Fermentation – an age-old process with a healthy twist!
There has been a revival of fermented foods and this is quite possibly going to a long term trend! Fermented foods such as yoghurt, cheese, wine and beer have been around for centuries. Fermentation involves added a controlled amount of a microorganism to a food, such as yeasts or bacteria. These microorganisms then ‘feed ‘on the food, producing several by products which give a fermented food its characteristic taste.
Fermentation improves shelf-life and the nutritional properties of a food
Fermentation increases both the shelf life, safety and organoleptic (smell, taste, touch) of a food. There is also increasing evidence that the fermentation process enhances the nutritional properties of a food which in turn can help to optimise health.
Yoghurt – an ancient, natural fermented food product
Yoghurt is an ancient fermented food believed to date from 500 BC when it was discovered that the curdling of milk helped to preserve the milk. Roll forward to modern times and yoghurt is produced by adding two main types of bacterial species, Lactobacillus bulgaricus and Streptococcus thermophilus bacteria. These bacteria break down the lactose, a type of sugar naturally present in milk and convert it to lactic acid. This gives yoghurt its characteristic tart flavour.
What are the health benefits of yoghurt?
Yoghurt is a nutritious food containing macronutrients such as protein as well as vitamins and minerals such as calcium, Vitamin A, B vitamins (B2 and B12) as well as calcium, magnesium and potassium. It’s a true ‘super food’! Yoghurt also contains bacterial cultures like the ones found in our gut microbiome. Research has ‘spot lighted’ the presence of these fermented cultures as a major contributing factor to yoghurt’s health benefits. The human gut microbiota (the living organisms in our digestive system) play an important role in supporting our digestive function and immune systems. They also play a role in energy regulation.
Yoghurt and the human microbiota
The bacteria present in yoghurt are known to have anti-inflammatory (able to reduce inflammation) and antipathogenic (ability to protect from organisms which can harm us) properties. These bacteria are naturally present in our microbiota already and research has identified that the bacteria present in yoghurt, particularly the Lactobacillus sp are able to survive the passage through our digestive tracts and reinforce the colonies of bacteria which live in our intestines.
Yoghurt consumption and chronic disease
Yoghurt consumption is associated with a reduced risk of chronic diseases and researchers have identified that the bacteria present in yoghurt are a factor in reducing this risk.
Yoghurt and weight
While there is a lack of clinical trials, some observational studies have found an association between yoghurt consumption (as part of a balanced diet) and weight loss although the results are not consistent. The potential mechanisms (reasons) for this are linked yoghurt’s calcium content and the possible benefit to the gut microbiota. Calcium has been identified as helping to support weight and fat loss. The bacterial cultures found in yoghurt may equally alter the human microbiota so that certain colonies found in our the gut microbiota become less efficient at storing energy. This in turn has a positive effect on fat accumulation (ie it supports a reduction in fat storage).
Yoghurt and Cardiovascular disease
A recent study in the American Journal of Hypertension found an association between a high yoghurt consumption (at least 2 servings a week) and lower cardiovascular disease risk in hypertensive men and women. The risk for men was reduced by 21% and the risk for women by 17%. The mechanism is not clear although again researchers link this benefit to a reduction in hypertension through the gut microbiota releasing signals which help to optimise the constriction and dilation of the blood vessel walls.
Yoghurt and Type 2 Diabetes
A study found that that a high yoghurt consumption (an average of 4-5 pots of 125 ml yoghurt) was associated with a 28% reduced risk of developing diabetes. Replacing the lower nutritional quality type of snacks with yoghurt also reduced the risk of developing type 2 diabetes. The nutritional profile of yoghurt with its protein, calcium and magnesium could be a contributing factor in this risk reduction. The researchers also identified that the beneficial effect could be linked to the bacteria present in yoghurt playing a role in lowering inflammation and improving insulin sensitivity.
Yoghurt consumption is associated with a lower risk of chronic diseases
Yoghurt has a high nutrient profile. It contains several nutrients which are essential for health such as protein, calcium and magnesium. There are increasing studies which associate its fermented properties with providing additional health benefits because of the presence of bacterial cultures contributing to the diverse microbiota in our guts. While additional clinical research is needed, yoghurt consumption is associated with a decreased risk of several chronic diseases such as obesity, type 2 diabetes and cardiovascular disease.
Adolfsson, O, Meydani, S and Russell, R (2004) Yogurt and gut function, The American Journal of Clinical Nutrition, 80 (2), pp. 245–256.
Buendia J, Li, Y et al (2018) Regular Yogurt Intake and Risk of Cardiovascular Disease Among Hypertensive Adults, American Journal of Hypertension, DOI: 10.1093/ajh/hpx220.
Jacques PF and Wang, H. (2014) Yogurt and weight management, The American Journal of Clinical Nutrition 99 (5), pp. 1229S–1234S.
O’Connor L, Lentjes M and ,Luben R et al. (2014) Dietary dairy product intake and incident type 2 diabetes: a prospective study using dietary data from a 7-day food diary, Diabetologia. 57(5), pp.909-17.