The phrase “you are what you eat” has long been embedded in popular culture. The notion that fitness and health depend largely on eating good food is long-standing, but nutrition applied to disease prevention or health promotion is now a thriving field. This has given rise to the concept of “nutraceuticals”, a term resulting from the blend of the words nutrition and pharmaceuticals that was first coined in 1989 by the US Foundation for Innovation in Medicine.

Nutraceuticals are defined as “any substance that is food or a part of food and provides medical or health benefits, including the prevention and treatment of disease”.

The most common form of nutraceuticals are dietary supplements, i.e. products that contain a dietary ingredient intended to supplement the diet, which may include vitamins, minerals, amino acids or herbal substances, for example. Nutraceuticals may also include functional foods, which are modified conventional foods that are enriched or fortified such as to restore the nutrient content to pre-processing levels. Additional nutrients or ingredients may also be added to give it a specific health benefit.

Despite being a hundred billion dollar market worldwide, nutraceuticals are still somewhat unregulated, with one of the main issues being whether the doses used are indeed effective. Although it is possible to find a substantial amount of information on the beneficial effects of numerous nutrients or ingredients, the doses used in experimental research do not necessarily match those used in commercially available dietary supplements of functional foods.

But there is indeed mounting evidence showing how specifically designed diets may be an effective complement or even an alternative to pharmacological therapies for cardiovascular or neurological diseases, for example.

An interesting example is the nutritional intervention for schizophrenia treatment. There are few therapeutic options for schizophrenia, with the main treatment options relying chiefly on the use of anti-psychotics. Recent studies have revealed some pathological mechanisms that can potentially be improved by nutritional approaches as an addition to anti-psychotic medication. An example is the cumulative evidence pointing towards an increased oxidative stress associated with the pathophysiology of schizophrenia; accordingly, supplementation with powerful antioxidants such as alpha lipoic acid, melatonin or vitamin C have shown some promising effects. Other nutritional approaches that have also shown some efficacy include vitamin B supplementation, neuroprotective and anti-inflammatory nutrients and exclusion diets, namely gluten-free diets.

Another research trend that is also somewhat associated with nutrition has emerged from the increased awareness of the importance of the bidirectional communication between the brain and the gut, referred to as the “brain-gut axis”. The mammalian gut is colonized an impressive amount of bacteria; in fact, it is estimated that there are actually 10–100 times more bacteria in the gut than eukaryotic cells in the human body. The presence of these commensal organisms is essential for the proper functioning of our immune system, nutrient processing, and even for brain development and function.

Recent research has been revealing how changes in the gut microbiota can impact normal physiology and contribute to disease onset. There are indications that the bacteria in the gut can communicate with the central nervous system through the autonomic and enteric nervous systems, and through neu­roendocrine, metabolic and immune pathways, thereby affecting brain physiology. This rising notion of a brain-gut axis suggests that therapeutic interventions targeting the gut microbiota may become alternative treatment strategies for neurological disorders.

The acknowledgement of the effect that the human microbiota can have on the brain has caused a paradigm shift in neuroscience, leading to a reassessment of many concepts of health and disease. It has been suggested that the brain-gut axis can play a role in autism spectrum disorder, anxiety, depression, mood, cognition and chronic pain.

Intestinal bacteria can obviously be strongly influenced by nutrition. One approach to the modulation of the gut microbiota is the use of probiotics. These are live bacteria and yeasts that have beneficial health effects, especially in the gastrointestinal tract. Probiotics can be found in some foods and supplements and there is increasing experimental evidence showing their beneficial effect in neuropsychological disorders. Although clinical evidence is still limited, experimental data shows a promising future for nutrition based therapies.

References

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Schmitz K, Barthelmes J, Stolz L, Beyer S, Diehl O, & Tegeder I (2015). “Disease modifying nutricals” for multiple sclerosis. Pharmacology & therapeutics, 148, 85-113 PMID: 25435020

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