Does sugar ‘feed’ cancer? Should we limit red meat? That & more with RD Karen Collins

Karen Collins photo (150x146)

Does sugar feed cancer? Limit red meat? That & more..

Karen Collins, MS, RD, CDN and I had the chance to talk in Philadelphia at the Academy of Nutrition and Dietetics Food and Nutrition Conference. I wanted to take the opportunity because of her expertise in cancer. (To watch the video click here or scroll to bottom.)

Neily:Karen is the nutrition advisor for the American Institute for Cancer Research. And you have been there how long?
Karen:Over 25 years.
Neily:Over 25 years. Fantastic. Let’s talk about some of the key things people need to know about the causes of cancer and also about some of the myths that might be out there. For example, does sugar cause (feed) cancer?
Karen:It’s one of those things you hear a lot—sugar feeds cancer and in the really technical sense it does because cancer cells, just like every cell, uses sugar for fuel but that’s talking about blood sugar.
Neily:Like glucose.
Karen:Right. So, where people get mixed up is when they are thinking that every little bit of sugar that they might consume in their diet is not directly siphoned off to cancer cells. What we know is blood sugar and the stronger driver are high insulin levels. If we can maintain a normal blood sugar and keep the insulin levels good, that’s the key.
Neily:Great. So, the added sugar in the diet—not the healthiest food but it’s not going to feed the cancer. Good message. Ok—red meat.
Karen:Yes. Too much red meat does increase risk of colorectal cancer.
Neily:Just colorectal cancer?
Karen:Yes. That’s the one that has the link right now. There is potential for others but the link now seems to be colorectal cancer. And a lot of people think that as long as they are choosing lean red meat, that they are protected. That is a guideline in terms of decreasing the risk of heart disease but the link of red meat to colorectal cancer does not seem to have to do anything with the fat content. It’s the higher content of a form of iron called heme iron, which is a readily absorpable form and it’s good in the sense of meeting our iron needs but too much causes some concerns because it seems that these high levels of heme iron can cause cancer-causing compounds within the gut and damage colon cells.
Neily:And recommendation for red meat per week?
Karen:No more than 18 ounces a week. This is for those who want to eat it. Some people choose not to eat it and that’s fine. But for those people who want to, it’s not like that they have to totally give it up. We don’t have that data but the data shows to keep it at no more than 18 ounces per week.
Neily:So, we are taking that meat and grilling it. Let’s talk about the char when you char-grill.
Karen:The char. That’s a problem. The char, the black substance, is really concentrated…a concentrated dose of carcinogens is in that char. If you suddenly think of it that way, it doesn’t taste that good. You could still grill. But there are several steps you can take to make grilling safer.

  1. One is, aside from the char, in the real intense heat of your grilling, whether it is on your gas grill or char grill, it doesn’t make any difference because the risk is the same. It’s that high temperature. So, turn the gas grill down, let the charcoal grill cool down a little bit. And just cool it enough so it takes a couple of minutes but at that lower temperature, fewer of these carcinogenic compounds called heterocyclic amine forms.
  2. You want to have less smoking because it’s in the smoke, there is a concentration of another kind of carcinogen. If you have less fatty meat grilling, you don’t have so much dripping on the coals, then you don’t get so much smoke. So, kind of multiple benefit.
  3. And the third thing is if you marinate. Whatever it is—the meat or the chicken or something like that before you grill it, that actually has been found to decrease more than 90% of the heterocyclic amine that otherwise forms.
Neily:So marinating is a very good thing.
Karen:It is.
Neily:That’s good to know. Let’s talk about a different kind of red meat, in the processed meats, lunch meats, deli meats things like that.
Karen:Processed meats are even more strongly associated with colorectal cancer risk than red meat is. And so, the recommendation there is to really avoid it as much as you can. Minimize the consumption.
Karen:When we talk about processed meats, we are talking about meat that is smoked, salted, cured or has added preservatives like nitrates and nitrites. And it is not a red or white thing as far as we know. So the concern will be the same if it is turkey hot dogs or turkey bologna or something like that. And really, the recommendation is to minimize it as much as you can.
Neily:So, bacon and sausage—find alternatives. What about Canadian bacon?
Karen: Canadian bacon will be the same thing. It’s leaner but it’s still cured. And it is that curing process—curing and smoking, that gets us..
Neily:So, ham as well?
Karen: Ham is too. So you want to think more about fresh meats, using chicken and turkey more.
Neily:I have seen lunch meats or deli meats that are nitrates and nitrites free. Is that something to be looking for on a package?
Karen: Well, it could be better but see here is the problem. It’s the four pieces that makes something processed. So it might be nitrite-free bacon but it is still smoked, you have still got these potential concerns about these polycyclic amine carbons that are coming from smoked food. So, really, it’s minimizing that whole category and looking for fresher alternatives.
Neily:And organic. Not necessarily when it comes to that because organic food doesn’t have anything to do with if it’s smoked or anything. So someone is not necessarily safe if they are going organic.
Karen: It could be a health halo that it sounds really good but it really comes down to looking for that salting, curing, smoking. And I think also, beginning to think more about vegetables. Roasted vegetable sandwiches. It doesn’t always have to be the Dagwood sandwich with the pile of meat that high. You can look at what you have made for dinner and think about other options and ways you can make extra vegetables for dinner and what you could do with them for lunch. So, there are a lot more options than just what most of us think of just because we get stuck in a rut.
Neily:So, those are some things that people shouldn’t do. What should they do to prevent risk of cancer? A plant-based diet?
Karen: There are several things—the main pieces are a predominantly plant-based diet, which means focusing your meals around vegetables, fruits, whole grains and beans. Doesn’t mean there is no room for animal food if you want them. But these foods should be the largest part of your meal. And we need to learn to make them taste so good that we want to eat them a lot instead of having them be the thing that is sort of sitting there. So, focus on those…
Neily:I have a great video on roasting vegetables. (click here)
Karen: Excellent. The other thing to remember is, sometimes we get so focused on the foods that we are eating that we forget that it matters how much we are eating. So, even if it is healthy food, if you are eating more than you can burn up in activity, it’s leading to an unhealthy weight. That’s really not healthy eating. Because what we are finding now is that the research that is strongest in terms of nutrition’s impact on cancer is, is how it affects your body composition, the extra body fat, the extra body weight.

  • sugar does not cause cancer,
  • red meat should be limited,
  • processed meat especially should be avoided
  • don’t char your meats

Good stuff.

Karen: And love those veggies…
Neily:Love those veggies! Eat a plant-powered diet. Again Karen Collins, nutrition advisor for the American Institute for Cancer Research.


  1. Sally Hara

    Excellent interview with lots of useful information! Thank you Karin and Jennifer!
    ~Sally Hara, MS, RD, CSSD, CDE

    • Neily

      Thanks Sally! Karen is an amazing resource in regard to cancer and nutrition. Appreciate the comment!


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