Medical Bulletin 01/ July/ 2024

Here are the top medical news for the day:

Researchers Create New Model to Assess Risks and Benefits of Eating Fish During Pregnancy

Researchers have developed a new model to help guide recommendations and improve evidence-based advice on the risks and benefits of fish consumption, particularly during pregnancy.

In a study published in The American Journal of Epidemiology, scientists from Brigham and Women’s Hospital, Harvard T.H. Chan School of Public Health, University of Rochester Medical Center, and Cornell University introduced a framework that considers the average mercury content in fish. This model helps balance the harmful effects of mercury against the nutritional benefits of fish, providing clearer guidance on safe fish consumption.

Methylmercury (MeHg) exposure can harm brain development. However, fish also contain many nutrients that are good for brain development, like polyunsaturated fatty acids, selenium, iodine, and vitamin D. Many studies measure mercury exposure by looking at how much mercury has built up in hair. But using hair samples alone makes it hard to separate the harmful effects of mercury from the benefits of eating fish. For example, eating a lot of fish with low mercury levels or a small amount of fish with high mercury levels can show the same mercury level in hair samples, but the health risks are different.

In the study, researchers examined the relationship between fish consumption—categorized into low, medium, and high average mercury levels—and neurodevelopment in children. They assessed neurodevelopment using tests for IQ, language, memory, and attention.

The findings showed that children whose mothers consumed more fish with low mercury levels had better neurodevelopmental outcomes. Conversely, children whose mothers ate fish with high mercury levels had poorer neurodevelopmental outcomes.

“For patients who are seeking guidance about fish consumption, public advisories can be confusing and lead to decreased fish intake. Our study finds that eating more fish was generally beneficial for neurodevelopment when pregnant individuals consumed fish containing low levels of mercury but detrimental when individuals consumed fish with the highest average mercury levels. It’s important for people to think about what kind of fish they are consuming rather than simply cutting down on fish intake entirely. Our goal is for our study to help facilitate better estimation of the risk-benefit trade-offs of fish consumption, a key component of many healthy diets,” said lead author Sally Thurston, of the University of Rochester Medical Center.

Reference: Sally W Thurston, David Ruppert, Susan A Korrick, A Novel Approach to Assessing the Joint Effects of Mercury and Fish Consumption on Neurodevelopment in the New Bedford Cohort, American Journal of Epidemiology, 2024;, kwae149, https://doi.org/10.1093/aje/kwae149

Study Links BPAs in Plastic Bottles to Increased Type 2 Diabetes Risk

A new study, presented at the 84th Scientific Sessions of the American Diabetes Association (ADA), has demonstrated for the first time that Bisphenol A (BPA) exposure may increase the risk of type 2 diabetes, highlighting the necessity for further research into the effects of these chemicals on human health.

Bisphenol A (BPA) is a chemical commonly used in producing hard, clear plastics and epoxy resins, found in everyday items such as bottles, food containers and tableware. BPA is known to disrupt hormone function and has been associated with an increased risk of type 2 diabetes (T2D).

Although there have been associations between BPA and diabetes, direct studies examining whether BPA exposure increases T2D risk in adults have been lacking. Previous research has mostly shown correlations without definitively establishing a relationship. This new study provides more direct evidence, highlighting the need for further investigation into the impact of BPA on human health.

In the study, participants were given either a placebo or BPA at the US EPA’s safe dose (50 μg/kg body weight) for 4 days to evaluate its impact on insulin sensitivity. The double-blind study included 40 healthy, non-active adults (22 females, 18 males) who first completed a 2-day low-BPA diet. During this initial period, researchers measured urine and blood samples and assessed peripheral insulin sensitivity using a 120-minute euglycemic hyper-insulinemic clamp.

Participants were then randomly assigned to follow a 4-day diet with either oral BPA (50 μg/kg) or a placebo, without knowing which one they received. The outcomes were analysed using repeated measures ANOVA, adjusting for sex, BMI, physical activity, and ethnicity.

The results showed that bisphenol A (BPA) exposure reduced peripheral insulin sensitivity after four days. While there was no significant change in body weight or fasting blood glucose levels between the placebo and BPA groups, urine BPA levels were significantly higher in those who received BPA.

Importantly, peripheral insulin sensitivity significantly decreased in the BPA group, whereas it remained stable in the placebo group.

These findings suggest that BPA found in food packaging may directly affect diabetes risk in adults, potentially influencing public health guidelines and policies.

“BPA, found in everyday products, disrupts hormones and may lead to insulin resistance, a precursor to type 2 diabetes. Vulnerable groups, like pregnant individuals and children, are especially at risk. Minimizing BPA exposure during development is crucial to reduce long-term health risks. Additionally, the combined effect of multiple endocrine disruptors can amplify health risks, including diabetes,” said the authors.

Reference: Todd Hagopian, PhD, Cal Poly Center for Health Research, et al.; 84th Scientific Sessions of the American Diabetes Association (ADA), Orlando, FL; BPAs in plastic bottles linked to type 2 diabetes risk

Turmeric and Black Pepper Supplements May Cause Liver Injury in Some People: Study

A study published in The American Journal of Medicine has found that turmeric supplements may be linked to several cases of liver injury.

Previous research and case studies have associated turmeric, or its active compound curcumin, with liver damage. The latest findings indicate that the incidence of liver injury related to turmeric supplementation may be on the rise.

Turmeric, derived from the roots of Curcuma longa, is a popular herbal product used to treat conditions like arthritis, respiratory infections, liver disease, and recently, COVID-19. The active component, curcumin, is believed to provide these benefits. While clinical trials have shown turmeric to be safe, rare cases of acute liver injury have been reported.

Turmeric supplements now often include piperine (black pepper) to increase curcumin's absorption. Piperine can boost curcumin's bioavailability by 20-fold, which may heighten the risk of liver injury.

For the current study, researchers assessed only high-confidence cases of liver injury related to herbal and dietary supplements, categorised as definite, highly likely, or probable. They analysed demographic, clinical, biochemical, and histologic features. Researchers tried to obtain the specific supplements taken by patients and sent them to the National Center for Natural Products Research for ingredient verification and contamination testing. Available liver biopsies were reviewed and scored for various histological features and overall liver injury patterns.

The results showed that chemical analysis confirmed the presence of turmeric in seven cases. Additionally, piperine was found in several of the more recent cases, suggesting it might have increased the bioavailability of turmeric, leading to toxic exposure and liver injury. However, since no cases of liver injury from piperine alone have been reported, this seems less likely. It is more plausible that piperine enhanced the direct toxicity of turmeric. Other methods to increase turmeric's bioavailability, such as using lecithin and packaging it in nanoparticles, have also been used.

“This study looked at turmeric supplements and the addition of piperine, which boosts absorption. The liver acts as the body's gatekeeper, processing supplements first and working hard to break them down and detoxify them. Because of this, the liver can get strained and injured, especially if it's already dealing with issues. About 1 in 3 people now have metabolic dysfunction-associated steatotic liver disease (MASLD), which makes it harder for the liver to function properly and increases the risk of injury,” said the authors.

Reference: Dina Halegoua-DeMarzio, MD, Victor Navarro, MD, Jawad Ahmad, MD, Elizabeth Phillips, MD, Andrew Stolz, MD, Raj Vuppalanchi, MD, et al,; Liver Injury Associated with Turmeric—A Growing Problem: Ten Cases from the Drug-Induced Liver Injury Network [DILIN]; The American Journal of Medicine; DOI:https://doi.org/10.1016/j.amjmed.2022.09.026