The Gist of Science Reporter: November + December 2015
Defeating Cancer with Healthy Nutrition
Cancer affects people irrespective of their age, gender or
social status. early 35% of all cancers are related to diet. Other factors such
as genetic mutations, environmental pollutants, UV rays and emotional stress are
also responsible for causing cancer. It is important to take steps to prevent
cancer but once cancer strikes, it is a tough road ahead. Once cancer is
diagnosed, coping with the disease and the harsh cancer treatments becomes a
difficult task. Cancer and its treatment’ leave a patient drained both
emotionally as well as physically.
When cancer strikes, it disturbs the normal physiological and
metabolic processes of the body. The complex interaction between the host tissue
and tumour result in metabolic aberrations which increase basal energy
expenditure as well as reduce utilization of nutrients by the host. Cancer cells
develop at the expense of the host tissue, adversely affecting the normal
metabolism of the body and resulting in loss of lean body mass due to increased
tissue protein breakdown.
The fast-growing cancer cells increase the body’s energy
needs so drastically that proteins are broken down to meet the energy
requirements leading to negative nitrogen balance in the body. This results in
muscle wasting, loss of body weight and muscular weakness in cancer patients.
Cancer patients are usually malnourished at the time of
detection which is quite evident from certain characteristic features like
weight loss, loss of appetite, muscular weakness and lethargy. It has been
reported that nearly 80% of the patients with upper gastrointestinal tract
cancer and 60% patients with lung cancer have already experienced significant
weight loss at the time of diagnosis. Significant weight loss is defined as at
least a 10% loss of body weight in six month’s time.
Protein energy malnutrition is a frequent secondary diagnosis
in cancer. The tumour and its effect on the body along with altered
physiological and metabolic changes cause significant reduction in the intake of
food. Since cancer cells multiply at an abnormally rapid rate as compared to
normal cell division, the metabolism of the body increases significantly thereby
increasing the demand for energy and protein.
There is no standard diet for all cancer patients, the
nutritional goals are highly individualized and variable. For the same patient,
the nutritional goals maybe different at different points of time during the
course of the disease. Nutrients are delivered to the patient by oral, enteral
or parenteral route. As long as the patient can eat orally, the other methods
are best avoided. Enteral feeding is also known as tube feeding in which food is
given in liquid form through a catheter or a tube. This method is used when the
patient cannot eat orally due to surgery of upper gastrointestinal tract or
difficulty in chewing or swallowing as in the case of cancer of the oral cavity
or oesophagus. Sometimes the tube feeding may be initiated along with oral
feeding to prevent malnutrition.
A well-nourished patient is better able to cope with the side
effects of cancer therapy and may even tolerate higher doses of certain
treatments. Getting enough calories and proteins in the diet helps one to be
better equipped to withstand the side effects of cancer treatments as the
patient has the nutrient reserves which will help in keeping up the strength,
prevent body tissue from breaking down, rebuild tissues and maintain defenses
Since the eating habits and eating pattern change during the
course of the disease and its treatment, adjustments need to be made to provide
food to the patient at odd times of the day. During cancer therapy, the patient
may develop a dislike for most of his/her favourite foods which makes it
challenging to feed the patient.
Here are some of the major nutritional requirements in
1. Energy: Sufficient energy in the form of carbohydrates and
fats needs to be given to prevent weight loss and to spare proteins for tissue
synthesis. The energy requirement is high due to increased metabolic demands as
a result of fast growing cancer cells. A well-nourished patient may require
around 2000 kcal/day. A malnourished patient may need 3000-4000 kcal/day
depending on the degree of malnutrition.
2. Protein: Protein requirement is increased due to breakdown of tissues and for
wound healing especially when healthy tissues are damaged due to cancer teatment.
A high protein diet supplying 1.5-2.0 gm/kg bodyweight is prescribed for cancer
patients. Proteins must be of good quality to support tissue repair and
Cancer therapies are known to cause unpleasant side effects
in patients. These treatments target the fast-growing cancer cells but also
damage healthy cells that normally grow and divide rapidly such as those in the
mouth, digestive tract and hair. The damage to healthy cells can produce side
effects such as hair loss which is quite common in patients receiving
Other side effects that cause problems with the food intake
such as those in the mouth and GI tract can actually cause nutritional problems
affecting the nutritional status of the patients. Patients who are already
malnourished at the time of receiving these cancer treatments run a high risk of
becoming severely emaciated with a lower life expectancy and increased chances
of getting infections.
Side effects of cancer therapy such as radiations,
chemotherapy, surgery, hormone therapy, etc. result in various nutritional
problems which need to be corrected in order to prevent the patient from
becoming malnourished. Surgery in the gastrointestinal tract (GI) can cause
difficulties in chewing, swallowing, and also lead to malabsorption of nutrients
due to impaired digestion and absorption. Radiations in the head and neck region
can cause chewing and swallowing difficulty due to dryness of mouth, mouth sores
or pain. Radiations in the lower GI tract as in the case of colon cancer can
cause diarrhea or constipation as side effects.
Coping with cancer and its treatment can be highly stressful
and enervating but with good nutritional support right from the beginning, one
is armed with the necessary strength and stamina required for overcoming the
challenges of cancer. There are many survivors who have successfully won the
battle against cancer, which shows that “Cancer is curable” when detected on
time and treated with a good nutritional support.
Health Nutrients for Healthy Eyes
The wonders of nature reveal themselves through the eyes of
the beholder. This essential part of the body, therefore, demands protection and
care throughout your life. Even a slight blemish to the eye should not be
neglected because over a period of time minor irritants in the eyes can turn
into chronic troubles.
For instance, one of the cause of damage to the eye is
light-induced lipid peroxidation. Simply put, when light enters the lens, it
reacts with lipids present in it generating free radicals that cause damage to
the eyes. There are several other eye disorders that arise due to the onslaught
of free radicals. And there are several others that are brought on due to the
deficiency of essential nutrients in the diet.
Vitamin A: This acts as antioxidant that can scavenge the
free-radicals formed within the eyes. It plays a major role in the cells of
the eye that are sensitive to dim light and is also necessary for the health
of mucous membranes that line the eyelid. Consumption of vitamin A in the
diet should be 15 mg daily.
Vitamin B2: This vitamin acts as coenzyme in various
redox reactions including the prevention of free radicals, thus acting as an
antioxidant. The consumption of vitamin B2 in the diet should be 0.3-1.0 mg
Vitamin E: It is an antioxidant whose deficiency leads to
inflamed eyelids and sensitivity to light. The consumption of this vitamin
in the diet should be 400-800 IU everyday.
Vitamin C: This also acts as antioxidant that can
scavenge the free-radicals in the eye. The daily intake of vitamin C in the
diet should be 2000-3000 mg.
b-carotene: This pigment acts as an antioxidant and its
consumption in the diet should be 25,000 IU daily.
Zinc and selenium: Zinc along with the enzyme retinal
dehydrogenase catalyzes the conversion of inactive retinol into its active
form, thus forming active antioxidants. Selenium is essential for the
formation of selenoproteins like glutathione peroxidase within the lens of
the eye. Glutathione peroxidase acts as an antioxidant that also prevents
the formation of free radicals that damage the eye lens. The daily intake of
zinc and selenium should be 25 mg respectively.
Eggs: Eggs are a good source of vitamins mainly vitamin A
(retinol) and vitamin B2 (riboflavin). They also contain a high amount of
the essential pigments lutein and zeaxanthin. Vitamin A and pigments act as
antioxidants and prevent the formation of free radicals that can damage the
eye. Lutein and zeaxanthin are yellow pigments that provide the yellow
colour to egg yolk. They absorb the damaging blue wavelengths of light from
sun that enters the eye.
Carrots: Carrot juice is among the richest sources of
vitamin A (thiamine). It also consists of the pigment b-carotene and
retinol. This increases the level of antioxidants which then prevent the
formation of free radicals.
Spinach: Spinach consists of vitamins like vitamin A
retinol and vitamin C (ascorbic acid). It has a high amount of
b-carotene pigment and also a rich source of antioxidants (vitamin A,
vitamin C, b-carotene and lutein).
Fortified cereals: Cereals like milk powder fortified
with vitamins and minerals contain vitamins including vitamin A retinol,
vitamin E (tocopherol), vitamin B2 (riboflavin), minerals like zinc and
lutein pigment. Vitamin A and E are antioxidants which prevent the formation
of free radicals. Vitamin B2 acts as coenzyme in various redox reactions
including the prevention of free radicals, thus acting as antioxidant.
Orange: Orange in the form of raw fruit is rich in the
pigment zeaxanthin, vitamin C (ascorbic acid) and vitamin A. But the juice
of orange has high amounts of vitamin C as compared to raw orange.
Milk and dairy products: Dairy products like milk,
cheese, yogurt, etc. are rich sources of vitamin A, vitamin B2, minerals
like zinc and amino acid like taurine. Among buffalo, cow and goat milk,
goat milk is the highest source of taurine. Taurine is the free amino acid
found in the retina of the eyes, thus maintaining the retina and eye health.
Seafoods: Seafoods including oysters Late rich sources of
minerals like selenium and zinc. Zinc along with the enzyme retinal
dehydrogenase catalyzes the conversion of inactive retinol into its active
form, thus forming active antioxidant0 Selenium and zinc, as antioxidants,
help in keeping away cataract and night blindness.
Guava: Guava is a rich source of vitamin C (ascorbic
acid). Consumption of guava as raw fruit is better than consuming in the
form of juice. Since vitamin C acts as an antioxidant, guava balances the
level of antioxidants within the eye, thus increasing immunity against
The right blend of nutrients in the diet can not only keep your eyes healthy
but also delay the onslaught of eye disorders that strike with advancing age.
Eyes are an asset - take care of them.