Sugar, seed oils, and avoiding sickness: your health questions answered

The actor recently posted a photo of himself undergoing a £10,000 procedure at a London clinic that claims to remove microplastics, forever chemicals and herbicides from the blood. But how settled is the science around the health risks of microplastics? To find out, Ian Sample speaks to Dr Stephanie Wright, associate professor of environmental toxicology at Imperial College London’s school of public health. She explains what we know so far about the effects of microplastics in the body, why the science is still evolving, and what we can do to reduce our exposure. Help support our independent journalism at theguardian.com/sciencepod

The number of women choosing to freeze their eggs has increased sharply, according to figures from the UK’s Human Fertilisation and Embryology Authority (HFEA). The number deciding to embark on the process abroad also appears to be rising. Madeleine Finlay speaks to the Guardian journalist Lucy Hough, who recently travelled to Brussels to freeze her eggs. She explains what prompted her decision and how she feels now that the procedure is over. Madeleine also hears from Joyce Harper, a professor of reproductive science at University College London, about what the freezing of eggs involves and why the small odds of success could be driving women to travel to do it. Help support our independent journalism at theguardian.com/sciencepod

In an interview last weekend, Iran’s ambassador to the UN said his country’s nuclear enrichment ‘will never stop’ because it is permitted for ‘peaceful energy’ purposes. It is the latest development in an escalation of tensions over Iran’s nuclear programme, which erupted when Israel targeted the country’s nuclear facilities in June. To understand why enrichment is so important, Madeleine Finlay talks to Robin Grimes, professor of materials physics at Imperial College London. He explains what goes into creating a nuclear weapon, and why getting to the stage of weaponisation is so difficult. Help support our independent journalism at theguardian.com/sciencepod

It has been 25 years since Bill Clinton announced one of humanity’s most important scientific achievements: the first draft of the human genome. At the time, there was a great deal of excitement about the benefits that this new knowledge would bring, with predictions about curing genetic diseases and even cancer. To find out which of them came to pass, and what could be in store over the next two-and-a-half decades, Madeleine Finlay is joined by science editor Ian Sample, and hears from Prof Matthew Hurles, director of the Wellcome Sanger Institute. Help support our independent journalism at theguardian.com/sciencepod

Ever since Pluto was demoted from planet to dwarf planet in 2006, astronomers have been wondering whether Neptune really is the most distant planet from the sun. Now, a new telescope could uncover what lies in the farthest reaches of the solar system. The Vera C Rubin Observatory released its first images this week, and soon the world’s most powerful digital camera will be pointing across the whole of the night sky. Scientists are hopeful that if planet nine exists, the telescope will find it within its first year of operation. Ian Sample is joined by Dr Scott Sheppard, an astronomer at the Carnegie Institution for Science, to find out how Pluto lost its planetary status, why scientists think there could be another super-Earth, and why planet nine has been so hard to find. Help support our independent journalism at theguardian.com/sciencepod