As with many crops, coffee plants are susceptible to pests and diseases. To protect the plants and ensure a good harvest, farmers often use pesticides. Studies have shown that pesticide residues can persist in commercial coffee, raising health concerns for consumers. In Brazil, a major coffee producer, about 15% of food consumed contains pesticide residues, which may lead to harmful health effects.

Organophosphorus pesticides (OPPs) are particularly concerning as they can block acetylcholinesterase in mammals, potentially affecting the nervous system. Exposure to these pesticides has been linked to increased mortality risk in Parkinson's disease patients and acute pesticide poisoning in some regions.

Mycotoxins are toxic compounds produced by certain molds that can grow on coffee beans, especially when stored improperly. The two main mycotoxins found in coffee are aflatoxin B1 and ochratoxin A, both considered potential carcinogens.

Studies have detected mycotoxins in both green and roasted coffee beans, as well as in brewed coffee. For instance, 33% of green coffee bean samples from Brazil contained low levels of ochratoxin A, while 18% of coffee brews in Portugal had detectable levels.

However, it's important to note that the levels of mycotoxins found in coffee are generally well below safety limits. Roasting can reduce ochratoxin A levels by 69–96%, further minimizing your risk. Decaf coffee and instant coffee tend to have higher mycotoxin levels, but still within safe limits.

Acrylamide is a chemical compound that forms during the coffee roasting process. It's classified as a Group 2A carcinogen by the International Agency for Research on Cancer, meaning it "probably" causes cancer in humans. However, most evidence comes from animal studies, and more research in humans is needed.

The amount of acrylamide in coffee varies depending on the roasting time. On average, coffee substitutes like grain and chicory root coffees contain the highest concentration (818 micrograms per kilogram), followed by instant coffee (358 mcg/kg), and natural roasted coffee (179 mcg/kg).

While coffee offers numerous health benefits, it's important to be aware of potential risks associated with contaminants.

The immediate impact of coffee contaminants can vary depending on the type and amount consumed. Pesticide residues, particularly organophosphorus pesticides (OPPs), can affect your nervous system by blocking acetylcholinesterase or AChase – an enzyme that breaks down the neurotransmitter acetylcholine into acetic acid and choline. This can lead to muscle disruption and other clinical signs related to nervous system function, as well as mental and cognitive function.

For those who don't regularly consume caffeine, you might experience insomnia as an obvious side effect. Caffeine can also cause headaches, nervousness, and anxiety in some individuals. Interestingly, caffeine can both trigger and alleviate headaches, depending on the person and circumstances.

Prolonged exposure to coffee contaminants may have more serious health implications. Long-term spraying of pesticides has been linked to increased mortality risk in patients with Parkinson's disease. A study in Tanzania showed that acute pesticide poisoning (APP) is a significant health threat, leading to an increased death rate among those exposed.

Roasting coffee at high temperatures can form potentially toxic substances. These include polycyclic aromatic hydrocarbons, acrylamide, furan and its derivatives, which are associated with neurotoxicity, carcinogenicity, and genotoxicity. The International Agency for Research on Cancer (IARC) classifies acrylamide as a probable human carcinogen (group 2A).

Other compounds formed during roasting, such as furan and 4-methylimidazole, are classified as possibly carcinogenic to humans (group 2B) by the IARC. While these findings sound alarming, experts maintain the levels of these compounds in coffee are generally within safety limits.

Growing Conditions: The environment in which coffee is grown plays a crucial role in shaping its chemical profile. High-altitude regions tend to produce coffee with higher concentrations of ethanal and acetone compounds, while lowland areas yield beans with higher levels of alcohol, aldehyde, hydrocarbon, and ketone compounds. These differences in chemical composition contribute to the unique flavors and aromas associated with coffees from different regions.

Harvesting Methods: The maturity level of coffee cherries at harvest time is critical for determining the final quality of your coffee. Ripe cherries contain specific flavor-precursor components that become raw materials in the fermentation process. Interestingly, chlorogenic acid levels are higher in immature beans compared to ripe ones, with total chlorogenic acid levels in ripe beans being 6.5-fold lower than in immature beans. (Chlorogenic acid – no related to chlorine– is an ester in the polyphenol family with demonstrated health benefits, including improving insulin resistance, lowering type 2 diabetes risk, and protecting against heart disease.)

Storage Practices: How manufacturers store coffee beans after harvesting can significantly impact the beans' chemical composition. Temperature plays a crucial role in preserving coffee quality. Research shows that beans stored at 68°F age the fastest, while those kept in chambers at 14°F and 50°F maintain their quality better. The type of packaging also matters. Jute bags allow exposure to external factors like moisture and air, while GrainPro polymer bags create an impermeable barrier, better preserving the beans' chemical integrity.

For home storage, there is a lot of debate around the best place to keep your coffee. In general, storing coffee at room temperature helps maintain both coffee beans' shelf life and taste. Avoid putting coffee beans in the fridge, as refrigerators are humid, moist, and light (not a friend to coffee beans). Also, the changes in temperature from taking coffee in/out of the fridge can cause condensation and microorganisms.

Organic Certification

To ensure your coffee is safer, look for certified organic options. Organic coffee is grown without synthetic pesticides, herbicides, or fertilizers, following strict guidelines set by certification agencies. This not only benefits the environment but also supports your health by reducing exposure to potentially harmful chemicals.

When shopping for organic coffee, check for certifications from reputable agencies like USDA Organic or Fair Trade. These labels indicate that the coffee has been grown, processed, and roasted according to organic standards. For decaf lovers, seek out solvent-free, chemical-free, Swiss-water, or certified organic options to avoid problematic chemicals like methylene chloride.

Organic, Shade-Grown

Organic, shade-grown coffee is (you guessed it) grown in shade similar to natural conditions where the coffee trees are planted and grow. The said method favors the creation of habitats for other species and also minimizes the use of pesticides. The canopy offers an environment that is more natural and safe to the plant, which makes the coffee is likely not to have any unwanted compounds.

Testing for Contaminants

While organic certification is a good start, some companies go the extra mile by testing for specific contaminants. Look for brands that test and share their results for pesticides and mycotoxins. This transparency can give you added peace of mind about the safety of your coffee.

Recent studies have shown that most organic and premium coffees tested were “clean” without traces of PFAS (also known as “forever chemicals”), pesticides, mycotoxins, or mold. However, it's still wise to be cautious, especially if you're sensitive to mold or pregnant. Consider asking your favorite coffee supplier if they test for mycotoxins, as increased consumer interest may encourage more companies to adopt this practice.

Your daily cup of coffee is a complex blend of chemicals, both natural and introduced. Understanding these components has a significant impact on making informed choices about your coffee consumption. By being aware of potential contaminants like pesticides, mycotoxins, and acrylamide, you can take steps to minimize your exposure and enjoy your brew more safely.

Choosing organic, properly stored, and well-processed coffee can help reduce the risk of harmful chemicals in your cup. Staying informed and making mindful choices allows you to savor your coffee with greater peace of mind. So, next time you reach for your favorite blend, you'll have a deeper appreciation for what goes into making that perfect cup.

1. Can the chemicals found in coffee be harmful? Yes, coffee contains small amounts of acrylamide, a compound that can be harmful in large quantities. There are concerns that acrylamide in coffee could potentially cause cancer.

2. What types of coffee are free from harmful chemicals? Coffees grown without harmful chemicals and roasted for optimal flavor provide a clean and guilt-free experience. Some brands that offer such products include Balance Coffee Rotate Espresso, Peak Performance, Isagenix, Kicking Horse Coffee, Bulletproof Original Coffee, Natural Force Clean Coffee, and Purity Coffee.

4. What beneficial chemical does coffee contain? Coffee is rich in antioxidants, such as polyphenols and hydrocinnamic acids. These compounds can enhance health and may help reduce the risk of several diseases.

3. What are coffee‘s top health benefits? Consuming a moderate amount of coffee, typically 2-5 cups per day, has been associated with various health benefits. These include a lower risk of premature death, reduced likelihood of developing diseases such as type 2 diabetes, heart disease, and certain types of cancer, and improved heart health. Additionally, coffee consumption may aid weight management, improve brain function, and enhance exercise performance. This is due to the presence of caffeine, a natural stimulant, and antioxidants that can address inflammation and protect against illness. However, excessive intake of caffeine can lead to negative effects such as sleep disturbances, decreased bone density, and elevated blood pressure. It is important to note that these adverse effects are primarily linked to caffeine rather than other components of coffee.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9681499/

https://www.healthline.com/nutrition/the-mycotoxins-in-coffee-myth

https://www.medicalnewstoday.com/articles/325295

https://www.healthline.com/nutrition/acrylamide-in-coffee

https://www.ama-assn.org/delivering-care/public-health/what-doctors-wish-patients-knew-about-impact-caffeine

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10138461/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8620865/

https://www.sciencedirect.com/science/article/pii/S030881462300105X

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10119118/

https://www.drinktrade.com/blogs/education/certified-organic-coffee-guide

https://3littleplums.com/blog/mold-pesticides-and-coffee

https://www.mamavation.com/food/premium-coffee-tested-for-mycotoxins-pesticides.html