An interview with nutrition advisor, Dr Chen Zhen-Yu, on the importance of digestive health and tips on how to maintain it
1. Why is intestinal health important? How would this be an increasing concern within the Asia Pacific region?
The intestine is one of the largest organ systems in human body. Its function is to absorb nutrients including water from foods consumed and eliminate the toxins and wastes. Numerous researches have shown strong associations between gut health and cardiovascular health, the immune system, mental health, endocrine disorders, and colon cancers. Intestinal diseases including constipation, irritable bowel syndrome, diverticular diseases, and ulcerative colitis had been thought of as diseases of the Western world, because their incidence and prevalence in Asia were much lower in the past. These diseases are beginning to emerge in Asian countries because of changes in lifestyle, diet, as well as urbanization.
2. What are some microorganisms in our bodies that are important for maintaining intestinal health, and what are their primary function?
Gut microbiota refers to the total number of microorganisms in humans’ gastrointestinal tract. (GI tract) Approximately 3 percent of human body weight is derived from bacteria. Previous studies have estimated the ratio of bacterial cells to human cells in the body to be 10:1. This emphasizes the importance of bacteria in human health. In other words, there are 100 - 300 trillion of bacteria residing in the human gut. The diversity usually refers to various types of gut bacteria in humans and there are 300-1000 species living in the gut of each individual.
Studies have demonstrated that a high level of gut microbiota diversity and composition directly correlates with host health. The gut microbiota diversity is a function of genetics, age, diet, lifestyle and other environmental factors. For example, obese people tend to have a higher number of phyla Firmicutes and a lower number of phyla Bacteroidetes. The Western diet tends to reduce bacteria belonging to Lactobacillus and Bifidobacterium. In the patients of irritable bowel syndrome, Lactobacilli and Bifidobacteria decrease, while Escherichia coli and ratio of Firmicutes to Bacteroidetes increase. Gut health is not maintained by a single bacterium, but by a balance and diversity of bacteria as a whole.
3. In what ways can Asia-Pacific consumers improve their digestive health?
The risk of diseases including inflammatory bowel disease, obesity, type 2 diabetes, cardiovascular disease, and cancers are increasing in Asia-Pacific region. These changes are partially due to a westernized diet and inactive lifestyle.
To maintain gut health and microbiota diversity, I would suggest:
- Having nutritional and balanced diet rich in fibre, but low in fat and sugar. A balanced and nutritional diet is a key to maintaining the diversity and composition of gut microbiota
- Exercising regularly, because an active lifestyle contributes to the maintenance of healthy gut microbiota
- Avoiding the use of antibiotics, because the frequent use of antibiotics affects the diversity and composition of microbiota
- Avoiding the use of tobacco
- Consider taking probiotics and prebiotics supplements if necessary
4. Could you highlight what are the current trends in the digestive health market?
The global digestive health products market size is about US$33 billion with a yearly increase of 7.3 percent. These products are mainly probiotics and prebiotics. The probiotics refer to the products containing alive microorganisms which when consumed in adequate amounts as part of food confer a health benefit on the host, while the prebiotics refer to the products containing a non-viable food component that confers a health benefit on the host associated with modulation of gut microbiota.
5. What ingredients would you advise to look out for when purchasing supplements for digestive health?
The probiotics products in the market are mainly based on three types of bacterium species, namely Lactobacillus spp., Bifidobacterium spp., and Bacillus spp.
Lactobacillus species can produce lactase and lactic acid, change the gut pH and inhibit the growth of pathogenic bacteria, and also enhance the absorption of nutrients such as minerals.
Bifidobacterium spp. reside in the large colon where they produce lactic acid and short-chain fatty acids, maintain the intestinal pH, ward off the pathogenic bacteria, and provide 70 percent energy to the large intestinal cells.
Bacillus spp. are spore-forming bacteria and produce lactic acid. It may be resistant to stomach acid, heat, and light, but when compared to the lactic acid bacteria (i.e. Lactobacilli, Bifidobacteria), the spore formers would survive well in the acidic stomach, alkaline intestinal bile, enzymatic digestion and low water activity within the lower intestinal tract. In addition, Bacillus spp. have been shown to survive processing conditions, such as high heating, freezing, pressuring, drying, and prolonged storage conditions.
Prebiotics are naturally present in foods such as in vegetables and fruits like bananas, onions, asparagus, garlic, artichoke, beans and pomegranate. The prebiotics offered in the market usually contain either oligosaccharides or non-digestible polysaccharides. The more common types of oligosaccharides include fructo-oligosaccharides (FOS), xylo-oligosaccharide, galacto-oligosaccharides (GOS), soybean-oligosaccharides and chitosan oligosaccharides, among many others. For example, FOS and GOS have been added to baby formulas to boost the growth and colonization of beneficial bacteria in the guts of infants. Polysaccharide-containing products usually consist of plant fibre, inulin and chitosan. They help to clean up the GI tract, promote the growth of probiotics, and maintain GI health. It is worthwhile to note that humans also need at least 25 grams of fibre each day.
6. What biological mechanisms do these ingredients support to help in improving digestive health?
The mechanisms by which probiotics are beneficial to the GI health in the host are mediated by one or more combinations of the following actions:
- Improving gut health directly by changing the gut microbiota profile of the host
- Alleviating lactose-intolerance
- Enhancing the immune system
The mechanisms by which the prebiotics are GI-beneficial are mediated by maintaining the integrity of GI cells, while promoting the growth and colonization of beneficial bacteria in not only diversity but also composition and number. Humans need both probiotics and prebiotics by either eating regular foods or taking health supplements.
Dr Chen Zhen-Yu, Nutrition Advisory Board, Herbalife Nutrition