Diet influences the development of cancer - this is undisputed today. About one third of all cancer cases are related to eating habits. Of course, other factors such as cancer-causing substances from the environment (for example smoking), heredity or infections also play a role.
Food: cancer-promoting vs. cancer retardant
Scientists have now been able to unambiguously detect cancer-causing food substances (carcinogens) such as benzpyrene in grilled or black smoked foods and aflatoxins in moldy foods. In addition, however, cancer-promoting factors (promoters), for example, alcohol and anti-cancer factors (antipromotors) such as vitamin C were determined. But no one feeds alone on grilled or vitamin C.
The DGE has therefore explored the question of whether there is a way of life or diet that can protect against most cancers. Epidemiological studies on the relationship between diet and cancer were reviewed and scientifically evaluated.
Plenty of vegetables and fruits, whole grains and a low-fat diet emerged as the best cancer food in the study. The protective effect of many nutrients and agents involved:
- Vitamin E and C
- Trace elements (for example selenium)
The study of their anti-cancer effects is still in its infancy. It is very likely that it is not individual food factors but their interaction throughout the diet that has a protective effect.
Diet and colon cancer
Colorectal cancer is the second most common cancer among women in Germany, the third most common among men. An estimated 24, 000 men and 28, 000 women fall ill annually. Nutritional habits are responsible for the development of tumors on the colon, but also low physical activity. If you prefer a low-fat diet with lots of vegetables, fruits, wholegrain products and fish and live sporty, you can protect yourself from colon disease. Vegetables - both raw and cooked - have the best protection of all foods.
Conversely, vegetable scoffers and lovers of a diet with a lot of grilled or roasted pork, beef and lamb as well as a lot of alcohol, white flour and sugar, possibly also a lot of egg and fat, are more dangerous. Studies on which types of vegetables are particularly good at protecting colon cancer do not yet show any clear results. To date, the best protective effect for tomatoes and legumes has been identified. Green vegetables and salad, however, also seem to be effective.
Which ingredients of the food are protective or carcinogenic?
That is not yet finally resolved. Fiber from whole grains and carotenoids from vegetables are discussed as possible protective factors. The effect of selenium and calcium is still controversial. For example, a study showed that a higher intake of calcium with low-fat dairy products normalizes the cell growth rate of the cells of the colon wall. However, this protective effect is probably more due to the reduced fat content of the milk.
A high-fat diet possibly promotes as well as abundant animal fats (fat meat, sausages) the development of colon cancer. Omega-3 fatty acids from fish and vegetable oils (such as rapeseed oil) have been identified as potentially protective.
Nutritional ingredients and stomach cancer
Risk factors for diet-related gastric cancer are high-salt foods (salted meat or fish) and frequent consumption of grilled meat or fish. On the other hand, a high intake of vegetables and fruits, probably vitamin C-rich foods and possibly carotenoid-rich foods, wholemeal cereals and green tea, have a protective effect.
Nitrates, which were previously discussed as triggers, are unlikely to have any effect on the development of gastric cancer, according to recent studies. Whether nitrosamines actually increase the risk still needs further investigation.
Breast cancer: most common form of cancer in women
Approximately 46, 000 women fall ill in Germany every year. The development of breast cancer is influenced by many things: predisposition, hormones, onset of menstruation, age at first pregnancy and childbirth, and nutritional factors. Heavy obesity and increased alcohol consumption probably increase breast cancer risk; Fruit and vegetable rich diet probably protects.
Some scientific studies suggest that high consumption of red meat (pork, beef, lamb) may increase the risk and that vitamin C, carotenoids and fiber may lower the risk of cancer. This needs to be further investigated as well as the evidence for a protective effect of vitamin E and certain phytonutrients, the so-called phytoestrogens.
DGE tip: Fruits and vegetables for the health
Fruits and vegetables protect against almost all types of cancer, even those that are not considered nutritional, such as lung cancer. In all countries where a great deal of fruit and vegetables are eaten, these diseases are much less common than in Germany, Austria and Switzerland. That's why the advice of the DGE is: Eat fruits and vegetables five times a day!