The Relationship Between Nutrition and Cancer in 7 Questions

Can foods labeled organic reduce cancer risk?

Organic is a term used to describe produce grown without synthetic chemicals. Feed for organically produced animal foods cannot contain hormones and/or antibiotics. Organic plant foods should be produced without insecticides or chemical fertilizers.

Many people believe that eating organic food can have numerous health benefits. The primary benefit of consuming organic food is environmental: it supports sustainable agriculture. There is very little evidence to say that organic food is more nutritious than food grown using conventional methods.

A recent study found that eating organic food reduced non-Hodgkin lymphoma. Very little research has been conducted on cancer risk.

Do pesticides in foods cause cancer?

Pesticides are chemicals used in agriculture. They are used to prevent or control harmful organisms. Occupational exposure to pesticides has a strong association with cancer; in other words, agricultural workers are the people primarily at risk from pesticide use. There are 2 types of pesticides: insecticides and herbicides. Herbicides are chemicals used against weeds. They can be toxic when used incorrectly in industrial, agricultural or occupational settings. The International Agency for Research on Cancer classifies 3 common herbicides as carcinogens. These are glyphosate, malathion and diazinon. All three are associated with non-Hodgkin lymphoma. Malathion and diazinon are associated with the risk of prostate and lung cancer, respectively.

Washing conventionally grown produce can remove some pesticide residues. It is important to remember that not everyone has equal access to vegetables and fruit. For people with limited resources, maintaining fruit and vegetable consumption may take priority over choosing organic produce. Vegetables and fruit have general health-promoting and cancer-protective effects regardless of whether they are grown organically or conventionally.

What is acrylamide, and does it increase cancer risk?

Acrylamide is a chemical used in industrial processing. It is found in food and tobacco smoke. Acrylamide in foods forms through the Maillard reaction (the amino acid asparagine reacts at high temperatures with sugar). After dietary intake, acrylamide is metabolized in the digestive system. Glycidamide, the main source of metabolites, forms during this process.

Acrylamide intake has caused gene mutations and tumor formation in laboratory animals. Many studies in humans have not found strong evidence of an association between dietary acrylamide intake and cancer.

The International Agency for Research on Cancer classifies acrylamide as a “probable carcinogen”; this means that there is sufficient evidence that it causes cancer in animals, but data for humans are limited (Group 2A carcinogen).

The main dietary sources of acrylamide are chips/french fries, cookies, canned black olives, coffee, biscuits, crackers and other processed potatoes. Among the foods that expose adults to the most acrylamide are chips/french fries at 49%, coffee at 34% and bread at 23%.

Experts have set the tolerable dose at 0.17 mg/kg/day. It should be remembered that tobacco smoke is a more important source of acrylamide than diet.

Can detox / smoothies provide protection against cancer?

Fruit and vegetable juices can be a valuable component of a healthy dietary pattern. However, juices contain less fiber than the whole fruits and vegetables from which they are made. They can also lead to a large intake of sugar at once.

This diet, known as a fruit detox, is promoted as a way to eliminate toxins. This claim is not supported by scientific evidence. There is no scientific evidence that consuming only juice for 1 day reduces cancer risk.

Toxins we ingest through food, whether liquid or solid, are continuously removed by the liver and kidneys. A diet containing only fruit juice may be deficient in some important nutrients. In some cases, it can lead to kidney damage and other health problems.

The effect of antioxidants on cancer

Oxidative metabolism causes tissue damage in the body. Components produced by the body itself and obtained through food are used for protection. This damage is associated with increased cancer risk. Antioxidants are thought to have a protective role against this damage.

Vitamins A, C and E and many bioactive components act as antioxidants. Vegetables and fruit are good sources of antioxidants. Studies have associated a diet rich in vegetables and fruit with a lower cancer risk. This benefit is thought to be related to the rich nutritional value of vegetables and fruit and their fiber content.

Antioxidant supplements have been examined in several clinical trials, which found that antioxidant supplements did not reduce cancer risk. On the contrary, some studies resulted in an increase in cancer risk. The best advice for reducing cancer risk is to obtain antioxidants through food.

Are genetically modified foods safe?

Plants are genetically modified to change their characteristics and increase their resistance to heat, cold or harmful microorganisms. This is done through natural/artificial selection or gene insertion. It is generally done to protect against insects, make transportation easier, or improve flavor or nutritional composition. GM (genetically modified) products went on sale in the United States in the 1990s and are now widely used around the world. Commonly consumed foods such as pizza, chips, cookies, ice cream, salad dressings, corn syrup and baking powder are among these foods.

In theory, these foods contain substances that may cause allergies. There is not yet evidence that they increase or decrease cancer.

- Related topic: Why and how are foods and animals modified? (in detail)

Do vegetarian/vegan diets reduce cancer risk?

Vegetarian diets exclude red and processed meats. They are low in saturated fat and contain plenty of fiber and vitamins. It is therefore reasonable to suggest that vegetarian diets may be beneficial for reducing cancer risk.

Studies have shown that vegetarian diets are associated with lower cancer risk than eating meat. It was unclear whether they offered a particular benefit over eating less meat than in a typical Western diet. A large British study found that people who ate fish had the same cancer risk as those following a vegetarian diet.

The available evidence recommends a predominantly plant-based diet with limited amounts of red and processed meat. Vegan diets exclude all animal foods, including milk and eggs. Deficiencies in some vitamins and minerals can therefore occur. People following a vegan diet, especially children and promenopausal women, need B12, zinc and iron supplements. These diets also contain little calcium. They therefore carry a higher fracture risk. Care should be taken to obtain enough calcium.

- Related Topic: What are the best diets?

Summary and Conclusion

Diet and nutrition make an important contribution to energy balance and affect it. They are important determinants of cancer risk, independently of body weight. Comprehensive reviews support dietary patterns rich in plant foods and low in animal foods and refined carbohydrates. The Mediterranean diet fits this pattern and is also associated with less weight gain.

The information above was compiled from the "American Cancer Society 2020 Diet and Physical Activity Guideline".

Since the publication of this guideline, the prominent steps have been as follows:

• In 2015, the joint view of the World Health Organization and the International Agency for Research on Cancer classified processed meat as “carcinogenic” and red meat as “probably” carcinogenic. Following this guideline, there has been greater emphasis on consuming less processed and red meat.
• There has been greater emphasis on reducing alcohol consumption.
• The aim has been to reduce barriers to healthy eating and active living.