Adding fermented foods to your diet can aid weight loss, boost energy, improve the immune system and even enhance your mood. Pass the sauerkraut…

Fermented foods pack a powerful punch because their natural probiotic content is essential for keeping our digestive tract in optimum health. ‘The gastric tract is the highway to health,’ says Kathie Madonna Swift, a clinical nutritionist whose book The Swift Diet will be published in January. In the US, Swift treats people with rheumatic conditions, mood problems, infertility and migraines – and her starting point is always the gut. ‘The balance of bacteria affects not only our digestion but our absorption of vitamins,’ says Swift. ‘If we are not absorbing our nutrients properly, it has implications for many processes in the body.’

An imbalance of gut bacteria can also cause ‘leaky gut’ syndrome. ‘When bacteria levels are unbalanced, the gut can become porous, allowing toxins and bad bacteria to leak from the colon into the bloodstream,’ says Swift. Health practitioners believe that foreign substances in the bloodstream can trigger an inflammatory reaction of the immune system, manifesting as problems such as irritable bowel syndrome (IBS), food intolerances, skin rashes, infertility or chronic fatigue syndrome.

The gut is thought to play a key role in our immune system, too. ‘One theory is that a healthy gut releases cytokines, chemical messengers that regulate our inflammatory and immune responses,’ says O’Shaughnessy. He points to studies showing that children without allergies have higher levels of good gut bacteria than those with allergies.