Eating better on a small budget: possible but not so easy

Although it is accepted that the diet of the most disadvantaged populations does not comply closely with nutritional recommendations, the relationship between budget and a dietary balance is not so simple. The journal Nutrition Reviews has just published a literature review conducted by the Joint Research Unit for Nutrition, Obesity and Risk of Thrombosis (INRA – -Inserm – Aix Marseille University), in collaboration with the University of Washington Center for Public Health Nutrition, on the contribution of food prices to social inequality regarding food choices and nutrition.sea bream  and ingredients

© Fotolia

At the end of the years 1980-1990, it was known that the most disadvantaged populations had the dietary behaviours least in line with nutritional recommendations, with a lower intake of fruits and vegetables, and a higher intake of refined cereal products (white bread, pasta, white rice, etc.), and perhaps of sweet products. However, these variations in dietary behaviours with socioeconomic status were mainly attributed to educational differences, and few nutritionists focused on the cost of a balanced diet. Thus the first French National Nutrition and Health Programme (PNNS, launched in 2001) was mainly based on large-scale dissemination of nutrition education messages. Subsequently, the impact of food environment (price and availability of foods, advertising, etc.) on food choices was gradually demonstrated, encouraging the development of nutrition policies centred not only on demand (consumer behaviour), but also on the food supply.

In this literature review, the researchers have focused on the economic determinants of food choices. They confirm that when foods are compared on the INCA scale, with price expressed in €/100 kcal (and not in €/kg), products rich in vitamins, iron, calcium and fibre are more expensive sources of calories than energy-rich, high-fat or high-sugar products. Whether along the production chain or for the consumer, products such as crisps, confectionery and biscuits, as well as pasta and rice, are easy to carry, store and prepare, and are non-perishable, which explains why they are cheaper than fresh produce[1].

Consistent with these observations on foods, a balanced diet generally costs more than an unbalanced diet, making it harder to achieve nutritional balance where budgets are limited.

However, observation and modelling studies show that it is possible to assemble a balanced basket of goods on a modest budget, provided that the latter is equal to or more than €3.5 per day per person.

This is possible on condition that one is prepared to depart more from dietary habits and cultural norms, and in particular to consume foods that are of good nutritional quality for their price, such as canned or frozen vegetables. 

Studies available to date, and analysed in this review, are based on mean or standard prices, but no-one buys food at the mean price. Over time, segmentation of agri-food markets has made it possible to make products available to consumers at all price levels, from entry level price to premium price, with everyone benefiting from good nutritional quality. It is therefore possible that a balanced diet is now within reach of all. What would be concluded from studies, if real prices were considered and not mean prices?

While awaiting this future research, it is important to take budgetary constraints and differences in food prices into consideration when drawing up dietary advice.

[1] The price of fresh foods includes the price of transport and refrigerated storage, and the higher risks of loss and waste.

A new virus in liver cancer

More than a cause of a simple infection, viruses are often involved in the development of serious diseases. Such is the case with liver cancer, which often develops in an organ that has been weakened by hepatitis B or C virus. Researchers at Inserm, the Paris Public Hospitals (AP-HP), Paris Descartes University, Paris 13 University (USPC), and Paris Diderot University have just identified the role of a new virus, hitherto unsuspected, in the occurrence of a rare type of liver cancer. 
This study, based on follow-up and observation of 193 patients, is published in the 24 August issue of Nature Genetics.

With over 8,000 new individuals diagnosed annually, liver cancer mainly affects men, and is a major cause of death worldwide. Among the different types of liver cancer, hepatocellular carcinoma usually occurs in a liver that has already been damaged by illness. The liver may, for example, have been weakened by excessive alcohol consumption, obesity, or chronic viral infection by hepatitis B or C viruses, which causes irreversible liver lesions leading to cirrhosis.

Cirrhosis patients generally undergo regular tests to detect cancer. However, in 5% of cases, liver cancer occurs in patients who had not reported cirrhosis, and the reason for developing the cancer remains to be identified.

Jessica Zucman-Rossi and her staff at Inserm Unit 1162, “Functional Genomics of Solid Tumors,” focused on these patients to determine the risk factors that had contributed to the development of their cancer.

In the genome of tumour cells of 11 patients, the scientists observed the insertion of a viral DNA segment from adeno-associated virus type 2, known as AAV2. This virus has been considered non-pathogenic for humans until now. In order to confirm the virus’s involvement in the cancer, the research team compared tumour tissues with normal tissues. They thus confirmed their hypothesis: the integration of viral DNA was found more often in tumour cells than in healthy cells in these 11 patients. Moreover, 8 of these patients did not have cirrhosis, and 6 of them presented no known risk factors for liver cancer.Expression de gènes

Hierarchical clustering analysis of the data of nominal chip expression of liver cancer DNA genes. ©Inserm/Zucman-Rossi, Jessica

By studying these malignant cells in greater detail, they discovered that the virus, when inserting its DNA into the genome of the patient’s cells, targets genes that are important in cell proliferation. Jessica Zucman-Rossi and her colleagues have shown that AAV2 leads to excessive expression of these genes which, according to the researchers, may favour tumour development.

By this work, the researchers have identified the involvement of AAV2 virus, previously thought to be harmless, in the occurrence of hepatocellular carcinoma, particularly in the rare cases of cancer that develop in the absence of cirrhosis and without an identified cause.

These results also call for caution: “AAV2 is often used as a vector in gene therapy. Although the insertion of its DNA into tumour promoting genes is rare, and probably a chance event, precautions must be taken regarding the use of this virus,” explain the authors.
This work was supported by the French National Cancer Institute (INCa) via ICGC and PAIR-CHC NoFLIC (with the participation of ARC Foundation) and the French National Cancer League. Tumour sequencing was performed by IntegraGen, in its laboratories located at Genopole, Evry.

The 5-colour nutritional labelling system is the most effective for consumers

While the French High Council for Public Health (HCSP) made public on Monday, 24 August 2015, a positive opinion regarding the relevance of the 5-colour code for the public, a team of researchers (Inserm/INRA/Paris 13 University) directed by Serge Hercberg, on publication of their article in the journal Nutrients, demonstrated that the 5-colour nutrition label (5-CNL) is the most effective nutritional information system for allowing consumers to recognise and compare the nutritional quality of foods, including “at-risk” populations (older subjects, those with a lower educational level, lower income, lower nutritional knowledge, and overweight or obese individuals)

Article 5 of the Health Act, introduced by Marisol Touraine, Minister of Health, and passed by the French Parliament, states, “…to make it easier to inform consumers and to help the consumer make informed choices, that the mandatory nutrition declaration may be accompanied by a presentation or complementary expression using graphics or symbols on the front of packaging.”

Several systems have been proposed at national and international level. In France, many learned societies support the establishment of the 5-CNL 5-colour nutritional labelling system (green/yellow/orange/fuchsia pink/red). The latter is based on the calculation of a nutritional quality score (nutrient profiling system, Food Standards Agency, FSA), which takes several elements present on the nutrition label into account (calories, simple sugars, saturated fatty acids, sodium, fibre, protein and percentage of fruits and vegetables per 100 g of product), to arrive at a unique indicator of the nutritional quality of the food.

Several studies have already contributed to the validation of the FSA score, by showing that the nutritional quality of foods consumed evaluated by the FSA score is linked to the overall quality of the diet and nutritional status of individuals, and in a prospective manner to the risk of disease. These scientific studies underscore the interest of putting the 5-colour nutrition label (5-CNL), based on FSA score, on the front of food packaging in order to better guide consumers in their food choices. This system is the subject of considerable controversy, fuelled among others by the various industrial stakeholders, who cast doubt on its value.

The study published today by EREN under the direction of Pauline Ducrot (PhD student in Nutrition) and Sandrine Péneau (Lecturer in Nutrition, Paris 13 University) in the journal Nutrients compares the effect of different nutrition labels on the front of packs of various foods on the ability of consumers to rank foods appropriately. The study was carried out on a sample of 14,230 adults participating in the NutriNet-Santé study. The impact of 4 simplified nutritional labelling systems was tested: the colour-based 5-CNL system; the Green Tick, similar to that used in some Scandinavian countries and the Netherlands; the Multiple Traffic Light system used in Great Britain, and the Guideline Daily Amounts (or Reference Intakes) system already used in France by some industrial companies. A logo-free situation was also used as a reference.

With the help of a Web-based questionnaire specifically developed for this study, participants in the study were asked to rank, on a relative basis (“less good,” “moderate,” “the best” or “I don’t know”) the nutritional quality of different series of 3 foods belonging to the same category.

Five categories of foods were tested: frozen fish products, pizzas, dairy products, breakfast mueslis and appetisers.


Example (5-CNL on fish-based frozen products):

Each participant had to randomly test a combination of food products and nutrition labels from the 5 categories. For this, 25 different versions of the questionnaire were used. A statistical design (Latin Square) made it possible to ensure an equal number of participants for each labelling/product category combination.

The results of this specific study on the comprehension of nutritional logos show that:

  • Generally speaking, individuals “at risk” of having a nutritionally poorer quality diet (older subjects, participants with a lower educational level, lower income, lower nutritional knowledge, and overweight or obese individuals) had greater difficulty in ranking food products according to their nutritional quality.
  • The various nutrition labels significantly increased the ability of individuals, including those at risk, to rank 3 foods in order of their nutritional quality, compared with a logo-free setting.
  • The nutrition labels had more impact than individual characteristics (education level, income, etc.) on increasing the ability of the individuals to correctly rank the foods by nutritional quality. The chance of correctly ranking the products was multiplied up to 12-fold with a logo, whereas individual characteristics enabled an increase in the chance by a factor of only 1.17.
  • Of the nutrition labels tested, the 5-colour nutritional labelling system (5-CNL) was the most effective in terms of comprehension. It performed better than the Traffic Light, Reference Intakes, or Green Tick labelling systems.
  • The 5-CNL system performed better, including among individuals with a relatively “unfavourable” diet in terms of nutrition and health. In particular, the presence of 5-CNL strongly increased (over twenty-fold compared to the logo-free situation) the ability of individuals with no knowledge of nutrition to correctly rank the products compared with a logo-free situation.

The results of this study emphasise the interest of nutrition labels for helping consumers, particularly those at risk of making food choices that are relatively “unfavourable” to their health, to identify the products most conducive to a balanced diet. 

The 5-colour logo (5-CNL) system turns out to be the best understood among individuals as a whole, and may therefore make it possible to inform consumers effectively and equitably on the nutritional quality of products, and thereby incorporate this information into determinants of their food choices.

World Championships in Athletics: D-7!

On Saturday 22 August 2015, the 15th World Championships in Athletics will be launched in Beijing. Until Sunday 30 August, athletes from all nations will compete, putting their muscles, as well as their heart, lungs, brain, etc. to the test.Sport

© Fotolia

How do muscles work? How do athletes attain such endurance? What is the brain’s role in physical ability? How do performance enhancing drugs act? What technique could help the athletes to improve their performance?

Inserm researchers work all year to find answers to these questions and in the area of physical exercise in general. For your interviews and reporting needs, see the “Physical Activity press-kit,” available as a download opposite, for a listing of the contact details of specialists in this discipline, together with the latest news from Inserm on the subject.

Bacteria that Prevents Type 1 Diabetes

Our bodies have ten times the amount of microbes than human cells. This set of bacteria is called microbiota. In some instances, bacteria known as pathogens can cause infectious diseases. However, these micro-organisms can also protect us from certain diseases. Researchers from Inserm, Paris Descartes University and the CNRS (French National Centre for Scientific Research), through collaboration with teams from China and Sweden, have recently shown how microbiota protects against the development of type 1 diabetes. This research is published in the Immunity journal, 4 August 2015.


A pancreatic islet of Langerhans expressing the immunoregulator antimicrobial peptide CRAM (in red). The insulin-producting beta-cells are in green and the glucagon-producting alpha-cells are in blue. © Julien Diana

To combat pathogens, the immune system has developed various mechanisms to detect, defend against and even destroy micro-organisms that are harmful to the body. This includes antimicrobial peptides and natural proteins that destroy pathogenic bacteria by disrupting their cellular membrane. Not only are they produced by immune cells, they are also produced by cells whose functions are not immune-related.

A research team coordinated by Julien Diana, an Inserm Research Fellow at Inserm Unit 1151 “Institut Necker-Enfant Malades” [Necker Institute for Sick Children] (Inserm/CNRS/Université Paris Descartes), is focussing on a category of antimicrobial peptides, i.e. cathelicidins. Apart from their protective function, these peptides have also exhibited immunoregulatory abilities against several autoimmune diseases. As such, scientists hypothesise that cathelicidins may be involved in the control of type 1 diabetes, an autoimmune disease where certain cells in the immune system attack beta cells in the pancreas which secrete insulin.

Firstly, they observed that beta pancreatic cells in non-diseased mice produce cathelicidins and that, interestingly, this production is impaired in diabetic mice.

To test this hypothesis, they are injecting diabetic mice with cathelicidins where production is defective.

“Injecting cathelicidins inhibits the development of pancreatic inflammation and, as such, suppresses the development of autoimmune disease in these mice” states Julien Diana.

Given that the production of cathelicidins is controlled by short-chain fatty acids produced by gut bacteria, Julien Diana’s team are studying the possibility that this may by the cause of the cathelicidin deficiency associated with diabetes. Indeed, researchers have observed that diabetic mice have a lower level of short-chain fatty acids than that found in healthy mice.

By transferring part of the gut bacteria from healthy mice to diabetic mice, they are re-establishing a normal level of cathelicidin. Meanwhile, the transfer of micro-organisms reduces the occurrence of diabetes.

For the authors, “this research is further evidence of the undeniable role microbiota plays in autoimmune diseases, particularly in controlling the development of autoimmune diabetes”. 

Preliminary data, as well as scientific literature, suggest that a similar mechanism may exist in humans, paving the way for new therapies against autoimmune diabetes.

Glutamate, a new player in addiction

Scientists have just identified in the mouse, and then confirmed in humans, a new factor that regulates addiction. Glutamate, a neurotransmitter[1], contributes to regulating dopamine release in the nucleus accumbens, one of the cerebral structures of the reward system. More precisely, it is its subtle balance with another neurotransmitter – acetylcholine – that prevents up-regulation of the system and entry into addiction. This discovery, which opens up new therapeutic perspectives, was made by neurobiologists in the Neurosciences Paris-Seine laboratory (Institut de Biologie Paris-Seine, CNRS/Inserm/UPMC) and the Douglas Mental Health University Institute (McGill University, Montreal, Canada), working in association with human genetics specialists at Institut Mondor de Recherche Biomédicale (Inserm/UPEC). Their work was published on 4 August 2015 in Molecular Psychiatry.

In the context of drug taking, dopamine levels rise in the cerebral structures that form the reward system.  The intensity and rapidity of dopamine release provide a basis for the processes that will lead to the development of addiction. The cholinergic neurons in the nucleus accumbens, one of the centers of reward, are known to regulate this dopamine release. While most neurons only release a single neurotransmitter, a French-Canadian team led by CNRS researcher Salah El Mestikawy showed in 2002 that these acetylcholine-using neurons are also able to utilize glutamate. These neurons, which are to some extent “bilingual”, can thus both activate (via acetylcholine) and inhibit (via glutamate) dopamine secretion.

In this new study, much of it carried out by Diana Yae Sakae for her thesis project supervised by Salah El Mestikawy, the scientists showed that when they inhibited a gene essential to this signaling by glutamate (called VGLUT3) in mice, the animals became more vulnerable to cocaine. They experienced enhanced stimulant effects of the drug, developing “addiction” more easily and being more likely to “relapse” after a period of abstinence. The glutamate from these acetylcholine neurons therefore plays an important regulatory role in limiting cocaine addiction.

The scientists then wanted to determine whether this mechanism also applied to humans. In cocaine and/or opiate-dependent adults, they looked for mutations of the gene that had rendered the mice “addicted”. At the Institut Mondor de Recherche Biomédicale, Stéphane Jamain’s team observed that a mutation of this gene was ten times more common among severely dependent patients than in individuals without psychiatric symptoms. This mutation may explain the greater vulnerability to addiction of these patients[2]. In any case, these observations appear to confirm the role of glutamate in the addictive mechanism.

This work has thus clarified the neuronal mechanisms that underlie the search for hedonic sensations: contrary to what scientists thought until now, these findings show that it is not acetylcholine alone that regulates dopamine release, but a balance between acetylcholine and glutamate.

 At the same time, the scientists identified an unsuspected target for the treatment of drug addiction. Indeed, although acetylcholine has numerous other functions in the brain and muscles, this glutamate signaling is more specific. The next step is to identify the receptor involved so that pharmacological therapies can be developed.

This work was funded in particular by the Fondation pour la Recherche Médicale (FRM) and the Agence Nationale pour la Recherche (ANR).

[1] In order to communicate, neurons use chemical substances called neurotransmitters. Conventional neurotransmitters include dopamine, serotonin, acetylcholine and glutamate, etc.

[2] That said, even within the group of severely dependent patients this mutation was only present in 5% of cases, indicative of the multifactorial nature of addiction and more generally the complexity of psychiatric diseases

From pluripotency to totipotency

While it is already possible to obtain in vitro pluripotent cells (ie, cells capable of generating all tissues of an embryo) from any cell type, researchers from Maria-Elena Torres-Padilla’s team have pushed the limits of science even further. They managed to obtain totipotent cells with the same characteristics as those of the earliest embryonic stages and with even more interesting properties. Obtained in collaboration with Juanma Vaquerizas from the Max Planck Institute for Molecular Biomedicine (Münster, Germany), these results are published on 3rd of August in the journal Nature Structural & Molecular Biology.
Cellules Souches embryonnaires

Human embryonic stem cells have the potential to form in vitro neural tube -like structures of the embryo. ©Inserm/Benchoua Alexandra

Just after fertilization, when the embryo is comprised of only 1 or 2 cells, cells are “totipotent“, that is to say, capable of producing an entire embryo as well as the placenta and umbilical cord that accompany it. During the subsequent rounds of cell division, cells rapidly lose this plasticity and become “pluripotent”. At the blastocyst stage (about thirty cells), the so-called “embryonic stem cells” can differentiate into any tissue, although they alone cannot give birth to a foetus anymore. Pluripotent cells then continue to specialise and form the various tissues of the body through a process called cellular differentiation.

For some years, it has been possible to re-programme differentiated cells into pluripotent ones, but not into totipotent cells. Now, the team of Maria-Elena Torres-Padilla has studied the characteristics of totipotent cells of the embryo and found factors capable of inducing a totipotent-like state.

When culturing pluripotent stem cells in vitro, a small amount of totipotent cells appear spontaneously; these are called “2C-like cells” (named after their resemblance to the 2-cell stage embryo). The researchers compared these cells to those present in early embryos in order to find their common characteristics and those that make them different from pluripotent cells. In particular, the teams found that the DNA was less condensed in totipotent cells and that the amount of the protein complex CAF1 was diminished. A closer look revealed that CAF1 -already known for its role in the assembly of chromatin (the organised state of DNA)- is responsible for maintaining the pluripotent state by ensuring that the DNA is wrapped around histones.

Based on this hypothesis, the Torres-Padilla team were able to induce a totipotent state by inactivating the expression of the CAF1 complex, which led to chromatin reprogramming into a less condensed state.

These results provide new elements for the understanding of pluripotency and could increase the efficiency of reprogramming somatic cells to be used for applications in regenerative medicine.