Cancer & Nutrition Guide

Cancer is one of the leading causes of death. Did you know you can reduce your risk of cancer by eating a nutritious diet? Research shows that as many as one-third of all cancer deaths are linked to lifestyle behaviors including diet and physical activity. Growing evidence points to certain dietary habits increasing or decreasing cancer risk. Eating well can help you prevent and beat cancer in a variety of ways. This may help you live well for years to come after treatment. In short, nutrition is thought to play an important role in treating and coping with cancer.

Cancer Risk Factors

Eating Too Much of Certain Foods May Increase Cancer Risk. It is difficult to prove that certain foods cause cancer. However, observational studies have repeatedly indicated that high consumption of certain foods may increase the likelihood of developing cancer.

Sugar & Refined Carbs

Processed foods that are high in sugar and low in fiber and nutrients have been linked to a higher cancer risk. Researchers have found that a diet that causes blood glucose levels to spike is associated with an increased risk of several cancers, including stomach, breast and colorectal cancers. One study in over 47,000 adults found that those who consumed a diet high in refined carbs were almost twice as likely to die from colon cancer than those who ate a diet low in refined carbs. Higher levels of blood glucose and insulin are cancer risk factors. Insulin has been shown to stimulate cell division, supporting the growth and spread of cancer cells and making them more difficult to eliminate. In addition, higher levels of insulin and blood glucose can contribute to inflammation in your body. In the long term, this can lead to the growth of abnormal cells and possibly contribute to cancer. To protect against cancer, limit or avoid foods that boost insulin levels, such as foods high in sugar and refined carbs.

Processed Meat

Processed meat a carcinogen something that causes cancer. Processed meat refers to meat that has been treated to preserve flavor by undergoing salting, curing or smoking. It includes hot dogs, ham, bacon, salami and some deli meats. Observational studies have found an association between consuming processed meat and an increased cancer risk, particularly colorectal cancer. A large review of studies found that people who ate large amounts of processed meat had a 20–50% increased risk of colorectal cancer, compared to those who ate very little or none of this type of food. Another review of over 800 studies found that consuming just 50 grams of processed meat each day — around four slices of bacon or one hot dog — raised the risk of colorectal cancer by 18%. Some observational studies have also linked red meat consumption to an increased cancer risk.

Overcooked Food

Cooking certain foods at high temperatures, such as grilling, frying, broiling and barbecuing, can produce harmful compounds like heterocyclic amines (HA) and advanced glycation end-products (AGEs). Excess buildup of these harmful compounds can contribute to inflammation and may play a role in the development of cancer and other diseases. Certain foods, such as animal foods high in fat and protein, as well as highly processed foods, are most likely to produce these harmful compounds when subjected to high temperatures. These include meat — particularly red meat — certain cheeses, fried eggs, butter, margarine, cream cheese, mayonnaise, oils and nuts. To minimize cancer risk, avoid burning food and choose gentler cooking methods, especially when cooking meat, such as steaming, stewing or boiling. Marinating food can also help.

Dairy

Several observational studies have indicated that high dairy consumption may increase the risk of prostate cancer. One study followed almost 4,000 men with prostate cancer. Results showed that high intakes of whole milk increased the risk of disease progression and death. More research is needed to determine possible cause and effect. Theories suggest that these findings are due to an increased intake of calcium, insulin-like growth factor 1 (IGF-1) or estrogen hormones from pregnant cows — all of which have been weakly linked to prostate cancer.

Obesity

Obesity can increase cancer risk in three key ways: 

1. Excess body fat can contribute to insulin resistance. As a result, your cells are unable to take up glucose properly, which encourages them to divide faster.
2. Obese people tend to have higher levels of inflammatory cytokines in their blood, which causes chronic inflammation and encourages cells to divide.
3. Fat cells contribute to increased estrogen levels, which increases the risk of breast and ovarian cancer in postmenopausal women.

The good news is that several studies have shown that weight loss among overweight and obese people is likely to reduce cancer risk.

[View More: Obesity and Health]

Cancer Fighting Foods

Malnutrition and muscle loss are common in people with cancer and have a negative impact on health and survival. While no diet has been proven to cure cancer, proper nutrition is vital to complement traditional cancer treatments, aid in recovery, minimize unpleasant symptoms and improve quality of life. Most people with cancer are urged to stick to a healthy, balanced diet that includes plenty of lean protein, healthy fats, fruits, vegetables and whole grains, as well as one that limits sugar, caffeine, salt, processed foods and alcohol.

Higher intake of plant-based foods has been associated with a reduced risk of cancer. Studies have found that people who follow a vegetarian or vegan diet have a reduced risk of developing or dying from cancer. In fact, a large review of 96 studies found that vegetarians and vegans may have an 8% and 15% lower risk of cancer, respectively.

Broccoli

Broccoli contains sulforaphane, a plant compound found that may have potent anticancer properties. Study showed that sulforaphane reduced the size and number of breast cancer cells by up to 75%. Some studies have also found that a higher intake of cruciferous vegetables like broccoli may be linked to a lower risk of colorectal cancer. One analysis of 35 studies showed that eating more cruciferous vegetables was associated with a lower risk of colorectal and colon cancer. Including broccoli with a few meals per week may come with some cancer-fighting benefits.

Carrots

Eating more carrots is linked to a decreased risk of certain types of cancer. An analysis concluded that eating carrots may reduce the risk of stomach cancer by up to 26%. Another study found that a higher intake of carrots was associated with 18% lower odds of developing prostate cancer. One study analyzed the diets of 1,266 participants with and without lung cancer. It found that current smokers who did not eat carrots were three times as likely to develop lung cancer, compared to those who ate carrots more than once per week. Try incorporating carrots into your diet as a healthy snack or delicious side dish just a few times per week to increase your intake and potentially reduce your risk of cancer.

Beans

Beans are high in fiber, which some studies have found may help protect against colorectal cancer. One study followed 1,905 people with a history of colorectal tumors, and found that those who consumed more cooked, dried beans tended to have a decreased risk of tumor recurrence. According to studies eating a few servings of beans each week may increase your fiber intake and help lower the risk of developing cancer.

Berries

Berries are high in anthocyanins, plant pigments that have antioxidant properties and may be associated with a reduced risk of cancer. In one human study, 25 people with colorectal cancer were treated with bilberry extract for seven days, which was found to reduce the growth of cancer cells by 7%. Another small study, gave freeze-dried black raspberries to patients with oral cancer and showed that it decreased levels of certain markers associated with cancer progression. Based on these findings, including a serving or two of berries in your diet each day may help inhibit the development of cancer.

Cinnamon

Cinnamon is well-known for its health benefits, including its ability to reduce blood sugar and ease inflammation. In addition, some test-tube have found that cinnamon may help block the spread of cancer cells. A study found that cinnamon extract was able to decrease the spread of cancer cells and induce their death. Another study showed that cinnamon essential oil suppressed the growth of head and neck cancer cells, and also significantly reduced tumor size. Including 1/2–1 teaspoon (2–4 grams) of cinnamon in your diet per day may be beneficial in cancer prevention, and may come with other benefits as well, such as reduced blood sugar and decreased inflammation.

Nuts

Eating nuts may be linked to a lower risk of certain types of cancer. For instance, a study looked at the diets of 19,386 people and found that eating a greater amount of nuts was associated with a decreased risk of dying from cancer. Another study followed 30,708 participants for up to 30 years and found that eating nuts regularly was associated with a decreased risk of colorectal, pancreatic and endometrial cancers. Brazil nuts are high in selenium, which may help protect against lung cancer in those with a low selenium status. These results suggest that adding a serving of nuts to your diet each day may reduce your risk of developing cancer in the future.

Olive Oil

Olive oil is loaded with health benefits, so no wonder it is one of the staples of the Mediterranean diet. Several studies have even found that a higher intake of olive oil may help protect against cancer. One massive review made up of 19 studies showed that people who consumed the greatest amount of olive oil had a lower risk of developing breast cancer and cancer of the digestive system than those with the lowest intake. Another study looked at the cancer rates in 28 countries around the world and found that areas with a higher intake of olive oil had decreased rates of colorectal cancer. Swapping out other oils in your diet for olive oil is a simple way to take advantage of its health benefits. You can drizzle it over salads and cooked vegetables, or try using it in your marinades for meat, fish or poultry.

Turmeric

Turmeric is a spice well-known for its health-promoting properties. Curcumin, its active ingredient, is a chemical with anti-inflammatory, antioxidant and even anticancer effects. In a test-tube study, curcumin was also found to decrease the spread of colon cancer cells by targeting a specific enzyme related to cancer growth.

Another test-tube study showed that curcumin helped kill off head and neck cancer cells. Curcumin has also been shown to be effective in slowing the growth of lung, breast and prostate cancer cells in other test-tube studies. For the best results, aim for at least 1/2–3 teaspoons (1–3 grams) of ground turmeric per day. Use it as a ground spice to add flavor to foods, and pair it with black pepper to help boost its absorption.

Citrus Fruits

Eating citrus fruits such as lemons, limes, grapefruits and oranges has been associated with a lower risk of cancer in some studies. One large study found that participants who ate a higher amount of citrus fruits had a lower risk of developing cancers of the digestive and upper respiratory tracts. A review of nine studies also found that a greater intake of citrus fruits was linked to a reduced risk of pancreatic cancer. These studies suggest that including a few servings of citrus fruits in your diet each week may lower your risk of developing certain types of cancer.

[View More: Benefits of Citrus Fruits]

Flax-seed

High in fiber as well as heart-healthy fats, flax seed can be a healthy addition to your diet. Some research has shown that it may even help decrease cancer growth and help kill off cancer cells. In one study, 32 women with breast cancer received either a flax seed muffin daily or a placebo for over a month. At the end, the flax seed group had decreased levels of specific markers that measure tumor growth, as well as an increase in cancer cell death. Flax seed is high in fiber, which other studies have found to be protective against colorectal cancer. Try adding one tablespoon (10 grams) of ground flax seed into your diet each day by mixing it into smoothies, sprinkling it over cereal and yogurt, or adding it to your favorite baked goods.

Tomatoes

Lycopene is a compound found in tomatoes that is responsible for its vibrant red color as well as its anticancer properties. Several studies have found that an increased intake of lycopene and tomatoes could lead to a reduced risk of prostate cancer. A review of 17 studies also found that a higher intake of raw tomatoes, cooked tomatoes and lycopene were all associated with a reduced risk of prostate cancer. Another study of 47,365 people found that a greater intake of tomato sauce, in particular, was linked to a lower risk of developing prostate cancer. Start including a serving or two of tomatoes in your diet each day by adding them to sandwiches, salads, sauces or pasta dishes.

Garlic

The active component in garlic is allicin, a compound that has been shown to kill off cancer cells in multiple test-tube studies. Several studies have found an association between garlic intake and a lower risk of certain types of cancer. One study of 543,220 participants found that those who ate lots of Allium vegetables, such as garlic, onions, leeks and shallots, had a lower risk of stomach cancer than those who rarely consumed them. A study of 471 men showed that a higher intake of garlic was associated with a reduced risk of prostate cancer. Another study found that participants who ate lots of garlic, as well as fruit, deep yellow vegetables, dark green vegetables and onions, were less likely to develop colorectal tumors. Based on these findings, including 2–5 grams (approximately one clove) of fresh garlic into your diet per day can help you take advantage of its health-promoting properties.

Fatty Fish

Research suggests that including a few servings of fish in your diet each week may reduce your risk of cancer. One large study showed that a higher intake of fish was associated with a lower risk of digestive tract cancer. Another study that followed 478,040 adults found that eating more fish decreased the risk of developing colorectal cancer, while red and processed meats actually increased the risk. In particular, fatty fish like salmon, mackerel and anchovies contain important nutrients such as vitamin D and omega-3 fatty acids that have been linked to a lower risk of cancer. For example, having adequate levels of vitamin D is believed to protect against and reduce the risk of cancer. In addition, omega-3 fatty acids are thought to block the development of the disease. Aim for two servings of fatty fish per week to get a hearty dose of omega-3 fatty acids and vitamin D, and to maximize the potential health benefits of these nutrients.

Takeaway

A diet high in whole foods like fruits, vegetables, whole grains, healthy fats and lean protein may prevent cancer. Processed meats, refined carbs, salt and alcohol may increase your risk. Though no diet has been proven to cure cancer, plant-based and keto diets may lower your risk or benefit treatment. Generally, people with cancer are encouraged to follow a healthy, balanced diet to preserve quality of life and support optimal health outcomes.