Increasing the amount of dairy foods, eaten by teenage girls, to three servings a day boosts their intake of nutrients of concern, as well as other nutrients essential for healthy growth and bones, according to this study.

Adolescent girls are at risk of a shortfall in nutrients, and vitamin D, calcium, potassium, fibre and iron are of particular concern. This study shows that increasing dairy food consumption can make up for the shortfall of three of these nutrients of public health concern – calcium, vitamin D and potassium. They can also improve protein, magnesium and zinc – all key nutrients essential for adolescent growth and bone health.

The authors used data from The National Health and Nutrition Examination Survey (NHANES) 2007–2010 – What We Eat in America – to carry out diet modelling exercises. The aim was to determine the effects of increasing consumption of plant-based foods versus dairy foods on energy and nutrient intake in adolescent girls.

They modelled three dietary scenarios: increasing consumption of plant-based foods, increasing protein-rich plant-based foods, and increasing milk, cheese and yogurt.

Doubling consumption of plant-based foods has pros and cons

In this dietary scenario, the intake of currently consumed plant-based foods (fruits, vegetables, total grains, legumes, nuts, seeds and soya) was doubled and the intake of animal products (eggs, meat, poultry, fish and dairy) was reduced proportionately.

This dietary change led to increased intake of dietary fibre, added sugars, vitamin E, iron and folate, and decreased intake of total fat, saturated fat, zinc, vitamin D, calcium and protein.

Hence if adolescent girls were to follow this dietary model, only two of the five nutrients of concern – fibre and iron – would improve, while the intakes of the other three – calcium, vitamin D and potassium – would worsen.

Doubling protein-rich plant foods fails to impact on protein intake

In this first, plant-based scenario, protein intake was reduced by almost 10 g/day when compared with the usual diet, meaning that the proportion of girls failing to meet the Estimated Average Requirement (EAR) for protein rose from 5.4% to 14.5%. Low intakes of protein are a cause for concern because of its key role in supporting numerous physiological processes and growth.

In anticipation of this protein intake fall, the authors’ second scenario doubled the girls’ intake of protein-rich plant foods such as legumes, nuts, seeds, and soya. However, they found that this had no real impact on protein intake because adolescent girls eat so little of these types of foods in their normal diet. It may therefore be difficult to encourage teenage girls to increase their consumption of protein-rich plant foods in their diet to a level that would achieve meaningful changes in their nutrient intake.

Doubling consumption of dairy products increases intake of protein and other nutrients critical for growth and bone health

However, the authors found a different picture when they increased the intake of dairy products. In the final dietary scenario, the intake of currently consumed dairy foods (milk, cheese and yogurt) was doubled to meet the recommended level in the USA for adolescents of 3-4 servings daily.

Protein consumption rose by 10.8 g/day and the proportion of girls not meeting the EAR for protein fell from 5.4% to 2.8%.

The higher dairy consumption also led to increased intakes of vitamin D, magnesium, zinc, calcium, potassium, energy, total fat, saturated fat, and added sugars.

An adequate intake of calcium during childhood and adolescence is essential to attain peak bone mass, important for reducing the risk of fractures and osteoporosis in later life. In this dairy model, the proportion of girls failing to meet the EAR for calcium fell from 76% to 41%. Vitamin D intake also increased, although 80% of adolescent girls were still not meeting the EAR for vitamin D.

Eating more dairy offers benefits to adolescent girls

The authors conclude that non-specific recommendations to increase intake of plant-based foods at the expense of animal foods has some nutritional benefits – such as reduced intake of total and saturated fat – but can also have some detrimental effects – reduced intake of zinc, vitamin D, calcium and protein.

Conversely, eating three servings of dairy foods daily improves intake of nutrients that are crucial for growth and bone health, including three nutrients of concern – calcium, vitamin D and potassium.

Find out more: read the original article.

Source:

Demmer E, Cifelli CJ, Houchins JA et al. The impact of doubling dairy or plant-based foods on consumption of nutrients of concern and proper bone health for adolescent females. Public Health Nutr. 2017;20(5):824-31.

Curious about lactose and maldigestion? Watch here the video and download the complete infographic to discover more about the benefits of yogurt in case of lactose intolerance.

Click below in the video to enlarge or to pause

Download here the infographic

This local symposium, tailor-made for Argentinian nutrition experts, was a great opportunity to review the scientific evidence about the benefits associated with the regular consumption of yogurt.

Here are the key messages for each talk as well as a selection of references for each of the speakers present at this special session that you will find on this website:

Adam Drewnowski talked about the nutrient and energy density of yogurt

• he showed that yogurt obtains high scores in terms of nutrient density and energy density
• and highlighted how yogurt has good scores in all nutrients calculation systems
• yogurt thus appears to be a nutrient dense food, which provides “useful” calories compared to empty calories
• yogurt provides minerals like calcium, potassium, magnesium, zinc; vitamins such as B2, B12, D and proteins
• he concluded on the fact that different studies have associated regular consumption of yogurt with better control of body weight

Read further from Professor Drewnowski

Andrew Prentice made a presentation of yogurt from a public health standpoint

• he explained that yogurt represents a cost-effective approach to public health
• according to him yogurt may have benefits in weight control & type 2 diabetes

Read further from Professor Prentice

Nancy Babio presented the epidemiological evidence about yogurt consumption and type 2 diabetes

• Nancy Babio reminded that yogurt consumption has been associated with a 28% lower probability of suffering from type 2 diabetes
• yogurt nutrients and peptides influence glucose and insulin sensitivity, reducing cardiometabolic risk
• evidence suggests that, independently of the fat or sugar yogurt contains, its consumption is associated with a reduced risk of type 2 diabetes
• intervention studies are needed to establish a causal relationship between yogurt and type 2 diabetes

Read further from Dr Nancy Babio

André Marette then talked about the possible role of fermented foods in reducing the risk of developing non-communicable diseases

• yogurt is obtained through the lactic acid fermentation of milk and contains live bacteria
• fermentation produces a certain number of modifications (taste, texture, shelf-life) as well as by-products (bioactive peptides)
• current studies focus on the identification of mechanisms by which the consumption of yogurt positively impacts our health
• yogurt’s positive impact on our health: digestion of lactose, reduced risk of type 2 diabetes and possibly in a reduced risk of heart disease

Read further from Professor André Marette

Maria Elisa Zapata then presented the results of her study about yogurt consumption in Argentina and diet nutritional density

• Dr Zapata’s results tend to show that simple food swapping, including yogurt, have an impact on diet quality
• when meals include dairy products or yogurt, their nutrient density – i.e. concentration of nutrients per amount of food – is greater.

Read more about healthy food swaps

Luis Moreno did a presentation on how yogurt qualifies as a healthy snack option for children

• epidemiological studies suggest that yogurt, which is an easily digestible food, is associated with healthy lifestyle habits
• obesity prevention is essential during the first years of life
• starting yogurt consumption at an early age may favor control of body weight

Read further from Professor Luis Moreno

Paula Smith-Brown (University of Queensland, Australia) commenced as a research student with the Children’s Nutrition Research Centre (CNRC) in 2012. She is currently investigating the association between diet, body composition and gut microbiota in young children. Paula is a Pediatric Accredited Practicing Dietician with a specialist interest in young child nutrition and growth. She completed a BSC Nutrition and Dietetics (First Class Honours) at Kings College London, in 2002, and was awarded the Maud Taylor Prize for best overall student. She has had a diverse career including clinical, community, industry and NGO roles internationally. Paula applied for the YINI Grant in 2016 and is now working on her project until 2018.

About the study

The first 1000 days (conception to 24 months) is when gut microbiota composition and eating patterns are established, and a critical period influencing lifelong health. Maturation of the gut microbiota has been shown to be related to growth while alterations in microbiota composition are proposed to be causally related to the development of overweight and obesity. Paula’s team has shown that dairy intake at 12 months is associated with fecal microbiota and fat-free mass at 2 to 3 years. In addition, at 2 to 3 years of age, yogurt intake was strongly associated with microbiota composition.

In her new project, she hypothesizes that yogurt intake is the ideal complimentary food to promote lean and, bone mass growth and optimal microbiota development due to the combination of bioavailable branch chain amino acids and live cultures. In addition, the texture and palatability of yogurt make it a suitable food for infants. Her cross-sectional study is anticipated to provide evidence:

1. To guide infant feeding advice regarding the consumption of yogurt during the period of complementary feeding with the aim of optimizing growth and microbiota development to promote long-term good health.
2. Explore modulations of microbiota composition as a mechanism of action for the association between yogurt consumption and body composition during growth.

It is expected that this project will result in the publication of a minimum of 2 peer reviewed manuscripts in a pediatric nutrition-related journal by 2018-2019.

Sauerkraut, kimchi, kombucha, … and of course, fermented milks like yogurt are growing in popularity, propelled by health claims and increasing knowledge about the gut microbiota. Several researchers around the world want Health Organizations to add a new category to the National Food Guide, that is fermented foods. Seppo Salminen (University of Turku, Finland) held this position.

Bacteria are an essential part of our environment and food. Beneficial bacteria  are notably present in fermented foods which have a long history of safe use. If you look at the history of fermented foods, they have been around humankind for as long as we can remember. Fermentation served firstly as a way of improving shelf-life but it also enhances nutritional quality and palatability and provide metabolites, enzymes (e.g. lactase) and flavor components. A lot of traditional foods are in fact made with fermentation around the world and as a consequence, we eat a lot of microbes every day. But how much we eat may vary from diet to diet and meal to meal.

Healthy Diet Has the Greatest Exposure

We are now beginning to know the impact of ingested microbes on the intestinal microbiota and the extent to which dietary microbes may impact human health. To date, some studies have shown that consuming yogurt could have an impact on certain diseases or disorders involving the gut microbiota, such as type 2 diabete, cholesterol, weight control, brain activity, allergy and cancer. Thus, consuming microbes could have health benefits.Yet, a comparative study introduced by Salminen characterized the microbiota of three different dietary patterns : (1) the Average American , mainly composed of convenience foods  ; (2) USDA (US Department of Agriculture) recommended, emphasizing fruits and vegetables, lean meat, dairy (yogurt and cottage cheese), and whole grains and (3) Vegan excluding all animal products. Based on plate counts, the USDA meal plan (which includes yogurt as a snack) had the highest total amount of microbes at 1.3 × 10 ⁹ CFU per day, followed by the VEGAN meal plan and the AMERICAN meal plan at 6 × 10 ⁶ and 1.4 × 10 ⁶ CFU per day respectively. Thus, a  dietary pattern  that doesn’t follow the USDA recommendations doesn’t provide enough microbes and yogurt appears to be a perfect snack to fill this gap !

Yogurt is the best source of key bacteria

Yogurt and fermented milks are part of the most significant sources of viable bacteria (1 Cup of Yogurt = 10 ^8-10 bacteria). Despite the impact of fermented foods and beverages on the gut microbiota, their many health benefits or recommended consumption have not been widely translated to global inclusion in world food guidelines. In Europe, only one health claim (EFSA, 2010) has been approved for beneficial microbes: live yogurt cultures improve lactose digestion. The microbes contained in yogurt may also affect the function of the resident gut microbiota, even if they do not affect its composition, as it has been suggested by numerous yogurt feeding studies. Indeed, the health benefits associated with the consumption of yogurt are more and more studied, and the importance of yogurt cultures Lactobacillus and Streptococcus in health promotion, by strengthening the intestinal mucosal barrier for example, have been recognized.

Why fermented foods should be represented in food guides

A European research revealed that five EU member states (Estonia, Germany, Italy, Poland, Spain) have national nutrition guidelines or recommendations that include either probiotics or fermented milks containing live bacteria. This supports that some EU member states recognize the health benefits associated with the consumption of live microbes, even if commercial marketing claims are not authorized.

Other countries include yogurt (as part of dairy products) in their food-based dietary guidelines. It is the case in Switzerland, USA, Canada, UK, Australia, Japan, Sweden, Russia, Argentina, India and Portugal. In this case, yogurt is recommended, not for the live microbes it contains, but for its nutritional value.

The idea that consuming live microbes through fermented foods should be recommended by official governmental channels is maturing, as observed by Salminen. In Canada, Western scientist Gregor Reid is further trying to get fermented foods such as yogurt and sauerkraut added as a daily portion to the Canadian Food Guide, because the fermentation process gives the foods added benefits for health.

Therefore, Salminen concludes that knowing the general benefits of traditional and supplemented fermented foods, consuming live microbes through fermented foods should be recommended by official governmental channels. Yogurt is one of the most readily available fermented foods, which can help to fill the gap in the current exposure of live microbes. 

Numerous epidemiological studies reported that yogurt consumption may be used as a new biomarker of a healthy lifestyle. What could explain the health benefits of yogurt? At the 5th Yogurt Summit, held in Buenos Aires (Argentina) on October 18th, Dr André Marette (Laval University, Québec) presented up-to-date evidence on bioactive compounds produced during fermentation.

Yogurt consumption has been associated with healthy dietary patterns and lifestyles, better diet quality and healthier metabolic profiles. Studies have shown that frequent yogurt consumers do not only have higher nutrient intakes, but also an improved diet quality, which includes higher consumption of fruits and vegetables, whole grains, and dairy products compared with low or non-consumers. This indicates better compliance with dietary guidelines. Dr Marette summarized recent epidemiological and clinical evidence, which also suggests that yogurt contributes to better metabolic health.

Cardiovascular Diseases, Type 2 Diabetes and Obesity

Strong consistent evidence from multiple meta-analysis on the association between yogurt intake and the risk of Type 2 Diabetes (T2D) reported consistent results. Hence, several studies suggest that there is high-quality evidence that supports an inverse association between the intake of yogurt and the risk of T2D. However, to date, there have been few to no randomized clinical trials (RCT), investigating yogurt intake in relation to cardiometabolic clinical outcomes. Therefore, we cannot determine a causal link.

Evidence also suggests that the association between yogurt consumption and CVD risk, as well as for coronary artery disease, hypertension and stroke, is neutral and this assessment is based on moderate-quality evidence.

In a recent systematic review, all epidemiological studies found an association between yogurt consumption and lower body mass index, lower body weight/weight gain, smaller waist circumference and lower body fat. The authors suggest an important role for yogurt in weight management, but cannot determine a cause-effect relationship.

Last but not least, there is a limited number of prospective cohort studies and no meta-analysis on the association between yogurt consumption and MetS (Metabolic Syndrome) risk. The quality of the evidence, relating yogurt intake to the incidence of MetS, is judged to be very low, and thus the association remains uncertain.

The Role of Ferments and Fermentation by-products (bioactive peptides)

In his presentation, Dr Marette also focused on recent evidence showing that dietary proteins are key regulators of immunometabolic factors and the gut microbiota. In addition, fermentation with bacterial strains generates bioactive peptides from dairy proteins resulting in a potentially greater beneficial effect of yogurt on metabolic health compared with non-fermented dairy products such as milk. He specifically outlined potential mechanisms, observed in recent animal studies, that could underlie the inverse associations between yogurt intake and incidence of cardiometabolic diseases (CMD) and these mechanisms seem to be related to its bacterial constituents and bioactive peptides released during fermentation. For example, data suggests that these bioactive peptides have physiological effects such as increased insulin sensitivity and glucose tolerance.

It seems that fermented dairy peptides and especially yogurt-type peptides also exerted greater anti-inflammatory effects (on intestinal inflammation and metabolic endotoxemia) than other dairy products. These immunometabolic effects are associated with taxonomic changes in the gut microbiota. Hence, microbes in fermented foods may contribute to human health in a manner similar to probiotics. However, whether specific bacterial species are modulated by peptides released during lactic fermentation remains to be determined.

In conclusion, these newly proposed mechanisms are surely promising, but require more research before being validated as a key factor in the protection against CMD, like type 2 diabetes or obesity.

Highlights

• Yogurt consumption may be considered a signature of a healthy diet through its nutritional content, impact on metabolic health including the control of energy balance, body weight and glycemia and its relationships with healthier behaviours and lifestyle factors.
• Fermented dairy products, like yogurt, generally exert greater metabolic and anti-inflammatory effects.
• These immunometabolic effects are associated with taxonomic changes in the gut microbiota.
• Peptides released during fermentation may explain some of the health benefits of yogurt consumption on cardiometabolic diseases

The 5th Yogurt Summit took place on October 18th, 2017 in Buenos Aires, Argentina. This fifth edition attracted a wide international audience with attendees from all over the world. This unique community of scientists came together to discuss the importance of fermented foods in global health. Robert Hutkins (University of Nebraska, USA) explored the interactions between ingested microorganisms and the gut microbiota, and the way exogenous microorganisms can change the gut environment.

For many years, humans have known that bacteria and other microorganisms are capable of transforming food substrates, making them both tasty and nutritious. More and more, chefs and other food makers are putting bacteria to work to produce fermented foods and the result is delicious. Apart from flavor, though, are there other reasons to seek out fermented foods? Scientists around the world are trying to answer this question by studying the possible health benefits of consuming live cultures.

What are fermented foods?

Fermentation is the process of deriving energy from the oxidation of organic substrates such as glucose, where the electron acceptor is an organic compound. Therefore, a food-friendly definition of fermented foods could be: the conversion of raw foods into fermented foods by microorganisms. Why have fermented foods been so popular for 10,000 years? In part, this is because products like fresh yogurt, aged cheese, and spicy kimchi have aromas and flavors unlike any other foods. There is also, of course, the intoxicating appeal of a fine wine, craft beer, or single malt scotch. Another reason for the popularity of fermented foods is the health benefits associated with many of these products. Wine, chocolate, and coffee, for example, are rich in natural antioxidants that promote heart health and fight disease. However, for many consumers, it’s the live bacteria that matters most. That’s because many of the bacteria found in fermented foods are associated with gut health and other benefits.

What are the health benefits of fermented foods?

Hutkins listed many potential reasons to add them to your diet. For example, epidemiological studies have shown that yogurt consumption is generally associated with reduced risks of type 2 diabetes (T2D), metabolic syndrome, and heart disease, and improved weight management. Although these products are good sources of protein, calcium, and other nutrients, the live microorganisms present in these products are now considered responsible for many of these health benefits. Included are the yogurt starter culture organisms, Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus, as well as strains of Bifidobacterium and Lactobacillus added specifically for their probiotic properties. One study found that fermented milk eased symptoms of irritable bowel syndrome, possibly due to beneficial changes in gut bacteria that such foods bring. Other fermented foods appear to relieve the diarrhea that people often suffer from after taking antibiotics. Hutkins also presented the latest areas of research on the microbiota-gut-brain axis, suggesting that probiotics and prebiotics could influence behavior.

How do we explain these healthy effects of fermented foods?

According to Hutkins, the transformation or change in the food brought about by microorganisms can explain the effects of fermented foods. More specifically, it’s probably the microorganisms that reach the gut and produce beneficial end products that are involved in these healthy effects. Actually, there is increasing evidence that food-borne bacteria contained in fermented products are biologically active in the colon… And such activities might be part of the mechanisms underlying beneficial effects. Several studies support the concept that fermentation can be leveraged to re-engineer the gut microbiome and improve dysbiosis-related diseases. One major topic of research for establishing a role for these organisms is the well-known phenomenon of colonization resistance.  The healthy human gastrointestinal tract contains a diverse, complex and stable microbiota that is resistant to colonization by exogenous microorganisms. These could include pathogenic organisms as well as bifidobacteria and lactobacilli that are added to fermented milk products as probiotics. However, recent research reported that regular consumption of yogurt appeared to increase the numbers of Lactobacilli in the gut. The microbial diversity in the gut also appears to slightly increase with yogurt consumption in some subjects. These findings suggest that bacterial species and functional genes absent in the gut microbiome of individual humans can be reestablished, providing opportunities for precise and personalized microbiome reconstitution. Another ongoing area of investigation for food scientists is to find out whether the method of delivering live microorganisms, otherwise known as the ‘food matrix’, matters for how the bacteria survive—and for how they contribute to health. The matrix can affect viability and survival of the organisms, such that some foods may be more-or-less hospitable than others,” explains Hutkins.

Don’t get confused between all fermented foods!

In his conclusions, Hutkins reminds us that not all fermented foods contain live organisms. Beer and wine, for example, undergo steps that remove the organisms (like yeast that allows fermentation). Other fermented foods are heat-treated and the organisms are inactivated. Bread is baked and sauerkraut is often canned. So, while these foods may be nutritious, they do not have probiotic activity, unlike yogurt, kefir or any other fermented dairy foods with added probiotics. We must also be mindful of the fact that a lot of fermented foods do not necessarily have any probiotic functions. By definition, probiotics must ‘confer a health benefit’. That means the probiotic must have been characterized and have clinical evidence of a health benefit. Cultures are not probiotic unless they have met this requirement. Therefore not all fermented foods can be qualified as probiotic, and not all probiotics take the form of fermented foods.

Read the newsletter

Kelsey M. Mangano is Assistant Professor and Director of the Nutritional Sciences Program in the Department of Biomedical and Nutritional Sciences at UMass Lowell. She is a member of the Center for Population Health at UMass Lowell. Dr. Mangano also holds an Adjunct Faculty appointment at the Institute for Aging Research, Hebrew SeniorLife, Harvard Medical School affiliate. Throwback time with this video interview for YINI during he 2nd World Yogurt Summit, which took place during the 2014 Experimental Biology meeting. Dr. Mangano’s research interests focused on protein intake patterns and how they are differentially associated with bone and muscle health. She is also studying the anti-inflammatory diet and its association with bone health, muscle mass, strength and function.

About the study

The YINI grant specifically awards her research identifying mechanisms underpinning the impact of daily yogurt supplementation on the gut microbiome, inflammation and bone biomarkers. Altogether, production of SCFA, particularly butyrate, by the gut microbiota may play a pivotal role in bone health. Altering the gut microbiome toward a greater butyrate-producing environment has the potential to reduce risk of osteoporosis by reducing bone resorption. Mangano’s study has tested if the consumption of yogurt could have the potential to shift the gut microbiota toward producing greater SFCA, thereby modulating the inflammatory response. Her results showed that daily consumption of 5 oz. of yogurt may support bacteria colonisation and establishment and consequently increase SFCA production. In his turn, the SFCA synthesis starts a cascade toward reduced systemic inflammation and subsequently a reduced number of bone remodelling markers. This study has therefore elucidated an important mechanism of action for yogurt in the gut, which has the potential to improve health and quality of life among aging adults.