Experts are warning about the overlooked food groups that protect against cancer following a major study.
They are encouraging people to eat more fiber, found in foods like oatmeal, beans and popcorn, and calcium, which is in yogurt, cow’s milk and sardines.
The new study estimated diets low in fiber, calcium and vegetables were responsible up to 35 percent of colon cancers in the US.
Looking at federal health data on 700,000 cancer cases, the researchers also looked at known risk factors such as smoking, radiation, and obesity.
While smoking was the most common risk factor for all forms of cancer, diet was still linked to one in 20 cases overall.
Researchers from the American Cancer Society found that diets low in fiber but high in processed meats could increase the risk of colorectal cancer
The above graph shows colon cancer cases among under 50s rising by more than 5,500 in 20 years. There is a drop in 2020 because the Covid pandemic led to fewer people coming forward for screenings
While fruit, vegetables and, in recent months, fiber, have been touted for their anti-cancer properties, the new study highlighted calcium as a major protector.
The mineral helps maintain bone, muscle, and heart health, among other functions.
But experts believe it may also help bind fatty acids in the colon, which helps prevent colorectal cancer cells from forming.
Health agencies recommend 1,000 to 2,500 milligrams per day from sources like rye bread, broccoli, milk, and yogurt.
There is about 300mg of calcium per cup of cow’s milk, including whole, skim and low fat options.
However, NIH data suggests that nearly half of Americans don’t get enough of the nutrient, putting them not only at risk of colon cancer but brittle bones and blood clots.
Fiber, on the other hand, is thought to prevent colon cancer by helping you have more frequent bowel movements, which can reduce the amount of time harmful chemicals spend in your bowel.
There is some evidence fiber binds carcinogens to stool, which helps expel them from your body.
It has other anti-cancer properties – such as keeping you full for longer, making you less likely to overeat. Being overweight dramatically spikes your risk of tumors.
The new study found a lack of fiber was responsible for 12 percent of colorectal cancer cases in both men and women under 50.
That could be significant, given recent analyses have shown that 95 percent of Americans don’t get enough fiber, which can be found in whole grains like oats and fruit like strawberries.
The American Heart Association recommends that adults consume 25 to 30 grams of fiber per day from food, not supplements.
Meanwhile, the latest study found men who don’t consume enough fruits and vegetables could be 30 percent more likely to develop throat cancer, with nearly nine in 10 cases preventable with a healthy diet.
The finding comes as the CDC estimates nine in 10 Americans don’t get enough fruits and vegetables per day – 1.5 to 2 cups of fruit and 2 to 3 cups of vegetables.
Increasing intake of folate-rich foods like kale and spinach could lower the risk of oral and throat cancer in men
The study, published last month by the American Cancer Society (ACS) found that overall, diet was associated with just four percent of cancer cases and deaths.
Unhealthy diets had the strongest association with colorectal cancer.
They found that about 13 percent of colorectal cancers could be blamed on processed meat like sausage, bacon, and hot dogs, which increases to 14.6 percent in men.
The ACS team found that just over half of colorectal cancers could be prevented with lifestyle changes, and 35 percent were linked to diet.
It’s still unclear why these meats may contribute to colorectal cancers, but other recent studies have presented theories.
A study led by researchers at the Cleveland Clinic, for example, found that compounds linked to processed meats called metabolites are at higher levels in younger people with colorectal cancer than those over 50.
The lead researcher of that study, Dr Suneel Kamath, previously told DailyMail.com that metabolites likely help feed cancer cells and ‘hijack’ normal cells. This causes tumors to grow while depriving healthy cells of needed energy to sustain normal functions.
However, it remains to be seen why younger levels of these metabolites than older people with the same disease.
Fiber is essential for several digestive functions. These include bulking up stool so it passes more easily and prevents cancer-causing chemicals from lingering in the colon and rectum.
Research from Ohio State University also suggests that diets low in fiber and high in sugar can ‘speed up the aging’ of cells, leaving them more vulnerable to cancer.
Fruits like pears, strawberries, and avocados, as well as whole grains like oats, have the highest fiber content.
Additionally, not getting enough calcium-rich foods like milk, yogurt, and sardines, was linked to about four percent of colorectal cancers, the ACS researchers found.
It’s unclear how exactly calcium may lower colorectal cancer risk, though previous studies suggest that it helps bind fatty acids in the colon that inhibit the growth of cancer cells.
Additionally, calcium may help form calcium-phosphate-bile acid complexes, which help the colon digest fat.
The ACS study also found that low fruit and vegetable intake contributed to one in three cancers of the oral cavity, esophagus, pharynx, and larynx, as well as 31 percent of deaths.
This could be because eating fruits and vegetables has been shown to lower the risk of human papillomavirus (HPV), a sexually transmitted infection that is the leading cause of cervical cancer in women and throat and oral cancer in men.
According to Moffitt Cancer Center in Florida, fruits and veggies with the compound folate are most likely to reduce HPV risk. These include spinach, kale, eggs, and citrus fruits like oranges.
The ACS team also found that as many as nine in 10 oral and throat cancers could be prevented with healthier lifestyle choices, such as stopping smoking and exercising.
