Eat fibre.
> I've developed a lot of food allergies
Really?
EDIT: http://www.scientificamerican.com/article/fiber-famished-gut...
>Your gut is the site of constant turf wars. Hundreds of bacterial species—along with fungi, archaea and viruses—do battle daily, competing for resources. Some companies advocate for consuming more probiotics, live beneficial bacteria, to improve microbial communities in our gut, but more and more research supports the idea that the most powerful approach might be to better feed the good bacteria we already harbor. Their meal of choice? Fiber.
http://www.sciencedaily.com/releases/2012/06/120628131358.ht...
> A University of Illinois study shows that dietary fiber promotes a shift in the gut toward different types of beneficial bacteria. And the microbes that live in the gut, scientists now believe, can support a healthy gastrointestinal tract as well as affect our susceptibility to conditions as varied as type 2 diabetes, obesity, inflammatory bowel disease, colon cancer, and autoimmune disorders such as rheumatoid arthritis.
> As these microbes ferment fiber in the intestine, short-chain fatty acids and other metabolites are produced, resulting in many health benefits for the host, said Kelly Swanson, a U of I professor of animal sciences.
http://press.psprings.co.uk/gut/june/gut308778.pdf
http://time.com/3936636/diet-gut-bacteria/
> The good news is that your initial Akkermansia levels are not your fate. People who started out with lower stores of Akkermansia had more after they followed the fiber-rich calorie-restricted diet. You can increase these bacterial populations by eating fiber, Cani’s research suggests, which acts as a prebiotic in the gut and has a beneficial effect on some bacteria.