Impact of Animal Agriculture on Health

The farming of animals poses alarming dangers to human health, especially as the animal agriculture industry continues to intensify around the world.

In the United States, 99% of farmed animals are raised on factory farms, on which thousands of animals are confined in overcrowded and dirty sheds — creating conditions that facilitate the spread of zoonotic disease, an illness that can be transmitted between animals and humans. Yet, small farms are not an exception.

Further damage is done in the consumption of animal agriculture’s products — meat, eggs, and dairy — which have been linked to increased risk of several diseases.

Antibiotic Resistance

  • Health officials around the world recognize antibiotic resistance — or antimicrobial resistance — as a serious and growing threat to public health. In 2019, 1.2 million people died of treatment-resistant bacterial illnesses.
  • Due to this crisis, the World Health Organization has called for an end to using antibiotics in healthy farmed animals to prevent disease and boost animal growth.
  • Around 70 percent of medically-important antibiotics in the U.S. are used in animal agriculture.
  • A 2023 report by World Animal Protection tied almost one million deaths to the use of antimicrobials on animal farms.


  • Scientists estimate that 75% of new and emerging infectious diseases in humans — and six out of every 10 that are currently knownare zoonotic in nature, which means they can be transmitted by animals.
  • Unprecedented outbreaks of avian flu have quickly spread through poultry farms, leading to the culling or deaths of nearly 60 million U.S. farmed birds.
  • Human cases of bird flu have been rare, but researchers are increasingly concerned as the illness spreads between other mammals, and at least eight zoonotic variants have been found in animal agriculture operations.
  • It is important to remember that while factory farms are conducive to outbreaks, disease is found on small-scale animal farms, too.
  • Researchers have warned that U.S. agencies are not prepared to handle animal-borne illnesses.

Diet-Related Diseases

  • An ever-growing body of evidence ties red meat intake to an elevated risk of cardiovascular disease and multiple types of cancers.
  • The World Health Organization has determined that processed meats, including bacon, are carcinogenic (cancer-causing).
  • A 2021 Oxford study linked regular meat consumption to a higher risk of heart disease, diabetes, and pneumonia.
  • Oxford research has found that each 50g of dairy consumed raised the risks of developing liver and breast cancer “significantly,” by 12% and 17% respectively.
  • While dairy is often touted as an essential calcium source, research has shown the acidity of dairy can cause our bones to leach calcium — and dairy consumption in adolescence has even been linked to a higher risk of hip fractures later in life.
  • Just one large egg contains 186mg of cholesterol, and researchers have found that egg consumption may increase the risk of death from cardiovascular disease.
  • On the other hand, plant-based diets have been linked to a reduced risk of cardiovascular disease and mortality in general.


  • A study published in 2021 found that 80% of 15,900 annual U.S. deaths tied to air pollution from food production were directly linked to animal-based foods.
  • Animal agriculture accounts for around 70% of U.S. emissions of ammonia, a gas that can irritate or corrode the skin, eyes and lungs — and in high concentrations, can even cause death. Workers and animals on farms are regularly exposed to ammonia emitted by animal waste.
  • North Carolina residents living near large-scale pig farms have been found to have a higher death rate and an increased risk for kidney disease, anemia, septicemia, tuberculosis, and infant mortality.
  • In 2022, a lawsuit alleged the EPA has no plan for enforcement of the Clean Water Act when it comes to violations by intensive animal farms.

Food Safety

  • An estimated 23% of U.S. cases of salmonella are caused by chicken and turkey
  • From 2015 to 2020, major U.S. meat producers sold “tens of thousands of meat products contaminated with campylobacter and salmonella,” according to the Bureau of Investigative Journalism.
  • A 2023 study linked E coli in meat to 500,000 urinary tract infections in the U.S. each year.
  • Treatment-resistant ‘superbugs’ were found in 40% of sampled meat from Spanish grocery stores.

And the COVID-19 pandemic revealed, as meat producers kept plants open despite outbreaks, workers in the meat industry are vulnerable to illnesses that spread throughout farms, too.

The good news is you can oppose the harms of animal agriculture.