Bug Spray: Not as Benign as You Think!

Sunday, June 11, 2017
By: Linda J. Dobberstein, Chiropractor, Board Certified in Clinical Nutrition

As we enter the summer months with backyard BBQ’s, outdoor events and camping, we are encouraged to use DEET or other bug sprays to ward of mosquitos and ticks to reduce risk of insect or tick-borne disease. Although generally regarded as safe to humans, we need to remember that common bug spray chemicals are insecticides. In fact, new research shows the insecticides DEET and permethrin cause neurological toxicity, especially in early-life exposure. These are toxic chemicals we apply to our skin and absorb and breathe in. We must ask the question: what risk do these chemicals pose? If we are going to use them, how can we protect ourselves and our children?

Common Insecticides: DEET and Permethrin

DEET and permethrin are two common types of insecticides to help with bug control.

DEET insect repellant is absorbed by the skin and excreted by the kidneys. Various concentrations of 5-100% are available on the market. Higher concentrations give longer hours of protection. Johnson & Johnson OFF brand products are one type of product that contains DEET.

Permethrin is a synthetic insecticide used to repel mosquitoes, ticks, and insects. The natural form of it is called pyrethrum which comes from the flower, Chrysanthemums. Permethrin is used on clothing and bed nets only, but is often combined with DEET that is applied to the skin.

DEET and non-DEET containing repellants are regarded as safe with minor toxic effects with acute ingestion. Repeated applications in a short time, not washing off the bug spray until later in the day or the next day, combining sunscreen with bug spray, combining more than one bug spray, or repeated environmental mosquito spray for pest control may increase risk for toxicity and adverse effects. 

Insect repellants may be like other compounds (BPAglyphosate, flame retardants, and thimerosal, etc.) that are given the stamp of approval for safe exposure but long-term effects may not be known until later. Scientists across the globe, however, are looking at long-term effects especially from early life exposures rather than acute toxic reactions. Listed below are some of the surprising findings. The results may have you looking at other health-conscious choices.

DEET and Permethrin: Adverse Consequences

Studies show that combined application of DEET and permethrin caused measurable toxic effects to DNA, brain mitochondria, and disrupted the blood-brain-barrier in rats. Neurological function was changed and genes were altered from the combined exposure of the insecticides.

Another recent study focused on DEET exposure with and without another insecticide called fipronil to human liver cells. Both chemicals caused changes on molecular RNA gene transcript levels within the liver cells. Fipronil was found to be 21 times more powerful than DEET at eliciting these cellular changes when applied at a 10-fold lower dose. However, when both DEET and fipronil were combined, RNA transcript changes were markedly affected more so than using either product alone. Transcript changes, in general, have been noted with estrogen receptor changes and cancer.

Gulf War Syndrome (GWS) and chronic pain have also been linked with high DEET and permethrin exposure. High doses of DEET led to the development and persistence of chronic pain. Delayed onset of memory changes, other neurological symptoms, and musculoskeletal concerns in GWS are suspected a result of permethrin and other insecticide chemical exposures.

The Journal of Toxicology and Environmental Health found that permethrin and allethrin, another popular insecticide, caused cellular and genetic damage to human lymphocyte cells. The greater the dose and the longer the cells were exposed to the chemicals, the greater the damage. Lymphocytes are types of white blood cells involved with T-cell, B-cell, and natural killer cell activity in the body. They play vital roles in managing cancer, infections, and autoimmune disorders. Other studies show a higher risk of non-Hodgkin’s lymphoma with exposure to permethrin and other insecticides. 

One study demonstrated that female rats exposed to permethrin for two weeks experienced degenerative changes in the ovarian tissues and damaged mitochondria within the reproductive system. Those animals that experienced the greatest damage had the highest exposure amounts.

A unique study evaluated insecticides in the environment and what happens to them in common urban settings. They evaluated what happened to permethrin when it was applied to concrete. They found “under outdoor conditions, permethrin, a heavily used pyrethroid insecticide quickly formed 3-PBA (3-phenoxybenzoic acid) that is a known endocrine disruptor…the level of 3-BPA persisted in runoff water (from concrete) even 3 months after treatment.” That certainly makes one wonder about groundwater and environmental health impact on life.

Early Life Exposures, Long-Term Consequences

Chronic use of insecticides in children is not well studied, but the literature and medical profession encourages the use of bug sprays to offset the potential risks of insect bites. The journal Archives of Pediatrics recommendation for topical insect repellant use when exposed to a need is: infants above 6 months once daily. For ages 1 to 12 years, two applications may be used, and 12 years of age to adults may use three daily applications of insect repellant. Guidelines even include the use of insecticides in nursing infants as young as 2 months of age once daily if there is a severe bug exposure risk.

Prenatal and early life insecticide exposures pose the most significant concerns as they are mostly likely misused and toxic effects to the nervous system can occur. Brain toxicity is recognized from insecticides, but there is more to it than that. Other effects have been identified in animal studies and the results are a cause for concern as they are rather striking.

Brain and Neurochemicals Affected

Low dose permethrin exposure to newborn rats was shown to induce changes well into rat adulthood at 500 days old. The insecticide exposure altered vitamin D, adrenaline, noradrenaline, nitric oxide, and cholesterol function in early life. The changes persisted into adulthood.

Parkinson’s Disease and Neurodegeneration

An animal study published earlier this year described the impact of permethrin on the progression of nervous system damage. The study found that permethrin exposure in early life replicated the disease progression of Parkinson’s. Loss of dopamine, cognitive impairments, difficulty with walking, impaired coordination, etc. occurred due to the permethrin exposure in early life as compared to the animals not exposed to the insecticide in the control group.

DEET and permethrin animal studies have shown that when these chemicals are used alone or in combination, no immediate terrible signs of neurotoxicity occur. However, it is recognized that real-life exposures of malathion, DEET, and permethrin “induce significant neurobehavioral deficits and neuronal degeneration in the brain”.

Gut Flora Affected

Antibiotics are not the only agent known to disrupt healthy gut flora. Other recent information shows that the gut flora was disrupted after permethrin exposure as this insecticide may occur in the diet. A recent study identified that very young rodents exposed to permethrin experienced detrimental effects to the beneficial bacteria - Bifidobacterium and Lactobacillus paracasei within their gut.

On the other hand, potential pathogens or non-beneficial gut bacteria Staphylococcus aureus and Escherichia coli flourished as a result of permethrin exposure. The authors concluded, “exposure to permethrin could affect the fecal microbiota and could be a crucial factor contributing to the development of disease.” We also know that gut flora is dramatically disrupted with glyphosate and Roundup pesticides. It would appear that common insecticide use like permethrin and probably others may be added to the list.

Heart Damage

Permethrin exposure in early life was found to cause heart damage and toxic cardiac effects in adulthood in animal studies. It was found that when rats were exposed to permethrin in the first three weeks of life, heart damage occurred in adulthood. Heart cells had increase increased DNA damage, changes in the heart cell membrane flexibility, increased cholesterol content, breakdown in proteins, and fats from free radicals within the heart. Permethrin also changed the heart size and heart genetics in adulthood. High levels of cholesterol, several inflammatory cytokines, and decreased antioxidants like glutathione with higher breakdown rates of glutathione in the mitochondria occurred in rats exposed to permethrin in early life compared to the control group. The authors felt that the heart cell changes, increased inflammation, and disease occurred because the chemical exposure in early life triggered genes associated with heart damage.

Finding Solutions

Lastly, an August 2016 review study in the Environmental Research journal is revealing publication about its wide-reaching damaging effects and puts things into a big picture perspective. It describes permethrin as the most frequently used synthetic Type 1 pyrethroid insecticide throughout the world and considered safe to humans and other mammals. Their review shows that evidence that permethrin and other insecticides may not be as safe as originally thought. Toxic effects are seen with the nervous system, immune system, heart, liver, reproductive, genes, blood, digestive system, and on cellular levels. Much of the toxic responses are believed to occur because of oxidative stress or free radical production (ROS, RNS, NO, etc) that occurs with permethrin exposures.

Free radical production affected several major detoxification and antioxidant systems like the glutathione enzyme system, nitric oxide, super oxide dismutase (SOD) and others. Several compounds were identified as helpful in management of the permethrin-induced oxidative stress. Key antioxidant support focused on glutathione, SOD, and beneficial nitric oxide. In addition to glutathione support, SOD, and nitric oxide, other support included coenzyme Q10, olive leaf extract, phosphatidylcholine, and resveratrol.

Glutathione is considered the master antioxidant enzyme system for the whole body. It requires several nutrients such as N-acetyl cysteine (NAC), phytochemicals like curcumin, resveratrol, cinnamon, and fisetin to help build intracellular glutathione concentrations. Several other nutrients like silymarin, B vitamins, r-alpha lipoic acid, and whey protein also help with the manufacture, protection, and recycling of glutathione.

Friendly, antioxidant-quenching nitric oxide is supported with nutrients like grape seed extract, tocotrienols, r-alpha lipoic acid, and choline. Choline may be made or supported by acetyl-l-carnitine, phosphatidylserine, phosphatidylcholine, and alpha-GPC. SOD or superoxide dismutase works directly with glutathione. Glutathione support will help SOD. SOD is found in sprouted plants, fruits and vegetables.

With the rapid rise of Alzheimer’s, Parkinson’s disease, heart disease, autoimmune disorders, and cancers across the globe in the last few decades, I can’t help think of the rise of the chemicals in use and how early life exposure may have contributed to these concerns. Cities repeatedly spray for bug control. Public and private places, like hotels, restaurants, military bases, schools and homes may perhaps nonchalantly use these chemicals. How about the kids who grew up in the 50’s and 60’s and ran behind the trucks that sprayed city streets for mosquitoes to play or the farm kids with work exposure that now face a plethora of health concerns. There is no doubt that insects carry diseases and appropriate care is needed, but if we use these chemicals, we must be diligent about protecting ourselves, especially our children. It becomes the question, what am I “feeding” my body and what effect does it have?

The answer to this question has to be antioxidants and lifestyle. A wide variety of plant-based antioxidants and nutritional supplementation must be utilized if we are to protect ourselves from these compounds. Focus on a diet rich in colorful fruits and vegetables with at least 5-13 servings per day.

Key nutrients like silymarin, r-alpha lipoic acid, astaxanthin, B vitamins, selenium, zinc, magnesium, N-acetyl-cysteine, curcumin, resveratrol, phosphatidylserine, coenzyme Q10 and others bind onto inflammation provoking free radicals invoked by insecticides.

Avoidance, limited use, protective clothing, etc. are other choices to chemical exposures. If possible, avoid dual use of sunscreens and insecticides as toxicity is enhanced.  Natural alternatives like lemon oil, sulfur-rich compounds and thiamin or other essential oils may help protect against nasty bug bites. With increased world-wide use and recommendations to protect ourselves from the Zika virus or other mosquito and tick-borne disease, we must not blindly apply more chemicals to our bodies. The evidence is growing. Adverse effects from DEET and permethrin, etc. do occur despite the low acute toxicity effects. These animal and cellular studies show that chronic exposure, especially in early life, creates lasting and serious challenges.

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