Improve your digestion and reduce your risk of obesity by making the most of prebiotics and probiotics in your food. By Caitlin Reid.
The health of your digestive tract is influenced by many things, including the bacteria inside your gut. There are actually more than 400 different species of bacteria living inside your large intestine, however not all are beneficial.
There is constant competition in our digestive system between good and bad bacteria and when the good guys outweigh the bad guys, you have a healthy gut. The good bacteria are known as probiotics and they feed on prebiotics. The more pre- and probiotics you have, the better your digestive system functions to absorb nutrients.
What are prebiotics?
Prebiotics are carbohydrates that pass through the body undigested until they reach the colon. In the colon, prebiotics are fermented, which leads to increased bowel function and the production of beneficial short-chain fatty acids. In the bowel, prebiotics also become an important fuel source for the healthy bacteria in our gut, helping them to grow in numbers. In others words, prebiotics are food for probiotics.
Inulin is a common prebiotic and it's naturally found in garlic, asparagus, onions, leeks and artichokes. However, prebiotics are also now added to many foods including breakfast cereals, bread, table spreads, drinks and yoghurt.
Recent studies show that prebiotics can be beneficial for our health in a number of ways.
Treatment for constipation: in both children and the elderly, increasing the intake of prebiotics can lead to reduced episodes of constipation and increased bowel frequency.
Reduced risk of developing osteoporosis: more research is needed but it's believed that prebiotics help to increase calcium absorption, maintaining and possibly increasing bone density.
Reduced risk of obesity and diabetes: prebiotics may play a role in reducing insulin resistance, which is associated with both of these conditions.
Classifying a prebiotic
In order for a substance to be classified as a prebiotic, it must:
Pass through the stomach and the small intestine undigested.
Be something that one or more bacteria can feed on.
Change the gut to a healthier environment by inducing effects that are beneficial to the health of the host.
What are probiotics?
Probiotics are live 'friendly' bacteria that help maintain a healthy gut by reducing the number of harmful bacteria that reside in our intestines. Probiotics are also important for a healthy immune system, for optimal absorption of nutrients and for the production of vitamin K. The most common types of probiotics are Bifidobacteria and Lactobacilli spp. They are found in yoghurts and fermented milk (such as Yakult). They are also added to infant formula and are available as dietary supplements.
Several health-related benefits have been associated with an intake of probiotics.
Immunity boost: probiotics can increase the number of cells that fight infection.
Reduce symptoms of irritable bowel syndrome (IBS): probiotics have been shown to reduce the symptoms of diarrhoea and constipation in people with IBS.
Treatment for diarrhoea: by preserving your intestinal integrity, probiotics can help to relieve diarrhoea, including antibiotic-associated diarrhoea.
Improved lactose intolerance: probiotics have been shown to improve lactose digestion, as lactase, the enzyme that digests lactose, is a by-product of fermentation.
Reduced risk of colon cancer: though the research is at an early stage, Lactobaccilli and Bifidobacteria were shown to decrease a particular marker for the risk of cancer development in studies where animals were exposed to a chemical carcinogen.
While probiotics are terrific, there are a few things to keep in mind in order to get the most benefits. You need to consume a variety of probiotics as you cannot get all the health benefits from just one individual strain. Probiotic foods must also contain living microorganisms, which need to survive food processing and storage in large numbers, then survive the passage through our digestive tract, where they are exposed to acids and digestive enzymes, in order to be alive by the time they get to the bowel.
To have the desired effect, a food product needs to contain at least a million of each different probiotic bacteria per gram. Most food products contain a couple million of each. You also need to eat food containing probiotics soon after opening the packet as the probiotics start to die.
Researchers are now looking into synbiotics - probiotics taken with prebiotics. It's thought the two can work together in a synergistic way to promote the survival of probiotics in the gut. Synbiotics are being developed as foods rather than supplements.
The keys to keeping your gut healthy
Iinclude carbohydrates and fibre in your diet, and moderate amounts of protein and fat. A diet too high in protein or fat can allow bad bacteria to flourish.
Reduce your stress as it can change the balance of bacteria in the gut.
The number of beneficial bacteria decreases with age, while the number of harmful bacteria increases. Counteract this by including probiotic-rich foods in your diet.
These fight bacterial infections, but can destroy some beneficial bacteria as well. Taking probiotics with antibiotics helps keep your intestinal flora balanced.
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