Medical Bulletin 25/September/2025

Consuming some types of fruits and vegetables can increase the levels of harmful pesticides detected in people’s bodies, according to a new peer-reviewed study by Environmental Working Group scientists.

The study was published in the International Journal of Hygiene and Environmental Health.

Pesticides have been linked to cancer, reproductive harm, hormone disruption and neurotoxicity in children. Residues of these chemicals are often detected on produce, creating exposure concerns for consumers. The new study may help inform future research into how dietary exposure to pesticides through fruit and vegetables might affect human health.

Participants who consumed more fruits and vegetables with higher levels of pesticide residues – like strawberries, spinach and bell peppers – had significantly higher levels of pesticides in their urine compared to those who ate mostly produce with lower levels of pesticide residue. These findings highlight how diet is a driver of pesticide exposure and provide a foundation for future research into how that exposure might affect human health over time.

EWG created a “dietary pesticide exposure score” to estimate people’s exposure based on the fruits and vegetables they ate, and pesticide levels on that produce. Pesticide amounts on produce were determined by how often and how much of each chemical was detected. EWG also factored in the concentration and toxicity of each pesticide.

Scientists then compared the exposure scores to 15 pesticide biomarkers, or indicators, in participant’s urine for three major classes: organophosphates, pyrethroids and neonicotinoids.

The results revealed a clear link between the specific produce people consumed and the levels of these pesticides that were detected in their urine, varying based on what they ate and the pesticides on those fruits and vegetables.

The study’s authors suggest that their methodology for estimating pesticide exposure from fruits and vegetables could give regulators and other researchers a powerful tool to assess real-world exposures and better safeguard vulnerable populations, particularly children and people who are pregnant.

Ref: Temkin A et al. A cumulative dietary pesticide exposure score based on produce consumption is associated with urinary pesticide biomarkers in a U.S. biomonitoring cohort; International Journal of Hygiene and Environmental Health: 10.1016/j.ijheh.2025.114654

Science has confirmed what sports lovers have always known from experience: exercise is good for the brain. It increases blood flow, inhibits stress hormones, and stimulates the release of ‘feel good’ endorphins. One way by which exercise is thought to yield these benefits on the brain is through a chain of processes that ultimately results in the release of the hormone BDNF. Produced by the liver, brain, skeletal muscle, and fat tissue, BDNF is known to promote the growth, survival, and maintenance of nerve cells.

Previous studies have suggested that the starting signal for this physiological chain is a high level in the blood of lactate, a by-product of the conversion inside muscle, the liver, and the blood of carbohydrates into energy when oxygen is limited – for example during high-intensity exercise. Now, a study in has found that the physiological benefits of exercise may be partly mimicked by a simple IV infusion of lactate.

The authors did a so-called ‘randomized crossover study’ on 12 healthy volunteers aged between 20 and 40 years old. After fasting overnight, these were invited to lie down while either receiving a one-hour long IV infusion of sodium lactate and then, seven to 30 days later, a one-hour long infusion of saline solution; or receiving these treatments in the reverse order. Blood was taken from each volunteer every 10 minutes during both treatments, as well as 15, 30, 45, 60, 90, and 120 minutes afterwards. A leg muscle biopsy was taken before and immediately after each infusion with lactate, as well as 60 and 120 minutes later.

The researchers measured the lactate concentration in each blood or muscle tissue sample. They further quantified the levels of pro-BDNF, a biologically active precursor molecule of BDNF, in addition to its mature molecular form mBDNF, in blood plasma, serum, and platelet-poor plasma – that is, plasma from which most platelets have been removed.

The authors concluded that IV infusion with lactate is sufficient to boost the levels of pro-BDNF in the bloodstream, but without affecting those of mBDNF. In other words, lactate infusion alone is enough to mimic some, but not all, of the physiological effects of high-intensity exercise. It is expected that such an increase of pro-BDNF will have similar beneficial effects on brain health, irrespective of the mechanism behind it.

Ref: Roja J, Ameller N F et al. Lactate infusion increases circulating pro-brain-derived neurotrophic factor levels in humans; Front. Cell. Neurosci., 23 Sept 2025; Sec. Cellular Neuropathology; Vol 19 : https://doi.org/10.3389/fncel.2025.1644843