Cancer is one of the world’s biggest killers. But recent research suggests that simple lifestyle changes, like following a healthy diet, could avoid 30–50% of all cancers. Increasing evidence points to some dietary practices increasing or decreasing the risk of cancer.
Therefore, nutrition is supposed to play a significant role in treating and coping with cancer.
Eating too much of certain foods may increase cancer risk
It is much difficult to prove that certain foods cause cancer. However, it has been observed that a high intake of certain foods may increase the probability of developing cancer.
Sugar and refined carbs
Processed foods which are low in fiber and high in sugar and nutrients have been associated with a higher cancer risk. Therefore, a diet causing blood glucose levels to spike can increase the risk of several cancers, such as breast, stomach, and colorectal cancers.
Also, higher levels of blood glucose and insulin can cause inflammation which can ultimately lead to cancer. That is why people with diabetes — a condition with high blood glucose and insulin — have an increased risk of developing cancer. For instance, the risk of colorectal cancer is 122% higher if you are diabetic. Therefore, to protect against cancer, avoid foods which boost insulin levels, like foods high in refined carbs and sugar.
The International Agency for Research on Cancer (IARC) believes that processed meat is carcinogenic, something which causes cancer.
Processed meat is the meat treated to preserve flavor by undergoing salting, curing or smoking. It includes ham, hot dogs, salami, bacon, and some deli meats. Strong evidence proposes that eating a large amount of processed and red meat can increase the risk of bowel cancer, pancreatic and stomach cancer.
A review of above 800 studies observed that consuming only 50 grams of processed meat each day, raised the risk of colorectal cancer by 18%. Red meat consumption can also increase cancer risk. But fresh white meat (like chicken) and fish are not associated with an increased risk of cancer. Some reviews which combined consequences from many studies found that the evidence linking unprocessed red meat to cancer is inconsistent and weak.
Cooking certain foods at high temperatures, like frying, grilling, broiling and barbequing, can yield harmful compounds such as heterocyclic amines (HA) and advanced glycation end-products (AGEs). Excess of these compounds can cause inflammation and the development of cancer and other diseases.
Certain foods, like animal foods high in protein and fat and highly processed foods, mostly produce these harmful compounds at high temperatures. These include meat — mostly red meat — butter, certain cheeses, fried eggs, cream cheese, mayonnaise, nuts, and oils.
To decrease cancer risk, avoid burning food. Choose gentler cooking methods, especially while cooking meat, like steaming, stewing or boiling.
Many observational studies have shown that high dairy ingestion may increase the risk of prostate cancer. One study surveyed nearly 4,000 men with prostate cancer. Results showed that high intakes of whole milk increased the risk of disease development and death.
Theories show that these may be due to an increased calcium intake, insulin-like growth factor 1 (IGF-1) or estrogen hormones from pregnant cows. But actually, they all are not strongly linked to prostate cancer.
Being overweight or obese is linked to increased cancer risk
Obesity is the biggest risk factor for cancer worldwide. It also increases your risk of 13 different types of cancer, like colon, esophagus, pancreas, and kidney, as well as breast cancer after menopause.
Obesity can increase cancer risk in three key ways:
• Excess body fat contributes to insulin resistance. Thus, your cells can’t take glucose properly, which boosts them to multiply faster.
• Obese people have higher levels of inflammatory cytokines in their blood, causing inflammation and encourages cell division.
• Fat cells increase the estrogen levels, which raises the risk of ovarian and breast cancer in postmenopausal women.
But fortunately, several studies have shown that weight loss among obese people is likely to reduce cancer risk.
Certain foods contain cancer-fighting properties
Scientists evaluate that eating the optimum diet for cancer may reduce risk by up to 70%. They consider that certain foods can combat cancer by blocking blood vessels which nourish cancer in a method called anti-angiogenesis.
However, nutrition is complex, and how certain nutrients fight cancer depends on how they are cultivated, processed, and cooked.
Some of the important anti-cancer food groups include;
Higher consumption of vegetables can cause a lower risk of cancer. Many vegetables comprise cancer-fighting phytochemicals and antioxidants.
For example, cruciferous vegetables, including broccoli and cabbage, contain sulforaphane, which reduces tumor size in mice by more than 50%. Other vegetables, like tomatoes and carrots, can decrease the risk of lung, prostate, and stomach cancer.
Fruits also contain antioxidants and phytochemicals, which may help prevent cancer. One review showed that three servings of citrus fruits per week lowered stomach cancer risk by 28%.
Flaxseeds have protective effects against certain cancers and may even reduce the spread of cancer cells.
Some studies have found that cinnamon may have anti-cancer properties. It prevents cancer cells from spreading. Additionally, curcumin, present in turmeric, may help combat cancer.
Beans and legumes
They are high in fiber. Higher intake of this nutrient may defend against colorectal cancer. One study above 3,500 people found that eating the most legumes can lower the risk of certain cancers by 50%.
Frequently eating nuts may be associated with a lower risk of certain types of cancer. For instance, one study in over 19,000 people found that people who ate more nuts had a reduced risk of dying from cancer.
Several studies show a connection between olive oil and reduced cancer risk. One large review found that people who consumed the highest amount of olive oil had a 42% lower risk of cancer.
It contains allicin, which has cancer-fighting properties in test-tube studies. Other studies have found a link between garlic intake and a lower risk of cancer, including prostate and stomach cancer.
There is evidence that eating fresh fish can help protect against cancer, possibly because it can reduce inflammation. A review of 41 studies found that commonly eating fish reduced the colorectal cancer risk by 12%.
The major evidence suggests that eating certain dairy products may decrease the risk of colorectal cancer. The form and amount of dairy consumed are also significant.
For instance, moderate intake of high-quality dairy products, like raw milk, milk from grass-fed cows, and fermented milk products may have a protective effect. But high consumption of processed dairy products is associated with an increased cancer risk.
Plant-based diets may help protect against cancer
Plant-based foods have been linked with a reduced cancer risk. Studies have found that persons who follow a vegetarian diet have a reduced risk of developing cancer. In fact, a review of 96 studies found that vegetarians and vegans may have an 8% and 15% lower cancer risk, respectively.
The right diet can have positive effects on people with cancer
Muscle loss and malnutrition are common in people with cancer and have a negative effect on their health and survival. Optimal nutrition can help prevent malnutrition and enhance the quality of life in people with cancer. A balanced diet with adequate protein and calories is best.
Ketogenic diet shows some potential for treating cancer, but the evidence is weak
The early research proposes that a ketogenic diet may lower tumor growth. It improves the quality of life without adverse side effects. A ketogenic diet lowers insulin and blood sugar levels, possibly causing cancer cells to starve. In fact, research has shown that it can reduce tumor growth and improve survival rates in animal and test-tube studies. However, further research is still needed.
The bottom line
Although there are no miracle foods which can prevent cancer, some evidence proposes that dietary habits can provide protection. Generally, people with cancer are stimulated to follow a balanced, healthy diet to improve the quality of life and support optimal health outcome.