By Gina Shaw
Reviewed By Cynthia Haines, MD
When you're being treated for cancer, it's more important than ever to eat right and get adequate nutrition -- but it can also be more difficult than ever. Your body is working overtime to fight the cancer, while it's also doing extra duty to repair healthy cells that may have been damaged as a side effect of treatments like chemotherapy and radiation. At the same time, many cancer treatments -- especially chemotherapy -- come with side effects that drain your strength and sap your appetite. So how can you make sure you're getting all the essential nutrients, vitamins, and minerals you need?
You might assume the answer lies in power doses of vitamin supplements. After all, if you're having trouble keeping food down, wouldn't it be easier to get nutrients from a simple capsule? Not necessarily. "If you want to supplement the nutrition you get from your regular diet, we recommend taking just one multivitamin per day from a reputable manufacturer," says Gary Deng, MD, assistant attending and assistant member in the Integrative Medicine Service at Memorial Sloan-Kettering Cancer Center in New York.
"We suggest that patients avoid high-dose multivitamins, because there is some concern that some of these, especially those with high-dose antioxidants, may interfere with treatment. As long as there remains controversy about this, we think it's prudent not to take high-dose multivitamins."
Plus, it's almost impossible to get "too much" of any given vitamin through food alone, while loading up on some vitamins in pill form can cause problems, like dangerous buildup in the liver. If a certain amount of a nutrient is good for you, twice or three times as much is not necessarily better.
Certain kinds of herbal supplements, like St. John's wort, can also interact badly with some types of cancer treatment. "Some complex herbal extracts may contain substances that can change drug metabolism, interfering with the way in which your body metabolizes chemotherapy," warns Deng. Talk to your doctor before taking any type of herbal product or supplement during cancer treatment.
Get Vitamins In Food, Not Capsules
Instead, say experts, focus on what you need most now: calories. When you're being treated for cancer, taking in enough calories to maintain your strength and keep your body going trumps pretty much everything else. "For many people undergoing chemotherapy, we're happy to tell them to eat whatever they like to eat. If it appeals to you and you can keep it down, then eat it," says Deng. "If you ask someone to eat too strict a diet, often they end up not eating enough."
If you have trouble eating enough at mealtimes, many experts recommend adding medical nutrition supplements -- like Ensure, Boost, and Instant Breakfast -- to the menu. These drinks can often help make up for some of the nutrition missed when you can't work up an appetite for dinner or the energy to prepare it.
"Go ahead and try to eat a meal, and when you've done your best, you can supplement it with one of these drinks to give you the calories, protein, and other nutrients you can't get in at mealtimes," advises Sally Scroggs, MS, RD, LD, senior health education coordinator at Houston's M.D. Anderson Cancer Center. Just don't rely on the drinks so much that you don't eat regular meals. "They're called supplements for a reason," she adds.
Next to getting enough calories in the first place, the most important nutritional rule for people with cancer is to focus on getting a well-balanced, healthy diet from natural sources, including fruits and vegetables, with a heavy emphasis on protein.
"Because the body is under stress from different treatments -- whether you're undergoing surgery, chemotherapy, radiation, or a combination of these -- we really need to emphasize proteins for healing and repair and strengthening of the immune system," says Scroggs. Red meat, fish, and poultry are excellent sources of protein (and iron as well, which is also important), but if you've lost your appetite for these, try other protein options like cheese, beans, peanut butter, eggs, nuts, milkshakes, and yogurt.
Some good food-based sources of important vitamins and nutrients for people with cancer:
- Eggs and nuts are great sources of B-complex vitamins, vitamin E, and protein. Egg yolks are a good source of vitamin D. Peanut butter and crackers are an easy, no-prep snack that pack nutrients and may be easier to keep down.
- Milk, cheese, meat, fish, and poultry are also good sources of B-complex vitamins, as well as protein. If you're having trouble eating hot dishes (the aroma of cooking food can sometimes trigger chemotherapy-related nausea), snack on mild cheeses, ice cream, yogurt, and other cold snacks. For larger meals, try chilled dishes like chicken, egg, and tuna salad.
- Beans and other legumes offer plenty of B vitamins while helping meet your protein needs as well.
- Since chemo-related mouth sores may make it painful to drink citrus juices or eat citrus fruits, which are the most common sources of vitamin C, consider alternative fruits and juices. "Peach and pear nectars, as well as applesauce, are good alternative ways to get vitamin C," Scroggs says.
- Green, leafy vegetables, of course, are great sources of vitamins like A, E, and K, as well as minerals like iron. Be sure to wash all fruits and vegetables carefully; your immune system can be compromised by cancer treatment and susceptible to contaminants in food.
Don't Lose Out on Liquids
Cancer treatments like chemotherapy and radiation can leave you dehydrated. Some drugs can also cause kidney damage if they're not flushed out of your system, so during cancer treatment, it's particularly important to get enough fluids. "Adequate hydration can't be supplied by a healthy diet alone," says Deng. "Along with drinking more water, patients should try sports drinks, like Gatorade, and other nutritional drinks."
Some people find it hard to drink enough water (chemotherapy can even make water taste strange), so Deng suggests getting some of your fluid intake through soups. "For some people, the added flavor of something like chicken noodle soup may make it easier to get the liquid down," he says.
Chicken soup has another benefit: It boosts your electrolytes (the collective term for the minerals sodium, potassium, chloride, calcium, and magnesium), which can often be depleted by the side effects of treatment. "It's very important to make sure that you have adequate electrolyte intake," Deng says. Gatorade and other sports drinks also help maintain your electrolyte balance.
The bottom line, according to Deng: "Don't get fixated on any one particular substance. There's no magic food or magic supplement," he says. "Nothing beats a well-balanced, diverse diet."
Published Aug. 6, 2004.
Medically updated Sept. 23, 2005.
SOURCES: Gary Deng, MD, assistant attending and assistant member, Integrative Medicine Service, Memorial Sloan-Kettering Cancer Center, New York. Sally Scroggs, MS, RD, LD, senior health education coordinator, M.D. Anderson Cancer Center, Houston . American Cancer Society.
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