Which are the greatest recent discoveries and the greatest future challenges in nutrition?

Folate-producing bifidobacteria: metabolism, genetics, and relevance

Folate (the general term for all bioactive forms of vitamin B9) plays a crucial role in the evolutionary highly conserved one-carbon (1C) metabolism, a network including central reactions such as DNA and protein synthesis and methylation of macromolecules. Folate delivers 1C units, such as methyl and formyl, between reactants. Plants, algae, fungi, and many bacteria can naturally produce folate, whereas animals, including humans, must obtain folate from external sources. For humans, folate deficiency is, however, a widespread problem. Bifidobacteria constitute an important component of human and many animal microbiomes, providing various health advantages to the host, such as producing folate. This review focuses on bifidobacteria and folate metabolism and the current knowledge of the distribution of genes needed for complete folate biosynthesis across different bifidobacterial species. Biotechnologies based on folate-trophic probiotics aim to create fermented products enriched with folate or design probiotic supplements that can synthesize folate in the colon, improving overall health. Therefore, bifidobacteria (alone or in association with other microorganisms) may, in the future, contribute to reducing widespread folate deficiencies prevalent among vulnerable human population groups, such as older people, women at child-birth age, and people in low-income countries.

Spontaneously fermented traditional beverages as a source of bioactive compounds: an overview

Fermented food has been present throughout history, since fermentation not only helps preserving food, but also provides specific organoleptic characteristics typically associated to these foods. Most of the traditional fermented foods and artisanal beverages are produced by spontaneous generation, meaning no control of the microbiota, or the substrate used. Nevertheless, even not being standardized, they are an important source of bioactive compounds, such as antioxidant compounds, bioactive beeps, short chain fatty acids, amino acids, vitamins, and minerals. This review compiles a list of relevant traditional fermented beverages around the world, aiming to detail the fermentation process itself-including source of microorganisms, substrates, produced metabolites and the operational conditions involved. As well as to list the bioactive compounds present in each fermented food, together with their impact in the human health. Traditional fermented beverages from Mexico will be highlighted. These compounds are of high interest for the food, pharmaceutical and cosmetics industry. To scale-up the home fermentation processes, it is necessary to fully understand the microbiology and biochemistry behind these traditional products. The use of good quality raw materials with standardized methodologies and defined microorganisms, may improve and increase the production of the desirable bioactive compounds and open a market for novel functional products.

Lactobacillus plantarum P2R3FA Isolated from Traditional Cereal-Based Fermented Food Increase Folate Status in Deficient Rats

Folate deficiencies are widespread around the world. Promoting consumption of folate-rich foods could be a sustainable option to alleviate this problem. However, these foods are not always available. Cereals, being a staple food, could contribute to folate intake. They are fermented prior to consumption in many African countries, and fermentation can modify the folate content. In Ethiopia, injera is a widely consumed fermented flat bread. The main drivers of its fermentation are lactic acid bacteria (LAB). The aim of this work was to isolate and identify folate-producing LAB from injera fermented dough and to evaluate their ability to increase folate status after depletion in a rat model. Among the 162 strains isolated from 60 different fermentations, 19 were able to grow on a folate-free culture medium and produced 1 to 43 µg/L (24 h, 30 °C incubation). The four highest folate producers belonged to the Lactobacillus plantarum species. The most productive strain was able to enhance folate status after depletion in a rat model, despite the relatively low folate content of the feed supplemented with the strain. Folate-producing L. plantarum strain has potential use as a commercial starter in injera production.

Why public dismissal of nutrition science makes sense: Post-truth, public accountability and dietary credibility

PURPOSE

The purpose of this paper is to critically engage with societal origins of public (dis)trust and public credibility of nutrition science and offer suggestions for addressing its public dismissal.

DESIGN/METHODOLOGY/APPROACH

This viewpoint presents a conceptual analysis of public dismissal of nutrition science, drawing together perspectives on the relationships between science and society from the history, sociology and philosophy of science.

FINDINGS

The origin of trust amongst scientists relies is actively tied to their social and moral status and science as a cultural activity is inextricably linked to institutions of power. Accordingly, trust in science relies heavily on public perceptions of those institutions, the ways in which citizens feel represented by them, and to what extent citizens consider these institutions to be held accountable. Ignoring this origin leads to expectations of science and scientists they cannot live up to and inevitable disappointment in those holding such expectations.

SOCIAL IMPLICATIONS

Managing responsible expectations asks that we first dismiss dominant portrayals of science as pure, neutral, value-free and fuelled by curiosity. Second, we should pursue a reorganisation of science, favouring social inclusiveness over scientific exceptionalism.

ORIGINALITY/VALUE

Post-truth dynamics are a source of concern in the dissemination of nutrition science. Rather than dismissing it as a consequence of public ignorance, a comprehensive engagement with post-truth arguments allows a constructive repositioning of nutrition science organisation and communication. It asks that we design research programmes and studies differently, incorporate different voices. Above all else, it asks humility of researchers and tolerant approaches to other perspectives.

Folate, vitamin B12, homocysteine and polymorphisms in folate metabolizing genes in children with congenital heart disease and their mothers

BACKGROUND/OBJECTIVES

The objective of the study was to assess the role of variations in serum folate, vitamin B12, homocysteine and the presence of genetic polymorphisms as risk factors for congenital heart disease (CHD) in children.

SUBJECTS/METHODS

A total of 32 children with CHD, and their mothers and 32 normal children and their mothers formed the study and control groups, respectively. Serum folate, vitamin B12 and homocysteine as well as genetic polymorphisms MTHFR C677→︀T, MTHFR A1298→︀C, MTR A2756→︀G and MTRR A66→︀G were assessed.

RESULTS

Low serum folate and genetic polymorphisms MTHFR C677→︀T and MTRR A66→︀G among children and their mothers and high homocysteine among mothers were noted as risk factors for CHD (P<0.05). Vitamin B12 levels were normal and showed no association. Presence of MTHFR C677→︀T and MTRR A66→︀G, both concurrently among children as well as mothers and simultaneously among mother-child pairs, showed several fold increase in the risk for CHD. On multivariate analysis, the risk factors noted for CHD were presence of MTHFR C677→︀T among children and their mothers and MTRR A66→︀G among mothers. Analyses for nutrient-gene interaction revealed significant associations between low serum folate and high serum homocysteine levels, and the presence of selected genetic polymorphisms.

CONCLUSIONS

Low serum folate, high homocysteine and presence of selected genetic polymorphisms among children and their mothers were noted as risk factors for CHD. Nutrient-gene interaction being a modifiable risk factor, the study recommends the use of peri-conceptional folate supplementation with vitamin B12 sufficiency for primary prevention of CHD.

Capable and credible? Challenging nutrition science

Nutrition science has enriched our understanding of how to stay healthy by producing valuable knowledge about the interaction of nutrients, food, and the human body. Nutrition science also has raised societal awareness about the links between food consumption and well-being, and provided the basis for food regulations and dietary guidelines. Its collaborative and interdisciplinary research has accomplished much, scientifically and socially. Despite this, nutrition science appears to be in crisis and is currently confronted with a public reluctance to trust nutritional insights. Though deflating trust is a general phenomenon surrounding the scientific community, its impact on nutrition science is particularly strong because of the crucial role of nutrition in everyone’s daily life. We, a Dutch collective of nutritionists, medical doctors, philosophers and sociologists of science (http://www.nutritionintransition.nl), have diagnosed that nutrition science is meeting inherent boundaries. This hampers conceptual and methodological progress and the translation of novel insights into societal benefit and trust. In other words, nutrition science is facing limitations to its capability and credibility, impeding its societal value. We take up the challenge to halt the threatening erosion of nutrition science’s capability and credibility, and explore a way forward. We analyse limitations to capability and credibility, then argue that nutrition science is caught in a vicious circle, and end by offering some suggestions to transcend the limitations and escape the current deadlock. We invite nutritional experts as well as scholars from adjacent disciplines to engage in the discussion.

Effect of national wealth on BMI: An analysis of 206,266 individuals in 70 low-, middle- and high-income countries

BACKGROUND

This study explores the relationship between BMI and national-wealth and the cross-level interaction effect of national-wealth and individual household-wealth using multilevel analysis.

METHODS

Data from the World Health Survey conducted in 2002-2004, across 70 low-, middle- and high-income countries was used. Participants aged 18 years and over were selected using multistage, stratified cluster sampling. BMI was used as outcome variable. The potential determinants of individual-level BMI were participants' sex, age, marital-status, education, occupation, household-wealth and location(rural/urban) at the individual-level. The country-level factors used were average national income (GNI-PPP) and income inequality (Gini-index). A two-level random-intercepts and fixed-slopes model structure with individuals nested within countries was fitted, treating BMI as a continuous outcome.

RESULTS

The weighted mean BMI and standard-error of the 206,266 people from 70-countries was 23.90 (4.84). All the low-income countries were below the 25.0 mean BMI level and most of the high-income countries were above. All wealthier quintiles of household-wealth had higher scores in BMI than lowest quintile. Each USD10000 increase in GNI-PPP was associated with a 0.4 unit increase in BMI. The Gini-index was not associated with BMI. All these variables explained 28.1% of country-level, 4.9% of individual-level and 7.7% of total variance in BMI. The cross-level interaction effect between GNI-PPP and household-wealth was significant. BMI increased as the GNI-PPP increased in first four quintiles of household-wealth. However, the BMI of the wealthiest people decreased as the GNI-PPP increased.

CONCLUSION

Both individual-level and country-level factors made an independent contribution to the BMI of the people. Household-wealth and national-income had significant interaction effects.

Efficacy of yogurt drink with added plant stanol esters (Benecol®, Colanta) in reducing total and LDL cholesterol in subjects with moderate hypercholesterolemia: a randomized placebo-controlled crossover trial NCT01461798

BACKGROUND

Cardiovascular diseases have become the leading cause of death from chronic diseases in the world. Main risk factors include hypercholesterolemia, which is caused in most cases by a high saturated fat diet. Plant stanol esters partly block cholesterol absorption in the digestive tract and thereby reduce total cholesterol and low-density lipoprotein (LDL) cholesterol serum levels. Based on epidemiological data, a 10 percent reduction of LDL cholesterol leads to a 20 percent decrease in the coronary heart disease risk throughout life. The aim of this study was to evaluate the efficacy of yogurt drink with added plant stanol esters (Benecol® yogurt drink) in higher doses than the typically used (2g/d stanols), in lowering blood lipids in moderately hypercholesterolemic subjects.

METHODS

A randomized double-blind crossover, placebo-controlled study in moderately hypercholesterolemic subjects (n = 40) aged between 20 and 50 years old.

RESULTS

Yogurt drink with added plant stanols (4 g) as esters (Benecol®, Colanta) consumption compared to regular yogurt drink caused a statistically significant decrease in total cholesterol and low density lipoprotein cholesterol by 7.2% and 10.3%. During the two periods and compared to controls, high-density lipoprotein cholesterol and triglycerides were not significantly different.

CONCLUSIONS

Yogurt drink with an active ingredient in Benecol®, plant stanol esters, reduced total cholesterol and LDL cholesterol in moderately hypercholesterolemic subjects.

TRIAL REGISTRATION

NCT01461798.

Lactic acid bacteria producing B-group vitamins: a great potential for functional cereals products

Wheat contains various essential nutrients including the B group of vitamins. However, B group vitamins, normally present in cereals-derived products, are easily removed or destroyed during milling, food processing or cooking. Lactic acid bacteria (LAB) are widely used as starter cultures for the fermentation of a large variety of foods and can improve the safety, shelf life, nutritional value, flavor and overall quality of the fermented products. In this regard, the identification and application of strains delivering health-promoting compounds is a fascinating field. Besides their key role in food fermentations, several LAB found in the gastrointestinal tract of humans and animals are commercially used as probiotics and possess generally recognized as safe status. LAB are usually auxotrophic for several vitamins although certain strains of LAB have the capability to synthesize water-soluble vitamins such as those included in the B group. In recent years, a number of biotechnological processes have been explored to perform a more economical and sustainable vitamin production than that obtained via chemical synthesis. This review article will briefly report the current knowledge on lactic acid bacteria synthesis of vitamins B2, B11 and B12 and the potential strategies to increase B-group vitamin content in cereals-based products, where vitamins-producing LAB have been leading to the elaboration of novel fermented functional foods. In addition, the use of genetic strategies to increase vitamin production or to create novel vitamin-producing strains will be also discussed.

Folic acid fortification prevents neural tube defects and may also reduce cancer risks

The prevalence of neural tube defect (NTD)-affected pregnancies ranges between 0.4 and 2/1000 pregnancies in EU. NTDs result in severe malformations and sometimes miscarriages. Children born with NTD suffer for the rest of their life of disability and chronic healthcare issues, and many women therefore choose termination of pregnancy if NTD is diagnosed prenatally. Women planning for pregnancy are recommended to eat 400 μg folic acid/d, whereas average figures across Europe indicate intakes of ∼250 μg/d for women of fertile age, a gap that could be bridged by implementation of folic acid fortification. The results of mandatory folic acid fortifications introduced in USA and Canada are a decrease between 25 and 45% of NTD pregnancies.

CONCLUSION

  Evidence-based NTD prophylaxis is now practised in more than 60 countries worldwide. EU countries worry over possible cancer risks, but ignore a wealth of studies reporting decreasing cancer risks with folate intakes at recommended levels. Currently, there are indications of a U-shaped relationship, that is, higher cancer risks at low folate intakes (<150 μg/day) and highly elevated folate intakes (>1 mg/day), respectively. However neither the global World Cancer Research review nor EU's European Food Safety Authority report present data on increased cancer risk at physiological folate intake levels. Therefore, EU should act to implement folic acid fortification as NTD prophylaxis as soon as possible.

Economic growth and obesity: an interesting relationship with world-wide implications

The prosperity of a country, commonly measured in terms of its annual per capita Gross Domestic Product (GDP), has different relationships with population levels of body weight and happiness, as well as environmental impacts such as carbon emissions. The aim of this study was to examine these relationships and to try to find a level of GDP, which provides for sustainable economic activity, optimal happiness and healthy levels of mean body mass index (BMI). Spline regression analyses were conducted using national indices from 175 countries: GDP, adult BMI, mean happiness scores, and carbon footprint per capita for the year 2007. Results showed that GDP was positively related to BMI and happiness up to ∼$US3000 and ∼$5000 per capita respectively, with no significant relationships beyond these levels. GDP was also positively related to CO(2) emissions with a recognised sustainable carbon footprint of less than 5 tonnes per capita occurring at a GDP of <$US15,000. These findings show that a GDP between $US5 and $15,000 is associated with greater population happiness and environmental stability. A mean BMI of 21-23 kg/m(2), which minimises the prevalence of underweight and overweight in the population then helps to define an ideal position in relation to growth, which few countries appear to have obtained. Within a group of wealthy countries (GDP>$US30,000), those with lower income inequalities and more regulated (less liberal) market systems had lower mean BMIs.

Human folate bioavailability

The vitamin folate is recognized as beneficial health-wise in the prevention of neural tube defects, anemia, cardiovascular diseases, poor cognitive performance, and some forms of cancer. However, suboptimal dietary folate intake has been reported in a number of countries. Several national health authorities have therefore introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost-efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bioefficacy. Other countries have decided against fortification due to the ambiguous role of synthetic folic acid regarding promotion of subclinical cancers and other adverse health effects. This paper reviews recent studies on folate bioavailability after intervention with folate from food. Our conclusions were that limited folate bioavailability data are available for vegetables, fruits, cereal products, and fortified foods, and that it is difficult to evaluate the bioavailability of food folate or whether intervention with food folate improves folate status. We recommend revising the classical approach of using folic acid as a reference dose for estimating the plasma kinetics and relative bioavailability of food folate.