The Nutri-Score is a 5-color front-of-pack nutrition label designed to provide consumers with an easily understandable guideline to the healthiness of food products. The impact that the Nutri-Score may have on consumers’ choices is unclear since different experimental paradigms have found vastly different effect sizes. In the present study, we have investigated how student participants change a hypothetical personal 1-day-dietary plan after a learning phase during which they learn about the Nutri-Scores of the available food items. Participants were instructed to compose a healthy diet plan in order that the question of whether the Nutri-Score would improve their ability to compose a healthy dietary plan could be investigated, independent of the question of whether they would apply this knowledge in their ordinary lives. We found a substantial (Cohen’s d = 0.86) positive impact on nutritional quality (as measured by the Nutrient Profiling System score of the Food Standards Agency) and a medium-sized (Cohen’s d = 0.43) reduction of energy content. Energy content reduction was larger for participants who had initially composed plans with higher energy content. The results suggest that the Nutri-Score has the potential to guide consumers to healthier food choices. It remains unclear, however, whether this potential will be reflected in real-life dietary choices.

The hypothesis that some children with attention-deficit hyperactivity disorder (ADHD) may show sensitivity or allergic reactions to various food items has led to the development of the oligoantigenic diet. The rationale of the diet is to eliminate certain foods from the diet in order to exclude potential allergens contained either naturally in food or in artificial ingredients with allergenic properties. The oligoantigenic diet attempts to identify individual foods to which a person might be sensitive. First, ADHD symptoms are monitored while multiple foods are excluded from the diet. Subsequently, if symptoms remit, foods are re-introduced, while observing the individual for the return of symptoms. An advantage of the oligoantigenic diet is that it can be tailored to the individual. A growing body of evidence suggests that behavioral symptoms of subgroups of children with ADHD may benefit from the elimination of certain foods. The effect sizes of an oligoantigenic diet regarding improvement of ADHD symptoms have been found to be medium to large. Available evidence suggests that the investigation of the role of food hypersensitivities in ADHD is a promising avenue worthy of further exploration. Further large-scale, randomized controlled studies including assessment of long-term outcome are therefore warranted.

Available evidence suggests that the consumption of edible insects may not only contribute protein and other valuable nutrients to the human diet but may also provide health benefits through various insect-derived peptides and bioactive compounds. Most studies of potential anti-obesity effects of edible insects have been conducted in vitro. The available in vivo evidence stems mainly from rodent models. Anti-obesity effects of various edible insect species, such as Tenebrio molitor, Hermetia illucens, and Acheta domesticus, have been suggested, and the findings of studies in mice models suggest the presence of bioactive compounds in edible insects with a potential efficacy in weight control. The mechanisms suggested to underlie the lipid-lowering and anti-obesity effects of edible insect extracts include the inhibition of pathways related to lipid metabolism, downregulation of genes involved in the metabolism of adipose tissue, effects on gut microbiota and increased satiety following consumption of insect-derived food products. However, any claims of health benefits of insect-derived compounds need to be sufficiently established, and trials in humans are a prerequisite. With respect to anti-obesity (and other health) effects, no such compound identified in insects has thus far been tested in humans. Further studies of the effects of bioactive compounds contained in edible insects on human health are therefore needed in order to validate the potential of edible insects as a novel measure in combatting obesity and promoting health in general.

Given its increasing global prevalence, Alzheimer's disease (AD) has become a major public health challenge worldwide. The symptomatic treatments available for AD have shown no significant efficacy, and no disease-modifying interventions are capable of slowing the progression of the disorder. The potential of lifestyle-related factors, including diet, is increasingly recognized as an important consideration in the primary prevention of AD. Numerous mechanisms potentially underlying neuroprotective effects of bioactive components contained in tea, such as (–)-epigallocatechin-3-gallate, as well as their preventive efficacy against AD, have been elucidated in preclinical studies. However, in contrast to the abundance of mechanistic findings in animals, clinical results demonstrating efficacy in humans are scarce. While epidemiological studies have provided some evidence indicating that green tea consumption is associated with a reduced risk of age-related cognitive decline and AD, a causal relationship cannot be established on the basis of these observations. The clinical evidence regarding preventive or therapeutic effects of green tea and its bioactive components is unsatisfactory. A role of green tea in the prevention of AD cannot be recommended until well-designed, randomized, placebo-controlled clinical trials using standardized formulations confirm the purported beneficial effects of green tea.

The available evidence, which derives from studies investigating mechanistic effects of tea, research on animal models as well as epidemiological studies and intervention trials in humans, suggests that compounds contained in tea may have the potential to aid in the prevention of depression or in its treatment as an addition to established therapies. A wide range of potentially antidepressive biological activities of tea components have been reported. However, the mechanisms of tea phytochemicals possibly capable of decreasing the risk of depressive symptoms are complex, multifaceted and not well understood. Potent pharmacological effects on circumscribed neurobiological systems may be produced not by individual tea components but rather by the synergistic action of various compounds on multiple pathophysiological mechanisms involved in depression. While epidemiological studies have generally demonstrated beneficial effects of tea consumption on mood and depressive symptoms, cross-sectional studies are unable to prove a cause-effect relationship. If positive effects on mood could be firmly established, tea drinking could support mental health. However, the moderate antidepressive effects observed in healthy people are not necessarily indicative of possible clinical effects in major depressive disorder. Randomized controlled intervention studies are needed to establish a causal relationship between bioactive compounds in tea and depression.

The findings of various epidemiological studies, interventions using randomized controlled trials and mechanistic experiments have suggested a protective role of tea and its bioactive components in cardiovascular health. The potential of tea in the prevention of cardiovascular diseases (CVDs) has therefore attracted increasing research interest. Polyphenols, in particular flavonoids, found in both green and black tea, have been suggested to play a primary role in the reduction of CVD risk. While promising results regarding the effects of tea on blood pressure and other CVD-related biomarkers have been found in preclinical experiments, the effects demonstrated in human studies are modest and less satisfactory. This discrepancy may be explained, at least in part, by different research strategies used in human and animal research. However, since tea is globally one of the most commonly consumed beverages, even small beneficial effects in humans may shift the population distribution of CVD risk, with major implications for public health. However, research conducted to date does not yield sufficiently robust evidence to allow a recommendation as to an optimal level of tea consumption as an element of health policies seeking to prevent hypertension and improve cardiovascular health.

Theories proposing a role of specific dietary components or food supplements in the prevention or treatment of COVID-19 have received extensive social media coverage.

A multitude of scientific publications have also pointed to the importance of food and nutrition in combating the COVID-19 pandemic. The present perspective critically addresses the question of what food science can actually contribute in this context.

Animal studies suggest that micronutrients, food bioactives or functional foods may carry the potential to augment viral defense. However, the specific roles of food components in viral infectious diseases in humans remain unclear. Rigorous research assessing the efficacy of food compounds in counteracting infections would require long-term randomized controlled trials in large samples. While no foods, single nutrients or dietary supplements are capable of preventing infection with COVID-19, a balanced diet containing sufficient amounts of macronutrients and diverse micronutrients is a prerequisite of an optimally functioning immune system. High-energy diets and obesity are major risk factors for a more severe course of COVID-19.

Therefore, population-wide body weight control and weight reduction in overweight people are important preventive measures. Diet may play a beneficial role in maintaining a healthy body weight and preventing non-communicable conditions.

Parkinson's disease (PD) is a slowly progressive neurodegenerative disorder with motor and non-motor signs, which begins long before the diagnosis can be made. Pharmacotherapy with dopaminergic drugs is the mainstay of PD therapy. There is no currently available cure or disease-modifying treatment. Diet and various foods have been proposed as possible risk factors for PD. Nutritional supplementation with omega-3 fatty acids, vitamin D, B vitamins, and coenzyme Q may have potential in the management of PD. In addition, several strategies could possibly lead to the development of medical foods in PD. For example, ketogenic diets may have effects complementary to pharmacotherapy. Gut microbial dysbiosis and altered microbial metabolites found in PD may lead to chronic low-grade inflammation in gut and brain. Interventions targeting gut microbiota, such as the supplementation of probiotics, may provide novel approaches to PD in regard to both symptomatic treatment and disease modification. High quality randomized controlled trials need to be conducted in order to evaluate whether these food-based strategies have symptomatic efficacy or the potential to delay the progression of PD.

Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Treatments achieving a marked improvement in symptoms or preventing or delaying the progression of the disease are not available. Various diet-related risk factors for AD have been identified. Evidence for a protective effect of the Mediterranean diet on AD risk is inconclusive. Medical foods are designed to meet specific dietary needs for certain diseases. Improvements in symptomatology and regional brain atrophy in AD have been claimed for several medical foods, for example, those providing ketone bodies as alternative energy supply to neurons, those containing precursors believed to improve synaptic function, and those addressing oxidative stress related to memory loss. Many methodological shortcomings render the interpretation of the available findings of medical food trials in AD difficult. Optimal results of medical foods in AD may be expected when administered in presymptomatic or early stages of the disease. This requires the reliable identification of minimal neuropathological changes related to AD. The outcome measures currently used may not be able to detect subtle changes in cognition and function in early AD. Large-scale clinical studies using valid, sensitive, and reliable assessment tools are needed to establish the efficacy of medical foods in AD.

Pattern separation keeps items distinct in memory and is mediated by the hippocampus. A relationship between hippocampal function and diet quality has been suggested by findings in both humans and animals. In the present study, rats were fed over seven generations a diet containing increased amounts of sugar and saturated fatty acids, reduced levels of polyunsaturated fatty acids and an increased ratio of omega-6/omega-3 fatty acids ("Western" diet). Spatial pattern separation (or local discrimination) performance of these animals was compared with that of rats fed a standard diet. A separation-dependent difference between the standard and Western diet groups was found in the number of discriminations performed in the pattern separation task, with rats of the "Western" group performing fewer discriminations. The present results suggest that behavioral assessment of spatial pattern separation can detect effects of dietary interventions in rats and that pattern separation can be impaired by transgenerational administration of a "Western" diet. Future studies should determine which components of this diet induce the memory impairments related to the hippocampus. The translational relevance of these findings in regard to mental disorders such as dementia and depression needs to be investigated.