Monday 3 May, 2021

The Science behind Nutrition and Cancer & Expert Tips

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When experiencing life with cancer, a lot of people wonder what it is they can do to power their bodies with the energy and nutrition they need.

We sat down with Dr. David Heber, MD, PhD and Founding Director of UCLA Centre for Human Nutrition, to talk about nutrition and cancer – its current role in cancer care, why it’s important, and advice he has to eat in a way that fuels your body before, during and after cancer. Dr. David Heber sheds on the topic with his insight, after more than 30 years of experience in the field. 

You can listen to the whole conversation in this podcast episode.

What we’ll cover in this blog: 
Why do people seldom get advice on nutrition from doctors?
Is nutrition becoming a more integrated element in cancer care? 
General tips to eat nutritionally
Getting started with improving nutritional intake
Single best advice for people currently undergoing cancer treatment 

Why do people seldom get advice on nutrition from doctors?

People who go through cancer are struggling to receive the qualified information they need from their healthcare team for a few different reasons, both cultural and scientific.

According to Dr. Heber, nutrition was not taught in medical schools. The US and UK tradition comes from military medicine where you simply get the soldier back onto the battlefield. So, nutrition and lifestyle, among other things, are not thought to be as important. That’s why they were delegated to dieticians and nurses, rather than doctors. 

“Most oncologists are focused on the treatment, using chemotherapy, radiation, and surgery, and the patients are more concerned about nutrition.”

Dr. David Heber, MD. PhD.

When it comes to research on nutrition, it’s split up into different areas. You have population research that clearly shows the association of cancer nutrition. Then you have animal studies which clearly define the mechanisms. But the hard part are so-called clinical trials, which are used to define drugs as useful, and that’s very hard to apply to nutrition. So the amount of clinical evidence is very limited and that clinical evidence is what motivates oncologists to include nutrition in evidence-based medicine. 

Is nutrition becoming a more integrated element in cancer care? 

Dr. Heber is optimistic about the future. Why? The discovery of the microbiome  – the 14 trillion bacteria in your body. We now know that this is important for immunotherapy. Recent studies on metastatic melanoma have found that people who got broad spectrum antibiotics would kill off the microbiome and in turn, wouldn’t respond to the immunotherapy. This pointed out the connection between the microbiome and the intestinal immune system. 

Of course, the microbiome is influenced by diet. We’re on the threshold of new studies to look at how the microbiome and immune system affected by nutrition will enhance all forms of cancer treatment. 

There’s very good evidence that chemotherapy and radiation and immunotherapy work through the microbiome. Both in terms of effectiveness and also side effects. So having a healthy microbiome can minimize the side effects. 

What are some general tips to eat nutritionally? 

First off, it’s not only what you eat, but it’s also exercise. The muscles are very dependent on exercise and the proper amount of protein. What Dr. Heber emphasizes in his research is assessing the body composition and then matching the protein intake to the muscle mass, combined with exercise. The general guideline is two grams per kilogram of lean body mass every day. This needs to be divided into various meals and eating at least 20 grams of protein within 30 minutes to one hour after completing daily exercise. 

In addition, the period of relapse prevention is really a period of rehabilitation, where you build up your body back to the metabolic state it had before you were treated for cancer. In order to do this, and to eat nutritionally in general, Dr. Heber breaks down what to eat into 7 color groups: 

  • Red: tomatoes and watermelons, which contain lycopene. 
  • Red-Purple: all berries and pomegranate, which have very powerful antioxidants. 
  • Orange: carrots, squash, and pumpkins which have alpha and beta-carotene.
  • Orange-Yellow: Lemons, oranges, and grapefruits, which have Vitamin C and citrus flavonoids.
  • Yellow-Green: Spinach, dark green lettuce and avocado are rich in lutein.
  • Green: broccoli, brussel sprouts, bok choy, horseradish, all of which are called cruciferous vegetables and have glucosinolates, which evidence points to are cancer preventative. 
  • White-green: onions, chives, garlic, and asparagus which have allyl sulfides. 

For all of these, there’s very good evidence in the laboratory and epidemiologically, and it’s been collected by the American Institute of Cancer Research around the world, but there’s very little clinical trial evidence. That’s the part that’s missing.

Where’s a good place to start for someone who’s just getting started with improving their nutrition?

First of all, it’s important to take into consideration the emotional burden of going through cancer. So, Dr. Heber says to listen to him about 87% of the time. Take that 13% and have some pleasurable eating that you enjoy. Don’t be over-restrictive. There are actual diseases, like orthorexia, where people are so concerned with everything they eat that it causes secondary emotional problems. So, Dr. Heber’s tip in one sentence is:

“Enjoy life, make your changes slowly, make good foods taste good, and get off of the foods that are being thrown at you.”

What is your single best advice that you can give to everyone undergoing treatment today? 

First of all, try to get your adequate calories in between treatments. With chemotherapy, we often tell people, “don’t eat your favorite foods on the day you get chemotherapy because you could get an acquired taste aversion when you get nausea and vomiting from the chemotherapy.” That’s less of a problem today than it used to be because very good drugs for nausea now exist. However, you’re going to have an inflammation so you need to rest after your chemotherapy and then re-nourish yourself over those next 24 hours. 

Read more about how to leverage nutrition to prepare for cancer treatment and download the War On Cancer app to join the conversation.

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