FAQs

Foods as vectors of microorganisms (fermented foods) Activities 2.2-2.6

I cannot see the quiz.

Apologies if you cannot see the exercise, this may be due to your fire wall settings, for those that cannot see the quiz, you may be surprised to learn that all these foods are fermented during processing: Beer, Bread, Yoghurt, Wine, Sauerkraut, Black tea, Kefir, Black coffee, Soy sauce, Salami, Kombucha, Cheese, Green coffee, Cocoa beans

Are all cheeses fermented?

Yes all cheeses are fermented, from soft cheeses (like cottage cheese, mozzarella, and others) to the long ripened cheeses like Parmigiano and Grana. Emmental is fermented as well, the holes it contains are gas bubbles created by fermentative bacteria (called Propionibacterium) producing carbon dioxide.

What type of fermentation occurs with coffee and tea? I don’t think these have sugars which need to be transformed and understand that heat is used to dry or roast the leaves/beans?

The fermentation of coffee takes place when the seed (bean) is still in the coffee fruit ‘cherry’. The cherries are collected and before the separation of the seed (green coffee) there is a short fermentation which can be wet (in water) or dry. Basically, the cherry is broken and the pulp is left in contact with the seed. The sugars contained are fermented mainly by yeasts. For the tea, the enzymatic activity, coming from the leaves, and impacts the final quality of the tea (high oxidative activities). Fermentation occurs because of the use of some low level sugars contained in the leaves. Lactic acid bacteria are usually found in these ecosystems.

I find it interesting to learn that sausages are fermented. I didn’t know that they are. Are all sausages fermented, or just certain types of sausage and, if so, which ones?

Actually, here there is an issue with the language and terminology since in England ‘sausages’ are not fermented. However, Salami and pepperoni are fermented. There is a lot of variety of products in the different countries and that’s why is difficult to use a strict terminology.

Food meets your gut microbiota (Activities 2.7-2.13)

Why are bananas grouped with high resistant starch foods?

Unripe bananas are rich in resistant starch, which is gradually lost during ripening. Read more about levels of RS in bananas here: https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/resistant-starch.html https://doi.org/10.1016/j.ijbiomac.2018.09.140 https://doi.org/10.1080/10942912.2020.1788077

It would be interesting to know roughly how far off we are from getting a camera that could be used instead of colonoscopy or gastroscopy.

Camera pills are already in use in some areas, see this post from Cancer Research UK: https://www.cancerresearchuk.org/about-cancer/cancer-in-general/tests/capsule-endoscopy

How much fibre is the recommended daily intake for a healthy adult?

UK Government guidelines say our dietary fibre intake should increase to 30g a day, as part of a healthy balanced diet. As most adults are only eating an average of about 18g day, so we need to find ways of increasing our intake. In Europe, for adults, the recommended amounts of dietary fibre for promotion of adequate laxation and for prevention of NCDs such as diabetes type 2, colorectal cancer, CVD or of overweight and obesity range from 25 to 38 grams/day https://ec.europa.eu/jrc/en/health-knowledge-gateway/promotion-prevention/nutrition/fibre

Can you provide further reading on research into Resistant Starch?

Sure, check out these papers An RS intervention improved insulin sensitivity in patients with metabolic syndrome: https://doi.org/10.1111/j.1464-5491.2010.02923.x

A meta-analysis indicated that certain subgroups of T2D patients are having more benefit: https://doi.org/10.1186/s12944-019-1127-z A diet rich in RS was shown to increase the Firmicutes to Bacteroidetes ratio: <a href="https://doi.org/10.1128/mBio.01343-17%20%20https://doi.org/10.1128/mBio.01343-17 < https://doi.org/10.1128/mBio.01343-17). Here is also another couple on Bifidobacterium and RS: https://doi.org/10.1016/j.clnu.2017.03.025 https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-016-0178-x

How do other grains used in the past, such as spelt and emmer, compare for Resistant Starch?

See this paper where they compare spelt and common wheat fvarieties or RS, but also looked at the breads made our of these: https://doi.org/10.1016/S0308-8146(99)00215-0

Influence of different bioactive food components on gut microbiome Activities 2.14-2.18

Can you provide further reading to go with the video on “Impact of diet in shaping gut microbiota” activity 2.14?

Sure, here are 3 https://pubmed.ncbi.nlm.nih.gov/20679230/ https://www.nature.com/articles/ncomms7505 https://doi.org/10.1038/ncomms4654

Probiotics, prebiotics, postbiotics, Activities 2.19 2.22

Probiotics vs fermented foods, please summarise the difference

Probiotic is a microbial strain that has scientifically proven benefits for human health. The products that contain probiotics can be labelled as probiotic food and should follow strict rules for the labelling. Fermented products most of the times do not contain probiotic bacteria. They contain live bacteria which not necessary are probiotics.