Week 2

WHAT IS THE MICROBIOTA?

The microbiota can be defined as the ecological community of commensal, symbiotic and pathogenic microorganisms that share an ecological niche. This means that we can define different microbiota in different ecosystems: gut microbiota includes microorganisms in the gut; food microbiota is present in foods; soil microbiota inhabits the communities in the soils. Nowadays, we also hear a lot about microbiome (e.g. human microbiome). The term ‘microbiome’ refers to all the genetic material within a microbiota (the entire collection of microorganisms in a specific niche).

HOW CAN I REDUCE THE FLATULENCE CAUSED BY THE CONSUMPTION OF LEGUMES?

Consumed all over the world, pulses are an excellent source of protein and dietary fibres. Their consumption has been recommended as part of a healthy diet. However, they contain various antinutrients such as indigestible carbohydrates called alpha-galactosides. These oligosaccharides ferment thanks to the action of the microorganisms present in the gut, hence producing gas and causing flatulence in healthy individuals – a fact which explains the reluctant acceptance of legumes in the Western diet. Various methods for effectively removing alpha-galactosides from different pulses have been tested: one of the most widely known processing combinations is soaking and cooking. Soaking is the oldest and most traditional method of removing alpha-galactosides from pulses. Dried pulses are placed in a bowl of water and allowed to rehydrate over a long period of time (generally overnight). The water-soluble alpha-galactosides are drawn out by osmosis into the soaking water. Furthermore, using a sodium bicarbonate solution drastically increases the amount of alpha-galactosides that are removed from pulses. Water-soaking removes 20-70% of alpha-galactosides: the longer amounts of soaking time remove a greater amount of alpha-galactosides. Cooking (that, in this context, specifically refers to the process of boiling food in water at 99°C) can remove 30-90% of alpha-galactosides, but a satisfactory removal only occurs if pulses are pre-soaked first. Another method used to reduce antinutrient content is germination. Germination is a method in which pulses are deliberately placed in optimal environmental conditions, so that the seed can sprout the germ within. As the seed develops its sprout, alpha-galactosidase (an enzyme naturally present in pulses) activity is enhanced, allowing for it to break down the alpha-galactoside contained in the seed. Combining different methods can ensure a more thorough removal of alpha-galactosides.

WHAT ABOUT SHRIMPS AND SHELLFISH?

Shrimps and shellfish are good sources of proteins and minerals, especially calcium and iodine. Even if relatively high in dietary cholesterol, they are very low in saturated fats, so they can be incorporated into a heart-healthy dietary pattern when paired with other lean or plant-based protein sources.

WHAT ABOUT EGGS?

Eggs are rich in high-value proteins, several minerals and vitamins (A, B9, D). Egg yolk is rich in cholesterol. In the past, there were concerns about consuming eggs and other cholesterol-rich foods as they could raise blood cholesterol levels, thereby increasing the risk of heart disease. However, in most cases dietary cholesterol does not influence blood cholesterol levels as much as the amount and type of fat eaten, except in some people who are sensitive to high cholesterol intakes. Current evidence suggests that egg consumption, as part of a healthy and balanced diet, does not significantly increase blood cholesterol levels in most people. The Mediterranean diet food pyramid recommends the consumption of two to four eggs a week.