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The double burden of malnutrition is characterised by the coexistence of under nutrition along with overweight and obesity, or diet-related no communicable diseases, within individuals, households and populations, and across the life course. (World Health Organization, 2019)
According to an infographic published by WHO, in 2014, more than 600 million adults worldwide were obese, 1.9 million were overweight and at the same time 462 million were underweight. (Who.int, 2019). In addition to this 42 million children under the age of five were overweight or obese, 156 million were affected by stunting (low height for age), and 50 million were affected by wasting (low weight for height). In the same year 264 million women of reproductive age were affected by iron-amendable anaemia.
The cause of the double burden of malnutrition is multifactorial and can include the changing global nutrition, economic and income growth, Climate change, rapid urbanisation, demographic change, increased risk of diet and lifestyle related epidemiology and globalisation but some of these causes can also be linked to the adaptation of the gut microbiota as a result of more predominant C-section deliveries, less breast fed babies, overuse of antibiotics, poor diet, stress, the hygiene hypothesis and the overconsumption of sugar and processed foods.
Four Contributing Factors worth highlighting
1/ Shift in Quality and quantity of human diets associated with economical development shifting from under-nutrition in populations to over-weight or obesity
Under nutrition doesn’t necessarily represent a lack of food as most people might think, there are many children eating an excess of poor quality high calorie food, resulting in obesity and malnutrition at the same time.
In most countries, people have access to calorie dense fast foods, sugar laden packaged meals and addictive sweetened beverages that are cheap, convenient and lacking in essential nutrients. Poor food choices and consumer choice are influencing the obesity epidemic and to combat it we must develop a culture of shared responsibility.
Poor nutrition continues to cause nearly half of deaths in children under five, while low- and middle-income countries now witness a simultaneous rise in childhood overweight and obesity – increasing at a rate 30% faster than in richer nations. (World Health Organization, 2019)
The simultaneous rise in obesity can possibly be explained by increased caloric intake, decrease in physical activity, changes in dietary composition and alterations to the gut microbiota.
High-fat diets generally lead to low presence of microbes from the groups of Bacteroidetes and Akkermansia and an over-representation in the groups of Firmicutes and Proteobacteria.
The same alterations have been associated with obesity, inflammation and subsequent development of related chronic diseases.
2/ Nutrition related epidemiology that has occurs over the past decades shifting from acute infectious diseases to chronic lifestyle diseases.
The coexistence of contrasting forms of malnutrition is a global challenge to say the least, we have in many parts of the world, the persistence of under-nutrition, along with a rapid rise in overweight and obesity significantly increasing the risk of a whole host of diet-related chronic health conditions such as diabetes, stroke, hypertension, cancers and heart disease.
As consumers, its important to accept the responsibility that the food choices we make have consequences that directly effects our health.
Type 2 Diabetes is known as a preventable obesity related lifestyle disease, which is also known as a comorbidity. Obese and diabetic persons have a different intestinal microbiota composition showing a lower abundance of the beneficial microbe Akkermansia muciniphila which influences body weight regulation, bile acid metabolism, pro-inflammatory activities, and secretion of gut hormones.
The number of people with diabetes has risen from 108 million in 1980 to 422 million in 2014 (Who.int, 2019)
3/ Low socioeconomic status, poverty and food insecurity that results in an inability to afford nutrient rich foods causing stunting from under-nutrition but correlating to a possibility of overweight or obesity in later life
Under-nutrition in children can have long-term health consequences because they need fast growth for their development. The gut microbiota of an under-nourished child remains immature in comparison with a healthy individual and this can have negative effects on cognitive development, immune system and growth rate.
Undernourished infants often miss bacteria from the Clostridium and Ruminococcus group, which are the bacteria that produce butyrate, which is an energy source for host cells that allows the microbiota to contribute to the caloric value of food.
4/ Biological early life experiences such as delivery method, breast-feeding and first 1000 days of life
Lactating mothers and pregnant women need more quality nutrition to ensure the healthy growth and development of the baby.
Since 1985, the international healthcare community has considered the ideal rate for caesarean sections to be between 10% and 15%. Since then, caesarean sections have become increasingly common in both developed and developing countries. (Apps.who.int, 2019)
The delivery method used when you are born has been shown to influence the microbiota found in the intestines, which can affect health conditions such as asthma, diabetes, obesity and allergies in later life.
A child who is vaginally birthed will have a microbiota that resembles that of the mothers vaginal microbiota but a child who is born via C-section will have a microbiota that resembles that of the doctor and mothers skin, with a lower diversity of microbes and a delay of the very important B.bifidobacterium.
The speculated hypothesis surrounding Caesarean disadvantages include:
- Different microbes colonising the intestines have different effects on the development and training of the immune system
- The microbes from the mothers lower body are specifically selected by her immune system and have been proven to aid in food digestion and symbiosis of the gut and vagina in turn decreasing the child’s potential risk of pathogens whilst increasing food degradation in the intestine.
The initial transmission of microbiota from mother to infant during a natural vaginal birth provides the child with microbes considered beneficial by the mother’s body.
Antibiotics are routinely administered during C- section deliveries, which can result in long-lasting shifts in the microbiota composition and metabolism. The shifts include depletion of bifidobacteria and the increased amounts of specific bacteria from the Firmicutes and different clostridial groups. This has been associated with the development and onset of allergic diseases. Antibiotic induced disturbances of the host microbial balance during early life can also play a role in overweight, and obesity development in later life though more research is needed to provide a solid causal effect.
Breast Fed or Formula Fed
Breastfeeding is an unequalled way of providing ideal food for the healthy growth and development of infants; exclusive breastfeeding for 6 months is the optimal way of feeding infants. Thereafter infants should receive complementary foods with continued breastfeeding up to 2 years of age or beyond. (World Health Organization, 2019)
Human milk is very different from infant formula. The main components of human milk are lipids, proteins, lactose, immune molecules and oligosaccharides. Oligosaccharides cannot be used by the infant and is used as a prebiotic dietary fibre that stimulates the growth of bifidobacteria in the microbiome. The most commonly found bifodobacteria in the gut of breast-fed infants are: Bifidobacterium bifidum, Bifidobacterium breve and Bifidobacterium longum infantis.
The bifidobacteria are extremely efficient in the degradation of lactose oligosaccharides and they form the short chain fatty acid Lactic acid, which contributes to the acidic environment that protects against pathogens. The process of cross feeding that takes place in a breast fed child enables microbes to grow leading to the establishment of a healthy microbial community and further more, the Bifidobacterium directly effect the intestinal epithelial cells and affects the immune response.
Gene regulation of intestinal cells is also different with breast fed babies showing enhanced expression of genes related to metabolic and immunological activities.
Human milk contains oligosaccharides and immune molecules as opposed to formula, which does not. These different conditions in the gastrointestinal tract in turn lead to a different selection of colonizing microbes.
Breast-fed infants typically have a microbiota dominated by bifidobacteria, while formula-fed infants have a more diverse microbiota. On top of this, Immunoglobulin A (IgA), is the most abundant immune molecule in human breast milk and this stimulates a healthy immune system.
Formula fed microbiomes are shown to mature faster resulting in an increased proportion of Propionate and butyrate and a different level of microbial fermentation, such as short chain fatty acids (SCFA’s) which can also be linked to an increased risk of health problems in early or later life, but also weight gain and obesity.
The first 1000 days are life is crucial for a child’s growth and development and good nutrition is necessary. The WHO recommend a minimum of 6 months then continuing with complimentary foods until at least 2 years because at 6 months the baby is still developing in terms of the microbiota, immunological and neurological composition.
A child is born with an undeveloped brain which doubles in size within the first year and reaches 80% volume by age three.
Malnutrition in early life can result in impaired cognitive ability in later life. The immune system develops in parallel with the intestinal microbiota immediately after birth leading to a healthy balance between the two. Low abundance of butyrate producing bacteria in the gut of a malnourished child is associated with allergic symptoms in later life.
The composition of the microbiota changes substantially at two stages in early life:
one from birth to weaning, and from weaning to adulthood driven by the further diversification of the diet.
The implementation of Sugar Tax
In some countries, policy makers have implemented a ‘sugar tax’. The sugar tax is a levy charged to drinks companies to crack down on high sugar levels in beverages. The surcharge varies depending on the sugar content of the product. In the UK, one tax is for drinks with a total sugar content of more than 5g per 100ml, while a second, higher tax is imposed on drinks with 8g or more per 100ml.
While the etiology of obesity is complex, increased consumption of free sugars, particularly in the form of sugar-sweetened beverages, is associated with weight gain in both children and adults. (Who.int, 2019)
On average, a single can of a sugary drink contains around 40 grams of free sugars2 (equivalent to around 10 teaspoons of table sugar). (Apps.who.int, 2019)
Despite recommendations by health organisations and medical professionals to limit consumption, sales of sugar-sweetened beverages are still increasing worldwide, especially in low- and middle-income countries as a result of heavy marketing.
Though the sugar tax has been met with some resistance from the sugar industry and there is a debate about consumers choice, I personally feel this Pegovian tax is a move in the right direction as it brings awareness to the sugar content of beverages and makes unhealthy drink consumption more expensive for the consumer while sending a clear message from the government to the sugar industry.
Of course, a tax alone is not going to solve the obesity problem but the taxes can be used to finance more health-orientated programmes designed to tackle and reduce obesity.
There is clear evidence that these sugary beverages are linked to the rise of obesity, type 2 diabetes, poor oral health and other diet-related epidemiology but they are not the only cause so the idea to extend the tax to other sugar laden products is promising but there also needs to be a better focus on education, improved selection in vending machines and school dinners and further restrictions on targeted marketing strategies that promote sugar consumption.
I feel a tough love policy is needed as an effective intervention as relying on the intelligence of the consumer’s choice is failing. The taxation strategy had a positive effect on tobacco in the fight against lung cancer so it could work for sugar to combat obesity and diabetes.
In Mexico, two years after the introduction of a tax on sugary drinks, households with the fewest resources reduced their purchases of sugary drinks by 11.7%, compared to 7.6% for the general population (Apps.who.int, 2019)
Over-weight and Under-weight (or wasting and stunting) within families
The microbiome plays an important role in under-nutrition, which is a specific type of malnourishment that refers to a shortage of essential nutrients and/or calories often due to a lack of available food. The result of this is often evident as underweight, wasting or stunting.
- Stunting refers to a person that has low height for age, it often causes delays in cognitive and physical potential and is a consequence of long-term under-nutrition during childhood.
- Wasting refers to a person that low weight for height and is often the result of an infectious disease that’s results in chronic diarhea
- Underweight refers to a child with low weight for age, who could also be wasted and/or stunted
In some families, we find both over and underweight or wasted and stunted individuals and the answer to this phenomenon lies in the gut microbiota. Commonly, members of the same family have more similarities to each other in the microbiome than they do to other individuals but there are a number of factors that can influence this.
As outlined above there could be differences in children within the same family (over-weight, underweight, wasted or stunted) depending on their birthing mode, environmental factors, dietary intake, food preferences, diversification, if they were breast fed or formula, antibiotic exposure, location, food availability and if they had ever had an infectious disease that resulted in chronic diarhea.
Under-weight, wasted or stunted children becoming obese in later life
A food system that does not deliver a sufficient amount of quality food can lead both to poor growth and to excess weight gain. A child who has grown poorly in his first years of life may turn into a short but overweight adolescent and then later in life, develop chronic disease as an adult. (Who.int, 2019)
The gut microbiota plays a role in the severity of under-nutrition by releasing less energy
from food substances. Undernourished children seem to have a microbial diversity that seems ‘younger’ but the introduction of solid food into a child’s diet is a life-changing event that causes a big shift in the microbiota.
Under-nutrition, particularly stunting, has also been known to result in overweight later in life. Stunting is a risk factor in early childhood that may result in overweight later in adolescence and adulthood. Promoting exclusive breastfeeding is important in preventing both stunting and overweight among children. Formula fed microbiomes are shown to mature faster resulting in an increased proportion of Propionate and butyrate and a different level of microbial fermentation, such as short chain fatty acids (SCFA’s) which can also be linked to an increased risk of health problems in early or later life, but also weight gain and obesity.
The microbiota also plays a major role in the nutritional value of food and the degradation of proteins and non-digestible fibers resulting in energy for the host. No matter how an infant was born or what the milk source was, upon the introduction of solid food, the initial differences in the microbiota development between individuals will disappear and the introduction of solid foods will mature the microbiota. The diversity of the microbiota increases and the short chain fatty acids (SCFA) profile shifts increasing Butyric levels to increase the nutritional value of new food sources.
Obesity in later life can possibly be explained by increased caloric intake, decrease in physical activity, changes in dietary composition and alterations to the gut microbiota. The introduction of a high fat High-fat diet can generally lead to low presence of microbes from the groups of Bacteroidetes and Akkermansia and an over-representation in the groups of Firmicutes and Proteobacteria. The same alterations have been associated with obesity, inflammation and subsequent development of related chronic diseases.
Influencing the gut Microbiota in a positive way
There is no single solution to fix the double burden of malnutrition because we know there are so many factors that exacerbate the problem. We must look at consumer behaviour, climate change, trade system, educational policies, marketing strategies, mass urbanization, agricultural systems, food production, child feeding, birthing methods and medical interventions.
Focusing on maternal health and early life interventions stages is crucial to tackling the double burden. The transmission of bacteria and the establishment of a stable microbiota depend on genetic makeup, environment and eating habits so these are good areas to focus on. Understanding this early interaction between the intestinal microbiota and the human body allows for the introduction of nutritional strategies.
Ways to keep your microbiota healthy
- Personalized nutritional strategies: taking into account physiological differences, diseases, habits, preferences, and societal environments.
- Prebiotics: these are fibers that escape digestion in the small intestine and when reaching the colon, they are partially or completely fermented by the gut microbiota. Because the microbes that can degrade the fiber are favoured in their growth the composition and the activity of the gut microbiota changes which is beneficial for the host.
- Probiotics: these are live microorganisms which, when administered in adequate amounts, confers a health benefit on the host. A probiotics can compensate an undesired change in our gut microbiota due to antibiotics or an infection by shortening the time of recovery of the microbiota. A probiotic can strengthen the immune system. It can also provide health-promoting short-chain fatty acids. And finally probiotics can prevent infection with pathogens.
- Synbiotics are mixtures of probiotics and prebiotics that beneficially affect the host: By combining these two in a food product, there is a better survival and activity of the microbes in the gut.
- Fecal microbiota transplants: The rationale behind a fecal microbiota transplant is to simple restore a gut microbiome that is out of balance. A healthy microbiota means there is an equilibrium in which there is hardly any room for pathogens to colonize.
- Next-generation probiotics: can be used for the improvement of bacterial cultivation, genome sequencing and to modify bacterial genomes.
- Donor breast milk: The WHO and UNICEF are not only creating campaigns to provide donor breast milk for low birth weight babies but they have also developed an effective breast feeding training course for health workers. Formula manufacturers are also adding additional fibers, like fructo-oligosaccharides (FOS) and galacto-oligosacchardes (GOS) to try to improve the resemblance between the microbiota of formula fed babies and human milk but the effectiveness of this is still not proven.
I believe that the WHO should offer more advice on ways to influence the gut microbiota for the better but I also think that as evidence based information related to the microbiome grows, more medical professionals and governments will focus treatments and nutritional strategies based around testing and treatment of the microbiome for a totally personalised approach.
As the occurrence of infections such as Colostrum Difficile grows, the paradigm of health will move towards a treatment of bugs not drugs. I’m excited to see where this new approach will take us.