sugar level.  For instance, we know refined/processed foods like white sugar, white bread, and white rice are high glycemic foods, but so are healthy foods like watermelon, dates, and potatoes.  The glycemic load of a meal takes into account the whole meal.  Sometimes eating higher glycemic foods along with lower glycemic foods can blunt the rise in blood glucose when eaten together.

Why is your blood sugar level a concern?  Because your body produces insulin and insulin-like growth factor-1 (IGF-1) whenever your blood sugar level rises.  We know insulin helps regulate blood sugar, but did you know insulin is also a growth hormone?  So is IGF-1, which reacts in response to insulin production.  So more sugar eaten = more insulin produced = more IGF-1 produced = more cancer cell growth. Yikes!  In fact, IGF-1 has been found through a number of studies to play a big role in promoting breast, lung, prostate, and other types of solid tumor growth.  IGF-1 has a growth-promoting effect on almost every cell in the body especially in muscle, bones, liver, kidney, nerves, skin, lungs and blood.  IGF-1 also affects the DNA synthesis within these cells.

If you have an advanced cancer, you need to be even more aware of your blood sugar level since rapidly growing cancer cells consume more glucose to keep up with their growth spurt.  And if you are on chemotherapy, high levels of insulin and IGF-1 can play a role in blocking chemo activity making cancer cells less responsive to chemotherapy.  If you have a hormonal cancer such as breast, endometrial or uterine cancer, then IGF-1 is also a concern as estrogen receptors on cancer cells can be stimulated by IGF-1.  IGF-1 has even been found to interfere with the effectiveness of the drug trastuzumab.

What can you do about it?

1. Plant in your mind that plants are best!  A plant-based diet lowers your daily glycemic load so less insulin and IGF-1 are produced in response to your blood sugar level.  A diet chock full of veggies, whole grains, nuts, beans, legumes, and fruits will not raise your blood sugar as much as a diet full of white stuff like white sugar, white rice, white bread, etc.  Foods that grow out of the ground are naturally low in sugar and high in fiber.  Fiber helps to slow the release of sugar into the bloodstream, resulting in the production of less insulin and IGF-1.  Now here’s the kicker: switching to a plant-based diet will help you to cut back or eliminate animal foods, which will lower your IGF-1.  Your body naturally produces IGF-1.  We need this growth hormone for – you guessed it – growth.  As babies, we need IGF-1 to help us grow, but then stop drinking mother’s milk.  Somewhere along the line, humans began drinking animal milks that also contain natural IGF-1.  Americans love milk and cheese and yogurt and ice cream … you get the picture.  IGF-1 in animals is identical to IGF-1 in humans, so the more we consume dairy, the more we consume IGF-1.  IGF-1 is also in animal meats and fats.  Eliminating red meat, poultry and dairy will significantly help reduce your IGF-1.
2. Stop eating junk!  Cut out refined and processed foods and stick to stuff Mother Nature made.  No more candy, soda, white bread, white rice, ice cream, or even white potatoes.  Switch to whole grains like brown rice, quinoa and steel-cut oats.  Choose starchy veggies like sweet potatoes, Yukon Gold potatoes, squash and pumpkin.
3. Watch your sweetener intake.  No more high-fructose corn syrup, evaporated cane juice or dextrose.  While you’re at it, cut out artificial sweeteners like sucralose, saccharin, aspartame and acesulfame potassium.  If you must sweeten your foods or if you like to bake, try stevia leaf, brown rice syrup, agave syrup or maple syrup in small amounts – less than five teaspoons per day.
4. Get moving!  Exercise helps to lower blood sugar levels by sensitizing cells to insulin and helps them take in more glucose for fuel rather than letting glucose float around in the blood where it can do damage.  Exercise also helps lower IGF-1 by increasing a binding protein that acts like a magnet to IGF-1 and makes it less available to cancer cells for growth.
5. Know your numbers.  Ask your doctor to check your fasting blood glucose, insulin and IGF-1 levels.  Most doctors would consider a normal glucose level to be between 70-100 mg/dL, but new evidence has suggests that glucose between 70-80 mg/dL is optimal.  Levels above 100 mg/dL might indicate prediabetes or even full-blown diabetes.  Insulin can help your doctor check for insulin resistance.  Insulin should be between 5-20 microunits/mL.  Anything above this could indicate insulin resistance.  Optimal IGF-1 levels are based on your age and sex.  Laboratory results will show your ideal range.  Your level should be in the bottom half of that range.

Jacki Glew originally posted this blog as a guest blogger on crazysexylife.com.

Jacki Glew, MS, RD, LDN, is the clinical nutrition manager at the Block Center for Integrative Cancer Treatment. She and four other dietitians work daily with the Block Center’s integrative staff to create individualized and scientifically based nutrition and supplement plans for people battling cancer.

Comments

[Dr. Reuven Rosenberg]

Depending on what you read Americans consume an average of 22 teaspoons of sugar per day, 2-3 pounds of sugar each week, or 135 lbs. of sugar per person per year! That is way too much.

Excess insulin is also provoked by excess cortisol due to being too stressed and not sleeping enough. Insulin is also a fat storage hormone, which in effect also will cause someone to "grow".

Sugar is acidifying, lowering the body's pH, and creating a wonderful environment for yeast, fungus, bacteria, viruses, parasites, and cancer.

If people would just stop drinking soda it would save billions in medical costs and prevent untold suffering.

Jackie's advise is excellent. Why not start implementing her suggestions before you get cancer?

[Kristine Noonan]

I wish you could be interviewed on TV, on shows like Oprah and Dr. Oz, to share this information with the American Public. Thank you for posting this much needed information.
Ironically, even renowned cancer treatment centers often have cafes and coffee bars that sell high glycemic food in abundance. Soemhow, there is a disconeect between what the research shows and what the Health care systems are expressly and implicitly educating patients to eat to prevent cancer growth and cancer spread.

[Niraja Golightly]

I'm doing all the right things that were listed, but my fasting glucose is 99. I guess it's more exercise for me! Thanks for listing the optimal ranges.

[June Slaught]

I don't eat a lot of sugar but when you say "No more X,Y,Z" that is a bit extreme. I want to enjoy life. Never have another ice cream cone? I don't think so.

[Jacki Glew, MS, RD, LDN]

Thanks for the great comments, everyone! It is wonderful to hear that people are realizing the dangers of eating too much sugar.

Sometimes I get a bit of resistance from some people when I begin to educate them about sugar. To them, saying no more refined sugar seems a bit extreme. However, to leave cancer unchecked and to continue to eat an unhealthy diet is asking for trouble. The food you put in your mouth can be as important as the medicine you take to help fight cancer. Our goal is to teach you to eat foods that help to fight cancer in one way or another. Simply put, foods like sugar, candy, soda, ice cream, white bread, and white rice do not contribute anything to your body to help fight cancer.

Does that mean you can never have these foods again? Well, if I said no then I would not be doing my job as a Life Over Cancer dietitian - LOL! But utimately, what you eat is entirely up to you. Remember, choosing life over cancer means enjoying life but not at the expense of promoting your cancer!

[Tom Gregoire]

You are so right about Tumors and Sugar. I have Cancer and one of my tumors is huge. It grows like crazy if I slip and have something with sugar in it.

[Deb]

Thank you for this clear explanation and for your continued encouragement for people to choose to eat nutritious foods and take good care of their bodies.

I've cut out most man-made "foods" and feel great, but when I do have the processed stuff, boy do I get bloated and uncomfortable!

I agree with Kristen's post, and there are too many examples of what she described. Earlier today, I looked at a website sponsored by a heavily-advertised cancer treatment group, and they featured a recipe for Caramel Nut Popcorn, using 2 bags of microwave popcorn, a half-cup of brown sugar, salt, butter, and brown rice syrup (more sweetener). Some almonds and unsweetened coconut appeared to be the ingredients that led their chefs to promote this as a healthful snack. UGH! It does not sound like a wise choice for people trying to make their way from cancerous to healthy.

Again, thank you Jacki and Dr. Block for your stellar research and efforts!

[Connie Bennett]

Yeah, I'm so glad to see this post. More people need to know about this!

I actually interviewed Dr. Block about the sugar-cancer connection for my book, Sugar Shock.

Listen, I'm trying to reach Dr. Block again to invite him to be on my Gab with the Gurus Radio Show to discuss this. Can you please help me connect with him. I couldn't get through on the office phone number. Thanks.

Connie Bennett
Author, Sugar Shock (http://www.sugarshockblog.com)

[joe evans]

people say they can't live without sugar, sweetners, etc. how about birch tree based xylitol.. its a win win sweetener,
takes plaque off your teeth, and doesn't cause doesn't cause diabetes!

[Holly Taylor, MS, RD, CSO]

Very nice article. Jacki, are you part of the Oncology DPG? They have a nice listserv that I think you might like to respond on sometimes.

[Bridget Kuhne]

I woke from a deep sleep early one morning hearing the words "cancer feeds on sugar". I researched on-line and found that it does. At that time I was not diagnosed with cancer, although I did have a sore on my forehead that would not go away. A couple weeks later I had it checked out and it was basil cell, skin cancer. I have quit eating sugar now for one month, all sugar. I read every label, if it contains sugar or substitute sugar I don't eat it. Are there specific cancers that feed on sugar, or just all cancers? I believe in God, and believe those words were spoken to me from Him.

[spokane health clubs]

Thanks for sharing some good info related to healthy foods . for weight loss try to drink more and more water and never eat ur food before going in bed because that will caused u to gain weight ...

[Deane Clark]

Is this an ongoing current blog? The last entry I see is in 2011. Do you recommend against having a PET scan because of the cancer cell's avidity for glucose?

[lisa haneberg]

Jacki: What about for cancers that do not image with glucose dye? I have MTC, Medullary Thyroid Cancer, c-cell cancer, and I know that it is a challenge for docs to see tumors as they spread because they say this type of tumor does not light up with sugar. Are their some cancers that are less affected, or not fed by, sugar? Thanks, Lisa