Michael Mosley finds out how learning a new language can help stave off dementia, surgeon Gabriel Weston asks whether 'detoxing' really works and GP Dr Zoe Williams looks at what you can do to improve your health if you're living with heart disease. Psychiatrist Dr Alain Gregoire finds out whether a night-time tipple can really help you get to sleep and Dr Giles Yeo asks whether man flu could actually be real.