Diet and Cancer: Link between the Food We Eat and Cancer

How does our diet affect cancer?

Many factors influence cancer formation.  Over the last 25-30 years, scientific research has revealed that diet, physical activity, and body weight—especially being overweight or obese—are major risk factors for developing certain types of cancer. The body’s ability to resist cancer formation may be helped by following a healthy diet, staying physically active, and avoiding excess body fat.   Study after study suggests that a healthful diet— one rich in a variety of vegetables, fruits, whole grains, and legumes (beans), and low in red and (especially) processed meat—can fight cancer. Decades of good quality research has taught us that this general pattern of eating provides vitamins, minerals, and protective and naturally-occurring plant substances known as phytochemicals (phyto = plant) and can help defend the body against cancer and other chronic diseases such as diabetes, high blood pressure and several mental health problems including stress, anxiety and depression. The scientific community has identified many naturally occurring substances in plant foods with the power to defuse potential carcinogens. Some of these nutrients and natural phytochemicals seek out toxins produced in our body and combat them before they can cause cell damage that may lead to cancer.  Others seem to make it easier for the body to make repairs at the cellular level. Still others may help stop cancer cells from reproducing. Even after a cell begins to experience damage that can lead to cancer, what you eat and drink, and how you live, such as an active versus a sedentary life-style can still help short-circuit the cancer process.

The most common question I get asked is, “does sugar feed cancer?”

The belief that white sugar in the diet somehow “feeds” cancer is very common, but the truth is more complicated. All cells, including cancer cells, in the body use sugar (glucose) from the bloodstream for fuel. Glucose is the primary fuel for our bodies and our brains. Blood glucose comes from foods containing carbohydrates, including healthful fruits, vegetables, whole grains, and low-fat dairy products. When there is not enough carbohydrate in the diet, some glucose is even produced by the body from protein-containing foods through a special process.  The connection between sugar and cancer is indirect. Eating a lot of high-sugar foods may mean more calories in your diet than you need, which can lead to excess weight and body fat. It is excess body fat that has been convincingly linked to greater risk of several types of cancer. Highly refined foods and foods with added sugars, such as sugary drinks and sweets, are also low in fiber and low in nutrients. They add little to the diet except calories. These foods may also increase insulin resistance, and this has been linked to an increased risk of developing diabetes, heart disease, and overweight and obesity.

Do I have to eat foods that are only grown organically?

A cancer diagnosis can not only place a huge burden on your physical and emotional well being, but also have a significant economic burden. In this situation patients are torn as most if not all cannot afford to buy organic foods. My take on that is that although, eating food cultivated using pesticides may increase cancer risk slightly; the jury is unanimous that consuming a diet rich in fruits and vegetables, whether grown conventionally or organically, is an important part of a diet that lowers overall cancer risk. If you decide to purchase organic produce, information from the Environmental Working Group (EWG) may be helpful. The EWG has published The Shopper’s Guide to Pesticides in Produce™ that lists certain foods they call the “dirty dozen plus two” (non-organic fruits and vegetables with the highest amount of pesticides) and the “clean fifteen” (non-organic fruits and vegetables with the least amount of pesticides). The EWG’s Guide is available at http://www.ewg.org/foodnews/ summary.php/

Obesity- A major unrecognized contributor to cancer causation

Obesity plays a role as a contributor to several major illnesses, including cardiovascular disease, diabetes, and cancer—in terms of both risk and mortality. In 2008, medical costs associated with obesity were estimated at $147 billion. Obesity is a major under-recognized contributor to the nation’s cancer toll and is quickly overtaking tobacco as the leading preventable cause of cancer. Research conducted by the American Society of Clinical Oncology has shown that Obesity is associated with worsened prognosis after cancer diagnosis and also negatively affects the delivery of systemic therapy, contributes to morbidity of cancer treatment, and may raise the risk of second malignancies and comorbidities.

Body Mass Index (BMI)-A better indicator of measuring obesity

Studies suggest that location of fat cells in the body matters. Fat that accumulates in the abdominal area—is called visceral fat. That means it lies deep inside the abdomen and surrounds vital organs. People with too much visceral fat have been shown to be at greater risk for developing obesity-related diseases and cancer. Another type of fat tissue, subcutaneous fat, is located directly beneath the skin. Subcutaneous fat is not as harmful as visceral fat. Studies show that visceral fat tissue (like belly fat) pumps out more inflammatory cytokines and hormones like insulin, leptin, and estrogen. Elevated levels of all these substances are associated with higher cancer risk. There are two easy methods for assessing body fat, Body Mass Index (BMI) and Waist Circumference. While these methods are not perfect, they can help people assess whether their weight and waist size fall within the healthy range.

Recommendations for prevention of obesity and cancer

• Maintain a healthy BMI between 18.5 to 24.9
• Avoid increase in waist circumference
• Consume foods with a higher glycemic index (GI) sparingly
• Eat at least five portions/servings of a variety of non-starchy vegetables and fruits every day. Examples of a serving: 1 cup raw or cooked vegetables or 1 medium apple.
• Eat whole grains and/or legumes (beans and lentils) with every meal.
• Avoid fast food as well as processed food as much as you can

Food with a high glycemic index (GI) or energy-dense foods *

• Drinks high in sugar content—soft drinks, sweetened ice tea, juice flavored drinks
• Baked goods such as desserts, cookies, pastries, and cakes
• Candy
• Chips such as potato and corn
• Ice cream, milkshakes
• Processed meat—hotdogs, salami, pepperoni
• Fast food such as French fries, fried chicken, and burgers
• Packaged and processed foods high in added sugars and fats

*Foods containing more than 225–275 calories per 100 grams (3 ½ ounces)

Impact of nutrition at the cellular level:

Phytochemicals

The word “phytochemical” means a naturally occurring plant (phyto in Greek) chemical. Phytochemicals provide plants with their color, flavor as well as aroma. In addition they also protect plants from infection and predators. Phytochemicals have the ability and potential to stimulate the immune system and thereby slow the growth of cancer cells and prevent DNA damage that has been implicated in cancer causation. In the human diet, some phytochemicals work to protect the human body from chronic inflammation, DNA damage and thereby developing cancer and other chronic diseases.

Antioxidants

These are compounds that protect the cells of an organism from oxidative damage caused by environmental pollutants such as air, food, water, chemicals, radiation. Preventing this type of damage could help prevent cancer formation as well as formation of other chronic diseases. A steady supply of antioxidants through nutrition is needed to protect the body from a constant onslaught of oxidative damage that the body has to face daily due to exposure from free oxygen radicals caused by environment to exposure. Many phytochemicals also work as antioxidants. Therefore, the best way to provide phytochemicals as well as antioxidants is to maintain a balanced diet that includes all grains, plant-based foods, nuts, seeds, legumes, sprouts and a variety of colorful fruits and vegetables.

Most cancer based nutritionists recommend the following:

• Eat mostly plant-based foods
• Eat at least 5 servings a variety of non-starchy vegetables and fruits per day for example 1 cup raw or cooked vegetables or 1 medium apple
• Eat whole grains and or legumes (beans and lentils)