Beauty on the inside may be a tired platitude, but Dr Siew Ng confirms that if your gut health is a mess, then so are you. We get the dirt on what lies beneath.
Dr Siew Ng, professor of medicine and the director of Microbiota – I Centre (MagIC) at The Chinese University of Hong Kong reveals the science of beauty at a guttural level. Quite literally. In this revelatory conversation, she discusses the benefits of a little dirt and grime and how over-cleaning – especially during the pandemic – may have more adverse effects than benefits. In fact, it transpires that there’s more than a little truth in Hippocrates’ saying that all disease begins in the gut.
Of the many fields in medicinal science, why did you opt to go into gut health?
I’m a gastroenterologist, so I specialise in the gut – the digestive system. Traditionally people regard the gut as an organ that breaks down food and provides nutrition, but in recent years it’s emerged that the human gut is capable of more than that – it’s an intriguing organ, like a “second brain”.
Living inside every person’s gut are trillions of microorganisms – bacteria, viruses, fungi and other life forms that are collectively known as the microbiome. They may be naked to the human eye, but they have powerful functions. In part, this dictates our health, our weight, our mind, our sleep, our predisposition to disease and even how well we age.
What does your medical centre focus on?
Our group has recently established a new Microbiome Innovation Centre at the Hong Kong Science and Technology Park, which aims at developing an effective new class of microbiome medicine that will revolutionise the diagnosis and treatment of many diseases and ultimately improve human health.
What do most people not know about the relationship between what’s happening inside and what’s reflected outside?
Beauty starts from the inside and inside you are loaded with trillions of bacteria which are tied to your probability of things like obesity, diabetes, depression and colon cancer. Like a fingerprint, each person’s microbiota is unique: The mix of bacteria in your body is different from everyone else’s mix. It’s determined partly by your mother’s microbiota – the environment that you’re exposed to at birth – and partly from your diet and lifestyle. The bacteria live throughout your body, but the ones in your gut may have the biggest impact on your wellbeing. They line your entire digestive system. Most live in your intestines and colon. They affect everything from your metabolism to your mood to your immune system. You also have bacteria that colonise your skin and they determine your risk of skin allergies, or eczema or acne.
What are the most common mistakes people make?
Taking too many unnecessary drugs, especially over-the-counter painkillers or drugs for headache, acid reflux, diabetes and psychiatric conditions; all have been linked to affecting our gut microbiome in a bad way. Among them the notorious culprit are antibiotics – they should be avoided and only prescribed when needed to fight bacterial infections, as they can also wipe out good bugs or germs that help build your immune system, and once wiped out it can take weeks to recover, so don’t take them unless you need them. Their use is also associated with obesity and allergies in animals. Even common medications like paracetamol and antacids can interfere with microbes.
We’re also way too clean as a society now (and now with the Covid pandemic it has become inevitable). The environment you grow up in matters a lot. More exposure to good germs and bacteria, within reason, can strengthen our microbiomes. You’ll be surprised to learn that children growing up playing in the dirt or playing with animals/have a pet have healthier guts. So don’t be too hygiene obsessed!
Now some uncomfortable truths for our readers: should they give up alcohol? Red meat? Sugar?
The good news is that in small quantities, alcohol has been shown to increase your gut diversity, which is beneficial, but large amounts are harmful to your microbes and your health. Limiting dairy, red and processed meats and refined sugars can also improve gut health. So can getting the recommended amount of fibre, from 20 to 40 grams a day. Beneficial gut microbes love plant foods and good fats. In return, they can keep your gut happy and your body healthy. Fibre intake has been shown to reduce heart disease and some cancers, as well as reduce weight gain. Steer clear of artificial sweeteners like aspartame, sucralose and saccharine. These additives disrupt the metabolism of microbes and reduce gut diversity – in animal studies this has led to obesity and diabetes. Ditch the processed foods too, as these also upset microbes’ metabolism.
Make sure to eat your vegetables – and fermented foods are gut-friendly. Stock up on dietary sources of probiotics, which are food for your microbiome. It’s important to feed these little guys to give them the energy they need to complete their very important task of managing your enteric nervous system.
How is the microbiome linked to overall health?
The bountiful bugs that make up the gut microbiome may be sensitive to stress and diet, and regulate your weight. One perfect example of this is in weight gain. The microbiome influences weight gain, in part by changing the degree to which your body accesses energy from the food you eat. It’s commonly thought that weight gain is the result of eating too much, but there’s much more going on. Research from our group and that of others have shown that even gut microbes can help explain why some people grow fat. Some microbes help protect us from weight gain and obesity by strengthening the gut lining and maintaining healthy metabolic markers. There’s a new reason to “trust your gut”.
Your gut and skin microbiome are even responsible for stopping the clock when it comes to your complexion and youth. As we age, the number of “good” bacteria in our skin’s microbiome naturally drops. Scientists can predict your age based on your microbiome. The trillions of bacteria on our skin produces short chain fatty acids that reduce inflammation and protect our skin’s DNA. In short, healthy microbiome, healthy skin.
It seems the secret to successful ageing may lie in part in your gut. Studies have shown that it might be possible to predict your likelihood of living a long and healthy life by analysing the trillions of bacteria, viruses and fungi that inhabit your intestinal tract. As people get older, the composition of this complex community of microbes tends to change and the diversity drops.
How has your own study affected your own life?
Unlike our genes (ie DNA), which we couldn’t change easily, the microbiome (the DNA of our microbes) can be modified to improve health. This knowledge has had a positive impact on my health. Our group has recently developed innovative ways that can provide a comprehensive view of an individual’s gut microbiome using our proprietary analysis platform and to inform people of their gut and metabolic health. Through this test, I can look at the types of good and bad organisms within my gut and help guide my diet. Based on the results, I’ve modified my diet and lifestyle that results in better health and skin. We’ve also developed a new technology that can help predict the risk of colon cancer or its pre-cancer lesions via a stool test. Using this test, I was reassured to discover that I had a low risk of colon cancer and I can be spared of a colonoscopy.
Despite the large number of probiotics available in the market, many of the bacteria may not reach the gut or even survive through low pH in the stomach. Using big data and machine learning, our team has developed a microbiome precision formula that aims to improve immunity against Covid-19 and other respiratory infections, which was tailored to population in Hong Kong and Asia. Preliminary data showed this formula also helps improve Covid-19 vaccine response and reduce vaccine-related adverse effects.
I believe Microbiome research will be a powerful driver of medical breakthroughs over the coming decades.
Can the damage done in the past be reversed now?
For now, remember that the gut microbiome is reactive and responsive to positive change. Just a little more exercise and few more servings of vegetables and whole grains are simple ways to get started.