Clinical trial on twins: are prebiotics good for cognition?

Cognition and prebiotics: new scientific leads

In this recent study (1), published in 2024 in the journal Nature Communications, 36 pairs of twins aged 60 or over took part in a randomised, double-blind, placebo-controlled trial.

Studying pairs of twins is particularly interesting: comparing the effect of a nutrient on two individuals who are genetically very close, sometimes identical, makes it possible to limit biological variations and obtain more detailed observations.

For 12 weeks, each pair of twins was divided into two groups:

• one twin was given 7.5 g/day of a prebiotic mixture consisting of approximately 3.4 g of inulin and 3.5 g of fructo-oligosaccharides (FOS)
• the other twin received a placebo of 7.5 g of maltodextrin (a carbohydrate blend)

The participants were assessed on standardised cognitive tests (memory, processing speed, attention), microbiotic and metabolic parameters and their general well-being.

The result: the twins who received the prebiotic performed better on cognitive tests, particularly those relating to episodic memory and information processing speed.

This clinical trial therefore suggests that certain prebiotics may have a favourable influence on brain function in the elderly, possibly via modulation of the intestinal microbiota and its metabolites.

Prebiotics: how do they work, and where can I find them?

Prebiotics are fermentable dietary fibres that our bodies do not digest.

They serve mainly as food for good intestinal bacteria (probiotics), in particular bifidobacteria and lactobacilli.

The most widely studied prebiotic fibres include:

• inulin, known for its progressive fermentation and its role in maintaining a diverse microbiota (2)
• FOS (fructo-oligosaccharides), capable of selectively feeding certain beneficial bacteria in the microbiota, in particular bifidobacteria (3)
• acacia gum (or gum arabic), a soluble fibre renowned for its excellent digestive tolerance (4)

Food is the primary source of prebiotic fibre: it is found in chicory root, garlic, onions and leeks, artichokes and Jerusalem artichokes, bananas, legumes, etc.

But when dietary intake is insufficient, it is also possible to turn to targeted food supplements.

Discover Fructo-Oligosaccharides, a prebiotic fibre supplement derived from beetroot, to be sprinkled daily in drinks or food.

Prebiotics, probiotics and the gut-brain axis

The results of the clinical trial suggest that prebiotics could influence certain aspects of cognition in senior citizens, via their action on the intestinal microbiota.

By fermenting, prebiotics encourage the growth of probiotics and stimulate the production of beneficial metabolites: SCFAs (short-chain fatty acids).

While probiotics are known to help balance the intestinal microbiota, they are also widely studied for their potential impact on the gut-brain axis (5-7).

Bifidobacterium lactis, Lactobacillus plantarum, Lactobacillus rhamnosus, Bifidobacterium breve and Akkermansia muciniphilaare just some of the strains currently attracting research interest (8-10).

Discover Probio Forte, a combination of 5 complementary strains to support the microbiota, with 8 billion microorganisms per capsule.

Discover Full Spectrum Probiotic, a unique broad-spectrum microbiotic food supplement, distinguished by its wide variety of strains (20 quality strains).

Protected by their spore envelope, spore probiotics are particularly resistant to gastric acidity.

They are, therefore, an interesting alternative for supporting the balance of the intestinal microbiota and harnessing the potential benefits for the gut-brain axis.

Discover SporesBiotics Formula, an exclusive synergy of 3 spore-forming strains designed to maximise colonisation of the intestine.

Finally, some food supplements combine prebiotics and probiotics for enhanced synergistic action.

Discover Lactobacillus Rhamnosus GG, a probiotic supplement containing inulin to stimulate the growth and viability of lactobacilli.

Which natural ingredients support cognition?

Certain nutrients and plant extracts are also being studied for their potential role in memory, attention or neuroprotection.

Ginkgo biloba: cerebral circulation and mental functions

An essential plant in traditional Chinese medicine, Ginkgo biloba contains antioxidant flavonoids renowned for their action on the circulatory system.

Ginkgo biloba is known to contribute to mental and cognitive activity (11). Certain standardised extracts of Ginkgo biloba may be associated with:

• the maintenance of certain cognitive functions with age
• improved cerebral blood circulation
• protection against oxidative stress

Discover Ginkgo Biloba, a standardised extract rich in natural active ingredients, which helps maintain good cognitive function and memory.

Alpha-GPC & uridine: the neuronal membrane duo

Alpha-GPC is an organic compound found naturally in the brain.

A precursor of choline, it is involved in the synthesis of acetylcholine, a neurotransmitter involved in certain cognitive processes such as memory, attention and alertness.

Uridine, for its part, is involved in several major biological mechanisms: the synthesis of cell membranes, neuronal signalling and some processes linked to the formation of synapses.

Several studies suggest that uridine may promote certain cognitive functions, in particular memory and brain plasticity (12-13).

Discover NeuroNutrition Formula, a complete formula combining 7 substances studied to protect the brain from the effects of ageing.

Bacopa, caffeine and L-theanine: memory and mental clarity

A major plant in traditional Indian medicine, Bacopa monnieri is widely studied for its potential effects on the cerebral system.

Some studies are looking at its possible association with cognitive processes such as memory and attention, although these effects cannot be generalised to the population as a whole.

Bacopa also contains antioxidant compounds naturally present in the plant, which are involved in biological mechanisms linked to oxidative stress, a phenomenon studied in the context of cellular ageing.

L-theanine, an amino acid found in green tea, is being studied for its interaction with the nervous system, with a particular interest in regulating stress and mental tension.

Caffeine, well known for stimulating alertness, forms with L-theanine one of the most studied combinations for supporting alertness, concentration and stable mental clarity (14-15).

Discover Smart Pills, a nootropic formula rich in bacopa and ginkgo, enhanced with L-Theanine, taurine and anhydrous caffeine.