islamabad - Harmful side-effects have been associated with antibiotics including damage to the immune system and memory problems by a lack of growth in new brain cells, according to a new study.

The findings serve as a reminder that while antibiotics can be powerful allies for the human body in the fight against disease, they can also do more harm than good if used in the wrong situations, BBC health reported.

Studies found that the way antibiotics kill off microbes in the gut can cause health issues, due to the way the delicate chemical mixes in our bodies can be thrown out of balance by the medication.

Study, led by researchers from the Memorial Sloan Kettering

Cancer Centre in New York, involved 857 patients receiving hematopoietic stem cell transplants - a treatment typically used to tackle blood and bone marrow cancers.

Antibiotics are usually given in these cases to prevent or treat infections linked to the transplants, but the researchers found that patient health varied depending on the types of antibiotics used.

They tested 12 of the most common types of antibiotics, finding that two combinations in particular - piperacillin and tazobactam, and imipenem and cilastatin - led to a higher risk of a life-threatening inflammatory condition called graft-versus-host disease (GVHD).

The hypothesis is that the ‘mass exodus’ these particular antibiotics caused in the patients’ gut microbiomes harmed the body’s immune system in some way. Similar results were observed when the researchers tried the same tests on mice.

Scientists have emphasised that there’s more work to be done, and further tests to be run before we understand exactly what this means for the way we use these antibiotics in the future. For the time being, though, it’s a good reminder that these drugs should always be carefully used - and not overused in any circumstances.

Higher BMI may not raise heart attack death risk

According to recent research, having a higher body mass index may not increase the risk of heart attack or death, though it does raise the risk of type 2 diabetes.

But according to study co-author Peter Nordström, Ph.D., of Umeå University in Sweden, and colleagues, a higher BMI may not necessarily raise the risk of heart attack and death.

The researchers came to their findings after analyzing 4,046 monozygotic - or identical - twin pairs, using data from the nationwide Swedish twin registry and the Screening Across Lifespan Twin (SALT) study.  The authors explain that because monozygotic twins are genetically identical, they enable the assessment of obesity-related health risks independent of genetic factors.

The researchers found that in each twin pair, the heavier twin - even those who had a BMI of 30 or more - was at no higher risk of heart attack or death during follow-up than the leaner twin.

When it came to onset of type 2 diabetes, however, the researchers found that the heavier twins were at greater risk than the leaner twins; a total of 345 cases of type 2 diabetes occurred among the heavier twins during follow-up, compared with 224 cases among the leaner twins.  Furthermore, they found that twins who had experienced an increase in BMI in the 30 years before study baseline were more likely to later develop type 2 diabetes, regardless of their baseline BMI.

Based on these latest findings and those of previous studies, Prof. Nordström and colleagues say the importance of obesity and the development of type 2 diabetes is “indisputable.”

“These results suggest a causal link between obesity and the risk of diabetes, independent of genetic influence,” they note.

However, while the authors say their study is unable to conclude that a higher BMI does not raise the risk of heart attack or death, they believe the results raise questions about the efficacy of weight loss strategies against such conditions:

“The association between obesity and diabetes was significantly stronger than the association with CVD [cardiovascular disease] and death. This finding may indicate that interventions to promote weight loss are more effective in reducing the risk of diabetes than the risk of CVD and mortality.”