Fermented food such as yogurt and cheese are popularly considered good for our health. All sorts of benefits have been suggested, from weight control to protection against killer diseases such as cancer, diabetes, heart disease and stroke. But how much of this is just wishful thinking, and how much is supported by real science?
A team of Swiss scientists has examined the evidence – and found that yogurt stands out among fermented foods as having the strongest evidence for a beneficial effect on risk factors for type 2 diabetes.
Fermented foods are made with the help of microbes and enzymes. They’ve been used since early human civilisations as a way of preserving food or improving the taste or nutritional qualities of a food. Fermented foods are present in all food groups including dairy, vegetables, cereals, fruits, meat and fish. Among these, the effect on health of dairy products such as yogurt has been a particular focus of research attention.
Reviewing the evidence: yogurt and reduced risks for diabetes
In an extensive review of studies looking at the effects of a range of fermented foods on diseases – heart disease, stroke, high blood pressure, diabetes, high cholesterol, cancer and inflammation – the authors found that the strongest evidence for a health benefit was for yogurt, on the risks associated with type 2 diabetes.
They also found some weaker evidence that cheese is associated with a reduced risk of stroke and that yogurt might help reduce weight gain. In most cases, they found no effect, either positive or negative, although there was some inconsistent evidence that total consumption of fermented dairy products could protect against cardiovascular disease.
The researchers also point out that fermented products such as yogurt and cheese can allow people with lactose intolerance to consume dairy products without suffering symptoms.
For all the other fermented food and drinks studied, such as pickles, wine, beer and coffee, there were many promising signs from laboratory trials. But none had been backed up by research in humans.
The researchers found no evidence to suggest that normal consumption of fermented foods might be harmful to health.
‘The strongest evidence for a beneficial effect of fermented dairy products was found for the effects of yogurt on risk factors associated with type 2 diabetes.’ Gille D et al, 2018
How yogurt might protect against diabetes
The evidence for yogurt’s positive effect against type 2 diabetes comes from five separate reviews looking at the health benefits of fermented dairy products.
The researchers suggest several ways in which yogurt consumption might achieve this protective effect against risks for type 2 diabetes. They point out that the probiotic bacteria present in yogurt have been shown to improve lipid profiles and the antioxidant status of people with diabetes. These probiotics can also improve cholesterol levels and may help boost insulin sensitivity, which becomes reduced in the run-up to type 2 diabetes. Fermentation by-products, such as peptides and vitamins, in particular vitamin K2, synthesised by live bacteria might also contribute to this beneficial effect.
Should yogurt be recommended in nutritional guidelines?
According to the researchers, only five EU states recommend either probiotics or fermented milks in their national nutritional guidelines. They suggest that further research into specific products such as yogurt could improve this guidance.
In order to strengthen the evidence for or against the health benefits of fermented foods, the authors also call for further well-designed studies to see the effect of fermented products in specific health conditions. This would allow clear recommendations to be made, for example, on the consumption of yogurt and diabetes, or cheese intake and stroke.
Find out more: read the original article.
Source: Gille D, Schmid A, Walther B, Vergères G. Fermented food and non-communicable chronic diseases: a review. Nutrients. 2018 Apr 4;10(4).