Healthy is defined as the absence of disease and maintaining a healthy diet aids in the maintenance of health. Most diets recommend a balanced mix of fruits, vegetables, protein, and whole grain products while cutting back or avoiding fat, sugar, salt and alcohol. For the average person maintaining a well-balanced diet can be quite difficult so imagine for an ill patient. Diet and exercise are pillars for health maintenance, and both are incredibly challenging for a cancer patient. When a person has cancer, their body tends to be in a catabolic state. Simply put, cancer cells are bullies which want to grow and, in the process, take food away from healthy cells to satisfy their own needs. This causes normal cells to starve and even die. Cancer cells then divide and grow and take up the space once occupied by normal cells.
Once diagnosed with cancer most patients will dive into a rigorous “healthy” diet in the hopes of improving their overall outcome and prognosis. In the process they cut their caloric intake because they are now avoiding high calorie foods like fat and sugar. Remember that at this same time bully cancer cells are indulging on whatever nutrients are circulating around and grow while normal cells now starve and die. Eating less is not a good approach but instead a healthier diet with a similar caloric intake is a better option. Keep in mind that nothing I say is meant to replace what your own doctor has told you. Every cancer patient is unique and there may be specific details to your condition which are known to your physician. There is no one size fits all approach when it comes to nutrition.
I have been treating cancer patients for over 17 years and I will provide my opinion on what I consider is good nutrition for the cancer patient. In full transparency I am not a dietitian, but I am a physician who has seen both sides of the coin including those patients who chose to pursue a strict “healthy” diet and those who chose to “just eat as much as they can.”
The first thing to consider is do you already have cancer or are you simply trying to reduce your chances of getting cancer. These are two vastly different scenarios. If you are trying to avoid cancer, then there are simple steps you can take to help reduce your chances. As already mentioned, a diet low in fat and sugar while consuming whole grains, fruit, and vegetables is a good place to start. Exercise is also a step to take which will promote health and in some cases is thought to help prevent cancer.
Now I want to pause and tell you that the most important things you can do to help prevent cancer is to not smoke or drink excessive alcohol. These two things alone will significantly reduce your chances of developing cancer.
Once you have cancer then there are two things to consider. Do you have a chance of a cure, or do you have metastatic disease (has your cancer spread)? These are quite different and should be approached very differently. If you have a chance of a cure, then your approach should be the same as if you never had cancer and are trying to prevent it. Follow a healthy diet to the extent possible. Remember that you have a chance of a cure so we should be as aggressive as possible at improving your chances of obtaining a positive outcome and helping to reduce the possibility of a recurrence or the development of a new cancer.
Now if you have metastatic disease then I think your strategy should change. I have seen cases where patients are diagnosed with very advanced cancer, and they then start a strict diet and the first thing that starts to happen is extreme weight loss followed by weakness. I usually look at my patient and ask myself what is our goal? I take into consideration their age, overall condition and other medical conditions the patient may have like hypertension, diabetes or chronic kidney disease. We then formulate a plan to help improve the patient’s outcome but at the same time improve their quality of life. Most cancer patients have or are undergoing surgery, chemotherapy, and or radiation. These tend to reduce appetite and lead to depression which further adds to appetite loss. The result is extreme weight loss, weakness, and a decrease in the patient’s quality of life.
So, what do I recommend for the patient with advanced cancer? The first thing is to calculate what is the patient’s life expectancy. If the patient is expected to live less than one year, then I usually tell them to indulge on whatever they like while maintaining common sense. Common sense in this case means moderation. Let them enjoy what they like to eat and most importantly limit weight loss unless the patient has morbid obesity. Patients or family members constantly tell me that they want to prevent cancer cells from eating sugar and growing. Remember that cancer cells are bullies and will eat whatever is readily available. The healthy cells will then starve, and the patient will start to lose weight and decline. Some patients also worry about diabetes and high blood pressure. Another thing to keep in mind is that diabetes and high blood pressure are chronic conditions which will hurt you in the long term unless very elevated so worrying about your mild or moderately elevated blood sugar or blood pressure while having an advanced cancer could be counterintuitive.
For patients with a longer life expectancy, I will then tailor my recommendations depending on the patient’s goals, overall condition and weight management. The key to treating a cancer patient is balance. Develop a strategy that will help improve outcome while still maintaining an acceptable quality of life.
These are your bodies main source of energy. Carbohydrates are found in bread, milk, potatoes, corn, nuts, pasta, rice, and fiber but can also be found in soft drinks and juices from sugar. The healthiest sources of carbohydrates are found in fruits and vegetables. Whole grains and fiber are also a very good source of carbohydrates. Fiber aids in preventing constipation. On average one gram of carbohydrate has four calories. Your daily caloric intake should consist of approximately 55% carbohydrates with less than 10% of calories coming from added sugars.
In summary, eat more fruit, vegetables, fiber, and whole grains and limit sugary drinks.
Contrary to popular belief fats are an important source of nutrition. Fats provide our body with energy and helps in the transportation of some vitamins. There are different types of fat, and some are better than others and some are harmful. Monounsaturated fat found in olive or peanut oil as well as polyunsaturated fat found in sunflower or corn oil as well as seafood are healthier forms of fats. Saturated fats found for example in bacon, cakes, and salami as well as trans-fat found for example in popcorn and stick margarine are unhealthy forms of fats and should be avoided. On average one gram of fat has nine calories. If possible, less than 10% of calories should come from saturated fats.
In summary, eat more nuts, olive/canola oil, sunflower seeds, and fish and less salami, bacon, and cake.
Protein has several vital functions. Protein helps us grow and helps with healing. Hormones, enzymes and even our immune system depend on an adequate amount of protein for proper production and function. Cancer patients usually require a higher amount of protein for tissue healing especially after undergoing surgery and if undergoing chemotherapy or radiation. Protein is found in a variety of sources including eggs, poultry, fish, lean red meat, dairy products, nuts and beans. One gram of protein has four calories.
Red meat and especially processed meat (for example salami, bacon, sausages) has been linked to colon and rectal cancer and if eaten in high quantities has also been linked to prostate cancer and pancreas cancer.
Red meat should be limited to a dietary recommend maximum of 455g (cooked) per week. That is approximately one small steak daily that fits within the palm of your hand.
Protein supplementation may be beneficial in cancer patients especially during times of wound healing or if undergoing chemotherapy or radiation. Many forms of protein supplementation exist including shakes, smoothies and powders in a variety of flavors. Many patients with cancer do not meet the recommended protein intake of (1.2–1.5 g/kg/day) and adding a supplement to your daily diet may help you obtain the recommended protein goals.
In summary, eat more egg whites, fish, and beans and less red meat and processed meat.
Water and Fluids
Hydration is an especially important part of healing and health. Cells depend on fluids for normal function. The recommended fluid requirements are approximately eight 8-ounce glasses of fluid per day. Keep in mind that if you have diarrhea or are vomiting you should try to replace what you have lost. Little urination or a dry mouth may also be an indication that you require a higher amount of fluids. Certain chemotherapy agents are also eliminated through your kidneys and dehydration may increase their toxicity.
In summary, try to drink more fluids.
Vitamins and Minerals
Vitamins play a key role in cell function, healing and even in our immune system. In developed countries most people do not have vitamin deficiencies and if you are consuming a well-balanced diet then you likely do not have a vitamin deficiency. Cancer patients on the other hand may have a lower caloric intake from a lack of appetite and from treatment side effects including nausea and vomiting and may benefit from a multi-vitamin. Talk to your doctor or dietitian before taking vitamins and supplements. Some vitamins may be harmful if taken in high quantities. If you do decide to take a vitamin then consider one with no more than the 100% Daily Value (DV) recommendation.
In summary, vitamins may be beneficial but may also cause harm if taken in high doses.
Selenium, zinc, lycopene, and beta-carotene as well as vitamins A, C, and E are known antioxidants. These bind to free radicals generated from normal cell metabolism and help prevent them from attacking normal cells. The problem is that some studies suggest higher doses of some antioxidants may not be beneficial and may cause harm. Using antioxidants while undergoing radiation may also reduce the effectiveness of this treatment. Always keep in mind that more is not always better.
In summary, antioxidants may be beneficial but may also cause harm so always ask your physician.
A common question I am asked is about herbal supplements. There are so many different types on the market it is impossible to keep track of them all. Keep in mind that these supplements may provide a benefit, but they may also have a risk. Often times, we do not know if an herbal supplement may have a drug-drug interaction with a chemotherapy agent or even reduce the efficacy of a drug. Always ask your physician before you take any medication especially if you are undergoing chemotherapy or radiation.
In summary, ask your doctor before you take it.
Cancer is a challenging diagnosis requiring multiple approaches to obtain the best possible outcome. Surgery, chemotherapy, and radiation are especially important treatments in the fight against cancer but equally as important are rest, exercise, and nutrition. Establish goals with your family, physician and more importantly yourself. Design a feasible diet which will help add to your cancer treatment success and not significantly reduce your quality of life. Eating more vegetables, fruit, whole-grains, fiber, and protein are wise while avoiding excess sweets and processed meat. In some cases, protein supplementation may be helpful especially if your caloric intake is diminished from a lack of appetite. Vitamins, minerals, and antioxidants may be beneficial but avoid higher doses and ask your physician before taking. Keep hydrated and listen to your body because believe it or not, it does communicate with you.
The most important thing I have witnessed in 17 years of working with cancer patients is that faith and a positive attitude are above all the most important.