A Deeper Look Into the Study on Poultry and Cancer

A recent study associating poultry consumption with increased mortality for gastrointestinal cancers questions the long-standing notion that poultry is a healthier protein source. However, as the study has some serious limitations, an expert says it may be too early to recommend removing poultry from the diet.

Poultry has long been seen as a healthier alternative to red meat, which may raise the risk of multiple cancers, including breast and colon.

When a recent study published in the journal Nutrients suggested that consuming more than 300 grams of poultry a week may be associated with higher overall mortality and death from gastrointestinal cancer, it immediately hit the headlines.

The Dietary Guidelines for Americans emphasize getting protein from lean meats and poultry, along with plant-based protein sources, rather than red meat. Meanwhile, the International Agency for Research on Cancer classifies red meat as 'probably carcinogenic to humans.'

Chicken is the most consumed type of meat in the United States, and previous research has shown wide-ranging health benefits of poultry. So, should the latest findings discourage us from eating it?

What did the study find?

The study included nearly 5,000 middle-aged Italian participants who were interviewed by medical personnel, including about their eating habits.

Over 1,000 participants died during the study period, with 108 (10.5%) deaths attributed to gastrointestinal cancers (GCs): 28 to liver cancer, 22 to pancreatic cancer, and 37 to colorectal cancer.

An additional 180 deaths (17.5%) were due to other cancers, such as lung, prostate, and breast cancers.

Those who died due to GCs consumed the most meat, both red and white, compared to those who died from other cancers and other causes.

The study found that individuals who consumed more than 300 g of poultry a week had a 27% higher risk of death from all causes than those consuming less than 100 g.

Moreover, consuming more than 300 g of poultry a week was associated with more than double the mortality risk from GCs, especially for men.

Evidence is 'not strong enough'

Marian L. Neuhouser, PhD, RD, an affiliate professor of epidemiology at the UW School of Public Health, says the findings should be interpreted very cautiously, and they aren't strong enough to recommend reducing poultry consumption to reduce GCs risk.

There were many models generated without any adjustments for what we call multiple comparisons – just by chance alone, some findings could show up as statistically significant, even if they aren't.

Marian L. Neuhouser, PhD, RD

Neuhouser notes that the study did not include many important covariates, such as physical activity, body mass index (BMI), stage at diagnosis, and treatment, which all can affect mortality.

There is strong evidence that higher levels of physical activity are linked to a lower risk of several types of cancer, including GCs like stomach cancer and colon cancer, according to the National Cancer Institute.

Moreover, Neuhouser says that the number of gastrointestinal cancers and other cancers in the study was fairly small, 108 vs 180, respectively.

Another limitation is that the participants self-reported their dietary habits, including meat consumption. Memory-based dietary assessment methods, such as interviews and surveys, are widely criticized, as they may not provide accurate data.

The study did not look into the level of processing, meaning there is no data on whether poultry consumption came from highly processed fast foods or minimally processed poultry products.

According to the American Institute for Cancer Research, every 50 g of processed meat, such as one hot dog or two slices of ham, eaten daily raises the risk of colorectal cancer by 16%.

The study did not consider the preparation method, which can also affect cancer risk. Pan-frying or grilling directly over an open flame may lead to the formation of heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) in all types of meat. These substances were shown to cause cancer in animal studies.

In other words, regular consumption of grilled chicken steak may have a different impact on cancer risk than frequently eating boiled chicken breast.

So, is poultry good for you?

Poultry is a rich source of commonly underconsumed essential nutrients, such as phosphorus, potassium, selenium, iron, and the B-group vitamins.

Unprocessed poultry products are naturally low in salt. This is important for those trying to stay within the recommended daily sodium limits of 2,300 mg daily set by the American Heart Association.

A 100 g serving of chicken contains 27.3 g of protein, about half the recommended daily protein intake for women and nearly half for men. With 239 kcal per serving, it may be an excellent protein source for those who want to keep a healthy weight.

When consumed as a part of a vegetable-rich diet, poultry is associated with a reduced risk of developing overweight and obesity, cardiovascular diseases, and type 2 diabetes.

The takeaway

The study authors concluded, "In our opinion, it is important to learn more about the long-term effects of this food category, white meat, that is widely consumed by the world population who, perhaps mistakenly, consider it healthy in absolute terms."

However, as the new study has some major limitations, the evidence may be insufficient to recommend reducing poultry consumption.