The Downsides of Pesticides

onventional farming routinely uses more than 400 pesticides and herbicides, and their residues are often present in non-organic food. These chemicals may be damaging to our health, and I believe they should be avoided when at all possible. Buying organically grown produce is a great way to reduce your intake of these potentially harmful toxins, but growing your own food is an even better path to eliminating exposure.

In your garden, you’re in complete control of what is used on your plants. Growing organically at home is easy to do, with many natural alternatives to chemical pesticides available to help you get the best yield possible from your crops (learn more on page 50). You may even find that through time-tested methods like companion planting—in which plants are strategically sown close together to enhance each other’s growth and repel pests—you don’t need outside pest control at all.

Exposure to many pesticides is associated with increased rates of cardiovascular disease, diabetes, and stroke—along with infertility. Here are just a few of the other chronic diseases recently linked to pesticides:

Amyotrophic lateral sclerosis (ALS). We don’t know for sure what causes ALS. About 10 percent of cases appear to have a familial component, but recent research has also found an association between ALS and pesticides.

Researchers at the University of Michigan compared exposures in a group of 156 ALS patients and 128 people who didn’t have the disease. They first estimated long-term pesticide exposure based on where each participant lived during the previous 30-plus years and their occupations. Then they analyzed blood samples from all of the participants to assess serum levels of 122 persistent environmental pollutants. Results showed that any exposure to pesticides over that time period was linked to a fivefold increased risk of ALS, compared to those who had no pesticide exposure. The study also concluded that exposure that occurred more than 30 years ago still tripled risk.

Bear in mind that the study didn’t prove that the pesticides cause ALS; it just showed an association between exposure and development of the disease— enough, though, for its authors to recommend avoiding these chemicals, particularly types strongly associated with ALS. That can be hard to do unless you’re eating food you’ve grown yourself: Although many of the specific chemicals implicated, including pentachlorobenzene and cis-chlordane, have been phased out, they can linger in the soil and air for years.

Parkinson’s disease. For some time now, experts have believed that unusual exposure to herbicides and pesticides may increase the risk of developing Parkinson’s disease.

In one Italian review of 104 previously published studies from around the globe, researchers concluded that exposure to bug and weed killers was associated with a 33 to 80 percent increase in risk of developing Parkinson’s. The investigators also assessed the risks associated with specific chemical compounds, reporting that exposure to paraquat (a weed killer) and the fungicides maneb and mancozeb doubled risk.

They didn’t look at whether exposure resulted from inhaling the pesticides, absorbing them through the skin, or working with and applying them. But their findings suggest that risk increases in a “doseresponse” manner—meaning, the higher the exposure the higher the risk. The Parkinson’s threat posed by pesticides is most likely to affect those with relatively high exposure to them, including farm workers and people who live in rural areas.

Cognitive impairment. A few years ago, Swedish researchers measured residues of organochlorine pesticides (OCPs) in the blood of 1,000 senior citizens and found that people with the highest residues had three times the risk of cognitive impairment as those with the lowest residues. Although some forms of OCPs have been banned for years in Sweden and other industrialized countries, including the United States, they can linger in the environment for quite some time. This study is evidence that low-dose, chronic exposure to OCPs can be harmful to the brain.

Another investigation into OCPs found that children born to women exposed to these chemicals during pregnancy have lower IQs, poorer working memory, and decreased perceptual reasoning.

Non-Hodgkin’s lymphoma and other cancers. Exposure to pesticides and other environmental toxins appears to play a role in the development of non-Hodgkin’s lymphoma. Pesticides have been linked with the disease among farmers and others exposed to higher-than-normal rates of the chemicals, such as dry cleaners, rubber workers, aircraft maintenance workers, and petroleum refining workers.

The World Health Organization (WHO) classified the popular herbicide glyphosate, mostly known as Roundup, as a probable carcinogen in 2015. And in 2017, California followed suit, requiring products containing glyphosate to carry warning labels. A review of human and animal studies published in 2016 linked glyphosate exposure to liver and kidney damage, endocrine disruption, and an increased risk of non-Hodgkin’s lymphoma. Most of the research was done in animals. Few human studies have investigated the health effects of glyphosate, and no federal agency monitors how much of it passes from the environment into human tissue, making it difficult to determine what level of exposure is potentially harmful to humans and whether current exposure levels are above or below that mark.

Coincidently, findings from a National Institutes of Health-sponsored study found no association between glyphosate and most types of cancer among licensed pesticide applicators in Iowa and North Carolina. However, the investigation did see an increased risk of acute myeloid leukemia, a type of cancer that begins in the bone marrow, among applicators who had the highest exposure to glyphosate compared to those with no exposure at all.

While the evidence isn’t unequivocal, it’s more than enough reason to sow and harvest as much of your own food, using organic garden products, as possible—and to choose organic produce from your grocery store and local farmers’ market for all your other dietary needs. Turn the page for steps to get growing.

IS HYDRO THE WAY TO GROW?

Hydroponic farming is the cultivation of plants in water without soil. Home growers may consider this approach because there is no need to fight weeds or most of the pests and soilborne diseases that can plague traditional gardeners. You can also grow in a much smaller space than is required for a regular garden—you can even get good results on an apartment balcony. Commercial growers cultivate hydroponic plants in greenhouses, either in water or in growing mixes composed of peat or bark.

In a traditional garden, plants get many of their nutrients from the soil. In a hydroponic garden, the nutrients must be supplied via specially formulated mixes. You can buy kits containing all the supplies needed to set up a home hydroponic garden online.

The question of whether plants grown hydroponically are as nutritious as those grown in soil has never been answered definitively, though at least one study showed significantly lower levels of nutrients such as lutein and beta-carotene in hydroponically grown lettuce compared to its field-grown counterpart.

While I haven’t been able to find enough large, recent studies to settle this issue one way or the other, I can personally speak to differences in taste, at least when it comes to tomatoes. Hydroponic growers often say they breed their tomatoes for flavor, but I’ve found that while the fruit often looks attractive, the flavor is usually insipid, totally unlike that of the best homegrown organic tomatoes. Nothing beats the burst of summer flavor that comes with tomatoes sun-ripened in your own garden.

Another question relating to hydroponics is whether these vegetables can be considered organic. Some commercial hydroponic growers use pesticides on their crops, and while you can purchase organic hydroponic media in which to grow your plants at home, most commercial operations rely on solutions of chemicals and minerals that don’t qualify as organic. If you decide to start a hydroponic garden, I encourage you to make it organic as well.