The Gist of Science Reporter: November + December 2015

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 against infections.

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 cancer.

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 regeneration.

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 chemotherapy.

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 per day.

  • 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 macular degeneration.

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.

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