Historically the fermentation technique was used as a way of preserving foods and drinks long before the days of refrigeration. During the process of fermentation, microorganisms such as bacteria, yeast or fungi convert organic compounds, such as sugars and starch, into alcohol or acids. For example, starches and sugars in vegetables and fruits are converted to lactic acid and this lactic acid acts as a natural preservative. Fermentation can produce quite distinctive, strong, slightly sour flavors.
The consumption of foods and drinks that have undergone fermentation contain benefits to health that stretch beyond food preservation. The transformation of sugars and starches enhances the natural, beneficial bacteria in food. These bacteria, known as probiotics or ‘good’ bacteria, are thought to help a multitude of health issues, specifically digestive health.
The bacteria that live in our gut are essential. They help with digestion, absorption and assimilation of nutrients. Plus, they play a role in the function of our immune system. However there are ‘bad’ bacteria that also reside in the gut and the challenge is achieving the right balance between the two. When the balance is shifted in favor of the bad bacteria, symptoms may arise such as bloating, constipation or diarrhea. This is known as ‘dysbiosis’ – the state in which the gut flora are out of balance.
Modern diets high in refined sugars, and busy, stressful lifestyles can contribute to dysbiosis by feeding the bad bacteria, enabling them to flourish. Eliminating refined, high sugar foods and including probiotic-rich fermented foods in the diet is thought to help bring the gut back into balance and support the immune system.
Fermented foods are rich in probiotic bacteria, so by consuming fermented foods you are adding beneficial bacteria and enzymes to your overall intestinal flora, increasing the health of your gut microbiome and digestive system and enhancing the immune system.
Digestion and absorption
As some of the sugars and starches in food have been broken down through the process, fermented foods are easier to digest. For example, fermentation breaks down the lactose in milk to simpler sugars – glucose and galactose – which, if you are lactose intolerant, can make products such as yogurt and cheese potentially easier to digest.
Synthesis and availability of nutrients
Fermentation can also increase the availability of vitamins and minerals for our bodies to absorb. Additionally, by boosting the beneficial bacteria in your gut, you are promoting their ability to manufacture B Vitamins and synthesize Vitamin K.
A large proportion of the immune system is housed in the gut. By consuming probiotic-rich foods, you are supporting the mucosa (gut lining) as a natural barrier, making the immune system more robust. A lack of beneficial bacteria allows disease causing microbes to grow causing inflammation in the gut wall. If you have recently taken a course of antibiotics, probiotic foods are particularly helpful.
Some natural compounds that interfere with the absorption of nutrients can be removed by fermentation. Phytic acid, for example, which is found in legumes and seeds, binds minerals such as iron and zinc, reducing their absorption when eaten. However, phytic acid can be broken down during fermentation so the minerals become available.
Mood and behavior
The gut and brain are linked, through the hypothalamic-pituitary-adrenal (HPA) axis. Technically called the enteric nervous system, the gut is lined with neurons that can influence our emotions and feelings. Serotonin – a neurotransmitter involved in mood – is made in the gut and research further suggests that as probiotic bacteria contribute to a healthy gut, they are also linked to a healthy mind.
The bacteria in our gut are not something we think about, yet research suggests they perform a number of vital functions. The links between fermented foods, gut bacteria and how they may affect our physical and mental health warrants considerable attention. For more information, take a look at the The Human Microbiome Project https://hmpdacc.org/hmp/overview/