The link between carbs and gut health..
Should you eat carbs, or avoid them, if you’re trying to improve your gut health?!!
Carbohydrates have been shunned in recent years, for fairly valid reasons… as the epidemic of highly refined carbs and added sugar in processed foods is thought to be one of the biggest factors in skyrocketing rates of chronic disease
Yet by cutting out all carbs, we actually end up missing out on a huge group of nutrients - not to mention creating restrictions that aren't needed 😯
Carbs are a diverse food group, ranging from simple carbs to complex, yet they often get lumped together, despite having very different effects on our health
Simple carbs include glucose, fructose and lactose - these are made of one or two sugar molecules that are quickly broken down and absorbed after eating, causing a spike in blood sugar. Over time, a high intake of simple carbs have been linked to inflammation, diabetes, weight gain, heart disease, dementia and potentially even cancer. So the advice to limit them is backed up well by research.
Yet complex carbs are entirely different - these are called oligo and polysaccharides, and are long chains of sugar molecules that are tightly joined, meaning the body cannot break them down and absorb them quickly like it can with simple carbs.
These do NOT tend to spike blood sugar, and are instead broken down by bacteria in the large intestine - complex carbs that do this are often also known as ‘prebiotics’ as a result.
These carbs are highly beneficial, they:
- feed gut bacteria
- help satiety (feeling full)
- aid in weight loss
- regulate blood sugars
- help the body excrete toxins and cholesterol
- improve hormones (fibre helps balance oestrogen levels)
- help absorb calcium
When gut bacteria digest fibre and starch, they also produce compounds called short chain fatty acids, which feed the gut wall, provide a protective barrier, reduce inflammation, protect against bowel cancer and stop 'leaky gut' (see our post on butyrate for more details.)
Fibre is the main fuel source used to produce SCFA, its a also complex carbohydrate, and comes in many forms - all from whole plant foods, and all essential for health.
And not surprisingly, high fibre diets are proven to protect against many diseases - depression, autoimmune disease, breast and bowel cancer, heart disease, diabetes, obesity, diverculitis, and even dementia!
Yet most western diets are very low in fibre, with the average person eating 10-15g/day - when the recommended daily intake is a minimum of 30g/day. Eating more than this has extra benefits, with some guidelines suggesting we should aim for up to 70g/day!!!
Unfortunately many people cut out fibre due to bloating, but this is actually harmful longterm - diets such as low FODMAP diets are only intended to be followed short term. Bloating is usually due to a lack of good bacteria able to process fibre, so the key to avoiding this is a slow gradual increase in fibre intake, to let them adjust.
Ideally, to get the best results, its recommended to try get fibre from as many sources as possible - they all have different benefits and a healthy gut and body relies on a big variety of food!! The '30+ a week’ rule is a great reminder - this refers to eating 30 different types of plant foods each week, to promote diversity.
Fibre from whole foods is also superior to fibre supplements prescribed, or added to commercial foods - these can still help but tend to be single types of fibre, without the other nutrients that whole foods contain.
As different gut bacteria thrive on different types of fibre and complex carbs, by eating a rainbow you are literally feeding your gut!!
And on the flip side, low carb or ketogenic diets that significantly restrict plant foods tend to be low in fibre, and have been shown to have an adverse effect on gut bacteria, as well as leading to a reduced gut mucin (protective coating lining the gut). Some studies have shown a dramatic reduction in good gut bacteria in as little as 2 weeks after starting a low carb diet 😬
If you do choose to follow a low carb diet, try focusing on including as many low GI plant foods and fibre as possible, to keep your gut healthy - it is possible to do, but requires a specific focus on maximising fibre. As fibre is only found in plant foods, this means aiming for a low carb/ketogenic diet that is predominantly plant foods (which is better for overall health anyway)
And in contrast to what many people think, people who follow high fibre diets rich in complex carbs actually lower their risk of obesity, diabetes, heart disease, and inflammation - it's not the carbs that are the real problem, its the processing of them (turning them to refined carbs), and the added sugar!!
In a harvard study of over 40,000 male health professionals, people following a high fibre diet had a massive 40% reduction in heart disease!! Another harvard study of female nurses showed similar results.
So don't cut out carbs if you can help it - just remember that not all carbs are created equal 😊
