Assessing Health Risks Associated with CAFOs

By Dr. Kirsten West, ND, LAc, FABNO

The stereotypical image of a farm is a pleasant one: happy animals, well-cared-for land, and green spaces. In fact – the vision may mirror Elderslie Farm (just outside of Wichita, Kansas), which is also featured in this issue.

Unfortunately, this ideal “farm life” image is increasingly being changed – and not for the better. Today, most of the food that is easily available at the supermarket is produced from animals living in dirty, overcrowded conditions, eating food they would not find on a traditional farm, and being given doses of antibiotics that impact the resulting food supply.

Unless food is sourced carefully, there’s a good chance it could be coming from a Concentrated Animal Farming Operation (CAFO). CAFOs are generally defined as agricultural meat, dairy, or egg facilities where animals are kept and raised in confined conditions. Food is brought to animals that have no access to grass or other vegetation for 45 or more days during the normal growing season. [1]

In 2020, the Environmental Protection Agency (EPA) reported more than 21,000 CAFOs, with at least one operation in all 50 states. [2] In addition to obvious concerns about food sourcing, loss of nutritional value, and respect for the animals, a significant health issue with CAFOs is manure and the resulting environmental

The number of CAFOs is multiplying, and the allowed capacity is also growing. A CAFO can house anywhere from hundreds to thousands of animals. For example, in Kansas, one cattle feedlot is permitted more than 150,000 cows. Another CAFO confines 198,000 mature hogs just miles from one holding 132,000 hogs. [3] This confined animal population produces a large amount of animal waste resulting in multiple impacts on health and the environment.

As far as health is concerned, the primary public health issue is manure. Its negative impacts include, but are not limited to, water, air quality, and universal health.


Arguments for CAFOs include low-cost sources of meat, milk, and eggs due to increased facility size and animal specialization, help for the local economy, and an increase in employment. It can also be argued that the cost to the communities, surrounding land, and the population at large outweighs those benefits. [4]

Contaminants in manure produced by CAFOs are a pressing public health concern. Those include, but are not limited to, nitrogen and phosphorus, E. coli, growth hormones, antibiotics, chemicals used as additives to the manure or to clean equipment, and more. [4] Approximately 4,000 CAFOs operate in Iowa, and aforementioned contaminants or E. coli impair nearly every mile of stream and acre of surface water in the state. [5] Nitrates in water can be a health threat to all people because they can lower oxygen in the blood, which has been linked to birth defects, miscarriages, poor general health, and “Blue Baby Syndrome.”

The ecological impact to surface water is significant. Lakes, rivers, and reservoirs are often polluted in areas near CAFOs, which affects both people and animals. According to the Centers for Disease Control, aquatic animals and plants die due to the hormones that are leached into the water, which also results in a significant decline in the fertility of female fish. Nutrient overloads also cause algae blooms, which can become toxic and kill not only plants and aquatic life but also be dangerous for humans. [4] If you’ve ever shown up to your favorite lake on a hot summer afternoon ready for some fun in the water only to find access restricted due to an algae bloom, a CAFO may be the source of the bacteria.

In the past, farmers and livestock growers used ground application as a way to dispose of manure, and while this was a problem, it was at a much smaller scale. However, the much larger volume created by CAFOs vastly amplifies the problem. The soil is unable to absorb and use the micro- and macro-nutrients, which then leach into the groundwater. This groundwater is the primary water source for many Americans, especially in the rural areas where CAFOs exist.

While CAFOs are technically required to hold permits that restrict the amount of manure discharge, enforcement is lax. Of the more than 21,000 CAFOs recorded by the EPA in 2022, only 6,266 had wastewater discharge permits under the Clean Water Act. [5]

Air Quality

If you have spent any time near one of these factory farms, you know they stink. Feedlot odors can travel for miles. Some studies estimate the standard distance odors from CAFOs can travel is 5-6 miles. However, weather plays a factor. When I lived in Denver, a town 60 miles north housed a CAFO. It was our best predictor of snow because Denver would always smell like manure because of the south-facing winds when a storm was coming.

With or without odor, manure can pose additional health risks. Pollutants commonly associated with CAFOs are ammonia, hydrogen sulfide, methane, and particulate matter. Potential health risks include respiratory irritation, chronic lung disease, inflammation of the eyes and respiratory tract membranes,
olfactory neuron loss, and asthma, especially in children. [4]

As an integrative oncologist, it is only logical to wonder about these pollutants and their effects on those who suffer from chronic allergies and, in turn, whether these odors increase risk of lung cancer. It is chronic irritation and inflammation in afflicted organs (and systemically) that have the potential to fuel tumor growth.

Insects and Antibiotics

Bugs are a nuisance, but beyond that, they spread disease. Flies are commonly associated with manure, and when produced in high volumes, that manure also attracts mosquitos and other insects. Flies can spread pathogens and other bacteria, including drug-resistant bacteria. Mosquitos are known to spread West Nile Virus, St. Louis Encephalitis, Equine Encephalitis, and other diseases. [4]

Diseases spread by these insects encourage the overuse of antibiotics and hormones. Animals in CAFOs are fed poor diets consisting heavily of grain and corn, which is a cheaper and easier way to encourage faster growth and higher meat production. These food sources alter an animal’s pH, causing systematic inflammation, bloating, infections, and a compromised immune system. This can result in an imbalanced inflammatory fatty acid profile, not only for the animal but those who consume the meat.

Antibiotics are given to decrease the risk of disease in these animals of poor health. However, hundreds of studies have been published linking the negative health effects to antibiotics and hormones. Studies have also shown a link to cancer in animals and people. Antibiotics in general are overprescribed and overused for viral pathogens, which are not effectively destroyed with antibiotics. Bacteria are much more effectively treated with antibiotics. This is a prevalent issue not only in CAFOs but in mainstream medicine as a whole.

Antibiotic-resistant strains of bacteria can be transferred to humans by handling or eating meat. Humans already experience overall health issues due to microbiome imbalance (dysbiosis) related to long-term overuse of antibiotics. This is a growing threat because fewer options exist to help people overcome
antibiotic-resistant diseases. [4] Additionally, we know that microbiome disturbance is associated with disease and chronic illness.

Animal Welfare

Can you imagine being held in close confinement in a pen with 50 to as many as 200 other people for 45 days (or more!), surrounded by dozens – if not hundreds – of similar pens? This is what life looks like on a feedlot. These animals are living creatures, and many people, including myself, feel strongly that they have rights. To stay focused on health risks, I will leave the dialogue about animal welfare there.

In Conclusion

As a Naturopathic Doctor specializing in integrative oncology, I always look for the root cause of a “dis”-ease. It is difficult to argue that CAFOs do not have a negative impact on public health. I strongly believe that all animal products produced by CAFOs should be labeled in the same way that GMO products are
labeled. However, that will not solve the entirety of the problem, as those living in communities close to a CAFO cannot escape the significant environmental health risks associated with these operations.



  1. Environmental hazards: Concentrated animal feeding operations (cafos) and public health. Wisconsin Department of Health Services. (2022, August 12). Retrieved February 7, 2023, from
  2. NPDES CAFO permitting status report: National Summary, endyear 2020 … (n.d.). Retrieved February 7, 2023, from
  3. CAFOs. CAFOs | Sierra Club. (n.d.). Retrieved February 7, 2023, from
  4. Centers for Disease Control and Prevention. (n.d.). Retrieved February 7, 2023, from
  5. Keith SchneiderCircle of Blue’s senior editor and chief correspondent based in Traverse City. (2022, December 1). Opposition to cafos mounts across the nation. Circle of Blue. Retrieved February 7, 2023, from
  6. What is a CAFO and why you need to know about it. NatureMed Clinic. (2019, April 12). Retrieved February 7, 2023, from