Fibre – yes I know, it’s not the most exciting thing in the world but a major study has been investigating how much fibre we really need to be eating and has found there are huge health benefits when we eat more.
It reduces the chances of debilitating heart attacks and strokes as well as life-long diseases such as type-2 diabetes.
It helps keep your weight, blood pressure and cholesterol levels down.
It’s cheap and widely available in the supermarket.
It makes us feel fuller and can help digestion and prevent constipation.
The researchers for this study, based at the University of Otago, in New Zealand, and the University of Dundee say people should be eating a minimum of 25g of fibre per day. “The evidence is now overwhelming and this is a game-changer that people have to start doing something about it,” one of the researchers, Professor John Cummings, has told BBC News.
The NHS recommends we should increase our fibre intake to 30g a day as part of a healthy balanced diet. So what does 30g of fibre actually mean?
To increase your fibre intake you could:
Choose a higher-fibre breakfast cereal such as plain wholewheat biscuits (like Weetabix) or plain shredded whole grain (like Shredded wheat), or porridge as oats are also a good source of fibre.
Go for wholemeal or granary breads, or higher fibre white bread, and choose wholegrains like wholewheat pasta, bulgur wheat or brown rice.
Go for potatoes with their skins on, such as a baked potato or boiled new potatoes.
Add pulses and legumes such as beans, lentils or chickpeas to stews, soups, curries and salads.
Include plenty of vegetables with meals, either as a side dish or added to sauces, stews or curries.
Have some fresh or dried fruit, or fruit canned in natural juice for dessert. Because dried fruit is sticky, it can increase the risk of tooth decay, so it’s better if it is only eaten as part of a meal, rather than as a between-meal snack.
For snacks, try fresh fruit, vegetable sticks, rye crackers, oatcakes and unsalted nuts or seeds.
Did you know? A small handful of nuts can have up to 3g of fibre. Always choose unsalted nuts, such as plain almonds, without any added sugars.
“Resistant starch?” I hear you ask, “what’s that?”
If you just happened to be watching that rather interesting programme the other night – “The Truth about Carbs” on BBC1 – you would have discovered that there is a little-known type of carbohydrate called resistant starch. And, just like fibre, resistant starch can help keep bowel cancer at bay.
Most of us love starchy carbohydrate foods like bread, pasta, rice and potatoes but they’re not always good for our health. Although starch is an important part of a healthy diet, it’s easily broken down. As soon as we consume starch the body very quickly starts to digest it, releasing sugars into the blood which in turn causes our bodies to release the hormone insulin.
WHAT IS IT?
Resistant starch is a form of starch that cannot be digested in the small intestine. Most starch is usually quickly broken down into glucose (which is used for energy) and if we eat too much, the glucose can then be stored as fat. Due to its molecular make up however, resistant starch doesn’t get broken down like normal starch, and instead it passes through the stomach and the small intestine intact until it reaches the large intestine. Resistant starch is then fermented in the large intestine, producing short chain fatty acids which serve as an energy source for colonic cells and our gut microflora. Foods that increase the amount of short chain fatty acids in the colon are thought to be beneficial to health by helping to prevent the development of abnormal cells in the gut.
Resistant starch is naturally present in some foods such as bananas, potatoes, grains, pulses and seeds and is also produced or modified commercially and incorporated into some food products.
There are several different types of resistant starch:
RS1: This is inaccessible to digestive enzymes due to the physical barriers formed by cell walls and protein matrices. Present in bread, seeds and pulses.
RS2: This type of resistant starch is protected from digestion due to its crystalline structure. Present in potatoes (higher amounts in raw versus cooked), bananas (higher amounts in unripe fruits).
RS3: This is retrograded starch which is formed when starchy foods such as potatoes and pasta are cooked and then cooled.
RS4: This is a chemically modified starch. Present in foods containing modified starches such as some bread and cakes.
Note: In addition, two different components have been proposed as RS5. Either amylose–lipid complexes, which either form during processing or are created artificially; or resistant maltodextrin which is processed to purposefully rearrange starch molecules.
Researchers have known about resistant starch for over twenty years now, so why the sudden excitement?
The volunteers had to undergo three days of testing in all, spread out over several weeks. On each occasion they had to eat their pasta on an empty stomach. The volunteers were randomised to eating either hot, cold or reheated pasta on different days.
On one day they got to eat the pasta, freshly cooked, nice and hot with a plain but delicious sauce of tomatoes and garlic. On another day they had to eat it cold, with the same sauce, but after it had been chilled overnight. And on a third day they got to eat the pasta with sauce after it had been chilled and then reheated.
On each of the days they also had to give blood samples every 15 minutes for two hours, to see what happened to their blood glucose as the pasta was slowly digested.
Just as expected, eating cold pasta led to a smaller spike in blood glucose and insulin than eating the freshly boiled pasta had. But unexpectedly, the team found that cooking, cooling and then reheating the pasta had an even more dramatic effect. Or, to be precise, an even smaller effect on blood glucose, reducing the rise in blood glucose by 50%. This certainly suggests that reheating the pasta made it into an even more “resistant starch”. It’s an extraordinary result and one never measured before.
The health benefits of resistant starch
When regular starch becomes resistant starch, most of the sugars it contains aren’t released in your gut and so your body will take in fewer calories from the same food.
Because less sugar is released into the blood stream from this resistance starch, there’s less of a blood sugar spike. In turn, this reduces the levels of insulin in the blood.
Resistant starch is indigestible and so shares many properties with fibre, helping food pass through the gut and generally improving digestion.
Once it reaches the lower gut, resistant starch feeds our beneficial bacteria, which in turn produce chemicals which can help our immune systems, cardiovascular health and many other benefits.
Freeze first then toast: make your bread work for you!
We love our bread. And it can be hard to give that up. But maybe we don’t need to. If you can’t stop eating bread, you can make the bread healthier for you by simply freezing it then toasting it. This turns some of the easily digestible starch into resistant starch. The act of freezing and then toasting means that your body gets far fewer calories from the bread. In effect, the resistant starch feeds your gut bacteria rather than feeding you. It really is that simple!
Thanks to: BBC Trust me I’m a Doctor BBC The truth about carbs British Nutrition Foundation