Diet and Healthy Eating Recommendations for Cancer – 2020 Guide

The information below was compiled from the "American Cancer Society 2020 Diet and Physical Activity Guideline". The American Cancer Society publishes a Diet and Physical Activity Guideline for public health every year. This guideline reflects the latest scientific evidence on diet, activity and cancer risk. In this article, we will examine the diet-related section of the American Cancer Society's recommendations on diet and physical activity.

Recommendations for general health briefly include maintaining a healthy body weight through adequate, balanced nutrition and adopting an active lifestyle. Making healthy choices and putting the guideline into practice may be difficult for many people. Instead of making healthy choices, removing unhealthy ones from your life may be a good first step.

Healthy eating patterns exclude the following or recommend consuming them in small amounts

• Processed meats or very large amounts of red meat
• Sugar-sweetened drinks
• Ultra-processed foods and refined grain products

A healthy eating pattern includes

• Fiber-rich legumes
• Whole fruits and vegetables in a variety of colors
• Whole grains
• Nutrient-dense foods that help achieve a healthy body weight

Let us briefly examine the effects of some food groups and dietary supplements on cancer:

Vegetables, fruit and legumes

The effect of fruit and vegetable consumption on body weight may indirectly affect cancer risk. Many vegetables and fruits are low in energy and high in fiber and water, which may increase fullness and reduce overall energy intake. They therefore contribute to weight loss and control.

The World Health Organization recommends consuming around 5 servings of fruit and vegetables daily. Legumes are also a good source of plant protein for people who want to limit red meat consumption. Because they do not contain gluten, they are a good alternative for people with celiac disease or gluten sensitivity.

Whole grains

Whole grains have been reported to reduce the risk of colorectal cancer. Each 30 g of whole grains consumed is estimated to reduce colorectal cancer risk by 5%. They also speed up the passage of food through the intestine, reducing the time the intestine is exposed to carcinogens.

Dietary fiber

Legumes, whole grains, vegetables and fruit, nuts and seeds reduce colorectal cancer risk, are associated with lower weight and are effective in controlling obesity.

Red and processed meats

Evidence that red and processed meat increases cancer risk has existed for decades. Health organizations recommend limiting consumption of these foods. There is strong evidence that processed meat particularly increases colorectal cancer. Recent studies suggest that red / processed meat may also play a role in increasing breast cancer risk. However, a study in the United Kingdom reported that the amount of nitrite in processed meat is central to increasing cancer risk (see the related study). Some food manufacturers use sodium nitrite to cure meat, improve its color or extend its shelf life. However, not all processed meats contain nitrites. For example, British and Irish sausages do not contain nitrites, while sucuk, salami and sausages from the United States and continental Europe do. In England, the government recommends that people limit processed meat consumption to 70 grams a day. The American Cancer Society recommends eating fish, poultry and legumes instead of processed meat.

- Related topic: Does sugar cause cancer?

Sugars

White sugar, brown sugar, sweeteners, high-fructose corn syrup and sugar-sweetened drinks are energy-dense and can cause rapid weight gain. Diets with a glycemic load (the potential to raise blood sugar) have been reported to be associated with a higher risk of endometrial (uterine) cancer. It is recommended to keep the share of total daily energy coming from added sugar below 10%.

Calcium and vitamin D

Calcium and dairy products have been reported to be effective in reducing colorectal cancer risk, while evidence regarding breast cancer is limited and suggestive. Consuming dairy products (2 glasses of milk or more daily) increased prostate cancer risk by 11%. We see that milk consumption reduces the risk of some cancers and may increase the risk of others. The American Cancer Society makes no specific recommendation about milk consumption for cancer prevention. A study published in the British Medical Journal recommended consuming 0-2 servings of milk and dairy products daily.

- Related topic: MILK and HEALTH – A Topic of Interest and Surprising Findings!

Vitamin D is known for its role in maintaining bone health. It is synthesized in the skin through sunlight. There are also a few dietary sources, such as oily fish, some mushrooms, milk and grains. To date, the most consistent evidence for vitamin D's cancer-risk-reducing effect has concerned colorectal cancer. However, new studies have not found an association between vitamin D supplementation and all cancers. Although vitamin D's role in cancer prevention remains a subject of interest and debate, avoiding deficiency is recommended.

Dietary supplements

Dietary supplements are a heterogeneous group of products. They have very important health benefits for people whose food intake is inadequate or who have absorption problems. However, many products marketed commercially are not really “dietary supplements.” Most contain substances not found in foods. Laws also do not guarantee that products sold as nutritional supplements are free of undeclared substances that may be harmful to health. Although plant-based diets may reduce cancer risk, we cannot say the same for dietary supplements. Supplements containing high doses of carotene and vitamins A and E have even been found to increase the risk of some cancers. If supplements are used for general health, they should be multivitamin/mineral supplements that do not exceed the doses we need daily. The American Cancer Society does not recommend supplement use for cancer prevention.

- Related topic: Vitamin and mineral supplements – doctors and users should know these points

Alcohol consumption

Alcohol consumption is an established cause of at least 7 types of cancer. The American Institute for Cancer Research has classified alcoholic beverage consumption as carcinogenic. The institute confirmed that it causes liver cancer. It also found that it may cause colorectal and breast cancers. The American Cancer Society recommends not drinking alcohol. For people who choose to drink, it recommends limiting intake to 1 drink daily for women and 2 for men.

Alcohol consumption causes 5%-6% of cancer-related deaths.

Physical activity

A healthy diet should be supported by physical activity. To increase physical activity, it is important to limit sedentary behaviors such as lying down and screen-based activities such as watching television. Studies support a linear relationship between physical activity and cancer prevention. However, there are no clear conclusions about the required amount and intensity of activity. Moderate physical activity is recommended for 1 hour daily for children and an average of 5 hours weekly for adults.

- Related topic: Exercise and the 14 types of cancer whose risk it reduces

Conclusion and Recommendations

Researching the role of diet in cancer prevention is very complex. The food supply changes continually, and how long a food has been consumed is not always known. However, excess body fat has been shown to cause coronary heart disease, diabetes and almost all types of cancer.

The “Mediterranean” dietary pattern, which closely resembles a healthy eating pattern, may reduce risks. Plant-based diets are associated with lower levels of inflammation (infection) and less oxidative DNA damage. Compared with a Western-style diet, a plant-based diet is associated with a higher proportion of beneficial intestinal bacteria.