The benefit of a diverse diet may be explained by the variety of bacteria species an individual possesses. The diversity of the microbiome is inversely related to an individual’s weight.
The idea of how a diverse diet is beneficial for the health has been around for centuries. Experience shows health arises from acquiring a diverse range of nutrients, by eating a variety of food, from vegetables to meat, fish and fruit. Today it is known why; it influences the makeup of the microbiome, the ecosystem of bacteria of the gut. These bacteria are essential for life and outnumber the cells in the human body, emphasising their immense influence on human health. Most are beneficial to the body and mostly converge in the gut to aid the digestion of food, the richness of the microbiota species regulates an individual’s health. Conversely, over-weight individuals display reduced bacterial richness, insulin resistance, dyslipidaemia and a more pronounced inflammatory response. The presence of only a few species of bacteria are necessary to identify whether someone may be lean or overweight.
The influence of diet appears to be particularly important in childhood. These are the formative years when an individual’s diet shapes the weight, health and habits which become entrenched by adulthood. The microbiome of a child appears to be richer and much more adaptable in conjunction with their weight. This may be the result of behavioural changes and biological alterations being more malleable in childhood. This may be partly explained by children consuming diverse foods before adult habitual diets, henceforth the microbiome remains relatively stable.
Differences in the microbiota and acquired genetic properties are seen in different individuals. An enrichment of corresponding genes within these bacteria is created through the ingestion of distinct nutrients. When infants start to receive adult foods, genes in the microbiome associated with vitamin synthesis and carbohydrate digestion are enriched. This enrichment may be further highlighted by an observation in which the Japanese possess a gene involved in the digestion of seaweed, which is absent in Americans. The diet of the Japanese contains the seaweed microorganism which transfers its genes to the microbiome. This epitomises the role microbes have in expanding the metabolic tools of the human gut allowing a sizable diversity of foods to be digested.
This process and dietary diversity may be limited today because 75% of the world’s food sources derive from 12 plants and 5 animal species. The UN estimates a 75% reduction in plant genetic diversity and livestock breeds. This and the use of agricultural antibiotics may further reduce the diversity of received microbiota. Importantly, a reduced composition of the microbiome forms the basis and development of many conditions, including average weight, type 2 diabetes and inflammatory conditions. Arousing a greater diversity of bacteria leads to a greater resilience to changes to this ecosystem and prevents many conditions. Introductions of certain species of bacteria are also known to reverse symptoms in some conditions. The significance of reducing the microbiome in relation to human health and weight may be also demonstrated by studies on antibiotics. These suggest early exposure to antibiotics has an effect on weight and metabolism later in adulthood. After all, the meaning of ‘bio” is “life”.
Ultimately, the diet is important for the health and may influence the microbiome within 3 days. Diversity may be paramount and it may be necessary to evade diets which eliminate certain nutrients. Natural foods are more beneficial to the health and are converted into supportive microbes unlike particular processed foods. However, each individual may need a personalised diet which requires the addition of particular foods and specific microbes, to thoroughly improve the health.
How do genes transfer from particular foods to the microbiome?