Volume XV, Number 4
Vegetarian Diets During Cancer Treatment
By Donna Paglia, M.S., R.D.
Editors' Note: The purpose of this article is to assist individuals who
are trying to follow a vegetarian or vegan diet while undergoing cancer
treatment. We are not recommending one form of cancer treatment over
another. We leave that up to patients and their medical adviser(s).
Donna Paglia is a clinical nutrition specialist at the Johns Hopkins Hospital
Oncology Center in Baltimore.
By now most of us have heard of the association between a vegetarian diet
and cancer prevention. A multitude of antioxidants and phytochemicals
in fruits, vegetables, and legumes are being studied intensely as
a result of some promising studies showing these foods' anti-cancer
properties. This research is leading us to believe that a vegetarian diet
may be one of the best preventive measures against certain cancers.
However, there is no clear consensus on the type of diet that is most
beneficial after a diagnosis of cancer. There are those who advocate
macrobiotic diets and various "nutritional therapies" as forms of cancer
treatment, but there is not enough scientific evidence to back up these
claims, and severe dietary restrictions can be detrimental to those
already at risk for malnutrition. So, is vegetarianism a wise choice
for someone with cancer?
A vegetarian diet can be both safe and beneficial for people undergoing
cancer treatment, provided they know how to make appropriate food choices.
In fact, vegetarian foods may even help people get through difficult times
during cancer treatment when their diets may be suffering.
However, the guidance of a registered dietitian is recommended for any
vegetarian undergoing cancer treatment, even if this diet is not new
to them. This article provides information for planning a vegetarian
diet that will satisfy the special nutritional needs of the cancer patient,
whether that person is yourself, a friend or family member, or a
Those who have been diagnosed with cancer and endured its treatment can
attest to the nutritional deficiencies and weight loss which can be
a difficult part of this experience. The foundation of this predicament
is the increased calorie and protein requirements that often result
from the presence of a tumor as well as from the need for repair of healthy
tissues damaged by chemotherapy and radiation therapy. To complicate
matters, these cancer treatments can challenge one's normal eating
habits because of a variety of potential side effects. Chemotherapy,
for example, works by attacking rapidly growing cells. This, unfortunately,
targets not only the tumor, but some healthy tissues as well, including
the lining of the gastrointestinal (GI) tract. While some of
these drugs produce only mild side effects, others can severely impact
quality of life. The effects of radiation therapy can be similar to those
of chemotherapy, but are usually related to the part of the body
that is being treated. Consequently, radiation to the head, neck, chest,
and abdomen can induce significant GI distress and a decreased tolerance
to many foods.
Following is a list of some of the more common problems experienced during
cancer treatment which can influence the ability to eat regularly: Decreased Appetite (Anorexia)
Feeling of Fullness (Early Satiety)
Nausea and Vomiting
Loss of Taste (Taste Blindness), or Taste Distortions (Dysgeusia)
Dry Mouth (Xerostomia)
Sore Mouth or Throat (Mucositis)
During cancer treatment, you may be counseled on a diet that is high in
both calories and protein in order to meet the body's increased demands,
as well as to maximize the value of a reduced volume of food. Small,
frequent, high calorie snacks may be helpful. The table below compares
a variety of foods which are relatively high in protein. If you are
unable to eat large amounts of foods, choose those which have more calories
Foods Supplying Approximately 7 grams of Protein Per Serving
|Meat, Poultry, or Fish
|| 55-100 |
|Nuts or Seeds
||1 cup, cooked
Vegetarian Foods for the Non-Vegetarian
Any of the treatment side effects mentioned can cause a change in food
preferences. Your favorite foods may now be less appealing. You may
develop an aversion to meat, poultry, fish, sweets, or coffee. Taste
distortions often occur so that strongly flavored (or strong smelling),
bitter, and sweet foods taste "off." From my experience counseling cancer
patients, I have found that red meat is commonly among the first
foods to be rejected, as well as coffee and highly acidic foods. This
aversion to meat may be due to a heightened sense of bitterness or a
metallic taste after the proteins are broken down in the mouth. Poultry
may or may not have this effect. Dairy products and eggs are generally
better tolerated. Smell sensitivity can also lead to a rejection of
meat, fish, and poultry, as the odors produced while cooking can trigger
nausea. In these situations, the adoption of vegetarian substitutes
for these foods can help make up for potential calorie and protein
deficiencies that could result from omission of these foods from your diet.
Lacto-Ovo Vegetarian Diet
For the lacto-ovo vegetarian, the choices of nourishing foods are many
. Dairy products supply protein and are a good source of calories, as
well as calcium, vitamin B12, riboflavin, and vitamin D. It is relatively
easy to meet high calorie and protein needs with the use of foods
such as milkshakes, cream soups, cheeses, and commercial nutritional
supplements. Although these foods may be high in fat, the diet is often
recommended only temporarily, and can also be adjusted according to
individual fat tolerance. Eggs, egg substitutes, and legumes can be
incorporated into the diet as additional protein and calorie sources.
Lactose intolerance is common in the general population, and even more
prevalent in people receiving cancer treatment, even if only temporarily.
This is especially true when diarrhea is a problem, as it can temporarily
"wash" away the lactase enzyme, thus creating an inability to
digest lactose. Fortunately, there are lactose-reduced and lactose-free
dairy products available now, as well as lactase tablets and drops.
These products may help some people digest milk products without
developing abdominal discomfort, excess gas, or diarrhea. However, I have
found that there are some people who just cannot tolerate any dairy
products, no matter what, and for those with chronic diarrhea, dairy
products may only worsen the condition. In these cases, vegan foods can be
extremely helpful in filling in dietary gaps.
Although it probably would be easiest for most non-vegetarians to make
the transition to a lacto-ovo vegetarian diet, a vegan diet can be
appropriate for the well-informed patient. If a vegan diet is new to you
, it should initially include as many familiar foods as possible, with
"new" foods to fill in the gaps. The trick is to use products that are
quick and simple to prepare, and can be easily exchanged for animal
products in familiar dishes. (If you were a vegan before diagnosis of
cancer, you should eat more of the most calorie- and protein-rich food
s in your diet.)
My personal opinion is that macrobiotic diets are generally too restrictive
for people with cancer, especially during treatment. The more
limitations placed on the diet of a person who is experiencing eating
difficulties or who may already be malnourished can set the stage for
additional problems. If you wish to follow a macrobiotic diet during can
cer treatment, you should consult a nutritionist who is familiar with
both the diet as well as the specific cancer-related nutritional problems
you may face.
The chart below lists several vegan substitutions for some common dairy
Vegan Food Substitutions
| cow's milk|
|fortified soy milk|
||vegtable oil margarine
| ice cream
soy/rice frozen deserts,
| sour cream
||soy "sour cream"
||soy "cream chees"
||tofu, egg replacer
Meeting the Special Needs of the Cancer Patient with a Vegan Diet
Coping with taste changes:
- For those with an increased sense of strong or bitter tastes, the mild
flavor of some soy products can be a welcome change.
- If taste blindness
is a problem, using marinades and seasonings for tofu
and tempeh can enhance the flavor.
- Dry beans and peas, nuts, peanut butter, and seeds are examples of foods
commonly eaten by non-vegetarians, but perhaps not very often or in
small quantities. These can be maximized to supply a greater percentage
of calorie and protein requirements.
- Shakes can be made with soy milk, tofu, and non-dairy frozen desserts
and can be flavored with fruit, chocolate syrup, or extracts to make a
tasty, calorie-rich treat.
- Many varieties of trail mixes are readily available and great for
Quick and Easy High Calorie Snacks:
Pizza, Bean Tacos/Burritos
Yogurt, Puddings and Custards
Cheese and Crackers or Frui
Creamed Vegetable Soups;
Dried Fruit, Nuts and Seeds;
Non-Dairy Frozen Desserts
Puddings and CustardsSoy Yogurt and Puddings
Peanut Butter on Crackers or Fruit
Bean and Chunky Vegetable Soups;
Dried Fruit, Nuts and Seeds;
What About Micronutrients?
Iron, calcium, and vitamin B12 are of particular concern with vegan diets.
Following is a list of vegan sources:
Calcium: Lacto-ovo vegetarians should be able to meet their calcium
requirements with approximately three servings of dairy products per day
, or combine them with some of the following non-dairy sources: tofu
processed with calcium sulfate, soybeans, figs, greens, blackstrap
molasses, fortified soy milk or orange juice, almonds, tahini.
Iron: legumes, blackstrap molasses.
Vitamin B12: Fortified cereals and soy milk, vitamin supplement.
A multivitamin/mineral supplement is often recommended for patients
undergoing cancer treatment, as you may not be able to eat a variety of
foods in sufficient amounts to meet your needs, whether following a
vegetarian diet or not.
Dwyer, J.T., 1991. Nutritional Consequences of Vegetarianism. Ann Rev
Nutr Vol. 11, pp. 61-91.
Dollinger, M., Rosenbaum, E.H., Cable, G. 1994.
Everyone's Guide to Cancer Therapy, 2nd ed. Kansas City: Andrews and McMeel.
Pennington, J.A.T. 1994. Food Values of Portions Commonly Used, 16th
ed. Philadelphia: J.B. Lippincott.
Zeman, F.J. 1991. Clinical Nutrition and Dietetics, 2nd ed. New York:
This article originally appeared in the July/August 1996 issue of the Vegetarian Journal.
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September 20, 1997
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