I am a former Mr. ironman - I have been in fitness for over 40 years (See website; fitnessismylife.com). 
I am 71 now, in great shape and still train daily and take supplements.
For the last 2 years I had a severe bought with a bad bacteria in my gut producing unbelievable amounts of gas and bowl problems, lost 40 pounds and thought my life was over, it sucked the life out of me. With the help of my new doctor I started taking a large dose of probiotics, VSL#3 (Not the prescription one, yet!), I ran out on 2 occasions and had to start back again.......Each time I have had at least 1 nightmare a day or night when sleeping - this being the second time starting back on probiotics (I had forgotten how the nightmares happened the last time over a year ago - so I goggled, can probiotics cause nightmares and here I am - please give your patience the real answer - yes probiotics cause nightmares (Bad ones!!). I'm 6 feet tall and weigh 200 pounds and am still a pretty tough guy - these nightmares are horrible. YOU NEED TO START WITH A LOW DOSAGE AND WORK YOUR WAY UP - The nightmares do go away.......We have a lot of baby boomers coming along that are going to need probiotics to stay healthy and digest there food - please pass this along - it will be in my next article for my website.
Denny Holmes
President / Owner
Fitness is your Life
                                                        
                                                     
                                                    
                                                        
                                                            
                                                            
                                                            
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                                                                Fri, 28 Aug 2015